外载荷下带有界面裂纹的DLC薄膜应力响应研究

Finite Element Analysis of Mechanical Response of Diamond-Like Carbon Coatings on Stainless Steel Substrate

用有限元分析的方法,对受法向和切向联合载荷作用下的带界面裂纹类金刚石碳(DLC)膜力学响应进行了模拟研究。分析了薄膜厚度、裂纹长度和裂纹宽度对内部应力的影响。数值模拟结果表明:薄膜厚度对表面和界面处的应力有显著的影响;Mises等效应力的幅值和最大应力的位置对裂纹长度非常敏感,而对裂纹宽度的敏感度低。在一定的范围内(0<t/a<0.1),较厚的DLC薄膜有利于薄膜系统内部应力的改善。模拟结果能够为不同膜系中薄膜基体结合力的评价以及界面失效临界应力的预估提供参考。

The mechanical response,of the diamond-like-carbon（ DLC） coatings with cracks at the interface of DLC coating / substrate of stainless steel,to the superposed external normal and tangential forceswas approximated,modeled,and simulated in finite element method. The impact of the length and width of cracks,and DLC filmthicknesson the stress distributions at the interface and on the surfaces was investigated. The simulated results show that the thickness of DLC coatings significantly affects the stress distributions on the surface and at the interface,and that the magnitude and peak location of Von Mises stress strongly depend on the crack length,but rather weakly on the crack width. We found that in a certain range,（ 0 t / a 0. 1,where t stands for DLC coating thickness and a denotes half-width of Hertz contact）,a thicker DLC coating with interfacial cracks reduces the internal stress,improves the stress distribution,and decreases the probability of stress-induced interfacial failure. We suggest that the simulated results be of much technological interest.