密布多孔构件的低周疲劳寿命予测和试验研究

一、多孔构件应力场有限元分析　　为了计算多孔的涡轮叶片和燃烧室等构件的应力应变 ,我们编制和开发了壳体弹塑性有限元分析程序。用退化方法从三维单元推导出的曲壳单元。这种单元直接离散连续介质力学的三维方程 ,避免了由一般壳理论带来的复杂。曲面等参元具有独立的转角自由度和平移自由度 ,三维应力应变就退化为壳体情形。本文编制的这种退化壳单元程序还可进行各向异性材料的应力应变分析1 ] 。涡轮叶片因开有很多孔而使结构强度大大降低 ,由于孔间的相互影响 ,应力场相当复杂。我们用下列三种简化模型作计算分析。三种平板尺寸为 …

THE LOW-CYCLE-FATIGUE LIFE PREDICTION OF A MEMBER WITH HOLES

The stress and strain field and the low cycle fatigue life of a structure member with holes are calculated theoretically and investigated experimentally.The calculated results show that it is reliable to calculate the stress and strain field of a member with holes by using the shell structural elasto plastic finite element program,which has been designed and developed by the author.The satisfactory results are obtained from LCF life prediction of a member with holes by the advanced local stress and strain method.The calculation and tests show that the stress concentration of the tensile plane member is intensified and the fatigue life reduces drastically when its holes are densified in the direction perpendicular to that of tensile;the stress concentration is mitigated slightly but the fatigue life is also shortened when they are densified in the tensile direction.