Development of Supporting System of Design to Release Thermal Stresses in the Functionally Gradient Materials with a Crack

带裂纹功能梯度材料热应力释放设计支撑系统的开发

• 批准号: 03650081
• 负责人: NODA Naotake
• 金额: $ 1.41万
• 依托单位: Shizuoka 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: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03650081/
• 关键词: Elasticity; Thermal Stresses; Functionally Gradient Materials; Thermal shock; Nonhomogeneous body; Crack; Stress intensity Factor; Finite Element Method; 物性値の温度依存性; 斜傾機能材料; 不均貭

This research project consists of two parts : [I] Theoretical treatises of thermal stresses in the functionally gradient materials(FGMs), [II] Developments of programming system to release the thermal stresses in FGMs with a crack by Finite Element Methods(FEM).PART[I] Theoretical treatises of thermal stresses in the functionally gradient materials.(1) The governing equation of transient heat conduction for the functionally gradient materials is nonlinear. We could solve the nonlinear transient one dimensional heat conduction equation by use a new transformation of a variable and the perturbation method. The large tensile stress occurs on the ceramic surface of the functionally gradient plate at the earlier stage of cooling. But this large stress region is restricted within a very thin layr.(2) We could solve the steady and unsteady thermal stress problems of the FGMs with an internal crack whose all material properties are some exponential functions of a variable. When the Young's mod … More ulus and the coefficients of linear thermal expansion in the FGMs largely change, Stress intensity factors K_I and K_<II> vary drastically. If we can optimally select the composition of FGM such that the Young's modulus of ceramic in FGM is higher than that of metal, but the heat conductivity and the coefficients of linear thermal expansion are lower than that of metal, the stress intensity factors K_I and K_<II> decrease drastically.PART[II] Developments of programming system to release the thermal stresses in the FGMs with a crack by FEM.(1) We could develop programming system to release the thermal stresses in the FGMs with a crack by FEM.(2) From the results of calculation for the time variation of the stress intensity factor of the functionally gradient plate with an edge crack by FEM, we obtained the following results. A very large stress intensity factor K_I occurs on the ceramic surface. The region of the large stress intensity factor K_I is restricted within a very thin layr. A length of crack growth is restricted within a very thin layr. Less

本课题包括两部分内容：[1]功能梯度材料热应力的理论研究；[2]基于有限元方法的功能梯度材料裂纹热应力释放编程系统的开发。[1]功能梯度材料热应力的理论论述。(1)功能梯度材料的瞬态热传导控制方程是非线性的。采用一种新的变量变换和摄动法，求解了非线性瞬态一维热传导方程。在冷却前期，功能梯度板的陶瓷表面存在较大的拉应力。但是这个大的应力区域被限制在一个非常薄的层内。(2)可以求解含内裂纹的fgm材料的稳态和非稳态热应力问题，其所有材料性能均为某变量的指数函数。当杨氏模量较大，线性热膨胀系数变化较大时，应力强度因子K_I和K_<II>变化较大。如果能优化FGM的组成，使FGM中陶瓷的杨氏模量高于金属，而导热系数和线性热膨胀系数低于金属，则应力强度因子K_I和K_<II>显著降低。第二部分：基于有限元法求解含裂纹fgm内热应力的编程系统的开发。(1)利用有限元法可以开发编程系统来释放含裂纹fgm内的热应力。(2)通过有限元法计算带边裂纹的功能梯度板应力强度因子随时间的变化，得到如下结果：陶瓷表面存在很大的应力强度因子K_I。大应力强度因子K_I的区域被限制在一个很薄的层内。裂纹扩展的长度被限制在一个非常薄的层内。少

项目成果

N.Noda,Z.Jin: "Thermal Stress Intensity Factors for a Crack in a Strip of-Functionally Gradient Material" Int.J.Solids and Structures. 30. 1039-1056 (1993)

N.Noda，Z.Jin：“功能梯度材料条中裂纹的热应力强度因子”Int.J.Solids and Structures。

Z.Jin,N.Noda: "An Internal Crack Parallel to the Boundary of a Nonhomogeneous Half Plane under Thermal Loading" Int.J.Engineering Science. 31. 793-806 (1993)

Z.Jin，N.Noda：“热载荷下平行于非均匀半平面边界的内部裂纹”Int.J.Engineering Science。

T.Fuchiyama, N.Noda, T.Tsuji and Y.Obata: "Analysis of Thermal Stress and Stress Intensity Factor of Functionally Gradient Materials." Functionally Gradient Materials edited by J.B.Holt etc. The American Ceramic Society. 420-430 (1993)

T.Fuchiyama、N.Noda、T.Tsuji 和 Y.Obata：“功能梯度材料的热应力和应力强度因子分析”。

Fuchiyama,Noda: "Analysis of Thermal Stress and Stress Intensity Factor of Functionally Gradient Materials" Second Int. Symposium on Functionally Gradient Materials.

Fuchiyama、Noda：“功能梯度材料的热应力和应力强度因子的分析”第二届 Int.

野田 直剛: "Steady Thermal Stresses in an Infinite Nonhomogeneous Elastic Solid Containing a Crack" Journal of Thermal Stresses.

Naotake Noda：“含有裂纹的无限非均匀弹性固体中的稳定热应力”热应力杂志。