纤维金属层板低速冲击试验和数值仿真

为开展纤维金属层板（FML）低速冲击有限元数值仿真研究，改进了传统的连续损伤力学（CDM）模型，然后对FML落锤低速冲击试验进行数值仿真，并与实验结果进行对比验证。分别采用5.11 J 和10.33 J冲击能量对FML进行落锤低速冲击试验，得到冲击载荷、位移和能量时程曲线，分析FML的动态响应和失效模式。建立了考虑塑性应变、压缩刚度衰减特征和纤维拉伸断裂损伤的新CDM模型，描述S2-玻璃纤维/环氧树脂（S2-galss/epoxy）复合材料的损伤本构，并编写VUMAT子程序，通过ABAQUS/Explicit求解器对FML落锤冲击试验进行数值仿真。研究结果表明：低能量冲击条件下，FML背面主要为鼓包和裂纹等失效模式，位移峰值随冲击能量的提高而增加，冲击载荷峰值在穿透前也随冲击能量的提高而增加；采用改进的CDM模型描述FML中S2-galss/epoxy复合材料铺层后，有限元数值计算可以较好地预测FML低速冲击载荷下的动态响应；有限元数值仿真结果表明，FML中第2层复合材料铺层发生的纤维断裂损伤比第1层的更严重。

Tests and numerical simulation on low velocity impact performance of fiber metal laminates

In order to investigate the low velocity impact performance of fiber metal laminates (FML) using the finite element numerical simulation method, a modified continuum damage mechanics (CDM) model was established and the numerical simulation of low velocity drop weight impact test on FML was conducted, the numerical simulation results were compared with the experimental results. The drop weight tests were performed with impact energies of 5.11 J and 10.33 J, respectively. The impact load, displacement and energy history for each test were obtained, thus the dynamic response and the damage pattern of FML were studied. Based on a continuum damage mechanics (CDM) model, the plastic deformation and compression stiffness attenuation of S2-glass/epoxy composite were supplemented as well as fiber tensile failure property, thus a new CDM model was established. The new CDM model was used to describe the constitutive and damage model of the S2-glass/epoxy composite in the FML, and was coded in user material subroutine (VUMAT). The numerical simulation of FML under drop weight impact test was then conducted through ABAQUS/Explicit solver. The results show that the main damage patterns on the rear surface of FML are bulging and cracking when impacted by low energy, and the peak displacement increases with increasing impact energy, while peak impact load increases with increasing impact energy before perforation. The dynamic response of FML is predicted well using finite element analysis when the S2-glass/epoxy composite layers are described by the modified CDM model. It is also found that the fiber tensile failure of the second composite layer is more serious than the first layer's through the finite element numerical simulation results.