Papers by Keyword: Thermal Stress

Abstract: Titanium alloy is a premium metal with properties of low density, high hardness and resistance against high temperature and corrosion, the application of which has gained serious explorations in manufacture and military. Laser pulses of different power, duration and beam spot size are employed under room temperature to investigate the thermal stress variation of a titanium alloy plate with the aim of proposing ideal coefficients in laser processing of titanium alloy. The experiment was carried out as numeric simulations of thermal response and thermal dynamo coupling of the titanium alloy plate by using the COMSOL software.

Abstract: Based on the thermo elasticity theory, the stress of femur prosthesis system was analyzed using finite element method. An evaluation for the selection of prosthetic material was presented after discussing the thermo physical property of material which had an effect on the stress of femur prosthesis system. The results indicate that the interface failure is the primary failure form of the femoral prosthesis system and the interface failure is accelerated for the reason of the thermal effect. So the prosthesis with low coefficient of thermal expansion should be selected which can moderate the interface failure in the certain degree.

Abstract: Converter body is the core device in oxygen converter, the thermal stress is the major factor affecting the lifetime of the converter, ansys the stress level in different parts of the converter is essential to improve the converter life. This article using ANSYS software to analysis the converter thermal stress, analyze the converter thermal stress distribution in different parts. The results can provide theoretical basis for the converter design.

Abstract: Both thermal stress and load stress, which are caused by temperature change and traffic loading, are important parameters used in the analysis of the new asphalt pavement design. In order to study the stress of asphalt pavement of lean concrete base, first of all, threedimension finite element model of the asphalt pavement of lean concrete base is established. The main objectives of the paper are investigated. One is calculation for stress of asphalt surface, and the other is calculation for stress of lean concrete base. The results show that load stress of lean concrete base increases quickly with the increase of load. Thermal stress of lean concrete base increases with the increase of thickness of base. Asphalt surface is in the state of compression. Maximum shearing stress decreases with the increase of thickness of asphalt surface.

Abstract: Based on thermodynamic principles,this paper uses ANSYS to simulate thermal stress of the concrete piers and analyzes the main factors, namely, structure size, concrete strength, boundary conditions and freeze-thaw cycle system which affect thermal stress. We then draw the conclusion that the existence of thermal stress will make the concrete structure undertake cracking risk. Thermal stress difference in massive concrete structures is large and the influence of thermal stress on concrete structures is only limited to a certain size range; thermal stress inside the concrete increases with the increment of concrete strength grade; thermal stress inside the concrete decreases with the increment of boundary constraint conditions; the rate of change of thermal stress increases with the acceleration of freeze-thaw cycles. Meanwhile, we propose that through increasing the thickness of the protective layer and boundary constraint conditions properly, cracking risk of concrete structures can be reduced.

Abstract: In order to analysis thermal stress of mass concrete accurately, material properties of mass concrete are studied by numerical simulation method, and the equivalent age is introduced to describe the mechanical properties of concrete. The calculation models of concrete mechanical parameters are summarized, and then the calculation procedures are established on the basis of equivalent age. In this way, the temperature and temperature history are considered in these models. Meanwhile, the governing equation and computer program of the thermal stress based on the equivalent age are developed. The comparison of the numerical example using proposed method and conventional FEM method shows that the proposed method performs more adaptable and accurate.

Abstract: The multi-tower large basement structure is some different with general super-long structure in crack control due to thermal stress. Characteristics of thermal stress in the multi-tower large basement structure were analyzed. The effective crack control measures aiming at multi-tower large basement structure are put forward. Low grade of concrete is preferred. The maximum concrete shrinkage should be limited in bid document. Double-layer two-way reinforcements in upper plate should be increased according to stress value to ensure crack width. Setting groove in exterior walls of the basement, spacing 30~50 meters, can effectively reduce thermal stress. Covering on upper plate should be overlaid timely as long as bearing capacity of the structure meets requirements.

Abstract: The working condition of the spin-flash dryer agitating blade is complex, and influencing factors of the blade strength are quite more. In order to research its mechanical properties under the condition of transient high temperature, the analysis of thermal structure coupling field was performed. By the analysis of thermal stress and thermal deformation, the agitating blade would be designed well.

Abstract: A software code for simulating thermal stress in castings was developed using finite difference method (FDM). The one way coupled map model was adopted to treat the relationship between the solidification and the thermal stress in castings. A method of killing the mold element whose temperature begins to decrease was employed to deal with the mold/casting interaction. The thermal stress and deformation in a stress frame casting were experimentally studied and analyzed by this software code. The results simulated and the residual stress measured are in good agreement. This indicates that the software code is a useful tool for predicting thermal stress and deformation in castings. Therefore, it provides a scientific way to improve the casting dimensional accuracy and reduce the defects caused by thermal stress.

Abstract: In this theoretical study, based on Trescas yield criterion and its associated flow rule, the elastic deformation of a centrally heated compound cylinder with fixed ends is investigated analytically by taking into consideration not only the geometrical but also the material parameters such as yield strength, modulus of elasticity, Poissons ratio, thermal conductivity and coefficient of thermal expansion. These material parameters are assumed to be independent of the temperature. The compound cylinder is assumed to be very long such that axisymmetric condition exists. Both of the constituent materials of the two layers are supposed to be elastic-perfectly plastic materials. There is heat generation in the interior solid cylinder but no heat generation in the outer hollow cylinder. Both of the cylinders are assumed to be bounded perfectly at the interface. Elastic stress analysis is performed to prevent yield in the compound cylinder. Keywords: Compound cylinder, elastic stress analysis, thermal stress, yield strength.