双复合材料结构基底厚度对薄膜裂纹的影响

针对薄膜-基体双复合材料结构的薄膜裂纹问题,研究了薄膜材料的力学行为,进行了裂纹垂直于薄膜与基底交界面,且尖端未达到交界面情形下问题的分析.基于Beuth理论,把模型简化为平面应变问题,并通过有限元分析程序评价了具有裂纹的薄膜-基底双复合材料结构的断裂机理,得到了薄膜与基底不同的弹性错配及薄膜与基底的不同的厚度比率,对薄膜裂纹应力强度因子的影响.结果表明:随着hs/hf的减小,应力强度有很大幅度的提高,当hs/hf≥10时,基底的厚度对薄膜裂纹的影响较小,可以忽略不计;当薄膜-基底结构退化为单一材料时,应力强度因数趋向于1.

Effect of substrate thickness of dual composite materials medium on film crack

This paper is focused on the study on a crack in the film oriented perpendicular to the film-substrate interface with the tip in the film.Based on Beuth's theory,this paper highlights the simplification of threedimensional model to plane strain problems and the evaluation of fracture mechanisms of a cracked film-substrate medium by designing universal program of finite element method.The stress intensity factor is affected by the different elastic mismatches and the thickness ratio between the film and the substrate.These results show that the stress intensity factor shows a remarkable increase with the decrease of the thickness ratio of film and the substrate.The effect of the fracture behavior of film is negligible when the thickness ratio of film and the substrate is 10;Stress intensity factor tends to 1 for the absence of any elastic mismatch between the film and the substrate.