层合板低速冲击损伤的数值模拟

Numerical Simulation of Low Velocity Impact Damage of Composite Laminates

为了分析复合材料层合板在冲击载荷作用下,层合板的损伤演化发展情况,结合采用单元失效技术和铺层刚度退化技术建立层合板低速冲击的三维有限元分析模型。在该模型中,当有限元模型中的单元发生某种冲击失效形式时,定义该单元发生部分失效,并将其刚度适当的退化。计算发现冲击背面容易产生基体开裂,并由此导致分层发生,而且靠近冲击背面的界面所产生的分层面积要较靠近冲击正面的界面的分层面积要大;随着冲击能量的增大,分层面积也增大;当冲击能量很高时,铺层内会出现纤维断裂,同时在层合板的边界处也容易出现损伤,计算结果和试验结果吻合。

Composite structures are susceptible to low velocity impact. To analyze the damage of composite laminated plate under low-velocity impact, a finite element analysis model （FEAM） is established in this study. In the FEAM, the element failure technique and material stiffness degradation technique are used. When there is damage within a finite element, the element is defined to have partially failed and the st iffness of the element is degraded. A laminated plate under low-velocity impact is analyzed with the FEAM. A good agreement between the numerical simulation and the experiment is achieved so the FEAM is effective for analyzing composite laminated plate under low-velocity impact. According to the results, we draw the following conclusions： （ 1 ） The FEAM is accurate in analyzing the delamination of laminated plate under low-velocity impact. （2） The delamination oceours usually between different oriented plies and has a characteristic peanut shape with its major axis oriented in the direction of the lower ply of the interface. （ 3 ） The damage of the plate becomes more and more serious from the top to the bottom. （4） There is energy threshold of laminate delamination. （5） There is a approximate linear relationship between delamination area and impact energy.