Xu Wenjun, Liu Longquan, Xu Wu
Laboratory of Aircraft Structure and Strength, Shanghai Jiao Tong University, Shanghai 20024, China.
Polymers (Basel). 2022 Apr 25;14(9):1744. doi: 10.3390/polym14091744.
Composites are widely used in aircraft structures that have free edges and are vulnerable to impact events during manufacturing and maintenance. On-edge impact may have a great contribution in terms of the compression strength loss of composites, but the influence remains unclear. This paper presents experiments and simulations of carbon-fiber-reinforced plastic (CFRP) materials with on-edge impact and compression after edge impact (CAEI). On-edge impact damage was introduced to the composite laminates through the drop weight method with 4, 6, 8 and 10 J impact energies, respectively. A special guide-rail-type fixture was used in the compression tests in which strain-force and load-displacement relationships were obtained. A continuous-step finite element model was proposed to simulate impact and compression. Continuum shell elements and Hashin failure criteria were used to simulate in-ply damage, and interlaminar damage was modelled by cohesive elements. The model was validated by correlating the experimental and numerical results. The investigation results revealed the relationships of the damage size and residual strength with the different impact energies. The crack length and delaminated area grow with the increase in impact energy. The residual compressive strength follows a downward trend with increasing impact energy.
复合材料广泛应用于具有自由边缘的飞机结构中，在制造和维护过程中容易受到冲击事件的影响。边缘冲击对复合材料的压缩强度损失可能有很大影响，但这种影响仍不明确。本文介绍了碳纤维增强塑料（CFRP）材料的边缘冲击及边缘冲击后压缩（CAEI）的实验和模拟。通过落锤法分别以4、6、8和10 J的冲击能量对复合材料层压板引入边缘冲击损伤。在压缩试验中使用了一种特殊的导轨式夹具，获得了应变力和载荷-位移关系。提出了一种连续步有限元模型来模拟冲击和压缩。采用连续壳单元和Hashin失效准则来模拟层内损伤，并用粘结单元对层间损伤进行建模。通过将实验结果和数值结果进行对比验证了该模型。研究结果揭示了损伤尺寸和残余强度与不同冲击能量之间的关系。裂纹长度和分层面积随着冲击能量的增加而增大。残余抗压强度随着冲击能量的增加呈下降趋势。
