Papers by Keyword: Thermal Stress

Abstract: Basing on that skutterudites-based thermoelectric module may be applied to the vehicle exhaust power generation system, a multi-field of thermal mechanical-electrical coupled model was established and investigated by finite-element method. The thermal stresses, open circuit voltage, output power and conversion efficiency of thermoelectric module (TEM) are calculated and obtained. The service environment is simulated with the hot side temperature data obtained by experimental measurements. An independent tank is adopted on the cold side, to develop a temperature difference for electric producing, and then achieve the thermoelectric conversion. By analyzing the working properties of TEM, the mechanical properties and thermoelectric characteristics are also discussed, which provides guidance for TEM practical application.

Abstract: For the development of the crystal pulling process for 450 mm-diameter defect-free Si crystals, the impact of thermal stress on intrinsic point defect behavior during crystal growth is studied using extensive density functional theory calculations. The impact of thermal stress on the so-called Voronkov criterion and on void formation is clarified and compared with published experimental results.

Abstract: For solving the crack in crankshaft, laser cladding remanufacturing was involved. There were three key points about laser cladding remanufacturing discussed in this paper.The three key points included process flow , process environment and laser cladding materials selection . Using the ANSYS analysis software, the simulated analysis of the temperature field , stress field and the residual stress of the three kinds of cladding layer have been carried on, the best cladding materials for single-throw crankshaft crack of base material 45# is determined by studying the repaired results about Iron-based,Cobalt-based,Nickel-based self-fluxing alloy powder cladding materials.

Abstract: The tungsten fiber reinforced titanium composite (W/Ti) was produced by the spot welding method. This manufacturing method used only a simple spot welding system, and it did not need a vacuum chamber and a high temperature furnace such as existing common methods. The arranged tungsten fibers were held between titanium plates (thickness 0.5mm) and fixed by spot welding. Therefore, this W/Ti composite produced by spot welding did not join at all positions between the tungsten fiber and the titanium matrix because of the partial welding in the spot welding point. The coverage, a rate of welding area to the whole plate area, became 150% for the sample in this study, because it should make up for the partial welding by this method. From the microscopic observation in the cross section of the W/Ti composite, it was conformed the good jointing in the whole position between the tungsten fiber and the titanium matrix. ON the other hand, the alteration of thermal residual stress under the thermal cycling was measured by the in-situ x-ray stress measurement technique. These results were discussed from the viewpoint of the thermal expansion coefficient between fiber and matrix.

Abstract: In this study, the distribution of the thermal residual stresses due to the adhesive curing in elliptical and circular bonded composite repairs is analyzed using the finite element method. The computation of these stresses comprises all components of the structures: cracked plate, composite patch and adhesive layer. In addition, the influence of these residual stresses on the repair performance is highlighted by analyzing their effect on the stress intensity factor at the crack tip. The obtained results show that the normal thermal stresses in the plate and the patch are significant.. The presence of the thermal stresses increases the stress intensity factor at the crack tip which reduce the repair efficiency.

Abstract: Involute helical gears are widely used in high-speed and heavy-load transmission systems of automobiles, helicopters, etc. Poor working conditions lead to fatigue crack and other faults of gear key parts such as tooth face and tooth root. To identify the root causes of gear faults, strain monitoring methods are often used to monitor the stress changes of gear key parts so as to work out individualized improvement plans. However, stress of gears in the work process is typically the result of the coupling effect of thermal stress and mechanical stress. The existing strain monitoring methods cannot separate them effectively, and thus it is impractical to quickly find the corresponding improvement measures. To reveal the coupling relationship between thermal stress and mechanical stress during gear meshing and find out the source of gear faults, this paper uses the transient finite element-based analysis method to study the coupling relationship between thermal strain and mechanical strain of a pair of helical gears in the test direction and find the coupling rules of thermal strain and mechanical strain among the strains of gears in the strain test direction that may provide effective guidance for the fault diagnosis of gear meshing.

Abstract: The high temperatures induced during the welding process cause transient thermal stresses and non-continuous plastic strains around the weld. Uneven heating and cooling processes together with these plastic strains result in residual (welding) stresses, [1]. This paper deals with the development of plastic zones, related to welding stresses and their effects on the bearing capacity from a Civil-engineering perspective.

Abstract: This paper analyzed the deformation and stress of the glass substrate and the supporting columns in the vacuum plate glass in high-temperature sealing process with Ansys, which can forecast and guidance for the vacuum flat glass of high-temperature sealing. By performance test of vacuum plate glass after sealing, conclude the organizational structure of glass and welding agent junction is well. The vacuum plate glass of high temperature sealing has a good sealing performance.

Abstract: With the given the boundary and initial conditions, the analysis of internal thermal stress and mechanical stress field distribution was conducted on the special silicon carbide bricks for metallurgical furnace. By the simulation of ANSYS, the results show that a high temperature gradient and thermal stress in the special silicon carbide bricks, with great distortion of pipe within the bricks and a low level of mechanical stress, and the mutual offsetting between mechanical stress and thermal stress in some areas. Key words: metallurgy; new; silicon carbide; thermal stress; mechanical stress.

Abstract: In this presented work, a coupled thermo-mechanical model is employed to analyze the thermo-mechanical behavior of ceramic functionally graded materials (FGMs) and the crack formation and propagation process of ceramic coating was simulated step in step and step by step using the RFPA (Realistic Failure Process Analysis) ^2D-Thermo code. The thermal shock fracture behavior is discussed based on the basis of the simulated crack morphology and elucidated the mechanism of crack deformation and crack propagation. The state change from compression to tension whose magnitude is large enough to exceed the tension strength of ceramic causes the vertical crack. The numerical results agreed well with the experimental results in the previous literature.