Optimization Of Impact Resistance Of CFRP Composites Based On Finite Element Simulation

In this paper,carbon fiber reinforced epoxy composite prepreg(T700/6240)was used to prepare T700/6240 composite laminate by hot pressing process.The influence on the damage of composite laminates was investigated by low-speed impact experiments under different impact energies.Damage forms and damage mechanisms were analyzed.The low-velocity impact model was established by using ABAQUS finite element software.By comparing the simulation results with the experimental data,the source of errors was analyzed,then the model was optimized,and finally the low speed impact model which was suitable for the whole energy field was established.Based on the low-speed impact model,the effects of glass fiber hybrid method,Kevlar hybrid method and interlaminar toughening method on the impact resistance of composites were studied.The results of low-speed impact experiments showed that the maximum impact load of T700/6240 composite laminates increased from 4230 N to 7538 N as the impact energy increased from 10 J to 25 J.When the impact energy was greater than 18 J,the growth rate of the maximum impact load began to decrease.Therefore,it was considered that the impact threshold of the composite laminate in this paper appeared near 18 J.Based on the ABAQUS finite element software,the three-dimensional Hashin model was more consistent with the experimental results.The maximum load error was less than 19% under the three impact energies,and the maximum displacement error of the punch was less than 14%.The model satisfied the modeling accuracy.The effect of different kinds of fiber hybrids on the impact resistance of laminates was studied.The best position of glass fiber hybrids was outer layers.The best mixing ratio was 1/6.Compared with single carbon fiber laminates,the maximum displacement of punches increased by 7.58%.The critical penetration energy increased by 1.7%.At the same time,for Kevlar fiber hybrids,the best hybrid position was the outer layer,the best mixing ratio was 1/6.Compared with single carbon fiber laminate,the maximum load was increased by 2.73%,the maximum displacement was increased by 7.16% and the damaged area was reduced by 28.20%.For the interlaminar toughening method,the optimized laminate was the intermediate toughened 12-layer laminate.The specific performance was that the maximum load was increased by 6.26%,the maximum displacement of the punch was increased by 7.23%,and the damage area of the fiber layer was reduced by 25.90%.The addition of the toughening membrane increased the energy release rate of the laminate,which absorbed more impact energy by providing greater deformation in the form of a shaped buckling.