模拟长纤维增强树脂层合板冲击损伤的数值方法

建立了一套模拟树脂层合板低速冲击下损伤过程的方法.该方法采用Mindlin板模型并考虑板的大变形,使用以前提出的一种修正的Newmark时间积分方案进行层板的动态分析,全面考虑了复合材料的脱层破坏、基体开裂和纤维断裂等破坏形式及其相互作用.还建立了一种适合于 Mindlin板的计算应变能释放率的方法;构造了一种连续的罚函数来动态加人弹簧约束以考虑脱层间的接触效应;证明了球板之间的冲击过程是刚性系统,应使用A（α）稳定的数值方法求解;实现了模拟过程中的自适应分析.使用所开发的软件NBHULI完成了长纤维增强碳/环氧复合材料层板在低速冲击下损伤过程的模拟,取得了一些重要的结果.

A NUMERICAL SIMULATION FOR IMPACT DAMAGE OF LONG-FIBER REINFORCED RESIN LAMINATES

A method for numerically simulation for impact damage process of composite laminates has been presented in this paper. The Mindlin plate with large deformation analysis and a modified Newmark time integration algorithm proposed by the author previously have been adopted here to analyze the dynamic response of laminated plates. Also, various damages including delamination, matrix cracking, fiber failure, etc., and their influences on each other have been studied. Moreover, in the present paper, a new technique to calculate the strain energy release rate for Mindlin plate model is proposed and dynamical spring constraints is employed to simulate the contact effect, which are added to the numerical model by a kind of continuous penalty function. We also proved that the impact process between a rigid ball and laminates is a stiff system, therefore a kind of A(a) stable method has been advocated here to solve the system equation of rigid ball, which is usually ill-conditioned. Finally, some techniques of adaptive analysis have been realized for improving the computational efficiency. Based on the proposed approach, we have developed a program, i.e. NBHULI and used it for the numerical simulation of damage process of long-fiber reinforced carbon/epoxy composite laminates under low velocity impact. The corresponding results in the numerical examples provided much valuable knowledge.