Papers by Keyword: Stress Evaluation

Abstract: The mechanical and thermal response of elliptical head with multi-opening subjected to thermal loads, were carried out using ANSYS software. By dispersing the structure finite elements, the mechanical and fatigue behavior were discussed by APDL language following JB4732, and the result about stress evaluation and fatigue analysis are given, from the result, we can conclude that high first plus second stress and stress concentration may be formed at the intersection between center nozzle and elliptic, as well as between eccentric nozzle and elliptic. The structural discontinuity degree and temperature fluctuation has a big influence on stress concentration, as the most common, opening nozzle of a pressure vessel, the checking of dynamic and static of the structure, especially fatigue-checking are necessary.

Abstract: Stresses are induced in a bulk high-Tc superconductor (HTS) by field-cooled magnetization. The stress distributions of a hollow cylindrical bulk HTS are numerically studied in the axisymmetric three-dimensional analysis. Shielding current distributions are obtained through a macroscopic numerical simulation with the Maxwell equations and the critical state model. Stress distributions are obtained by using the finite-difference method and iterative calculations. Maximum hoop stress during the field-cooled magnetization is discussed for open and fixed boundary conditions.

Abstract: Temperature and thermo-mechanical coupling stress distributions of the electrical three-way valve body in a high pressure heater are investigated by using finite element method analysis. Maximum stress at the outer wall region of the valve body has exceed the allowable stress of the material is obtained. The weak place is improved by increasing the wall thickness and the stress meet the requirement of the allowable stress of the material after FEM analysis. And the thermo-mechanical coupling stress are classified and evaluated in the most dangerous section. The evaluation results show that the various types of stress all meet intensity requirements, which provide a guideline for the design and optimization of the high temperature and high pressure valve in the future.

Abstract: Measuring residual stray field (RMF) signals provides a promising tool to analyze the stress in ferromagnetic welded materials. In this paper, the variations of the normal component of the RMF, Hp(y), perpendicular to welded seam are measured. The finite element method is used to model residual stress in the specimen. The influence of residual stress on the Hp(y) component is shown. It is found that the distributions of the Hp(y) component are described by a Boltzmann fitting curve, show a good qualitative correlation with residual stress. A quantitative method for the evaluation of residual stress in ferromagnetic steels based on the gradient of the Hp(y) component and equivalent (vonMises) stress is presented.

Abstract: The constant reduction of production costs and the development of materials during recent years are favoured the development of Austempered Ductile Iron (ADI) because of favourable combination of technological and structural properties. The process of forging on ADI makes it possible to obtain final parts with good dimensions. Moreover, Austempered Ductile Iron has a remarkable workability. ADI has many advantages, including the possibility of modifying and of improving the mechanical characteristics by thermo mechanical treatments while preserving a relatively low production cost, thus competing with many categories of steels. The study presented relates to the influence of the parameters of the thermo mechanical treatments on the proportion of residual austenite allowing modification of the mechanical characteristics of the material and on the evaluation of the residual stresses.