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Cooling technologies have been widely applied to protect the turbine blades at high inlet temperature, which also makes the aero-thermal coupled phenomenon more remarkable. Nevertheless, the aero-thermal phenomenon had not been considered in traditional throughflow methods and led to challenges of cooled turbine design. This paper proposes a new cooling model for the aero-thermal coupled throughflow method which was first proposed by the same author. The cooling model considers the variation of the temperature caused by air cooling both along the stream and span direction to improve the heat flux calculation accuracy. The impacts of heat transfer on mainstream enthalpy and entropy are further studied in this paper. The equivalent blade thickness and the estimation method of the heat exchange area were also introduced into the cooling model. The cooling model is validated with experimental data of the Mark II profile. This paper applies the method in the design of a high-pressure axial turbine, of which the first stator is cooled with convective cooling. With the prescribed blade temperature limitation, the flow field properties and the coolant requirement are predicted. The three dimensional CHT analysis is performed to validate the aerothermal coupled throughflow method, and the aerodynamic parameter predicted by the throughflow method is in accordance with the 3-D CHT analysis.Copyright © 2016 by ASME

This paper presents a series of experiments on the Aerostatic Seal, a dynamic clearance seal for steam turbine application first described at the 2015 ASME Turbo Expo (Paper Number GT2015-43471). This dynamic clearance seal moves with rotor excursions and so has the potential to deliver a smaller clearance than traditional seals. The concept is an extension of the retractable seal design which is widely used in existing steam turbines. The experimental program was carried out in a low cost static test facility using an aerostatic seal design. The seal exhibited a dynamic clearance response and will therefore respond to rotor excursions. 3D CFD was also used to aid the understanding of flow features not captured by the analytical design tool. Adjustments to both the design process and to future seal designs are proposed in the body of the paper. This paper therefore describes an experimental proof of concept for the aerostatic seal and paves the way for future development in rotating facilities.

The present paper is the second part of a two-part paper focused on the design and the analysis of an optimized rotor blade for a geared open rotor engine. This part is focused on the experimental investigation of the three-dimensional unsteady flow field at the exit plane of a rotor row installed in a large scale single-stage low speed research turbine. The investigation is aimed at in depth characterizing the wake-boundary layer and the vortex-vortex interaction processes induced by the rotor-stator relative motion. Measurements have been carried out at a typical aeroengine cruise condition Reynolds number. The rotor blade aerodynamic loadings at different blade spans have been measured. A five-hole probe has been used to assess the row efficiency and detailed hot-wire phase-locked ensemble-averaged data have been analyzed to characterize the three-dimensional time-dependent flow field at the rotor exit plane. Results clearly highlight a significant distortion of the rotor blade wake and tip vortex during the migration of the high turbulence regions (wake and secondary flows) associated with the upstream stator. The unsteady interaction between the stator secondary flows and the rotor passage vortex provokes a time dependent movement of the low momentum area at the hub surface, sensibly modifying the penetration of the rotor secondary flows in an incoming stator wake passage period. The comparison of deterministic and random velocity fluctuations also allows the distinction between the structures generated by the stator and those due to the rotor.

Accurate unbiased assessment of transfer length for prestressed concrete railroad ties requires detailed knowledge of the longitudinal variation of geometrical cross-section parameters responsible for establishing the resulting surface strain profile. This is because the complex cross-sectional shape produces a non-uniform strain plateau region, which makes the accurate evaluation of transfer length more difficult. In particular, human judgment of a “plateau region” for assessment of the average maximum strain becomes subject to large uncertainty, and clearly this procedure cannot be used in any type of automated in-plant transfer length diagnostics. The important geometrical tie parameters include the cross-sectional area, centroid, moment of inertia, and the eccentricity of the prestressing wires. If a CAD drawing is available, this information can be digitally extracted from the CAD model representation of the crosstie. In fact, this digital extraction has been done and has already been in use for some time in assessing transfer length for one of the common crosstie manufacturer designs. However, current research efforts are investigating the characteristics of existing crossties which have been in track for many years, for which CAD drawings of the original designs are unlikely to be available. The objective of the current research is to develop a comprehensive understanding of the material characteristics that have caused splitting failures in prestressed concrete railroad ties, and those characteristics that have resulted in ties that have performed well after many years in track. As part of this effort, a three-dimensional (3D) Optical Scanning System is being used to accurately scan and quantify the surface geometry of previously manufactured ties that have been in service, so as to produce an accurate 3D CAD model for later analysis associated with the above long-term research objectives. For the initial phase of this work, a sample from the CXT crossties of known geometrical characteristics that were subjected to representative long-term loading at the TTCI Facility in Pueblo Colorado, was scanned so as to accurately map out detailed 3D tie surface geometry. These ties were cast using the same concrete materials but with different prestressing wires, and were all subjected to the same extreme in-track loading for a period of several years. A commercially-available 3D Laser-Based Optical Scanning System, having a maximum spatial resolution of approximately 0.1mm, was used to perform the surface scanning operations presented in this paper. The CXT tie provides a useful initial evaluation of the accuracy and general feature capture capability of the scanning procedure, since a 3D CAD model for this tie has been provided by the manufacturer. A detailed qualitative and quantitative analysis is presented which compares the 3D CXT CAD model geometry with the 3D geometry of the experimentally scanned ties. Illustrations as to how this 3D technique can reveal such features as abrasion and wear, along with the longitudinal variation of the above mentioned cross-section parameters associated with longitudinal surface strain and transfer length assessment, are included in this paper.

Ballast compaction and particle rearrangement cause ballast to rotate and move vertically and horizontally. Ballast movement, including translation and rotation, has a significant effect on track performance. Large movement of ballast particles leads to track geometry roughness, e.g., hanging ties, and thus increases potential of damage and deterioration to rails, ties and fastening components. This study investigated ballast particle movement at different locations beneath a crosstie. In the paper, a wireless device — “SmartRock” was utilized to monitor ballast movement under cyclic loading in laboratory tests. The SmartRock has a shape of a realistic ballast particle. Inside the SmartRock was imbedded a tri-axial accelerometer, tri-axial gyroscope, and tri-axial magnetometer with 9 degrees of freedom so that particle translation, rotation and orientation can be interpreted, relatively. The real-time measurements were recorded by the SmartRock and then sent to a computer via Bluetooth. In the laboratory tests, a ballast box was constructed. In the ballast box, a half section of a typical railroad track was constructed. Five hundred cyclic load repetitions were applied on the top of the rail. Translational and rotational accelerations of the particle were recorded by the “SmartRock”. Three ballast box tests were conducted. Two SmartRocks were placed beneath the middle of tie and the edge of tie, respectively but at different depths during each test — right under the tie, 12 cm beneath the tie and 25 cm beneath the tie. The results indicated that (1) ballast particles had translational as well as rotational modes under cyclic loading; (2) ballast particles had rotation together with horizontal translation; (3) particle rotation were higher beneath the edge of tie than those beneath the middle of tie; (4) Ballast movement were significantly reduced with depth. The paper also further confirmed that the SmartRock was capable of recording real-time translational and rotational accelerations, which would not have altered the motions of surrounding ballast particles due to its realistic shape of a particle, hence, provided a new means to monitor ballast particle movement in railroad engineering.Copyright © 2016 by ASME

In house development of lubrication oil pump of gerotor type used in gas turbine engine is described in this paper. A host of geometrical parameters determine the inner and outer rotor profiles which in turn define the flow characteristics of the pump. In this paper, a simulation model has been developed based on AMESim and MatLab which used to predict the flow characteristics of a pump. This model incorporates both the methodologies of design and parametric analysis of the pump which aids to design the pump in accordance with designer needs by varying the parameters. A gerotor pump is designed having fixed geometrical parameters using this model. The prototype pump has been tested for its flow characteristics and compared with estimated result. The comparison indicates that simulation results agree well with the measured data. Thus, this simulation model will be useful in designing and analyzing the lubrication pump of a gas turbine engine.Copyright © 2015 by ASME

Market demands such as generating power at lower cost, increasing reliability, providing fuel flexibility, increasing efficiency and reducing emissions have renewed the interest in Integrated Gasification Combined Cycle (IGCC) plants in the Indian refinery segment. This technology typically uses coal or petroleum coke (petcoke) gasification and gas turbine based combined cycle systems as it offers potential advantages in reducing emissions and producing low cost electricity. Gasification of coal typically produces syngas which is a mixture of Hydrogen (H) and Carbon Monoxide (CO). Present state of gas turbine technology facilitates burning of low calorific fuels such as syngas and gas turbine is the heart of power block in IGCC. Selecting a suitable gas turbine for syngas fired power plant application and optimization in integration can offer the purchaser savings in initial cost by avoiding oversizing as well as reduction in operating cost through better efficiency. This paper discusses the following aspects of syngas turbine IGCC power plant: • Considerations in design and engineering approach • Review of technologies in syngas fired gas turbines • Design differences of syngas turbines with respect to natural gas fired turbines • Gas turbine integration with gasifier, associated syngas system design and materials • Syngas safety, HAZOP and Hazardous area classification • Retrofitting of existing gas turbines suitable for syngas firing • Project execution and coordination at various phases of a project This paper is based on the experience gained in the recently executed syngas fired gas turbine based captive power plant and IGCC plant. This experience would be useful for gas turbine technology selection, integration of gas turbine in to IGCC, estimating engineering efforts, cost savings, cycle time reduction, retrofits and lowering future syngas based power plant project risks.

Cloth has always been the most worldwide of all imported and exported commodities. It is an enlightening example of the movement of knowledge, skills, goods and investment across wide geographic seats. South Asia has been dominant for making of these worldwide interactions over period. This capacity grants advanced research that discovers the dynamic ways in which various textile production and trade regions generated the ‘first globalization’. A series of specialists connect this worldwide commodity with the dramatic political and economic alterations that characterised the India in the recent centuries. Together, the papers transform our understanding of the contribution of South Asian cloth, specifically Indian cloth to make the modern world economy. India is the largest share of its exports being textiles and apparels to the world. Also weaving is second only to agriculture sector in terms of providing employment in India. This paper a simple spreadsheet program method of calculations for the complete kinematics and dynamic analysis of the shedding mechanism of the classical powerloom is presented. Shedding is one of the important processes used in weaving technology of textile machineries. Most of the powerlooms of India uses staubli’s M5 module for shedding. These modules are activated through the traditional slider-crank mechanism. The source energy for these modules is through electric motor coupled with clutch and resulting output is shedding action of warp threads of cloth. Objective of this work is to address the kinematics and Dynamics simulation of linkage assembly of shedding mechanism of textile machinery considering all the links of the model as rigid one. Also this paper examines the effect of dynamic forces on various joints of conventional kinematic model. Subsequently the optimisation of mechanism is carried out by varying the design factor ratio of the slider crank mechanism. Length of connecting rod to radius of the crank shaft has been taken into account for defining design factor ratio for the analysis. Altered varieties of models having various design factors are modeled using 3D modeling package Solidworks. Simulation test results and force analysis of these models were carried out using ADAMS. Being a single degree of freedom mechanism as defined by its crank angle, the spreadsheet program can be used to answer what - if? situation queries through tables and graphical plots to evaluate variations of key motion and loading parameters with changes in the design factor. Thus, it allows for the conduct of parameter studies in selecting optimum crank-and-connecting-rod linkage dimensions and speeds. Thus, this work provides an alternative solution and scope for further research in shedding mechanism’s simulation analysis.Copyright © 2015 by ASME

Mechanical linkages are widely used in the industry and the synthesis of such mechanisms may require optimization depending on the number of precision positions required. Many intelligent optimization techniques (Genetic, Tabu, Simulated Annealing, etc) have been proposed in the literature, one of them being the Ant-Search which was first proposed by the authors in 2007. In this paper, a Modified Ant-Search (MAS) technique is proposed to optimize the synthesis of a four-bar mechanism with a path generation task. Two major improvements are applied over the previous algorithm: ants pheromone update and exploration/exploitation techniques are both modified. Unlike the previous work where a constant quantity of pheromones was added during each iteration, in this paper, the pheromone deposit rate is proportional to the error of the objective function. Such a modification in the pheromone update rule is expected to differentiate between the behaviors of different ants and better govern their motion in the subsequent iterations. Moreover, the second major improvement targets the exploration/exploitation techniques followed by the ants. Unlike the previous work where exploration dominates during the early iteration stages and exploitation during the late ones, this work implements a more dynamic strategy where ants enter and leave the exploration/exploitation processes as governed by parameters related to the objective function error and pheromone deposit levels. Such modifications applied to the Ant-Search (AS) technique are expected to ensure a better chance of converging to a global minimum. The MAS technique is applied for a few path generation tasks with prescribed timing along with a set of linear constraints. Results are compared with previous work in the literature where the newly proposed technique showed appreciable improvement as evaluated by the structural error objective function. Future work possibilities are also introduced.Copyright © 2015 by ASME

A new rotor model is developed in this paper to explore the dynamic coupling effect of roll-yaw motion. The rotor model employs a 6 degree-of-freedom Jeffcott rotor with a breathing crack. Based on the energy method and Lagrange principle, equation of motion is derived in yawing coordinate system with consideration of unbalance mass. The breathing crack model is established by Zero Stress Intensity Factor (SIF) method based on the crack released strain energy concept in fracture mechanics. SIF method is used to determine the crack closure line by computing SIF for opening mode. The vibration responses of the cracked rotor system are solved by Gear’s method. The coupling effect of yawing and rolling motion is studied in this paper to investigate vibration response of cracked rotor system. With the yawing motion, the dynamics of the rotor-bearing system is changed by additional stiffness and force terms. The parametric study is conducted to analyze the effect of yawing rate and acceleration on the crack breathing behavior. Finally, the vibration responses of the nominal and damaged rotor systems are analyzed to find out the indication for the damage detection and health monitoring.Copyright © 2015 by ASME

In this paper the coal-fired power plant with CO2 capture by integrating MCFCs system and the integrated coal gasification with CO2 capture by integrating MCFCs combined cycle system are compared with each other in different ways. The effects of the key parameters of MCFC on the performance of two systems, such as CO2 utilization factor, fuel utilization factor and the current density of MCFC, have been analyzed and compared. Aspen Plus soft is used to develop the system models and the key parameters of MCFC are calculated, analyzed and optimized. The flue gas of the coal-fired power plant (CFPP) or the Integrated Gasification Combined Cycle (IGCC) system is used as the reactant gas of MCFC cathode side, reacting with fuel in the anode side and producing power. The anode exhaust gas burns with pure oxygen in the afterburner. The CO2 in the flue gas is further concentrated and captured with the lower energy consumption. The results show that, the efficiency of the coal-fired power plant integrating MCFCs system is about 45.75% when the CO2 capture rate is 88.07%, and the efficiency of the IGCC system integrating MCFCs is about 47.31% when the CO2 capture rate is 88.14%. Achievements in this paper will provide the valuable reference for CO2 capture of coal-fired power plant and IGCC with low energy penalty.Copyright © 2015 by ASME

The purpose of this paper is to describe an independent study project required before graduation with a master of engineering degree in the department of mechanical engineering at Rochester Institute of Technology. The goal of this graduation project was to design and build a Pin-on-Disk Tribometer. The tribometer will be used by the department for future student research projects. This paper includes the details of the design process, such as adaptations from existing tribometers, all required calculations, and descriptions of the machining and assembly. New design concepts presented demonstrate simplicity of construction and use. The required calculations include shear and bending moments in the arm, bearing calculations, lead screw load analysis, counterweight balancing, torque calculations for selecting the correct motor, and strain calculations for determining the correct strain gage set-up. The paper details part selection, pricing, machining, and assembly. Mistakes and alternate design considerations are also discussed.Copyright © 2015 by ASME

For low to medium production volumes or products with short life cycle, dedicated manufacturing lines often end up being a commercial burden. The high initial non-recurring expenses of the manufacturing infrastructure are eventually passed onto the cost of the product, limiting its commercialization potential. In such cases, flexible frameworks for manufacturing are ideal, at least in theory, with reusability of the same hardware for different product developments. From an implementation standpoint, however, flexible manufacturing platforms are difficult to deploy as they suffer from inherent uncertainties that severely constrains the overall precision in task execution. Low cost flexible robotic manipulation systems, configured using individual modules from an assortment of positioners, often lack the precision required for assemblies with stringent tolerance budgets and therefore have to rely on expensive feedback systems for reliability at the trade-off of process throughput. In order to overcome this fundamental challenge with flexible or modular assembly and packaging systems, this paper presents a novel precision evaluation and control technique. The proposed solution estimates and tracks the end-effector position errors in a robotic manipulation system resulting from the kinematic configuration as well as the dynamic parameters for each specific task; thereby, allowing the automation application to compensate for these errors in run-time. The computation does not require active feedback, thus ensures high throughput while maintaining high reliability. The experimental results provided in this paper demonstrate the efficacy of the proposed approach in the case of a high precision micromanipulation task using a custom robotic manipulation system. The analysis also demonstrates that different system configurations offer different levels of precision metrics.Copyright © 2015 by ASME

Wind is a one of the clean resources of energy and has the ability to contribute a considerable share in growing world energy consumption. The small wind turbine plays a vital role in fulfillment of energy needs preferably for household purpose. In order to unleash the budding of applicability of small wind turbine, it is necessary to improve its performance. The performance of a small wind turbine can be distinguished by the manners in which power, thrust and torque vary with the wind speed. The wind power indicates the amount of energy captured by the wind turbine rotor. It is convenient to express the performance of small wind turbine by means of non-dimensional performance curves, therefore in this paper the most graphs are drawn to power, thrust and torque coefficients as a function of the tip speed ratio. This paper presents the effect of design parameters such as the tip speed ratio, angle of attack, wind speed, solidity, number of blades, etc. on the aerodynamic performance of small wind turbine and proposes the optimum values of these parameters for the newly designed blade. The new designed blade consists of two new airfoils and named as IND 15045 and IND 09848. This new profile blade is designed for a wind turbine of 1 kW rated power. The blade is divided into ten sections. The designed length of blade is 1.5 m and it is made using IND 15045 airfoils at three root sections and IND 09848 airfoils for remaining seven sections. Q-Blade is used for the numerical simulation of wind turbine airfoils and blade. It is integrated tool of XFOIL and blade element momentum theory of wind turbine blade design. Also the effect of constant rotational speed operation, effect of stall regulation effect of rotational speed change and the effect of solidity on the performance of wind turbine is discussed. This paper delivers a broad view of perception for design of small wind turbine and parameter selection for the new wind turbine blade. Also in this paper the effect of different losses viz. tip losses, drag losses, stall losses and hub losses on the small wind turbine are discussed. The efficiency of the small wind turbine varies significantly with wind speed, but it would be designed such a way that maximized efficiencies are achieved at the wind speed where the maximum energy is available.Copyright © 2015 by ASME

The fresh market apple industry currently relies on manual labor for all harvesting activities. The lack of mechanical harvesting technologies is a serious concern because of rising labor costs and increasingly uncertain labor availability. Researchers have been working for several decades to develop mechanical harvesters for tree fruit. The two fruit removal methods considered include mass mechanical harvesters and selective harvesting with robotics technology. Whereas mass mechanical harvesters have demonstrated unacceptable damage rates, robotic systems have been limited by insufficient speed and robustness. This paper describes the design and analysis of a novel underactuated end-effector fabricated for the robotic harvesting of tree fruit. The device has been optimized around a set of target tasks, the most critical being speed, low complexity, suitability for a highly variable field environment, and the replication of hand picking so as to minimize fruit damage. Development of the end-effector has been facilitated by a thorough study of the dynamic forces involved during the manual harvesting of apples. The end-effector produces a spherical power grasp with a normal force distribution and picking sequence replicating selected human patterns. An underactuated, tendon-driven device with compliant flexure joints has been adopted to improve system performance in the presence of position errors as well as enhance robustness to variable fruit size, shape, and orientation. The prototype end-effector also uses minimal sensors and incorporates open-loop control to reduce complexity and improve picking speed. This paper presents the theoretical analysis of the end-effector kinematics and discusses the selection of key geometric parameters. Experiments have been conducted to determine the normal forces developed during grasping of the apple. Results indicate that open-loop, feedforward control can be used to produce optimal normal force patterns.Copyright © 2015 by ASME

This paper demonstrates the performance analysis of various arrangements of thermoelectric generators to be used for the combination of a Low Temperature Difference Stirling Engine-Thermoelectric Generator hybrid system. To estimate whether the deployed Stirling Engines will perform on satisfactory level it is necessary to determine if a sufficient thermal flux can be provided to the heating part of the Low Temperature Difference Stirling Engine (LTD SE) from the “cold” side of the thermoelectric generator or their combination. This paper reports study results on the performance of a single layer and a cascaded two-layer thermoelectric generator made up of bulk material. These two generators were connected in series and in parallel to produce the combined thermoelectric module operating as a three-layer generator. Also computational data on the temperature distribution across the layers has been obtained using Finite Element Analysis as a part of ANSYS software. Results obtained demonstrate that both the single and two-layer generators provide sufficient heat flux to drive LTD SEs but the total power output from the two-layer generator-Stirling Engine system is considerable higher when the engine is coupled to a single and three-layered thermoelectric generator.Copyright © 2015 by ASME

Few products are designed for disassembly or easy dismantling. As manufacturers recognize their responsibility for products at the end of their operational lives, the dismantling of products has emerged as a serious consideration in manufacturing. Disassembly is generally achieved by taking apart individual components or subassemblies of a large product. In situations involving integrated design principles, certain assembly procedures or joining techniques can make the disassembly of a product and separation of components into useful and non-useful groups very difficult. Designers are becoming steadily aware of the problem, and are employing techniques that allow them to design with greater responsibility - Design for Disassembly (DFD) is such techniques. In the case of a durable good with a long life cycle or a product with parts subject to wear, maintainability/serviceability may be more important than initial product acquisition cost, and the product must be designed for easy maintenance. The DFD principles identify the ease with which products can be fabricated, maintained, serviced, and recycled. This paper examines a special case of evaluation of escalator housing using DFD method. Escalator system plays an important role in transporting passengers safely between underground and station platforms. However, due to the complex working conditions such as uneven load, extreme weather etc. of the escalator system, maintenance is constantly needed and unexpected failure and repair also happens frequently. The escalators used in train subway/metro stations are exposed to some extreme operating conditions such as extreme weather/temperature, uneven loads and shock etc. that can greatly shorten their life span. The increase to labor and maintenance cost impedes the escalator’s ability to efficiently serve its riders and affects its overall stability. The failure and repair of the escalator systems take a significant amount of labor and cost, in addition to customer dissatisfactions. This paper examines and identifies different types of failure modes and defects that occur in the major components of escalator drive systems, such as the motor and its drive chain system, handrail and its drive system, bearings/lubrication systems that are in adjunct with the bearing shaft assembly. The normal maintenance and repair of these sub systems is time consuming. For evaluating the design of the in the escalator, a new approach involving Rating Chart is used. This paper examines various existing DFD techniques and compares them with the Rating Chart method to evaluate DFD efficiency. The paper concludes by showing the robustness of the new DFD methodology in an environment where the products are exposed to extreme working conditions.

The industrial sector is the largest consumer of produced electric energy worldwide. Electric motor systems account for about 70 percent of the total industrial electricity demand and possess a great cost and energy saving potential. The paper provides an overview of global and regional efforts to create awareness for potential cost drivers in the industry. Various software and excel-based tools for a preliminary estimation of the energy consumption of electric motor systems are available in the market, but a holistic approach is missing. Therefore a framework and a systematic process for the estimation of potential energy savings in motor systems running on alternating current are illustrated in this paper. Moreover a new software tool is discussed, that allows a holistic view on all motor systems within a company without cost-intensive measurements or the use of external consultants.Copyright © 2015 by ASME

Pressure surges and fluid transients, such as steam and water hammer, are events that can occur unexpectedly in operating power plants causing significant damages. The steam hammer normally occurs when one or more valves suddenly close or open. In a power plant, the steam hammer could be an inevitable phenomenon during turbine trip, since valves (e.g., main steam valves) must be closed very quickly to protect the turbine from further damage. When a valve suddenly stops at a very short time, the flow pressure builds up at the valve, starting to create pressure waves along the pipe runs which travel between elbows. Furthermore, these pressure waves may cause large dynamic response on the pipeline and large loads on the pipe restraints. The response and vibrations on the pipeline depend on, one hand, on the pressure waves amplitudes and frequencies of the applied transient loads and on the other hand, on the natural frequencies and dynamic characteristics of the pipeline itself. The piping flexibility or rigidity of the pipeline (piping configuration plus support locations and types), determines how the pipeline will respond to these waves and eventually the magnitude of the loads on the pipe restraints. Consequently, the design of the piping system (pipe configuration and pipe support arrangement) is closely related to the dynamic amplification of applied steam hammer loads. This paper investigates how the pipe support arrangement and the flexibility of the pipeline relate to the dynamic amplification of the piping system due to steam hammer transient loads. The paper examines the correlation that exists, between the applied steam hammer transient spectrum and the pipe frequencies of the pipeline with the dynamic load amplification. Furthermore, it establishes the relation between the dynamic amplification of the pipeline and the pipe support configuration by examining various piping systems from very rigid (many supports) to very flexible (fewer supports). The typical pipe configuration of hot reheat line in a power plant is analyzed for steam hammer due to sudden valve closure (turbine trip) for six cases of closure time (50, 100, 200, 300, 400, 1600 ms). The transient loads on each pipe segment are generated using the PIPENET program and used as an input to CAESAR II stress analysis program to perform a dynamic time history analysis. The dynamic analysis is performed for a range of different pipe support arrangements, from very rigid to a very flexible. The magnitude of the restraint loads from the time history analysis, for each selected pipe support arrangement, is compared with the transient load spectrum associated. The analysis is performed using the PIPENET transient module and CAESAR II pipe stress analysis program, for a range of different pipe support arrangements, from very rigid to a very flexible. The results from the dynamic analysis are compared with the applied transient spectrum, and a dynamic load factor is established for the selected pipe support configuration. The dynamic load factor calculated based on the analysis results is compared with the factor proposed in standard industry practice. The information and the methodology presented in this paper aim to assist the design engineer in the power plant industry to select an optimum support arrangement that will cause the minimum dynamic amplification on the pipeline, thus reducing the steam hammer effects, the size and the cost of pipe supports.

Common rail injection system (CRIS) is an advanced technology which meets the stringent emission standards of diesel engines and satisfies consumer demand for better fuel efficiency and increased power. The coherence of fuel injection quantity is the key injection characteristic for CRIS to match diesel engines successfully. As a critical component for CRIS, the variation of injector characteristic parameters has significant influence on the coherence of fuel injection quantity of the system. In this paper, combining numerical modeling and design of experiments, the response predicted relation between fuel injection quantity fluctuation of CRIS and its influence factors had been investigated. A numerical model of common rail injector was presented for the purpose of creating a tool for simulation experiments. The model is developed using power bond graph method, which is a modeling method that has shown its superiority in modeling systems consisting of sub-models from several energy domains in a unified approach. Experiments were conducted at the same model conditions to validate the model. The results are quite encouraging and in agreement with model predictions, which imply that the model can accurately predict the fuel injection quantity of CRIS and it can be used to simulation and design experiments. Experiments were designed using D-optimal method in which the characteristic parameters of common rail injector were chosen as design factors and the fuel injection quantity fluctuation was selected as the response. The fuel injection quantity fluctuation responses at different design factor levels were obtained using the developed numerical model which had been validated. A regressive prediction model of fuel injection quantity fluctuation was suggested according to the simulation experiments by means of partial least-squares regression (PLR) analysis. Analysis of variance, normal distribution of standardized residuals and relation between observed and predicted fuel injection quantity fluctuation for the regressive prediction model were analyzed which demonstrate the favorable goodness of fit and significance of the regressive model to predict fuel injection quantity fluctuation of the system. By changing design factor levels, the comparisons between numerical results of the bond graph model and the predicted fuel injection quantity fluctuation of the regressive prediction model were conducted. Results show that the regressive prediction model can reliably predict the fuel injection quantity fluctuation caused by the variation of characteristic parameters of common rail injector. Research results of this paper can provide novel ideas to predict fuel injection quantity fluctuation and a theoretical guidance for design and parameters optimization of CRIS.Copyright © 2015 by ASME

This paper describes the development of a water cooled, lean burn, gaseous fueled engine designed for distributed power installations. Electric generators have become popular because they provide a portable supply of electrical power at consumer demand. They are used in critical need areas such as hospitals and airports, and have found their way into homes frequented with power outages or homes in remote locations. Gensets are available in a wide variety of sizes ranging from 1 kilowatt (kW) to thousands of kilowatts. In the mid-range the power sources are typically spark ignition, automotive type internal combustion engines. Since engines designed for automotive use are subject to different emission regulations, and are optimized for operation at RPMs and BMEPs above that of electric generator engines, modifications can be made to optimize them for gensets. This work describes modifications which can be made during remanufacturing an automotive engine to optimize it for use as a generator engine. While the work recognizes the potential for cost savings from the use of remanufactured automotive engines over that of using new automotive engines and the majority of the design constraints were adopted to reduce engine cost, the main focus of the work is quantifying the increase in fuel efficiency that can be achieved while meeting the required EPA emission requirements. This paper describes the seven combustion chamber designs that were developed and tested during this work. Friction reduction was obtained in both valve train and journal bearing design. The engine optimized for fuel efficiency produced a maximum brake thermal efficiency of 37.5% with λ= 1.63. This yielded an EPA test cycle average brake specific fuel consumption (BSFC) of 325 g/kW-hr. Modification of the spark advance and low load equivalence ratio to meet EPA Phase III emission standards resulted in an EPA test cycle average BSFC of 330 gm/kW-hr. When the engine used in this research was tested in its unmodified, automotive configuration under the EPA Compliant Test Cycle it’s EPA test cycle average brake specific fuel consumption was 443.4 gm/kW-hr. This is a 34% increase in fuel consumption compared to the modified engine.

The scientific paper proposes a method to analyze and optimize the drawing press and the deep drawing process with a virtual model. It focuses on hydraulic multi-point die cushions since they offer a wide range of possible adjustments and a high potential to increase production quality and efficiency. The operator can apply individual die cushion cylinder forces to the blankholder which enables the control of the forming process and manual die spotting can theoretically be reduced to a minimum. Utilizing the virtual model can improve the drawing press’ behavior and significantly reduce the set-up time for drawing presses during try-out of new tools or when tool sets are transferred to a different machine. The paper presents a system simulation model of a deep drawing press including its mechanics, hydraulics, and control. It serves as a basis for developing an advanced control system which improves system performance with potentially higher slide speeds, and therefore, a more efficient production. Another aspect in the paper is the development of a coupled simulation consisting of the machine model and a process model. This includes the elasto-static as well as the dynamic behavior of the drawing press and allows for simulations with the highest possible level of detail. The model was used to determine individual set forces for the die cushion cylinders which allowed for the production of sound quality parts without manual die spotting.

This paper presents an approach for the evaluation of the effects related to the behavior of the journal bearings on the operation of external gear machines (EGMs). In EGMs journal bearings usually support shafts of both gears. The prediction of their instantaneous axis of rotation is a key feature of EGMs, affecting the displacing action of the inter-teeth volumes and the leakages at the tip of each tooth. Past approaches presented in the literature for the evaluation of the radial micro-motions of the gears are based on classic simplified models for the hydrodynamic journal bearings based on steady-state solutions of the fluid film neglecting important hydrodynamic effects due to film squeeze — which can be relevant in case of significant radial loads variations — or they concentrate the focus of the study on the journal bearing itself regardless of the impact on the global machine operation. This work presents a CFD model coupled with a rigid model for the evaluation of the radial motions of the journal that permits to overcome the above-mentioned limitations of the existing approaches of study. The paper details the proposed model, in particular as concerns the CFD approach to solve the film flow and its coupling with a previously developed model (HYGESim) developed by the authors’ team for the evaluation of the overall operation of the EGM, used also to find the instantaneous loads on the gears. The potentials of the proposed approach are shown for the case of a pump for high pressure applications. For this case the results show how it is necessary to have a detailed approach for the evaluation of the journal bearings for a correct evaluation of the overall EGM behavior. In particular, the importance of hydrodynamic squeeze effects are shown, by comparing the model prediction with those given by the commonly used simplified steady-state approach. The comparison of simulation results with experimental data is also shown as pertain to pump case wear associated to the break in process.

In the area of linear motion, infinite stroke only is provided by electric actuators today, until now there has been no hydraulic alternative. The novel linear hydraulic actuator consists of two double acting cylinders with a common piston rod. The working principle of this actuator for short movements is that at least one piston is connected to the piston rod and the actuator works like an ordinary hydraulic double acting cylinder. For longer movements one of the pistons is connected alternatively to the piston rod providing the drive. In this way the two pistons are moving the piston rod alternatingly in a kind of rope climbing motion. The critical element is the clamping mechanism which is an already known machine element but used in this new application. Advantages of this concept are as follows: The actuator is compact. Very long strokes and piston rods are allowed without side effects of common cylinders. This property is the origin of the name “infinite cylinder”. The cylinder has small chamber volumes and so high hydraulic stiffness and low capacitance. It has also potentially no external leakage. The cylinder can provide twice the rated force for short strokes. Applications for this feature are the plate opening stroke of injection molding machines, or presses with low work to travel stroke ratio, like a press brake. The paper includes a detailed description of the design and the working principle. One critical component is the clamping mechanism which temporarily connects the pistons to the piston rod. The clamping mechanism together with the piston represents a new kind of machine element in the mechanical engineering field. Here the focus will be on the function and the control strategy. With simulation the proposed control strategy and function will be presented and the performance analyzed. The simulation model is backed up by first results from experiments on the early prototype. The experiments carried out so far on the hydraulic clamping mechanism, which is the critical component in the system show very promising results that the required function can be achieved. Furthermore, the function of the whole cylinder has been simulated with good result. For the full paper results from a functioning prototype is also to be expected.

A novel Vane Pump Power Split Transmission (VPPST), applied to a class 1 pickup truck, is demonstrated in this paper. The VPPST, a power split hydraulic transmission consists of Vane Pump Power Split Unit (VPSU) and a variable displacement hydraulic motor. The VPSU is a double acting vane pump with a floating ring. The floating ring is coupled to the output shaft, which is connected to the drive shaft. The input shaft of the VPSU is coupled to the engine. The control flow of the VPSU is fed to a variable displacement motor mounted on the VPSU output shaft. The transmission ratio is adjusted by controlling the displacement of the variable motor. The resulting continuous variable transmission allows for optimum engine operation by decoupling the engine speed from the drive speed. The transmission also has an integral clutch that allows de-clutching the engine from the drive train by retracting the vanes of the VPSU. In this paper, a quasi-static simulation approach is used to study the performance of the transmission.Copyright © 2015 by ASME

Digital hydraulics is a key part of the continuing applicability of fluid power in the modern world. In order to realize the potential of digital hydraulic circuits, valves which are able to switch at high frequencies whilst retaining high flows are first required. This paper details the development of a valve which is capable of switching in 0.5ms whilst providing a flow rate of over 50L/min at a 10bar pressure drop. Unlike most of the other valves currently in development, position control is used as opposed to the more common bang-bang actuation. This has obvious benefits for valve robustness and offers the possibility of a hybrid control approach which utilizes both throttling and switching control. This paper will detail the design and empirical testing of the valve and benchmark it against published and commercial valves before proceeding to discuss the challenges present in developing the valve further.Copyright © 2015 by ASME

This paper deals with active vibration isolation of unbalance-induced oscillations in rotors using gain-scheduled H∞-controller via active bearings. Rotating machines are often exposed to gyroscopic effects, which occur due to bending deformations of rotors and the consequent tilting of rotor disks. The underlying gyroscopic moments are proportional to the rotational speed and couple the rotor’s radial degrees of freedom. Accordingly, linear time-varying models are well suited to describe the system dynamics in dependence on changing rotational speeds. In this paper, we design gain-scheduled H∞-controllers guaranteeing both robust stability and performance within a predefined range of operating speeds. The paper is based on a rotor test rig with two unbalance-induced resonances in its operating range. The rotor has two discs and is supported by one active and one passive bearing. The active support consists of two piezoelectric stack actuators and two collocated piezoelectric load washers. In addition, the rig is equipped with four inductive displacement sensors located at the discs. Closed-loop performance is assessed via isolation of unbalance-induced vibrations using both simulation and experimental data. This contribution is the next step on our path to achieving the long-term objective of combined vibration attenuation and isolation.Copyright © 2015 by ASME

In this paper, fatigue life assessment of a tensioner is studied through dynamic load analysis, stress analysis, and stress-life fatigue analysis approach. Tensioner is a critical part of an automotive front end accessory drive system, providing pre-tension to the belt. The front end accessory drive systems are responsible for transmitting power from the crankshaft to the accessory components. Due to the engine pulsation, components of the accessory drive including the tensioner are subjected to dynamic loads leading to fatigue failure. The fatigue life assessment of a mechanical component highly depends on loading, geometry, and material properties. In addition, the dynamic behavior of the front end accessory drive is complicated due to coupling between several modes of vibrations in belt, pulleys, and the tensioner arm. Duo to the complexity of the parameters involved and complicated dynamics, the fatigue life analysis of FEAD components is a challenging task. This paper includes three main parts, namely stress analysis, fatigue properties prediction, and life estimation. The dynamic analysis of a generic front end accessory drive system is performed in order to obtain effective loads on the tensioner. Stress state for the tensioner in case of different applied loading conditions is performed via a series of Finite Element (FE) analyses, and the critical region of the part is determined. Finally, fatigue life is estimated through strain-life approach. Modest work has been found in this area providing a comprehensive solution to the fatigue life investigation of power train components. The present study offers a comprehensive modeling approach which predicts the automative tensioner lifetime. The lifetime of any FEAD system components can be determined using the developed fatigue life prediction approach.Copyright © 2015 by ASME

Error averaging effect of the pressured oil film allows for a high motion precision in hydrostatic bearings. This has many applications to ultra-precision machine tools rotor-bearing system. This paper mainly focuses on the studying factors affecting the rotor-bearing system error for hydrostatic rotation table and hydrostatic spindle in ultra-precision grinding machine. Radial run-out error was selected as precision evaluation index. A precision prediction model was established, which takes into structural and dynamic parameters of hydrostatic radial bearing rotor-bearing system into consideration. Effect of assembly tolerance, structural parameters and working conditions on the accuracy of the rotor-bearing system were analyzed. Precision measurements for the ultra-precision hydrostatic rotary table and spindle were carried out. Prediction errors of radial run-out error was found to be less than 23.5%. The model proposed in this paper has high prediction precision and can be used to guide the precision design and optimization of the ultra-precision machine tools rotor-bearing system.Copyright © 2015 by ASME

The paper presents the design and development of a new robotized assembly system of optical backplanes in high-capacity ICT (Information and Communication Technology) apparatus, mainly used for switching stations and distribution networks. The optical backplane solution consists of several optical fiber ribbons positioned on a planar backplane according to an innovative and optimized full-mesh layout where the overall optical interconnection is partialized into a plurality of different independent sub-circuits. Each optical interconnection sub-circuit consists of optical fiber ribbons with standardized optical and mechanical interfaces and customized components that have to be carefully and precisely assembled in order to achieve connections with low optical power losses. The paper describes the method and the main devices and tools conceived for the automatic assembly of optical interconnection sub-circuits, highlighting the critical aspects and the proposed solutions towards the automatized assembly of the whole optical backplane.Copyright © 2015 by ASME

This paper presents a method to utilize the pitch-roll nonlinear energy transfer phenomenon in vessels for off-shore wave power generation. This paper builds on an existing design where the power generator is a horizontal pendulum on board a vessel. The surface waves result in rocking of the ship, which in turn results in rotation of the pendulum. The pendulum is connected to a DC generator to produce power. The coupled electro-mechanical system is modeled using energy methods. The design in this paper utilizes the nonlinear coupling between the roll and pitch motions of the generator vessel. The natural frequency of the roll motion of the vessel is tuned to be twice the fundamental frequency of the pitch motion. In this specific condition when the vessel is excited in the pitch direction, the energy is nonlinearly transferred to the roll mode and the vessel oscillates in the roll direction. It is shown that the combination of the pitch as well as roll motion is far superior to the pitch motion since the combination results in full rotations of pendulum. A pendulum in full rotations generates orders of magnitude more power compared to a locally oscillating pendulum.Copyright © 2015 by ASME

This paper explores an automated methodology to design eight-bar linkages for five positions, by constraining the user defined 4R open chain and 6R closed chain using RR dyads. The application in focus is that of rectilinear motion. The paper lays down the rules for systematic selection of link pairs for the application of RR constraints, that help automate the synthesis of eight-bar linkages. The methodology performs a random search within the user specified tolerance zones around the task specifications to increase the number of candidate linkage solutions. These linkages are then subjected to forward kinematic analysis using the Dixon determinant elimination procedure to find all possible linkage configurations over the range of motion of the input link. Linkages that have all the task configurations on one branch ensure their smooth movement through them. The result is an array of defect-free eight-bars that can perform approximate rectilinear motion. This method provides increased flexibility and control over the synthesized linkage compared to other known rectilinear motion linkages, owing to the ability to specify the backbone chain. A couple of examples are presented to illustrate the results.

Risk analysis in engineering design is of paramount importance when developing complex systems or upgrading existing systems. In many complex systems, new generations of systems are expected to have decreased risk and increased reliability when compared with previous designs. For instance, within the American civilian nuclear power industry, the Nuclear Regulatory Commission (NRC) has progressively increased requirements for reliability and driven down the chance of radiological release beyond the plant site boundary. However, many ongoing complex system design efforts analyze risk after early major architecture decisions have been made. One promising method of bringing risk considerations earlier into the conceptual stages of the complex system design process is functional failure modeling. Function Failure Identification and Propagation (FFIP) and related methods began the push toward assessing risk using the functional modeling taxonomy. This paper advances the Dedicated Failure Flow Arrestor Function (DFFAF) method which incorporates dedicated Arrestor Functions (AFs) whose purpose is to stop failure flows from propagating along uncoupled failure flow pathways, as defined by Uncoupled Failure Flow State Reasoner (UFFSR). By doing this, DFFAF provides a new tool to the functional failure modeling toolbox for complex system engineers. This paper introduces DFFAF and provides an illustrative simplified civilian Pressurized Water Reactor (PWR) nuclear power plant case study.Copyright © 2015 by ASME

This paper is motivated by a need identified by steel makers, namely, the need to produce steel products with new and often more stringent set of specifications and enhanced performances (such as fatigue life and corrosion behavior) using existing equipment cost-effectively. Manufacturing a steel product involves series of unit operations, each having a significant bearing on the properties of the end product. This paper focuses on studying the effect of one such unit operation, namely, ladle refining. The performance like corrosion behavior and fatigue life and properties of advanced high strength steel are greatly influenced by its cleanliness and by maintaining composition within specified bounds. Cleanliness of steel is assessed in terms of the count and nature of inclusions present and the levels of tramp elements such as sulfur, phosphorus and total oxygen present in the liquid steel. The desired composition is maintained with respect to alloying elements (Ni, Cr, Mn, etc.) that are added to impart certain properties to the steel. The ladle furnace is one of the key unit operations for carrying out deoxidation and desulfurization to maintain the levels of oxygen and sulfur within a tolerable limit. Deoxidation reaction during refining lead to formation of a number of which are deleterious in nature and should be removed. The effectiveness of the ladle operation is thus influenced by conflicting goals such as inclusion removal efficiency, desulfurization and the cost of refining. George Box is reputed to have observed that all models are wrong and some are useful. In keeping with George Box’s observation we suggest that our challenge is to determine the set points for the ladle unit operation using computational models that at best capture the essence of reality but not reality itself. Therefore, the need is to find solutions that are relatively insensitive to the inherent uncertainties embodied in the computational model while satisficing the conflicting goals. In this paper we present a method for visualizing and exploring the solution space using the compromise Decision Support Problem (cDSP) as a decision model. We illustrate the efficacy of our method, for use by steel producers, by determining the set points for a ladle, in an industrial setting.

Automotive Theft has been a persistent problem around the world. Design and manufacture of anti-theft systems have become more and more intricate due to the rise in complexity of theft in the system. Most of the anti-theft systems existing in the market, are the alarm types which audibly prevent some thieves away but do not prevent one’s car from being stolen and even are not good enough to meet the growing complexity of theft in the country. This paper presents a simple and an efficient anti-theft system which provides enhanced security by the use of efficient access mechanisms and immobilization systems. This security system can immobilise an automobile and its key auto systems through remote control when it is stolen. It hence deters thieves from committing the theft. It also effectively prevents stealing of key auto systems for reselling by introducing four layers of security features written in the form of firmware and embedded on the Electronic Control Units (ECUs). The particulars of system design and operation are defined in the paper. The experimental outcomes show that this system is feasible and the owner can steadily control his vehicle within a few seconds.Copyright © 2015 by ASME

Numerous works have been done on modeling compliant modules or joints, and the closed-form models of many widely-used compliant modules have been developed. However, the modeling of complex compliant mechanisms with considering external forces is still a challenging work. This paper introduces a constraint-force-based method to model compliant mechanisms. A compliant mechanism can be regarded as the combination of rigid stages and compliant modules. If a compliant mechanism is at static equilibrium under the influence of a series of external forces, all the rigid stages are also at static equilibrium. The rigid stages are restricted by the constraint forces of the compliant modules and the exerted external forces. This paper defines the constraint forces of the compliant modules to be variable constraint forces since the constraint forces vary with the deformation of the compliant modules, and defines the external forces as constant constraint forces due to the fact that the external forces are specific forces exerted which do not change with the deformation of the compliant mechanism. Therefore, the force equilibrium equations for all rigid stages in a compliant mechanism can be obtained based on the variable constraint forces and the constant constraint forces. Moreover, the model of the compliant mechanism can also be derived through solving all the force equilibrium equations. The constraint-force-based modeling method is finally detailed demonstrated via examples, and validated by the finite element analysis. Using this proposed modeling method, a complex compliant mechanism can be modelled with a particular emphasis on considering the position spaces of the associated compliant modules.Copyright © 2015 by ASME

Race cars are known for their brilliant acceleration as well as cornering performance. This requires optimization of each and every component of the car to shed every ounce of extra weight while maximizing the performance. This paper focuses on optimization of the powertrain of a Formula Student electric vehicle. The electric vehicle in question is a Formula style rear-wheel driven electric single person race car. The rear wheel drive is achieved with separate motors for each wheel controlled by electronic differential. Extensive research has been done in the area of gear design and several standards have been set. This paper follows the AGMA 2001-D04 standard as given in Shigley’s Mechanical Engineering Design [4]. A planetary gearbox was developed for a Formula Student vehicle with permanent magnet DC motor by Bakshi[2] et al. This paper tries to optimize the planetary gearbox and considers other suitable designs.Copyright © 2015 by ASME

The Organic Rankine Cycle (ORC) is an effective technology to recover the waste heat of the internal combustion engine (ICE) exhaust gas and coolant water. Performance prediction and matching of the expander is a key issue, during designing the ORC system. Radial turbines have the advantage in the ORC system for the ICE waste heat recovery because of its small size and high efficiency compared with volumetric expanders. But the ORC turbines design database is insufficient and the organic gas test rig is difficult to be constructed. As a result, this paper, based on similarity theory, establishes a performance prediction method for fully using the mature design and experimental datum of air turbines. By this prediction method, turbine performance can be obtained when its working fluid is changed from the air to the organic gas. Computational fluid dynamics (CFD) solution has been obtained for a calculation example, and the validity of the turbine performance prediction method is demonstrated by comparing the ORC turbine’s predicted performance with the simulated performance. The results show that almost all of the performance parameter’s predictive deviation is less than 5%. This paper comes to a conclusion that designing an R123 gas turbine is similar with designing an air turbine whose rotation rate is twice that of the former, expansion ratio is twice that of the former, power is four times twice that of the former at the same mass flow rate.Copyright © 2015 by KSME

This paper presents the implementation of a Carbon Fiber Reinforced Polymer (CFRP) composite system as a long term replacement for a non-safety, non-seismic, non-QA, low pressure service water buried pipeline. The existing pipeline (to be replaced) consists of approximately 1800 feet of large diameter (primarily 54in.), carbon steel, spiral wound, seam welded pipe, which was built and installed using AWWA standards, but is maintained in accordance with the B31.1 Power Pipe Code [1]. The CFRP pipe installation is to be done as an internal repair, and designed to comply with ASME B31.1 as a stand-alone pipe (pressure boundary). In lieu of using the limited evaluation of PCC-2 [2], which is focused on local repairs; a complete design evaluation of the entire piping system to B31.1-2010 is conducted, which is consistent with and acceptable under PCC-2. Since B31.1 does not provide detailed guidance on the design of buried piping systems, the criteria presented in this paper use the base design requirements of B31.1 adjusted to include applied soil and surcharge loads. The selected CFRP repair is the TYFO® Fiberwrap® system which consists of a carbon fiber fabric (CFRP, TYFO SCH-41-2X), and glass fiber fabric (GFRP/dielectric barrier, TYFO SHE-51A), saturated with epoxy. This composite system is built up of unidirectional CFRP layers; thus, the presented design approach also considers anisotropic material behavior, and evaluates the hoop and axial loads and capacities separately. The criteria are presented for plants considering alternative repair and replacement techniques for buried and above ground non-safety pipes.

25 years ago, Ron Winter presented the seminal paper “Gasket Selection: A Flowchart Approach” to the ASME Pressure Vessel Piping (PVP) community at the June 1990 PVP conference in Nashville, Tennessee [1]. Much has changed since then. New gasket materials have been introduced, and existing materials have been combined in new forms. High temperature vermiculite-based gaskets have come on the market. Further testing has demonstrated failure mechanisms specific to certain gasket materials; new assembly methods have been explored to reduce the effects of bolt elastic interaction and “cross talk”. Grooved profile gaskets, also known as “kammprofiles”, are now listed in ASME B16.20 [2] and widely (and economically) available in the United States. Spiral wound gaskets are obtainable world-wide. A new generation of engineers is responsible for sealing performance in today’s industrial and power plants. Environmental and emissions regulations have evolved. European codes now mandate design methods using gasket leakage while the US and other countries consider it. Much has stayed the same since 1990. New engineers need to learn what is required to seal a bolted flanged joint reliably — this is not typically explored in universities. Many of the steps to select and implement a good gasket seal are the same in 2015 as they were in 1990. This paper reviews and expands the gasket selection process to enable today’s engineers to make informed choices for reliable bolted flanged joints with gasket sealing elements.Copyright © 2015 by ASME

Stress Intensification Factors (SIFs) are factors relating to fatigue characteristics of piping components. SIF is fatigue correlation which compares fatigue life of a typical piping component such as a tee and elbow to the reference fatigue life, that is girth butt welds in straight pipe subjected to bending moments. In order to calculate localized stress of such piping component, above mentioned figured out SIF shall be multiplied by nominal stress. ASME B31 contains several formulas for stress intensification factors considering limitation that those formulas are valid only for D/T≤100 (diameter to thickness). Extending the valid range mentioned in ASME B31 this paper is dedicated to SIF calculation for D/T≤100 and also for D/T>100 by utilizing Finite Element Analyzing (FEA) for welding tee. The computed SIF for D/T>100 welding tee can now be placed to typical pipe stressing program which analyzes piping system using beam elements. In addition, this paper investigates the effect of Rx (the magnitude of corner radius of shoulder at branch) on SIF of Welding Tee Connections.Copyright © 2015 by ASME

The current state of the art nondestructive evaluation (NDE) techniques used in nuclear reactor structural inspection are manual labor intensive, time consuming, and only used when the reactor has been shut down. Also, despite periodic inspection of plant components, a failure mode such as stress corrosion crack can initiate in between two scheduled inspections and can become critical before the next scheduled inspection. In this context, real time monitoring of nuclear reactor components is necessary for continuous and autonomous monitoring of component structural health. In this research, an active ultrasonic based on-line monitoring (OLM) framework is developed which can be used for real-time monitoring of degradation of nuclear power plant systems, structures, and components. Nonlinear system identification technique such as Bayesian Gaussian Process technique method is investigated to estimate the structural degradation in real-time. Active broadband ultrasound input is used for damage interrogation and a multi-sensor configuration is implemented to improve spatial resolution of state estimation. The damage index at any particular time is computed using nonlinear techniques such as Gaussian Process probabilistic modeling and the necessity of sensor data fusion is evaluated. The framework was demonstrated through the monitoring of an anomaly trend in a nuclear reactor steam generator tube undergoing stress corrosion cracking (SCC) testing.Copyright © 2015 by ASME

Real-time estimation of the fatigue usage factor of nuclear reactor components are helpful tools for on-demand assessment of component structural integrity. Real-time measurements of field variables, such as stress and strain, along with the use of historic/available stress/strain versus fatigue life data and a Bayesian-probabilistic framework can not only help to estimate the fatigue usage factor of reactor components in real time but also can help to estimate the associated confidence bounds. In this paper, a Gaussian Process based Bayesian-probabilistic framework is proposed for real-time estimation of mean fatigue usages factor and associated probabilistic bounds. The preliminary proof of concept was demonstrated through fatigue experiments with 316 stainless steel specimens under different conditions: a) under 300 °C and pressurized water reactor (PWR) water chemistry, and b) room temperature and in-air condition. At present the proposed probabilistic monitoring approach is not part of any code requirements, however the proposed framework is output of a futuristic basic research work, which requires more advancement. Also the results discussed in the paper are part of very preliminary basic research and requires advance validation such as under realistic nuclear reactor conditions.Copyright © 2015 by ASME

In USA there are approximately 100 operating light water reactors (LWR) consisting fleet of both pressurized water reactors (PWR) and boiling water reactors (BWR). Most of these reactors were built before 1970 and the design lives of most of these reactors are 40 years. It is expected that by 2030, even those reactors that have received 20 year life extension license from the US nuclear regulatory commission (NRC) will begin to reach the end of their licensed periods of operation. For economical reason it is be beneficial to extend the license beyond 60 to perhaps 80 years that would enable existing plants to continue providing safe, clean and economic electricity without significant green house gas emissions. However, environmental fatigue is one of the major aging related issues for these reactors, and may create hurdles in long term sustainability of these reactors. To address some of the environmental fatigue related issues, Argonne National Laboratory (ANL) with the sponsorship of Department of Energy’s Light Water Reactor Sustainability (LWRS) program trying to develop mechanistic approach for more accurate life estimation of LWR components. In this context ANL conducted many fatigue experiments under different test and environment conditions on 316 stainless steel (316SS) material that is or similar grade steels are widely used in US reactors. Contrary to the conventional S∼N curve based empirical fatigue life estimation approach, the aim of the present DOE sponsored work is to understand material ageing more mechanistically (e.g. time dependent hardening and softening) under different test and environmental conditions. Better mechanistic understanding will help to develop computer based advanced modeling tools to better extrapolate stress-strain evolution of reactor component under multi-axial stress states and hence to help predicting their fatigue life more accurately. In this paper (part-I) the fatigue experiments under different test and environment conditions and related stress-strain results for 316 SS are discussed. In another paper (part-II) the related evolutionary cyclic plasticity material modeling techniques and results are discussed.Copyright © 2015 by ASME

Chapter of Repair, Replacement Activities (RRA) in Fitness-For-Service (FFS) Code of the Japanese Society of Mechanical Engineers (JSME) includes rules of article RB-3000 for temporary repair techniques in the use of covering leakage during operation of a Nuclear Power Plant (NPP). Temporary repair techniques are RB-3010 Plating, RB-3020 Adhesion and RB-3030 Infill. In this paper, rules of these temporary repair techniques are summarized as well as the meaning of ‘temporary’, intention and benefit of them. On the other hand, these rules of temporary repair techniques were provided by Thermal and Nuclear Power Engineering Society (TENPES) at first in 1986, about thirty years ago. “Plant Operation and Maintenance Standards (POMS) Plan” developed by Japan Power Engineering and Inspection Corporation (JAPEIC) in 1996 incorporated those rules of temporary repair techniques, then JSME FFS Code has taken over them from POMS. Because the design rules of these temporary repair techniques have had much margin since origin, it may result in excessive design, or time-consuming procurement of parts. Especially, since these temporary repair techniques are often applied to the leakage around valve gland and flange, simpler and more practical modified rules could provide more benefit for effective repair activities. In this paper, an orientation of possible revision is described on temporary repair techniques rules in JSME FFS Code.

During the welding process, the pore defects may be produced in the weld body. Statistic results showed that welding defect is one of the main causes for pipeline failure. According to this factor, this paper presents a detailed description of numerical research to assess the structural condition of circumferential weld seam pipeline with pore defects. Based on elastic-plastic theory, a set of nonlinear finite element analyses of pipelines with pore defects are carried out to study the influence of different sizes and locations on failure mode. Aimed at evaluating the load bearing capacity of pipeline with pore defects, limit stress states are investigated in this paper by using the finite element analysis. By comparing the present analysis results with the relevant standards, a proposed acceptance criterion is brought out. The results presented in this paper can be used to make suggestions on welding procedure qualification and continued safe operation of pipelines.Copyright © 2015 by ASME

High cycle fatigue failure is likely to occur when a rather undamped offshore installation is operated over a long period of time. Especially welded parts are vulnerable to fluctuating stress ranges, if the structural components, such as the small bore side branches, are loaded in resonance. In particular, the welded connections at e.g. tie-in points can be critical. Therefore, it is important to know what the current status of existing welded connections is and how long they can still be operated at any specific operating condition without failure. This paper describes an advanced fatigue assessment method to determine the cumulative damage in the critical parts of the system. The method is developed for industrial applications where the available information is limited. The method comprises of a mechanical analysis and a fatigue assessment based on a fracture mechanics crack growth model. The method enables determination of inspection intervals and at the same time layout optimization for a long term safe operation. This paper pays special attention to complex, braced small bore side branches. Standard fatigue stress assessment methods can be conservative for the fatigue assessment of high frequent stress ranges with relatively low stress ranges. The current paper shows the effect of the fracture mechanics procedure for an example of a braced side branch connected to the main piping: both a fracture mechanics model and a detailed 3D FE model are made. With these models, the hot spot stress in the welds is evaluated and tailor-made S-N-curves are derived. With information of the operating history, the cumulative damage is determined for the weld detail. This knowledge on the current damage status is crucial for future operations.

The use of a flange joint is a popular method to close the end of pipes or connect pipes in manufacturing industries. As the pipes are often subjected to vibrations and cyclic bending, fatigue cracking may occur at the welded part between the pipe and flange. It is therefore important to detect and monitor the cracking in this part to ensure safety of the whole piping system. The direct-current potential difference method (DC-PDM) is known as a suitable non-destructive technique to monitor the initiation and growth of cracks and it has been applied to cracks and wall thinning on the inner surface of pipes. In this study, finite element analyses were carried out to clarify the relationship between the size and location of cracks at the pipe-flange welded part and the potential difference. An evaluation method of circumferential crack length angle by DC-PDM was proposed.Copyright © 2015 by ASME

ASME Code Case N-513-3 allows evaluation of flaws in elbows to be evaluated as straight pipe if the flaw is located within a distance √Rt from the weld, provided the elbow is welded to straight pipe. The recently published revision to N-513-3 (N-513-4) provides guidance for evaluation of flaws in elbows when the flaw is remote from the butt weld, but this approach may be overly conservative for flaws near the butt weld. This paper will utilize finite element models to examine the stress distribution in elbows with uniform wall thickness. The results of this paper may be used as supporting evidence to modify the √Rt limit in evaluation of flaws in butt welded elbows in a pending revision to Code Case N-513-4 (N-513-5).Copyright © 2015 by ASME

In the power industry, steam hammer piping analyses (and fluid transient loads) are often based on incompressible flow principles. Consequently, it is common to use either computer programs based on the Method of Characteristics for incompressible flow or simple hand calculations such as that described by E. C. Goodling (ASME PVP, Vol. 149–157, 1989). Goodling’s paper provides a simplified method to visualize and estimate transient loads resulting from stop valve closure in a main steam system. To account for compressibility effects, the calculated loads are sometimes adjusted by using a correction factor directly applied to the fluid loads with the fluid sound speed assumed constant in time and space. For example, Goodling’s paper suggests that a load increase of 5% may be used. In this paper, a sample steam hammer problem is solved using the Method of Characteristics for compressible flows, where the fluid is assumed to behave as a perfect gas. The effects of steam compressibility are then discussed. Specifically the shortening of the characteristic valve closure pressure wave length, resulting from the increasing magnitude of the sound speed as the pressure wave moves upstream from the closing valve, and resulting higher loads in straight pipe segments shorter than the pressure wave length, are then discussed. It is shown that in these shorter pipe segments fluid transient loads may almost double those calculated using the MOC for incompressible flows or the Goodling methodology (without correction factors) if the distance upstream from the closing valve is of sufficient length.Copyright © 2015 by ASME