联合载荷下无裂纹DLC薄膜的内应力有限元分析

Finite Element Analysis of Internal Stress of Diamond-Like Carbon Films

本文用有限元分析的方法,对受法向和切向联合载荷作用下的无裂纹类金刚石(DLC)薄膜系统内部应力进行了模拟计算,分析了不同摩擦系数和膜厚比对于内部应力的影响,数值模拟结果表明:较大的摩擦系数可以使得界面处剪切应力和Mises等效应力以及y轴Mises等效应力显著增大,而对于界面处的y向压应力影响不是很大。在一定的范围内(0<t/a<0.1),DLC薄膜的厚度越大越有利于薄膜体系内部应力的改善。模拟结果能为不同膜系系统中涂层基底结合力的评价以及界面失效临界应力的预估提供参考。

The internal stress distributions of the fracture-less,diamond-like carbon（DLC） films,exerted by tangential and normal forces of the load,were calculated in finite element method（FEM） to evaluate the impacts of the film thickness and its friction coefficient on the internal stress.The simulated results show that the film thickness and its friction coefficient strongly affect the stress on the surface and at the interface of the film and substrate.For instance,the friction coefficient considerably influences the magnitude and peak positions of von Mises stress,indicating that as the friction coefficient increases,the tangential and Mises forces increase rapidly,whereas the normal force remains basically unchanged.An increase of the DLC film thickness considerably reduces the stress.We suggest that the simulated results be of much interest in evaluation of the interface adhesion,and the critical stress responsible for film peeling off.