多条表面裂纹相互作用的应力分析

STRESS ANALYSIS OF MULTIPLE SURFACE CRACKS WITH INTERACTIONS

  • 摘要: 脆性材料在热冲击载荷作用下,表面上经常会出现一些裂纹。含裂纹的构件可能会突然出现部分的或完全的失效。多条表面裂纹之间的相互作用通常会影响机械构件的寿命。该文采用迭加法研究了在热载荷下有限厚度的无限大板中N条中心对称分布的半圆形表面裂纹的相互作用问题:首先解析地求得板中不含裂纹时的应力分布;然后,根据叠加原理,有限元建模将反向等值载荷加在裂纹面上,从而得到问题的解。该文研究了多种裂纹构型下的应力强度因子,并以图的形式给出。

     

    Abstract: The existence of multiple surface cracks is a common problem in brittle materials under thermal shock loadings. Such structures have suffered sudden partial or total failure. The interaction of multiple surface cracks may affect the life-span of mechanical structures. In this paper, the thermal stress problem of an infinite plate of finite thickness containing multiple centrosymmetric semi-circular surface cracks normal to its face is investigated. The problem is resolved by using the superposition technique. The thermal stresses in the plate without the cracks are evaluated analytically. The perturbation problem for the cracked plate is modeled with the crack face tractions so as to negate the afore-mentioned thermo-elastic stresses through finite element method. Stress intensity factors of different crack configurations are obtained and illustrated.

     

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