显式有限元侵蚀接触搜索算法研究

侵蚀接触是弹体穿甲/侵彻等冲击动力学问题数值模拟与显式有限元程序的核心算法.文中基于接触界面的点-面离散模型，发展了一种有效、精确的侵蚀接触搜索算法.新算法通过引入历史状态量跟踪从点对主片的穿透历史，并结合接触强度方法，克服从点对主片穿透定义的歧义性，精确确定出从点-主片接触对及其相应的接触方向；对于接触点计算，建立了一种非迭代的计算方法，提高了接触计算的稳定性.文中算法基于自主研发的大型并行显式有限元程序PANDA-Impact实现，并利用典型算例进行了验证.数值模拟结果表明，文中建立的侵蚀接触搜索算法可以用于复杂问题模拟并具有较高的计算精度. 

Study on Erosion Contact Search Algorithms for Explicit Finite Element

An efficient and accurate erosion contact algorithm is essential for numerical simulation of impact dynamics problems, such as projectile perforation/penetration, high velocity contact, etc. Also,it is one of the most crucial algorithms of the explicit finite element code. In this paper one accurate and robust erosion contact searching algorithm was developed based on the node-to-segment discrete modeling. The ambiguity of contact between slave node and potential contacting master segments was resolved by introducing one history variable together with the contact strength conception. As a result, the slave node-master segment pair and the corresponding contact direction is determined accurately. In contact point computation, one kind of non-iterative algorithm was established, to improve the stability of erosion contact algorithm. All the algorithms were implemented based on explicit finite element code PANDA-Impact, and the effectiveness and robustness were verified by typical numerical examples. The simulation results show the proposed algorithms can be used to simulate complex engineering problems with high accuracy.