Search

The Optical Fiber-based communication system has established its proficiency and inevitability towards regular progress and advancement worldwide. The most attractive wavelength for optical fiber communication is 1.55 μm, as it represents the lowest loss. The other challenging parameter ‘Material Dispersion’ gets reduced to ‘Zero’ at 1.27 μm wavelengths for conventional pure silica-based Optical Fiber. To improve the system towards a better unification between the loss and dispersion, the Dispersion Shifted Fiber (DSF) has been introduced. The Dispersion Flattened Fiber has introduced the concept of flat dispersion over a wide range of wavelengths. But the effective combination of the mechanisms to compensate for all the challenges is yet to be established properly. The said mechanisms are complex to design and implement. So, there is an immense scope to search for an alternative to get control over the loss and dispersion. At present, a fair number of material compositions of optical fiber are reported with different specifications. Our study on some of these fiber compositions has produced some interesting data towards the broader flatness and the minimum dispersion effect over a considerable range of wavelengths around the Zero Material Dispersion Wavelength (ZMDW). It helps to have more effective wavelength division Multiplexing (WDM). In this paper, we have studied different prospective options of optical fiber doping profiles to explore and propose an effective and optimized alternative among the available fiber profiles. We have studied the samples of pure SiO2 fibers along with B2O3 and GeO2 doped fibers and samples of Fluoride-based ABCY and ZBLAN glass Fibers to propose an effective combination of materials among the available options to get the optimized conjugation of loss and dispersion. Our report on the comparative study of different fiber materials has produced some effective results to have minimum material dispersion at the lowest loss wavelength to invite worldwide attention from system designers.

The important characteristic in the creation of longitudinal splitting cracks in pretensioned concrete members has found to be the geometry of the pre-stressing wire indents. Longitudinal splitting along prestressing tendons can result in severe splitting of prestressed member in the field under loading over time. The research evaluated the influence of wire type indentation on the longitudinal splitting in prestressed concrete members fabricated with different concrete mixtures and different compressive strength of concrete. A key objective was to find the best type of wire to avoid failures in the field. A study was conducted at Kansas State University to understand the effect of wire type on the longitudinal splitting between prestressing steel and prestressed concrete. Three different types of wires will be presented in this paper denoted as “WB”, “WF” and “WQ”. The wires have different parameters which include indent depth, indent width, indent sidewall angle, indent pitch and indent volume.

The paper aims to report preliminary researches towards to development of new hybrid welding system by coupling a microwave beam with a TIG torch. The main research was focused on the designing of hybrid system as well as to establish the heating/welding mechanism by coupling two different thermal sources. Therefore, a specific welding chamber was designed taking into consideration the limitations provided by microwave waveguide technical specs, geometrical shape and dimensions of the TIG torch as well as the temperature monitoring during welding process and video surveillance for data recording. A microwave generator with adjustable power from 0 to 1250 W was coupled with a TIG torch and welding power source in order to establish the main parameters for hybrid system. The preliminary researches reported that the MW-TIG hybrid welding could be applied to eutectic joining of materials using low power (up to 600 W) injected from microwave generator as well as low welding current (up to 20 A). The flow of shielding gas have been established initially to 2 l/m. The research related to stabilization of MW-WIG plasma arc have been studied by increasing the flow of shielding gas up to 10 l/m. The results have shown that the microwave generator and TIG torch can be coupled to obtain hybrid-welding process without any matching tuning devices but with risks for damaging the microwave generator. Further researches will be done in order to design auxiliary devices to optimize the hybrid-welding process and to avoid any unwanted plasma arc discharge from welded base materials to microwave generator. In terms of temperature monitoring, an infrared pyrometer has been used. The IR pyrometer was targeted to the base materials in order to be able to measure their temperature without any influences from plasma arc. The results obtained have shown a stable plasma at average microwave power around 400 W even without any TIG current.

The paper presents a series of experimental researches performed using the design of experiments method RSD (Response Surface Design) for modeling and optimizing the welding process of PE 100 pipelines, used in natural gas distribution. In this sense, the aim was to analyze the influence of controllable factors such as pressure, temperature and time on the objective functions, aiming to obtain certain characteristics of the welded joint. By modeling the welding process, based on the results obtained, an optimal welding procedure was established and validated to meet the conditions imposed on the objective functions.

For the characteristics of the hammer handle is under bending stress and impact constantly alternating and the the main of the hammer is Withstand strong impact and friction in use，the paper designed a new type of composite casting process of hammerhead. It has two wear block imbedding in the below of the hammer ，and it set in on both sides of the axis of the hummer wiche with Inverted trapezoidal dovetail structure. The wear block was cast by high chromium cast iron, and it is properly heat treatment and surface cleaning before casting, but Into the mold after re-heated to temperature above 600 °C，At the same time，poured into the cast high-manganese steel quickly，so the block and hammer handle fused together，the block of composite hammer does not wear off in the use, and the wear resistance of the hummer improved significantly.

Evaluated with the yield of litsea cubeba essential oil, water extraction technology of essential oil from the seed of Litsea Cubeba (Lour.) Pers. assisted by microwave and ultrasonic is studied for the first time in this paper. The optimal water extraction technology of litsea cubeba essential oil assisted by pure microwave is as follows: extracting time 40 minutes, microwave power 650 W, solid-liquid ratio 1:4 (g/mL). Average yield of litsea cubeba essential oil is up to 10.287% (g/g) under the above optimal technology. The optimal water extraction technology of litsea cubeba essential oil assisted by microwave together with ultrasonic is as follows: extracting time 8 minutes, microwave power 600 W, solid-liquid ratio 1:7 (g/mL), extracting temperature 85 . Average yield of litsea cubeba essential oil is up to 14.188% under the above optimal technology. Microwave and ultrasonic can effectively enhance the extraction process of litsea cubeba essential oil.

This paper presents optimisation of hot press forming using design of experiment for high hardness properties at maximum cooling water temperature and minimum quenching time. Samples were boron steel blanks of 60x50 mm dimension. Hot press forming was conducted using a hydraulic press machine with 20 tonne maximum load. Results of this research work show that parameters obtained by single response optimization through desirability analysis route will increase hardness by 66.72%. The hardness properties of samples were between 477 and 551.4 HV(0.1). These findings were important to design tailored ultra-high strength automotive components at different process parameter settings and to reduce production cost consumption and improve production rate.

The requirement of the welding technology is very rigid in modern shipbuilding industry. This paper firstly analyzed the different forms of welding joints and grooves in detail, then described the function of NX-based welding technology. The difference of the features of Fillet Weld and that of Welding Joint were compared in the paper. Finally, a case was employed to explain the process of feature creation.

This paper contains results of tests performed in order to determine mechanical properties of steel P460NL1, used as filler material during the execution of welded joints. Arc welding of samples from which the specimens were taken was carried out through the application of welding process 111, because it is one of the processes for the execution of pipelines for pressure equipment. Microspecimens with diameter of Ø1,5 mm were tested in order to determine tensile properties of material taken from the heat-affected zone and weld metal, while specimens with diameter of Ø6 mm were tested in order to determine tensile properties of parent material. Standard Charpy V-notch specimens were used in order to determine impact energy. Results of metallographic tests which refer to the structure of a pipe welded joint are also presented.

The paper proposes the analysis of an alternative technology for manufacturing deodorant roll-on balls of polypropylene. With the current extrusion-blowing technology, the manufacturing of these balls results in an uneven wall thicknesses and a large technological runner of material that needs to be grinded and reintroduced into the injection equipment, which involves additional raw material and energy consumption.The proposed alternate method of manufacturing these balls (as spherical objects) is to form the ball from two ball halves joined together by infrared radiation welding. This process will result in significant savings in raw materials and energy.Further improvements of dimensional capabilities and control of welding parameters are required prior the transfer on high productivity manufacturing lines. Additionally, this technology can be assimilated into other applications where hollow balls of plastic are used.

This paper presents experiments regarding the welding with electron beam of multiple overlapping Ni-based amorphous ribbons produced by "Planar flow casting" method [1]. Welded samples were performed, using the electron beam welding equipment “Chamber Machine EBG 45-150 K14” [2]. The welded joints were analyzed by SEM, EDX, XRD in order to optimize some technological parameters to avoid deterioration of the amorphous ribbons during the welding process [3].

The paper proposes to present the results of the evaluation of glass fiber reinforced plastics (GFRP) used in the construction of wind turbine blades. In a wind turbine, the blades are the most exposed to damages and the defects which appear are various and are connected with the type of manufacture, simple/complex loading, environmental conditions etc. In order to increase the lifetime span and to analyze the degradation phenomena during the materials functioning, destructive evaluation tests are performed to determine the mechanical property, by testing pure shear on specimens Iosipescu, from GFRP with woven reinforcement at [± 45°] and [0°/90°], with the shear fixture, endowment of Technical University Gh.Asachi Iasi.

The results of impact testing of welded joint specimens taken from a welded plate made of P460NL1 steel are presented in this paper, and analysed with regards to the cooling time t8/5, that was previously calculated. The aim was to determine how the cooling times that were measured, some of which were below the minimum required values, affected the toughness, in terms of total impact energy and its components, crack initiation and crack propagation energy. In addition, this analysis included the effects of temperatures measured at the opposite ends of the plate during the welding process, since this had also affected the cooling times for each welding pass. After observing the differences in total, crack initiation and propagation energy between the tested specimens taken from different parts of the welded plate, it was determined that the specimens from the part where the higher temperatures were measured had shown better, more uniform results, whereas the average total impact energy for specimens from both groups were very similar. It was also noticed that the ratio of crack propagation to crack initiation was more favourable (greater) in the case of specimens from the second group (with higher temperature), as the values of crack initiation energy decreased slightly and the crack propagation energy increased.

The paper presents studies carried out in order to determine the causes of destruction, by cracking, of a crankshaft from the composition of a tractor used to process soil.Experiments were carried out in two directions, namely a step by step study on the degraded area and a investigation into the operating conditions of the machine, on that specific work cycle.The degraded shaft was investigated visually at a magnification of 10x and by hardness tests on the areas with embrittlement cracking.Hardness test enfolded large variations (in hardness), of up to 40%, leading to a high sensitivity to cracking by mechanical fatigue, induced by the structural tension concentrators. However, hardness examination did not reveal areas of shaft degradation due to fatigue, which determined us to study the operating conditions. The shaft cracking occurred during soil processing, using a multilayered plow and in difficult exploitation conditions.Variations of mechanical characteristics of soils in the area of ​​operation of the machine, is relatively large, fact which corroborated with the lack of safety elements when overloaded, of the endowment of the tractor-plow system, led to the overcoming of the permissible load, which on a background of high hardness material, determined the embrittlement cracking of the crankshaft. Research performed highlighted, for the area in which the machine activates, the necessity of introducing in the power-generating system of safety and protection elements to prevent the destruction of components.

A grapple is a device that includes at least one gripping arrangement. The gripping arrangement is configured to grip and traverse objects so as to reach a desired location on site and to anchor it, therefore allowing the work to be carried out. [1] A method for controlling the fill volume of a grapple, such as a bulk-material crane grapple which includes at least one hoist-and-closure unit, may include adjusting the fill volume of the grapple is during the grapple closure process by adjusting/controlling the grapple hoist height. The grapple hoist speed and/or grapple hoist height may be the controlling parameter for the adjustment of the fill volume of the grapple. [2]Grapples geometric configuration is established by calculating the useful load mass. In the experiments performed in the present paper the load mass was 3000 kg. In exploitation, in cases where relatively low density materials, if compared to standard materials, are being moved/processed, changes to the volume capacity must be done; [3] changes that need to be correlated with the new materials and the exploitation conditions.The tractor attachment is a grapple assembly, and the grapple assembly kit includes a mounting assembly, a plurality of clamping units, and a plurality of support units. [4] A connection system for coupling an claw to a work vehicle includes a receiver assembly that needs to be implement and configured to a connector assembly of an arm of the work vehicle. [5]The solution developed by the authors consists in prolonging and consolidating the active elements of the grapple, by equipping it with additional elements that take and process load tensions, in the present case hard wood logs; and a consolidation and protection system that protects it from wear, that mostly appears when the hook crane repeatedly hits the ground in order to collect the deposited logs.The additional elements for handling and processing logs are made out of low alloyed steel, thus by configuring the tips we assure the good gliding of processed materials on the active/used surfaces. The self-protection system to wear is made out of boron micro-alloyed steel sheets that have hardness values up to 500 HB. Joining the grapple ensemble with specialized elements was performed through welding.

The paper presents technologies for the manufacturing of modulated bi-metal elements, used as interchangeable reinforcement, according to patent RO129865. The bi-metal was developed by surface build-up of functional layers that have increased hardness, on a low alloyed steel substrate, so as to ensure maximum lifespan in exploitation. Welded layers deposited on active areas has a thickness of 3 mm and have high hardness (about 50-60 HRC) in order to ensure a good resistance to wear by abrasion, possibly combined with fatigue, erosion or corrosion. The modulated elements sizes are equal to or higher than the wear additions, up to 10%, being dimensioned on the principles of preventive-repetitive maintenance. The interchangeable bi-metal elements are welded on the steel components of machines, used for hot or cold processing of parts and semi-finished products manufactured in series.

Aim of this paper is to present a numerical method for modeling of the so-called “equivalent box section fiber beam concrete element”. By comparing hysteresis curves of specimen of the concrete structure plotted with rebar beam with those plotted with the equivalent box section beam under a set of loading cases, the following conclusions are obtained: 1) The modeling technology of equivalent box section beam can overcome the difficulty which the rebar in beam can only be used in static calculation, and the fiber beam element can be applied to dynamic explicit analysis; 2) By comparing hysteresis curves which are plotted by the rebar beam with those obtained with model of equivalent box section beam, it is found that results are in good agreement for a specific typical loading case; 3) By comparing hysteresis curves of the equivalent box section beam with experimental data under given loading case, numerical results indicate that numerical results obtained with proposed modeling technology can fit the experiment phenomena very well.

In this paper is presented a study regarding the possibilities of commandinga virtual robot using a haptic interface. In order to demonstrate the functionality of this concept, a dedicated device with 1 DOF was developed. This device consists of twin motor-gearbox able to acquire and transmit the angular data of the shaft and return a haptic feedback corresponding to the robot movement. The proposed haptic device makes it possible to command one joint of an industrial robot and can be used as an essential component for the development of an exoskeleton for human arm and is able to generate a haptic interaction for all the joints. The exoskeleton solution will allow a structural similarity between the haptic device and an articulated robot arm. The test results with haptic feedback scenarios show that the proposed system can help inexperienced users to handle robot operation and programming tasks in an intuitive way.

With the example of the parametric CAD system of the rolling bearing, the parametric design method to the second development of the AutoCAD system based on VB by using extra database is introduced in this paper. This system can visit the extra database by ADO technique, complete the total design of the system, create the system database, realize the parametric design and parametric drawing.

The papers aim is to detail temper bead realization, as a possible solution to the removal of heat treatments. Applying temper beads could be a solution for repair, in case surface heat treatments are required, provided they are correctly applied. The paper presents the main ways of applying temper beads, presenting in the same time what the outcomes could be in case of not respecting the prescribed work sequence.

The paper will try to evidence the importance and the role of the Welded Structural Designer and explain also the critical joints to the dynamically loaded welded structures susceptible to fatigue. In case of the important structures the decision of the Welded Structural Designer is essential, because his decision allows the change the type of joints, the type of materials.

Turbine and generator rotors and shafts undergo high stresses during regular working life and, from a safety and operational aspect, are the most significant components of a power generation system. Depending on the appropriate operating conditions, like temperature and/or corrosion the, shafts can be fabricated out of low/high alloy heat resistance material or of low alloyed, highly toughened material for different application. Despite known good practice and developed operation procedures, the failures of shafts sometimes occur. The right and well-defined failure analysis is the basis for feasibility analysis of repair method in the power generating industry. The analysis of direct and indirect costs of repair after the failure analysis as well as the analysis of the repair and post-repair conditions of the repaired element is the vital for decision on the key question. Is it possible to repair this element and what is the optimal repair strategy? This paper compares and analyses two approaches, by weldability analysis and weld cycle simulation, in order to determine welding feasibility analysis of cracked hydro turbine shafts.

We approached a new hybrid technology that integrates ultrasonic energy with FSW welding. By integrating ultrasound in the FSW process, a number of benefits are expected in terms of welding quality, forces and tool life. Our research aimed at developing a new technique of friction stir welding assisted by ultrasonic energy, namely FSW-US, which can improve the process, it can contribute to the decrease of forces that develop during the welding process and can increase the quality of welded joints. Metal welding and processing technologies that use ultrasonic vibrations, either as a primary source to achieve prescribed performance, or as a source of assistance to improve the efficiency of the operation and product quality, are currently being researched or discussed in the international scientific environment. The present paper analyzes the effects of overlapping ultrasonic vibrations with heat generation, temperature distribution and material flow generated by applying the FSW process. Mechanical effect plays a dominant role in the welding process assisted by ultrasonic vibrations, while thermal effects are insignificant. Overlapping ultrasonic vibrations on the friction stir welding process can produce a stream of improved plasticized material, increases the welding speed and efficiency, it can also improve weld quality by increasing the flow / volume of plastic material around the tool. [1]

This paper presents experiments regarding the welding with electron beam of Ni based amorphous ribbons produced by "Planar flow casting" method with the aid of "Politehnica" University of Timisoara equipment. Welded samples were performed in partnership with Graz University of Technology, Institute of Materials Science, Joining and Forming, using the electron beam welding equipment “Chamber Machine EBG 45-150 K14”. The welded joints were analyzed by SEM, EDX, XRD in order to optimize some technological parameters to avoid deterioration of the amorphous ribbons during the welding process.

The paper presents the characteristics of TiO2 coatings realized by HVOF spraying process by two different processing paths, i.e. using the classical method of preparing the substrate by sandblasting and by applying a fast laser texturing of the substrate (instead of sandblasting) before the actual HVOF spraying respectively (a duplex treatment). The obtained coatings’ morphology were characterized by SEM before and after electrochemical measurements in NaCl solution. The textured sample presented better resistance to corrosion compared with classical processing path. Keywords: coatings, fast laser texturing, HVOF spraying, duplex surface treatment, anticorrosive.

This paper presents a summary of a live demonstration for a numerical simulation of laser welding process using Ansys Workbench platform. The main steps of this simulation are: creating the geometric model, mesh generation, defining contacts, applying initial conditions and boundary conditions, defining thermal loads, general setting and solving the transient thermal analysis and finally the coupling of this analysis with a structural one to predict stresses due to the thermal field generated by the thermal analysis. After solving, the results are visualized and interpreted.

The paper presents representative aspects of the blades and the characterisation of excavator blades, namely frontal loader in the quall resistance to wear version. In exploitation the active surfaces of the blades are subjected to wear through abrasion under high and medium pressure, combined with mechanical fatigue with variable cycles. Retiring the blades is determined by significant degradation of the side zones. The solution developed in order to confront the mentioned phenomena is of modular type, namely equipping the blades with intelligent protection and self-protection systems to wear, which are deposited by cladding with welding on the supports. The blades support is made out of low alloyed steel, which have a controlled hardness and are micro alloyed with boron. The rods used to develop the wear protection systems are type Fe-25%Cr-4%W-Ti-V-La which deposit layers that have a minimum hardness of 55HRC. The challenges solved are related to welding compatibility, in working conditions, of the base materials and the welding ones, through manual electric welding procedure and respective deformation due to residual tensions in the welded structure.

The paper presents the concept of designing active hammer edges of horizontal mills for grinding tungsten carbide waste by making composite layers deposited by welding. The new generation of hammers is carried out on the principles of preventive and repetitive maintenance, by endowment with wear addition, predetermined as volume and geometric configuration, depending on the specific conditions of uninterrupted use for a period of time established for economic reasons. The main demands that affect the integrity of the active areas of grinding mills (high pressure abrasion wear, thermo-mechanical fatigue) generate both material losses and output from working rates, as well as excessive elongation of the support elements under the combined action of centripetal force and of the pressure exerted by the ground load. Under these conditions, the technically and economically optimized solution is to design the modular active elements in the form of easily assembled detachable components, made of a low alloy steel with average tear resistance (450-600MPa) on which we deposit by welding layers of composite austenitic steel, hardened by compression, so as to increase the lifetime of the hammers by up to 35% compared to the present solution, which can be upgraded up to 3 times for reuse.

The objective of the paper is to present the newest results of our complex research work. In order to determination and comparison of the fatigue resistance, fatigue crack growth tests were performed on different grades of S690QL quenched and tempered, and S960TM thermomechanically rolled high strength steels.15 mmand30 mmthick base materials were used for our investigations. Welded joints were made from these base materials, using gas metal arc welding with matching, overmatching, and undermatching filler metals. In the paper, the performance of the welding experiments will be presented, especially with the difficulties of the filler material selection; along with the results of the fatigue crack growth examinations executed on the base materials and its welded joints. Statistical aspects were applied both for the presenting of the possible locations of the cracks in the base materials and the welded joints and for the processing of the measured data. Furthermore, the results will be compared with each other, and the possibility of derivation of fatigue crack propagation limit curves will be referred.

Within the WELLFORMED research project, ongoing at the CEMSIG Research Center of the Politehnica University of Timisoara, a new technological solution was proposed for built-up beams made of corrugated steel sheets for the web and thin-walled cold-formed steel profiles for the flanges, connected by spot welding. The research project integrates an extensive experimental program on such beams, using full scale specimens, to demonstrate the feasibility of the proposed solutions and to assess their performance, followed by numerical simulations to characterize and optimize the connecting details. The present paper presents the results of a large experimental program, on small specimens subjected to shear, consisting of two or three layers of steel sheet connected by spot welding.

This paper describes a curved-layer additive manufacturing technology that has the potential to print plastic components with integral conductive polymer electronic circuits. Researchers at AUT University in New Zealand and the National University of Singapore have developed a novel Fused Deposition Modeling (FDM) process in which the layers of material that make up the part are deposited as curved layers instead of the conventional flat layers. This technology opens up possibilities of building curved plastic parts that have conductive electronic tracks and components printed as an integral part of the plastic component, thereby eliminating printed circuit boards and wiring. It is not possible to do this with existing flat-layer additive manufacturing technologies as the continuity of a circuit could be interrupted between the layers. With curved-layer fused deposition modeling (CLFDM) this problem is removed as continuous filaments in 3 dimensions can be produced, allowing for continuous conductive circuits.

A flux switching permanent magnet (FSPM) machine has the advantage of high power density, high torque density, inherently sinusoidal back EMF, stable structure, and the disadvantage of magnetic field uncontrollable. This paper proposes a novel axial-flux hybrid excitation flux-switching (AFHEFS) motor, which offers three phase symmetrical sinusoidal flux linkage and linearly regulated electromagnetic torque as well as excellent flux regulation capability and even field elimination ability with a size ratio of 1:2 between PM stator and electrical stator. The results are validated by 3D finite element (FE) analysis.

The uniformity of thickness of insulation layer on communication cable is an important technique index to guarantee the communication cable has good mechanical and physical properties. Therefore the control method for uniformity of insulation layer on communication cable is desiderated to be researched. In this paper, a control system which took two laser displacement sensors as a detection unit, a CS1G-H PLC of OMRON as a central control unit, two servo drivers and two servo motors of the SMARTSTEP-A series of OMRON as a servo system, a touch screen as a man-machine interface and applied PID and PDFF control algorithms was designed. The system was proved that the operation was reliable and the desired requirements could be achieved based on laboratory simulation and debugging.

This paper deals with the use of waste materials from processing of stone in the construction industry. The tested mixtures consisted of Portland cement CEM I 42.5 R, micronized waste marble powder and crushed waste limestone. The article examines the effect of varying the amount of waste on the mechanical properties of the cement composite. At first, samples were tested non-destructively for determine the dynamic modulus of elasticity and then were tested destructively for determine tensile bending and compressive strength.

This paper is concerned with the selected aspects, which are discovered during a design stage of cable and membrane structures, known as “form-finding” process. The aim of this paper is the understanding of the basic principles of the form-finding process and their explanation of the very simple examples. The use of the finding a shape of a tension membrane that is in static equilibrium as an analogy with the search condition of minimal surfaces is explained. The basic principles are demonstrated on simple 2D example, in which the finding a stable minimal surface passes in the finding a stable minimal length.

The contribution of this paper is to provide the effect of chemical composition on both cost and mechanical properties for steel used to wind turbine tower. Each chemical element has been chosen to contribute to the desired final properties. After establishing the chemical composition has been set up metallurgical route. To determine the influence of chemical composition and thermomechanical treatments a series of experimental tests were conducted to evaluate the structure and mechanical properties. A detail analysis involving macroscopic feature and microstructure analysis of the microalloyed steel was also performed by optical microscopy (OM).The mechanical properties were evaluated by tensile test and Charpy V-Notch test. The experimental tests and analysis results show that there are significant improved in the material properties of thick steel plates when comparing it with the Standard, EN10025/3-2004.

The paper addresses the development of advanced welding technologies with two and three solid wires for joining of HSLA API-5l X70 (High-strength low-alloy) steel plates with thickness of 19.1 mm. The experiments were performed using a multi-wire Submerged Arc Welding (SAW) system that was developed for welding of steels with solid, tubular and cold wires, in different combinations. The main goal of the research was to assess the mechanical performances of the welded joints achieved by multi-wire SAW technology and then to compare them with the single wire variant, as reference system. The welded samples were firstly subjected to NDT control by examinations with liquid penetrant, magnetic particle, ultrasonic and gamma radiation, with the aim of detecting the specimens with flaws and afterwards to reconsider and redesign the corresponding Welding Procedure Specifications (WPS). The defect-free welded samples were subjected to tensile, Charpy V-notch impact and bending testing in order to analyse and report the mechanical behaviour of API-5l X70 steel during multi-wire SAW process. The experimental results were processed and comparatively discussed. The challenge of the investigation was to find the appropriate welding technology which responds simultaneously to the criteria of quality and productivity. Further research on metallurgical behaviour of the base material will be developed, in order to conclude the complete image of the SAW process effects and to understand how the multi-wire technologies affect the mechanical and metallurgical characteristics of the API-5L X70 steel used in pipelines fabrication.

The development of welding technologies and techniques used for advanced materials joining should be closely linked with the design and development of equipment and also with the expectations of end-users involved in the cutting-edge manufacturing engineering. In order to reach this objective, the researchers, developers and producers should work together for designing new welding processes, technologies and equipment that meet the requirements of productivity and cost-effective manufacturing processes. Combining the multiple-arc & multi-process welding solutions, the system presented in this paper was designed to perform longitudinal butt and fillet welds of high-strength low-alloy (HSLA) steels plates of medium and large thickness, frequently encountered in shipbuilding, oil and gas onshore and offshore industries. The welding system can be easily used for achieving long seams specific to complex ship blocks or sections, pipelines sections, beams, girders and stringers for railway wagons. Based on the modularity concept, the architecture of this innovative welding system was designed as a structure of multiple interchangeable slides, used for positioning and assembling the welding heads typical for gas metal arc welding, submerged arc welding and Laser welding processes. Due to its versatility, adaptability and functionality, the system allows end-users to select the suitable combination of welding processes, in order to obtain butt and fillet HSLA steels welded joints. By controlling and monitoring the process parameters in real time, significant advantages such as weld geometry, high deposition rate and high penetration and, consequently, improved productivity, controlled cooling rate and, hence, reduced stress and strain are achieved. Due to its modularity and versatility, the system can be successfully used in different industrial applications, in several combinations of GMAW, SAW and LASER-hybrid welding processes, for joining of similar and dissimilar materials.

The objective of this research work was to study the influence of the iron oxide phase resulted during steam oxidation of the sintered steels specimens obtained by powder metallurgy (P/M) route. Steam oxidation is a surface treatment applied to sintered iron parts, as an economic way to reduce the interconnected pores. In powder metallurgy products, the networks of pores are specific, who can be stress concentraions and can produce cracks in material. By steam oxidation treatment the interconnected porosity is closed by sealing them with iron oxides phases. Also, other properties of sintered PM steels are improved. The specimens analyzed in this paper were produced from atomised iron powders, compacted at room temperature at pressures of 600 MPa, sintered for 120 minutes at 1150o C in a laboratory furnace and then subjected to a continuous steam oxidation at 550o C for 60 minutes. Investigations on the structural, mechanical and abrasive wear properties were performed. The microstructure and the pore morphology of the sintered and steam oxidation samples were studied on using optical microscope.

The paper presents the experimental results on the surface quenching by CO2 continuous wave laser action of solid phase steel with 1%C obtained, using different absorptive (ZnO, TiO2, ZrO2, graphite) powder coatings. The absorptivity of these coatings was determined by resolving the thermal conductivity equation for the irradiation with an energy punctual source on the massive body. Among the four investigated powders, for thermal treatment with laser of tools carbon steel it is recommend the powder of zinc oxide as coating with most efficient absorption capacity.

Magnetorheological elastomers (MREs) are a kind of smart materials, which change the mechanical properties (viscoelastic characteristics) under the magnetic field action. In the paper the determination of damping properties (reactive force) of specimens made out of magnetorheological elastomers is presented. The specimens made out of MREs have been fabricated as a composite with matrix made out of silicone rubber with certain contents of magnetisable particles (carbonyl iron powder). The cylindrical specimens have been tested in compression loading, controlled by an electro-mechanic system. The MRE characteristics of the specimens have been determined in the presence of a magnetic field produced with an electromagnet (coil device). The reactive force occurring in the MRE specimen has been determined on the basis of the measured data during loading. The variation curves of the reactive force versus magnetic field induction are drawn. As a conclusion, the rigidity of the MRE specimen is increasing since the magnitude of the magnetic field induction is increasing.

Carbon fiber reinforced silicon carbide composite (Cf/SiC) is the new high temperature ceramic composite developed in recent years, widely used in the aviation, aerospace and other high-tech fields. In this paper, a variety of joining methods of Cf/SiC composite to metallic materials, including active filler brazing, solid phase diffusion welding, liquid infiltration joining, as well as chemical vapor deposition of niobium transition joining technology were introduced. At the same time, the features and disadvantages of each technique were evaluated. This review is intended to provide a comprehensive guide to the design and application of Cf/SiC composite joining to metals.

This paper studies how the addition of Carbon nanotubes (CNT) influencing the properties, especially the mechanical properties and colorimetry of ethylene propylene diene rubber (EPDM)/SiO2 composites. The results show that the increased content of CNT can turn EPDM/SiO2 composites from lighter, redder, and yellower to darker, greener and bluer, respectively. The total color change (ΔE) of EPDM/SiO2 composites would be acceptable when the CNT content is below 3%. When the CNTs content reaches 4%, the tensile strength of EPDM is the maximum.

In order to study the influence of different types of weld defects, such as slag inclusion, porosity, incomplete fusion, incomplete fusion, burn through, crack on the mechanical performance of X65 marine pipe welding joint (Φ323.9 x 16 mm), the test on the mechanical properties of static tensile, fracture toughness CTOD and fatigue life were carried out to achieve the maximal defect tolerance size allowed in this paper. Research shows that the existence of crack defects would significantly reduce the fracture strength and the fatigue life of welded joint, the application of the maximal defect tolerance size allowed based on crack defects assessment can provide referential basis for the safe and stable operation of marine pipelines.

The use crowd of escalators involves a wide range of people. Therefore, the safety research of escalator is concerned and should be pay more attention to continuously. In the present paper, the multiple material damage modes of escalator drive chain were analyzed. The material damage modes mainly contain the micro cracking, the wear damage and the decarburization defect. The tensile tests and friction&wear experiments were performed to investigate the influence of the material damage modes on the performance of the escalator drive chains in service. The tensile properties of the new drive chains without material damages were superior to those with decarburization defect and wear damage. The friction&wear experimental results indicated that the decarburization defects reduced the wear resistance of the escalator drive chain. The research results implied that the strict quality control and improved maintenance of the escalator drive chain was meaningful for the escalator using security.

A new method to estimate the Doppler and multipath time delay is presented in impulse noise environment. First, the Doppler is estimated by energy cumulation of multipath component based on fractional lower-order-frational correlation transform. Then, an order-reduced signal is reconstructed combining the Doppler with the prior knowledge of the transmitted signal, and the echoes signal is converted to many single-frequency signals. Finally, the multipath time delay is obtained by the fractional lower-order power spectrum method. The method is adapted for low SNR noise, can restrain the affection of the cross-items, and has a high time-delay estimation resolution. Some computer simulations are given in this paper and the results show that the new method is valid.

In this paper, an innovative approach for contact zone analysis of skive hobbing is presented. This process is characterised by varying tool engagements and very small chip thicknesses. The paper describes the process-modelling and the analysis of the workpiece-tool contact. For efficient modelling, a novel dexel-based method for the description of a gear segment with discretized stock allowance is presented. Characteristic for the method is an analytical description of the target workpiece contour which allows to describe points of the surface by Cartesian coordinates on the winding off. On this workpiece contour, dexel are modelled in surface-orthogonal direction. The initial lengths of these dexel describe the stock allowance. By cutting these dexel with a tool, a time-and position-dependent prediction of material removal values, like width of undeformed chip, undeformed chip thickness or cutting directions can be obtained. Selected results are presented and interpreted.

The transition towards renewable energy implicates more decentralized and time-dependent ways of energy generation. In order to deal with the resulting fluctuation in energy supply, local storage systems are necessary. Larger systems may consist of thousands of battery cells. Therefore, the reliable interconnection between the individual battery cells is the basic prerequisite for the production of these systems. It has been demonstrated that laser beam welding is a suitable process for the contacting of batteries. However, due to the high requirements regarding the heat input and the reproducibility of the joining process, further investigations are necessary. Within this work, experiments on pulsed laser beam welding of nickel-plated DC04 steel were conducted. Four different pulsed welding strategies were analyzed in a preliminary study in order to develop a method for obtaining suitable process parameters while reducing the amount of free parameters. Subsequently, a comparative study between the rectangular pulse, the shaped pulse, the spike pulse and the sloping pulse was carried out. The weld seam properties as well as the electrical and the mechanical properties of the connection joints were evaluated. The results presented in this paper indicate a high eligibility of pulsed laser beam welding as a joining process for the connection of battery cells. For all analyzed pulsed welding strategies a homogeneous weld seam without full penetration was observed. Similar electrical resistances for all strategies were measured despite the comparatively small total joint area for the discretely pulsed weld seams.

Due date reliability is a critical competitive factor for manufacturing companies and hence a central objective in logistics. Nonetheless, many businesses are unable to meet their own schedule reliability standards. The reasons for the insufficient achievement of logistical targets are inherent in the diverse and interdependent influential factors that affect schedule reliability. However, logistical models enable to determine these interdependencies. This paper introduces the operating curves of output lateness of a single workstation for various sequencing methods. The parameter studies comprise the preliminary work necessary to provide a complete, model-based description of production schedule deviations.

Autonomous control is a promising approach to cope with increasing dynamics in production environments. However, an important issue for the acceptance of autonomous control is the provision of a sufficient planning accuracy, e.g., regarding order sequences or workstation assignments. Therefore, transferring autonomous control into practical application requires the coupling of autonomous control with commonly used central planning methods. This paper introduces coupling strategies with different degrees of planning adherence. The introduced strategies are applied to the example of a job shop environment based on real data. The simulation-based comparison considers performance indicators concerning the logistic performance and planning adherence. Besides varying the level of dynamic influences, the simulation study also analyses the impact of different method combinations onto the coupled methods’ performance.