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Strand debonding patterns and release (prestress transfer) practices can result in significant local stresses at prestressed girder ends, which are not accounted for in design. This article presents a numerical and analytic study of various single-webbed prestressed concrete girder shapes for which large amounts of prestressing are necessitated by the use of 0.7 in. (17.8 mm) diameter strands. Shapes with wide bottom flanges are shown to potentially exhibit large stresses that effectively pry, or peel, the portions of the flanges extending from the web away from the web. Such peeling stresses can be mostly mitigated by partially debonding strands in the recommended pattern from the outside in. Similarly, releasing or cutting strands in a uniform manner mitigates peeling stresses. While releasing all strands simultaneously is optimal, it is unlikely to be practical for large prestressed components. For conventional release operations, the results presented in this article indicate that a symmetrical top-down method would not result in significant peeling stress. Moreover, prestressed girder end region detailing requirements aimed at providing adequate flange confinement and strand anchorage at the ultimate limit would be adequate to control peeling stresses, including those resulting from the inadvertent use of a poor release sequence. [ABSTRACT FROM AUTHOR]

Taking the maximum contact pressure as the objective function for, the optimal design model of the offshore flange connector was established to analyze the impact of the flange cone's angle and the curvature radius of the lenticular gasket's contact surface on the sealing performance of the connector. An optimized three-dimensional model of the offshore flange connector was constructed using the MATLAB software's fmincon function to obtain the optimal size of the cone angle and curvature radius. The maximum contact pressure and maximum equivalent stress values of the nonoptimized and optimized offshore flange connectors under the cross combination of two design pressures and six operating temperatures were analyzed by Workbench software, and the sealing performance of the non-optimized and optimized offshore flange connectors was compared according to the sealing judgment basis. The results show that compared with the previously studied offshore flange connector, the sealing structure of optimized offshore flange exhibits maximum increase in contact pressure increase but maximum decrease in equivalent stress. Under actual operating circumstances, the optimized offshore flange connection performs better in sealing and is less prone to breakage. [ABSTRACT FROM AUTHOR]

Precision metal stamping is an industrial process that uses machines equipped with dies to transform flat sheet metal, either in blank or coil form, into various custom shapes. In addition to stamping, these metal presses can also perform a wide range of processes such as stamping, tooling, notching, bending, punching, flanging, coining and more. Precision metal stamping is widely used for the production of a wide range of products. It can be performed as a single-step operation where each stroke of the metal press produces the desired shape on the plate or in a series of steps. The increasing demand for precision metal parts in various industries from medical to automotive and aerospace has pushed precision metal stamping to the forefront of today's manufacturing. This is because it provides a high degree of design flexibility for defining and implementing tiny features with tight tolerances and unique configurations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Compared with traditional multi-girder bridge systems, an I-girder system using two main girders simplifies the construction process and saves material consumption and is becoming a representative system used in bridge industrialization in China. However, owing to the low torsional stiffness and poor stability of the traditional I-section, more lateral connections (diaphragms or cross-frames) and stiffeners are required to form a frame to ensure safety and structural performance during the construction process. This article proposes an innovative girder system with hollow top tubular flanges to replace the top plate of the traditional I-section with a hollow rectangular tube that improves the torsional stiffness of the traditional I-section, but the bending performance is basically unchanged. In this article, the structural performance of this innovative system is studied, and compared with the traditional I-girder system. The analysis results show that the innovative bridge system using tubular flange has better performance than the traditional I-girder system, and can be applied to industrialized bridge construction. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study extends an extensive research program carried out at the University of Sherbrooke to design and assess the potential use of rectangular, concrete-filled fiber-reinforced-polymer tube (CFFT) beams post-tensioned with steel tendons in bridge applications. This paper describes research to enhance the flexural performance of post-tensioned CFFT beams. Five rectangular post-tensioned CFFT beams were tested up to failure, and the effects of attaching a thin carbon-fiber-reinforced polymer (CFRP) laminate embedded in tension flange and its total reinforcement ratio as well as tube structure fiber laminate were investigated. Last, a simplified design approach is proposed based on strain combinability and force equilibrium to estimate the flexural moment capacity of the tested beams. The specimens with two inclined fiber patterns in the hoop direction or added CFRP laminate strips embedded in the bottom flange of the tubes exhibited substantially greater flexural strength, absorbed energy, and serviceability performance than the control specimens. The ductility index and energy ratio ranged from 8.3 to 10.6 and from 82% to 87%, respectively, which indicates ductile behavior. Also, adding CFRP laminate strips embedded in the bottom flange of the tubes enhanced the flexural strength by 17% on average compared with post-tensioned CFFT without CFRP laminate. The specimen with the CFRP laminates in the bottom flange of the tube achieved flexural strength and energy absorption that was comparable to the flexural strength and energy absorption of the specimen with two layers of inclined fiber patterns. The findings suggest that the design can be optimized to achieve more efficient post-tensioned CFFT structural members. The proposed design approach successfully predicts the flexural strength of the tested beams with an average of 1.05 ± 0.05 for the partially confined concrete model and an average of 1.11 ± 0.07 for the unconfined concrete model. [ABSTRACT FROM AUTHOR]

A study of the structural performance and engineering application of a long lasting composite bridge with tubular steel flanges was carried out. The flexural, shear and torsional resistance of high-performance composite girders with tubular flanges were analysed comparatively based on tests and finite element simulation. Based on the research and design rules achieved above, the first two typical composite girder bridges with rectangular tubular flanges using high-performance weathering steel have been constructed in China. The structural performances were compared of a composite girder bridge with tubular flanges and a composite girder bridge adopting traditional I-shaped steel girders. A long-term performance evaluation was conducted for a weathering steel composite bridge with tubular flanges, which included an insitu inspection and rating assessment of the patina and life cycle cost evaluation of the whole bridge. Learned from the application experience and evaluation results, weathering steel composite girder bridges with tubular flanges revealed superior long lasting structural performance including improved torsional stiffness and resistance, fewer web stiffeners and cross beams, fast construction, and easy and less maintenance during the in-service stage. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A Coupling is a gadget which is answerable for the employable force transmission between two shafts turning at specific RPM. Coupling is utilized to interface two unique shafts at their end and can slip or come up short contingent on as far as possible. It is the essential piece of any force transmission and may keep going for long time whenever planned and looked after appropriately. The current investigation of this paper is to diminish the most extreme pressure by choosing a reasonable material for spine coupling. For this reason, displaying of the unbending rib coupling is completed in scoundrel apparatus strong works and dissected in ANSYS Workbench, with static and dynamic stacking conditions and determined outcomes like distortion, anxiety and shear pressure and wellbeing factor, regular recurrence esteems. From every one of these qualities tables and diagrams we can talk about the every material strength and stress esteems at long last can close our undertaking with reasonable material. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the out-of-plane shear performance of a newly developed shape memory alloy (SMA) connector and a commonly used shear/alignment connector. The innovation lies in developing a durable and easily installed and maintained flange-to-flange connector between precast concrete double-tee members. The proposed connector consists of a superelastic SMA curved bolt inserted into a duct that is then cast into the precast concrete member. Two types of sealant materials were used: polyurethane elastomeric sealant and nonshrink cementitious grout. The shear/alignment and SMA connectors were tested under monotonic vertical shear. The tests were conducted on 4 ft × 4 ft × 4 in. (1.2 m × 1.2 m × 100 mm) slab specimens. The resulting capacities and associated damage were summarized. Higher stiffness and lower ductility were observed for the SMA connector with nonshrink grout compared with the shear/alignment connector with polyurethane elastomeric sealant. The average stiffnesses of the SMA and shear/alignment connector specimens were 116,681 lb/in. (20,434 kN/m) and 31,300 lb/in. (5481 kN/m), respectively. The ductility of the SMA connector was improved when using polyurethane elastomeric sealant; however, more tests should be done to confirm this behavior. The SMA rod was reused in several tests through reheating of the SMA element. The shear/alignment connector cannot be reused. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes the construction, research and comparative analysis of adaptive control systems of elastic oscillations suppression of electric drive transmissions of joints and the unleashing of the interrelated dynamics of the degrees-of-freedom of manipulation arms robots under conditions of nonlinearity and uncertainty of their mathematical description with the aim of improving the accuracy and speed of spatial trajectory movement of the robot flange. The strategy of solving the two mentioned interrelated problems is based on the decomposition of the nonlinear mathematical model of the manipulation arm onto the rigid and elastic subsystems, which allows to introduce unification of the construction of combined (composite) adaptive electromechanical systems, using the accurate method of the calculated moment (Li-Slotine) and the approximate method of majorizing functions. [ABSTRACT FROM AUTHOR]

This paper proposes a new joining by plastic deformation process to connect sheets to rods that extends a previous idea of the authors to connect sheets to thin-walled tubes. The process makes use of boss forming for compressing the outer radius of the rods and pile-up material into annular flanges with controlled cross-section geometry and size. Special emphasis is put on the identification of the major operating parameters and on understanding their influence on material flow. Two different modes of deformation are identified and a distinction is made between unacceptable chip formation and successfully material pile-up to form the annular flanges that are needed to connect the sheets to the rods. Special design of the upper die to include a pressure ring is introduced as an efficient solution to prevent cracking of the new freshly formed surfaces of the rods during material pile-up. The presentation is supported by experimentation and finite element modelling and the overall performance of the new proposed joint is evaluated by means of a destructive pull-out test. [ABSTRACT FROM AUTHOR]

Bolted flange joints are widely used in the nuclear power plants and other industrial complexes. During their assembly, it is extremely difficult to achieve the target bolt preload and tightening uniformity due to elastic interaction and criss-cross talks. In addition to the severe service loadings, the initial bolt load scatter increases the risk of leakage failure. The objective of this paper is to present an analytical model to predict the bolt tension change due to elastic interaction during the sequence of initial tightening. The proposed analytical model is based on the theory of circular beams on linear elastic foundation. The elastic compliances of the flanges, the bolts, and the gasket due to bending, twisting, and axial compression are involved in the elastic interaction and bolt load changes during tightening. The developed model can be used to optimize the initial bolt tightening to obtain a uniform final preload under minimum tightening passes. The approach is validated using finite element analysis (FEA) and experimental tests conducted on a NPS 4 class 900 weld neck bolted flange joint. [ABSTRACT FROM AUTHOR]

Based on a brief review of existing tubesheet (TS) design standards and the pertinent technical literature, a unified analytical method of stress analysis for fixed TS heat exchangers (HEXs), floating head and U-tube HEXs is proposed by removing the midplane symmetry (MPS) assumption, which assumes a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the HEX or one TS needs be considered. The unified method can be successfully extended to the situations for different TS materials, unequal TS thicknesses, different TS edge conditions, different TS temperatures, pressures drop and dead weights on two TSs. The effects of pressure in TS perforations and temperature gradient in TS thickness direction are also considered by the unified method. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the unified method. Numerical comparison indicates that predictions given by the unified method agree well with finite element analysis (FEA), while ASME results are not accurate or not correct. [ABSTRACT FROM AUTHOR]

Thermal closure of the engine casing is widely used to minimize undesirable blade tip leakage flows thus improving jet engine performance. This may be achieved using an impingement cooling scheme on the external casing wall, provided by manifolds attached to the outside of the engine. The assembly tolerance of these components leads to variation in the standoff distance between the manifold and the casing, and its effects on casing contraction must be understood to allow build tolerance to be specified. For cooling arrangements with promising performance, the variation in closure with standoff distance of z/d = 1-6 were investigated through a mixture of extensive numerical modeling and experimental validation. A cooling manifold, typical of that adopted by several engine companies, incorporating three different arrays of short cooling holes (chosen from previous study by Choi et al. (2016, "The Relative Performance of External Casing Impingement Cooling Arrangements for Thermal Control of Blade Tip Clearance," ASME J. Turbomach., 138(3), p. 031005.)) and thermal control dummy flanges were considered. Typical contractions of 0.5-2.2 mm are achieved from the 0.02-0.35 kg/s of the current casing cooling flows. The variation in heat transfer coefficient observed with standoff distance is much lower for the sparse array investigated compared to previous designs employing arrays typical of blade cooling configurations. The reason for this is explained through interrogation of the local flow field and resultant heat transfer coefficient. This implies that acceptable control of the circumferential uniformity of case cooling can be achieved with relatively large assembly tolerance of the manifold relative to the casing. [ABSTRACT FROM AUTHOR]

This paper proposed a new method of constructing an ontology-based expert system with an expandable knowledge base for process planning in cold forging of flange nuts. There are two essential parts of this method. In the first part, the software Protégé is used for expressing the experiential knowledge as a Web Ontology Language (OWL) ontology and Semantic Web Rule Language (SWRL) rules. The inference is executed in Java by means of the API provided by Jess, the rule engine for the Java platform. In the second part, new knowledge is acquired from parameter optimisation experiments, combing process simulation and Taguchi methods. Deform-3D was adopted as the process simulation engine. Then the tool wear of front punch at the 4th stage was predicted for the tool life evaluation. A modified Archard wear model is used for tool wear prediction during the simulation. On the other hand, Taguchi methods is used for designing an optimal tool which makes the tool life longer than that of the existing design. The novelty of the proposed system is that the new knowledge is represented as an OWL ontology and SWRL rules, which makes the knowledge base of the system expandable. The knowledge base can thus be expanded if there are modifications or new knowledge. The system is capable of inferring a workable forging process for flange nuts. It could recommend dimensions of tools after the necessary information, such as the nominal size and specifications of the product, has been input. Users are able to reduce tool design time by taking the results from the system as a process planning decision support. In this way, when the manufacturer gets a new quotation from the client, engineers can search from the company tooling database for feasible forging tools and make the cost estimation based on the forging process plan generated by this system. [ABSTRACT FROM AUTHOR]

Inner-splined flange (ISF) is a special component with multi-splines on the inner surface. This non-rotary feature is traditionally manufactured by machining which has disadvantages of material waste and insufficient material properties as compared to plastically formed parts. Flow forming is an innovative rotary incremental forming technique to manufacture hollow profile parts. During the forming process, a workpiece is positioned on a die with profile section which makes rotating motion. A roller tool with multi-rolling balls is pressed on the outer surface of the workpiece, which makes axial feed movement. This allows the workpiece to be formed gradually to the expected section shape by the radial pressure between the die and rolling balls. In this paper, flow forming was adopted to manufacture an ISF. To demonstrate the feasibility, FE simulations for the flow forming of ISF were tried including different process parameters. The metal flow law during the forming process was analyzed, which helps develop a better understanding of the deformation mechanism of this flow forming concept. The effects of different process parameters were discussed, which enables a design basis for this technique. Based on the simulation results, experiments for the flow forming of ISF were carried out. The results show that the ISF can be net-shaped by the flow forming potentially. This study offers an innovative potential method for manufacturing ISF with high precision and performance and it maybe spread for other hollow profile parts. [ABSTRACT FROM AUTHOR]

In order to produce T-bars with dimensions suitable for ships, a new T-bar rolling technology employing universal and edger mills is being developed. T-bars with various section sizes are required in ships. Although the new process makes it possible to manufacture T-bars with different thicknesses with the same rolls, individual rolls must be prepared for each outer dimension (web height or flange width). In the case of different flange widths, rolls suitable for each product flange width are necessary for both the breakdown mill and the edger mill. In order to use the same breakdown rolls for T-bars with different flange widths, a method which makes it possible to change the flange width by more than 25 mm in universal rolling was investigated. In T-bar universal rolling, larger flange thickness reduction relative to web thickness reduction causes larger flange spread. This large flange spread should make it possible to produce T-bars having different flange widths with the same breakdown rolls. A series of laboratory rolling experiments was carried out to demonstrate this idea. The model scale was 1/5, and pure lead was used as the model material. Thick pure lead T-section bars suitable for products with a flange width of 100 mm were rolled with a model universal mill. Two draft schedules were examined for the two product flange widths of 125 and 150 mm. As a result, the flange widths of the rolled pure lead T-bars satisfied the target flange widths in 5 to 7 passes. The results of this research demonstrated the possibility of flange width control in universal rolling with the aim of realizing common use of breakdown rolls with different flange widths. [ABSTRACT FROM AUTHOR]

Modelling and calculations of asymmetrical nonlinear multi-bolted connections treated as a system composed of four subsystems are presented. These subsystems are: a couple of joined elements (a flange and a support), a contact layer between the elements, and a set of bolts. The physical model of the system on the assembly state is described taking into account the bolt preloading conducted according to a specific sequence. For the modelling the finite element method is used. The flange and the support are built with spatial finite elements. The contact layer is formed as a nonlinear Winkler model, and the set of bolts are modelled using simplified beam models (named as rigid body bolt models). The calculation model is presented, by means of which changing force values in the bolts during the preloading of the system and at its end can be determined. Results of calculations for the exemplary multi-bolted system are presented. [ABSTRACT FROM AUTHOR]

In this paper, a cold forming process is used where the connection between a pipe and a flange is created by means of radially expanding tool segments inside the pipe. The method is investigated with two purposes, to set up a robust procedure for the process that allows for connections to be made on site, and to set up finite element (FE) simulations that can capture the forces and deformations when pulling the pipe axially out of the flange. Experimental data and FE simulations are used to describe and understand the forces and deformations during the connection process. The rapid increase in radial stiffness experienced when the pipe comes in full circumferential contact with the flange is identified as the best end-of-process indicator. Also, experimental data and FE simulations are used to predict the axial load capacity of a pipe flange connection, and the FE model is utilized in designing the appropriate ridge height of the tool segments. [ABSTRACT FROM AUTHOR]

Gasketed flange joints are widely used in pressure vessels and piping systems. They are subjected to bending load due to differential thermal expansion, wind load, self-weight, etc., in addition to assembly and internal fluid load. Most of the flange designs are based on equivalent pressure method to include the effect of external bending loads. The behavior of gasketed flange joint is complex due to the nonlinear hysteretic behavior of gasket material and contact interfaces between joint members. It becomes more complex when the joint is subjected to bending load at elevated temperatures. In the present work, performance of a flange joint has been studied under internal pressure and external bending load at elevated temperatures. A 3D finite element model is developed, considering the nonlinearities in the joint due to gasket material and contact between its members along with their temperature-dependent material properties. The performance of joint under different bolt preloads, internal fluid pressures, and temperatures is studied. Flange joint with two gaskets (twin-gasketed flange joint, TGJ) placed concentric is also analyzed. The results from finite element analysis (FEA) are validated using four-point bending test on gasketed flange joint. The sealing and strength criteria are considered to determine the maximum allowable bending moment at different internal fluid temperatures, for both single- and twin-gasketed flange joints with spiral wound gasket. Twin gasket is able to withstand higher bending moment without leakage compared to single gasket. Results show that the allowable load on flange joint depends on operating temperature and gasket configuration. [ABSTRACT FROM AUTHOR]

Bolted connections inserting gaskets such as box-shape flange connections have been widely used in mechanical structures, nuclear and chemical industry, and so on. They are usually used under internal pressure. In designing the box-shape flange connections with gaskets under internal pressure, it is important to clarify the gasket stress distribution for evaluating the sealing performance of these connections. However, no research in which the sealing performance of these connections is examined under internal pressure has been carried out. Thus, the design for box-shape connection such as thickness of flange cover, number of bolts, gasket width, and so on is not clarified. In this paper, the contact gasket stresses of these connections under internal pressure are analyzed using the finite element method (FEM), taking into account a hysteresis in the stress-displacement curve of the gasket. And then, using the contact gasket stress distributions obtained from FE analysis and the relationship between gasket stress and leak rate obtained from a gasket sealing test (JIS B2490), a method for estimating an amount of leakage is examined. Leakage tests were also conducted to measure an amount of gas leakage using an actual box-shape flange connection with a gasket. The estimated results are in reasonable agreement with the experimental results. In addition, the effect of gasket width, flange cover thickness, and flange cover material is examined on the sealing performances of box-shape flange connections under internal pressure. The effects of the above factors are discussed on the sealing performance in designing box-shape flange connections. [ABSTRACT FROM AUTHOR]

The stress analysis method for fixed tubesheet (TS) heat exchangers (HEX) in pressure vessel codes such as ASME VIII-1, EN13445, and GB151 is based on the classical theory of thin plate on elastic foundation. In addition, these codes all assume a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the unit or one TS is needed to be considered. In this study, a refined general theory of stress analysis for TS is presented which also considers unequal thickness for two TSs, different edge conditions, pressure drop and deadweight on two TSs, the anisotropic behavior of the TS in thickness direction, and transverse shear deformation in TS. Analysis shows floating and U-tube heat exchangers are the two special cases of the refined theory. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the refined theory. Numerical comparison results indicate that predictions given by the refined theory agree well with finite element analysis (FEA) for both thin and thick TS heat exchangers, while ASME results are not accurate or not correct. Therefore, it is concluded that the presented refined general theory provides a single unified method, dealing with both thin and thick TSs for different type (U type, floating, and fixed) HEXs in equal detail, with confidence to predict design stresses. [ABSTRACT FROM AUTHOR]

A novel method is developed for the design of pressure vessels with tooth-locked quick-actuating closures by considering the contact between the teeth and utilizing the surface-to-surface contact model with contact element and coulomb friction. Elastic and elastic-plastic analyses via the finite element method were employed. It is shown that these pressure vessels can meet the requirements of strength and fatigue. [ABSTRACT FROM AUTHOR]

Bolted flange joints are widely used to connect pressure vessels and piping equipment together and facilitate their disassembly. Initial tightening of their bolts is a delicate operation because it is extremely difficult to achieve the target load and uniformity due to elastic interaction. The risk of failure due to leakage and fatigue under service loading is consequently increased. This paper presents a study on the effect of elastic interaction that is present during the tightening of bolted flange joints using three-dimensional nonlinear finite-element modeling and experimentation. The nonlinear nonelastic behavior of the gasket is taken into account in the numerical simulation. The scatter in bolt preload produced during the tightening sequence is evaluated. Based on the elastic interaction coefficient method, the initial target tightening load in each bolt for every pass is determined by using the nonlinear finite-element model to obtain a uniform preload after the final tightening pass. The validity of the finite-element analysis (FEA) is supported by experimental tests conducted on a NPS 4 class 900 weld neck bolted flange joints using fiber and flexible graphite gaskets. This study provides guidance and enhances the safety and reliability of bolted flange joints by minimizing bolt load scatter due to elastic interaction. [ABSTRACT FROM AUTHOR]

This paper describes investigation of flange which is installation into the test station for bearings. Flange is loaded with axial force, radial force, angular velocity and preload bolted joints. Load consists of 45 load steps. It was calculated von Mises stress for each load step in the critical position then was calculate fatigue life of flange. Fatigue life of part was determined with using theory of Palmgren-Miner linear damage accumulation. [ABSTRACT FROM AUTHOR]

A numerical analysis and experimental validation of T-stub steel joint with pre-loaded bolts is done. Design codes have a very imprecise analysis methodology that might not take into account the actual behavior of this joint. The calculations are done with state-of-the-art open source software Code_Aster by taking into account large strains, nonlinear plasticity and contact mechanics. Experimental validation of truss T-stub joint's ultimate load and displacements shows good agreement with numerical simulation results. Parametric studies show, that the ultimate load and stiffness is highly affected by the pre-loading level of bolts and thickness of flange. By increasing the thickness of flanges up to 40 mm, nearly equal stress distribution in all bolts is obtained. The joint with 70% pre-loaded bolts has around 30% higher ultimate load than the joint with 0% pre-loaded bolts. The design of T-stub flanges can be significantly improved by using state-of-the-art open-source finite element simulation tools. [ABSTRACT FROM AUTHOR]

The problem of determining the effective flange width for reinforced concrete T-sections subjected to bending was presented in the paper. The numerical analysis was performed in order to define an influence of parameters on the width value. Multi-span reinforced concrete slabs monolithically connected with two-span concrete beams were considered in the analysis. Two material models were used: elastic for concrete and plastic for reinforced concrete. [ABSTRACT FROM AUTHOR]

Hollow tubular flange girders (HTFG) overcome the weakness of the conventional I-sections to resist the lateral buckling. This leads to higher capacity, resulting in fewer steel quantities and reducing the carbon emissions from the steel industry. This paper presents a numerical analysis to investigate the behavior of HTFG under bending and validate the AISC design equations. The gain of the bending capacity is found similar in different flange classes but decreases with the reduction of the web class. The capacity for the compact section is higher than the yielding moment, but the section could not be fully yielded. The AISC in slender web is very conservative, unlike for non-compact web. Adjustments of the plastic limit and adaptation in terms of torsion constant are proposed, and the results show good agreement. The reduction of the embodied carbon caused by the material saving after using HTFG is calculated for a case study. [ABSTRACT FROM AUTHOR]

Strengthening existing structures under load by welding plates is often conducted but little research into this subject was presented. Some researchers claim that the column strengthened under load has the same ultimate capacity as the column welded without preloading. Others disagree and recommend safe design not allowing the steel to yield. The paper presents the parametric study of wide flange columns HEA 100 strengthened under load via two plates parallel to flanges conducted on numerical models validated by experiment. The varying parameters are thickness of strengthening flange, column length, initial bow imperfection, preload magnitude and direction of the axis which is pinned while the other axis is fixed. The experimental research consisted of two columns welded without preload and two columns strengthened under preload ratios (preload magnitude divided by base column ultimate strength) equal to 0.5 (200 kN) and 0.75 (300 kN). All columns were 3 m long and the boundary conditions were determined by knife-edge bearings which ensured pinned supports in the direction perpendicular to the strong axis and fixed perpendicular to the weak axis. All strengthening plates were welded to columns with intermittent welds. All columns failed via flexural buckling. The numerical models used for the parametric study were created in ANSYS software. Design values and procedures recommended by EN 1993-1-5, Annex C were used. The most commonly used steel grade S235 was selected for all plates. Shell 181 element type was used for mapped meshing of steel plates. Element birth and death feature was convenient to simulate strengthening under load. [ABSTRACT FROM AUTHOR]

The stress analysis method for fixed tubesheet (TS) heat exchangers (HEX) in pressure vessel codes such as ASME VIII-1, EN13445, and GB151 all assume a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the unit or one TS is need to be considered. In this study, the midplane symmetry assumption is discarded. More common situations are considered such as unequal TS thickness, different edge conditions, pressure drop, and dead weight on two TSs. Based on the classical thin plate and shell theoretical solution, an analytical method of stress analysis for TS is presented. The proposed method is suitable for different types of HEX due to fewer assumptions employed in this study. Analysis shows that floating and U-tube HEX are the two special cases of the proposed method. Theoretical comparison shows that ASME method can be obtained from the special case of the simplified mechanical model of the proposed method. Typical geometries and loading are considered, and the proposed method is used to check the adequacy of design. Predictions are compared with the results obtained from axisymmetric finite element analysis (FEA) and current ASME method. Comparison results indicate that predictions given by this paper agree well with FEA while ASME results are not correct or not accurate. [ABSTRACT FROM AUTHOR]

In this paper, curved welded flange-plate beam-to-column connections are introduced and investigated analytically. The connection is comprised of two curved flange-plates installed on beam flange to transfer bending moment and two web angles for transmission of shear forces. Theoretical relationships are established for initial stiffness, ultimate moment, and ultimate rotation to be used for calibration of a bilinear model of moment-rotation. Furthermore, finite element analyses are conducted on eighteen specimens designed based upon the results of theoretical study. Analyses are in good agreement with theories verifying modeling procedure. Block shear rupture, tension rupture, and formation of three plastic hinges in semi-circular portion of the flange-plate are identified as the major failure modes. The failure due to formation of three plastic hinges in the flange-plate is suggested to govern the connection design, which leads to a ductile behavior. As a result, a flow chart is suggested to design the proposed connection. [ABSTRACT FROM AUTHOR]

The paper studied the stress-strain state of the discharge antivibration pipe of the flexible joint of piping systems from the effects of overpressure. The estimation of the distribution of contact forces and stresses in the fastening elements of the pipe shell and contact areas with metal flanges has been carried out. Newmark method was used in solving problems with geometric nonlinearity. [ABSTRACT FROM AUTHOR]

The simulating of the composite cylindrical shell of the antivibration pipe based on a study of stress-strain state caused with excess pressure was carried out. Contacting interaction of the pipe shall wall in the area bordering the metal flange was conducted. The conducted finite element analysis of the stress state of the composite shell reveals the most loaded areas which represent potential danger in terms of the destruction of rubber-cord array. [ABSTRACT FROM AUTHOR]

The technology HPDC (High Pressure Die Casting) of metals represents accurate casting which approximates the most ideal effort of direct change of basic material to finished product. The die casting itself is characterized by mechanical method of casting with the molten metal being forced-in under high pressure (specific pressure) into the divided metal mould by a plunger acting upon the melt in the filling chamber. The HPDC technology has in recent years achieved an expansive growth in the volume as well as the range of production and that is particularly in aviation and automobile industry. The presented paper deals with the experimental assessment of the impact of specific pressure on the mechanical properties of the alternator flange from EN AC 47100 in HPDC technology. [ABSTRACT FROM AUTHOR]

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Metal to Metal contact (MMC) bolted flange joint, which appears between gasket centering ring and flange facing, is widely used in nuclear and petrochemical industry for severe conditions. Compared to the floating type joints, the gasket outer metal ring is compressed after bolt-up and the stored energy can compensate the loss of residual gasket stress due to internal pressure, bending moment and creep, resulting in a low leakage. As it is difficult to assess the flanged joint integrity affected by creep analytically, a three-dimensional nonlinear finite element model is developed to highlight the creep behaviour of MMC flanged joint under different load cases at elevated temperature. The results show that MMC flanged joint can reduce the unloading effects due to creep and a suitable preload is recommended. [ABSTRACT FROM AUTHOR]

Joining of steel pipes and pipe flanges use today the conventional method of fusion welding, where the flange is girth-welded onto the pipe. However, fusion welding of flanges to pipes is associated with many disadvantages such as the final quality of the weld, degradation of the mechanical properties of the base pipe near the heat affected zone, defects and cracks appearing in the weld, misalignments, to mention a few. The current study proposes a novel pipe-flange connection to replace the fusion welding process of steel pipes with a method based on cold working. The method is based on that the steel pipe is inserted into the neck of the flange, in which two circumferential grooves are manufactured. An expansion tool having two teeth is entered from the open side of the connection and is expanded hydraulically such that the teeth deform the pipe and cold work it plastically into the grooves. This will provide a strong joint between the flange and pipe. In this study the performance of the connection is maximized by optimizing the design of the flange and the expansion tool. [ABSTRACT FROM AUTHOR]

The tightness of bolted flange connections is the important guarantee to meet the safety operation for a long period, the creep effect of gasket may affect the tightness of bolted flange connections under high temperature conditions due to its creep deformation. Considering the creep effect of metal flexible graphite composite gasket under high temperature, the deformation compatibility equation of bolted flange connection system was deduced. The time-dependence of flange rotation, the gasket deformation and the gasket contact stress were studied systematically. Moreover, the influencing factors of leakage rate were analyzed in detail. Finally, based on the theory of tightness, the safety assessment method due to leakage rate was constructed under high temperature. Results presented the gasket stress increases linearly from inside to outside and the gasket stress became lower and lower with the creep time extended. The time-dependent leakage rate of bolted flange connections was deduced, and the tightness assessment can be made conveniently according to the proposed method. [ABSTRACT FROM AUTHOR]

In a Metal-to-Metal Contact (MMC) bolted flange joint the stress of sealing surfaces is constant. It canwithstand higherbolt load. So, under the operating conditions of high temperature, high pressure or their fluctuations, the sealing effect of MMC bolted flange joints is better than of floating (FLT) bolted flange joints. According to the structure characteristics of MMC bolted flange joints, a new tightening method (SH-Method) was recommended in this work. The bolt forces during the tightening process of a MMC bolted flange joint with SH-Method were calculated and analyzed with the finite element analysis Software ANSYS. The calculating model and results were experimentally verified. Both calculating and experimentally results showed, the new tightening method ‘SH-Method’has the advantages of fewer steps, simpler operation, more uniform bolt force, and better sealing effect, compared to the star pattern and the alternative pattern #3 of ASME PCC-1, in which only the pattern methods for FLT flange joints are recommended. [ABSTRACT FROM AUTHOR]