摘要
本文采用非均匀等参有限元的方法研究了薄膜梯度涂层/均匀基材中的界面裂纹问题,并与双材料界面裂纹情况进行了对比计算。研究表明:在均匀基材上采用梯度涂层,与双材料相比可以有效地降低裂尖场应力强度因子;同时还分析了涂层厚度与梯度参数对界面应力强度因子的影响。结果表明:当薄膜厚度大于或等于裂纹长度时,应力强度因子(KI、KII)对其尺度的变化显得不敏感;对梯度参数的影响而言,当材料性能曲线的幂指数m大于1时,裂尖场的应力强度因子KII相对KI很小且基本不随m变化,因此裂尖场与均匀材料情况类似;当m小于1时,应力强度因子KII随m减小而急剧增大,裂尖场由KI及KII控制,断裂趋于混合型。
In the paper, an inhomogeneous isoparametric finite element method is employed to investigate an interfacial crack between the gradient coatings and homogeneous substrate, as well as that of bimaterials for comparison. It turns out that the stress intensity factors (SIFs) can be effectively reduced in the gradient coatings than in bimaterials. In addition, the influences of coatings?thickness and gradient parameter on the SIFs are also studied in detail. The results indicate that when the thickness of coatings is greater or equal to the length of crack, the SIFs are insensitive to the variation of coatings?thickness. Concerning the influence of the gradient parameter, for the power index m > 1, the SIF KII, which is very small as compared to KI, keeps virtually unchanged with variation of m, and the field near the crack-tip is similar to that of homogeneous materials. Whereas for m<1, the SIF KII is sharply increased with the decrease of m, and the crack-tip field is obviously governed by KI and KII, suggesting that the fracture is mixed mode.
出处
《工程力学》
EI
CSCD
北大核心
2002年第4期118-122,共5页
Engineering Mechanics
基金
国家自然科学基金项目(19772064)
关键词
梯度涂层材料
裂纹问题
非均匀元分析
应力强度因子
有限元
inhomogeneous isoparametric element
functionally gradient materials
interfacial crack
the stress intensity factors
