Mechanical Behavior And Fracture Failure Mode Simulation Of CFRP

As one of the most effective technologies to solve the huge energy consumption and vehicle exhaust emissions caused by the rapid development of automobile industry,automobile lightweight technology has been booming in recent years.CFRPs are widely used in automotive strength design because of their excellent specific strength,specific stiffness and fatigue resistance.In the actual use process,in order to adapt to different working environment and mass production needs,it often uses different molding process and laying method.Understanding the mechanical properties and failure modes of carbon fiber composites with different processes and selecting accurate simulation calculation method can facilitate the selection of parts preparation process and improve the efficiency of vehicle lightweight design and optimization.In this paper,the experimental samples are the unidirectional CFRP laminates,which were prepared by HP-RTM,WCM and PCM,these processes are commonly used in the mass production of CFRP for vehicles.A large number of basic mechanical properties experiments were carried out on these samples,and the corresponding mechanical parameters were obtained.The differences of mechanical properties were compared,and the reasons were analyzed combined with metallographic structure,failure mode and fiber content.Then,based on the collected mechanical parameters,the fiber reinforced composite progressive damage model and composite laminate continuous damage model in Ls-Dyna software are used to simulate the mechanical response of the composite under different load conditions.The mechanical response and failure mode were obtained and compared with the experimental results to evaluate the applicability of the two models in the simulation of mechanical properties of carbon fiber composites.Finally,a material card for simulation calculation is formed,and verified by tensile and compression tests of carbon fiber composite laminates with specific ply structure.The results show that there are some differences in fiber density,microstructure and properties of the composites prepared by different processes,in which the fiber content mainly affects the mechanical properties,while the difference in microstructure and properties is reflected in the failure mode.PCM has the highest fiber content,the best mechanical properties in “1” direction,but the poor mechanical properties in “2” direction;HP-RTM has a better performance in shear properties;WCM has the most balanced performance,no obvious deficiency.In the aspect of finite element simulation,composite laminate continuous damage model can better simulate the mechanical response of composite materials under different loads,which is in good agreement with the experimental curve,and the error in predicting composite laminates of multi angle ply structure is less than 10%,which has a good accuracy,and has a certain reference significance for material selection and structural design in subsequent engineering applications...