界面裂纹问题中的通用权函数法  

Universal weighted function method for determining the stress intensity factors of interfacial cracks

作　　者：李龙[1] 吴化平[1] 鲍雨梅[1] 卢炎麟[1] 柴国钟[1] 

机构地区：[1]浙江工业大学特种装备制造与先进加工技术教育部/浙江省重点实验室,杭州310014

出　　处：《应用力学学报》2013年第2期173-178,299-300,共6页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(11002126;50975259);浙江省自然科学基金(Y6100425;Y1100108);浙江省教育厅项目(Y201018497)

摘　　要：热载荷和机械载荷共同作用下复合材料中的裂纹扩展往往发生在界面处。传统求解热冲击及机械载荷共同作用下界面裂纹尖端的应力强度因子的数值方法(如有限元、边界元法等),计算工作量大、效率低。通用权函数与时间无关,运用通用权函数法可以免除对每个时刻的应力分析,计算效率可得到很大提高。本文将通用权函数法推广到求解热载荷和机械载荷共同作用下界面裂纹尖端的应力强度因子过渡过程的问题中,推导出求解平面双材料界面裂纹问题应力强度因子的通用权函数法计算格式。基于此格式,计算热载荷和机械载荷共同作用下界面裂纹尖端的应力强度因子。通过实例计算比较,表明此方法得到的结果可以达到与相互作用积分法相当的工程应用精度。最后,应用此方法研究了热障涂层受热冲击及表面力共同作用时裂纹长度以及涂层厚度对应力强度因子的影响。结果表明:在一定边界条件下,当热障涂层中存在边缘裂纹时,随着涂层厚度的增加,更容易导致裂纹的扩展和涂层的剥落。Crack propagation in composites tends to occur at the interface when they withstand thermal and mechanical loadings.The traditional numerical methods such as finite element method and boundary element method for the determination of transient stress intensity factors of interfacial crack under mechanical and thermal loadings are inefficient due to large amount of calculation.The Universal Weight Function(UWF) is independent of time,which can avoid the repeated determinations of stress field for individual time instants and has an enhanced efficiency.In this paper the UWF method is extended to deal with the bi-material interfacial crack problems.The formulation of finite element implementation of UWF method is deduced and the transient stress intensity factors of interface crack of plane bi-materials is calculated based on the formulation.Numerical results obtained show that the UWF method is of good accuracy as the interaction integral method.The changes of stress intensity factors with thickness and crack length for thermal barrier coating under traction and thermal loading are also studied by using the UWF method.Results obtained reveal that,with the increase of coating thickness,it is more easily to cause crack propagation and eventually cause spalling of the coating for the thermal barrier coating contains edge cracks under certain boundary conditions.Results presented possess some significance for practical engineering applications.

关 键 词：界面裂纹 通用权函数法 应力强度因子 有限元法 

分 类 号：O346.1[理学—固体力学]