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Development of Polar Nonhomogeneous thermoelastic theory and its Application to Thermal Stress Analysis of Porous Functionally Graded Materials

极性非均匀热弹性理论的发展及其在多孔功能梯度材料热应力分析中的应用

基本信息

批准号：
06650079
负责人：
SUGANO Yoshihiro
金额：
$ 1.15万
依托单位：
Iwate University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

Based on an inference that reduction of thermal stress due to pores in functionally graded materials (FGMs) is produced by the presence of couple stress, a plane-strain thermoelastic problem with couple-stress was formulated for nonhomogeneous bodies using Mindlin's couple-stress theory. But analytical solutions to the governing differential equations were not obtained because of arbitrary nonhomogeneities with respect to thermal and mechanical properties of functionally graded materials and complexity of couple-stress theory. Then, in the present research, because of consideration on initiation of vertical cracks of ceramics 100% layr and spallation caused by linking-up of verticalcracks, an approximate three-dimensional analysis method was proposed for thermal stresses related to the initiation and linking-up of vertical cracks in a functionally graded material plate with temperature variation and nonhomogeneous properties only in the thickness direction. It was revealedthrough the a … More nalysis and numerical calculation for PSZ/SUS304 functionally graded plate that the reduction of tensile thermal stresses in the ceramic 100% layr on the heated surface is significantly dependent on composional distribution, and that ceramics-rich compositional distribution is very effective for the thermal stress recuction. Secondary, analytical solutions was obtained for temprature and thermal stresses in a functionally graded plate subjected to intermittent heating on its surface. The transient temperature field was derived from the solution for a transient heat conduction problem in the same functionally graded plate heated continually on its surface that is analyzed by Vodicka's method. Thermal stresses were analyzed based on Rogers and Spencer's solutions which were expressed in terms of the solution to the approximate, two-dimensional, thin-plate, governing equations for an equivalent homogeneous plate. Numerical calculations for the transient temperature and thermal stress distributions in PSZ/SUS304/PSZ functionally graded plate revealed effectiveness of ceramics-rich compositional distribution for the tensile thermal stress reduction on the heated surface during thermal-cycle loading. Less

基于偶应力的存在对功能梯度材料中孔隙热应力的降低起作用的推论，利用Mindlin偶应力理论建立了非均匀体的偶应力平面应变热弹性问题。但由于功能梯度材料的热、力学性质的任意非均匀性和偶应力理论的复杂性，控制微分方程的解析解一直没有得到。在此基础上，考虑到陶瓷100%分层垂直裂纹的萌生和垂直裂纹贯通引起的空间变形，提出了一种近似三维的分析方法，用于分析仅在厚度方向上具有温度变化和非均匀性能的功能梯度材料板中垂直裂纹萌生和贯通时的热应力。这是通过a ...更多信息通过对PSZ/SUS 304功能梯度板的分析和数值计算，发现加热表面100%陶瓷层的拉热应力的减小与成分分布有很大关系，而富陶瓷成分分布对热应力的减小非常有效。其次，得到了功能梯度板在间歇加热下的温度和热应力的解析解。通过求解表面连续加热的功能梯度板的瞬态热传导问题，利用Vodicka方法得到了其瞬态温度场。热应力分析的基础上罗杰斯和斯宾塞的解决方案表示的近似，二维，薄板，控制方程的等效均匀板的解决方案。对PSZ/SUS 304/PSZ功能梯度板瞬态温度场和热应力场的数值计算表明，在热循环加载过程中，富含陶瓷的成分分布对降低受热表面的拉伸热应力是有效的。少