镁合金无水化学转化膜表面裂纹行为的计算机模拟

Computer simulation of surface cracks behavior in anhydrous chemical conversion coatings on magnesium alloy

摘要:

在转化膜中,总是会出现许多均匀分布的表面裂纹。但是表面裂纹行为很少被研究到,这是由于在实际的测试条件下,裂纹很快就萌生完成了。在本文中,借助ABAQUS软件,采用有限元的研究方法实现无水化学转化膜表面微裂纹行为及内应力产生的计算机模拟,得到Mises应力分布、S11应力演变和应力-时间曲线。研究结果表明,转化膜在开裂过程中,内应力随着时间增加而增大,膜片中心处和裂纹边缘处的应力比其他地方都大然而中部区域的S11应力要比靠近边界区域的S11应力大。裂纹在转化膜膜片之间慢慢产生最终形成V型的裂纹。随着转化膜膜片收缩角度的不同,相互间的裂纹开口宽度也不相同。

Abstract:

In the conversion coatings, some uniformly distributed micro surface cracks always occur but the surface cracks behavior is rarely studied due to the frequent initiation in the real test conditions. In this work, computer simulation of micro surface cracks behavior and internal stresses generated in the anhydrous chemical conversion coating was carried out using the finite element method with the help of ABAQUS software. The Mises stress distribution, S11 stress variation, and the stress-time curves are obtained. The results show that the internal stresses generated in the conversion coating increased obviously with increasing time, and the stresses at the center and boundary of coating pieces are bigger than the ones in other areas while the S11 stresses around the center are bigger than the ones near the boundary. The cracks at the interface of coating pieces developed gradually and were as V-type cracks finally. The width of crack mouth opened was different since the contraction degree of each coating piece is different.