Experimental And Numerical Research On The Response Of Composite Laminate Subject To Low Velocity Impact

Due to lightweight requirements, Carbon fiber reinforced compositematerials are widely used in aircraft because of their high specific stiffnessand specific strength. However, this material is vulnerable to low impactdamage which may lead to huge reduction on the strength. Therefore, it isnecessary to do the research on the response of composite materials underlow-velocity impact. Although this issue has been widely studied, there arestill problems on the simulation study: the failure modes of compositematerial such as fiber breakage, fiber kinking, matrix cracking, and matrixcrush lead to the complex of the damage model and make it hard to predictthe damage of composite materials under impact load. This paper presents anew damage model to predict the response of composite material and givesome conclusions based on experiments.In this paper, the dynamic behavior of composite laminates was studiedby dropping weight method. The change rules of the shape of contactforce-time curve, the maximum contact force, dent depth, the damage areawere analyzed. The physical meaning of the―inflection point‖on themaximum contact force-impact energy cure was revealed. The equivalenceof low-velocity test and quasi-static indentation test had been proved bycomparing the force-displacement curves.Based on continuum damage mechanics (CDM) approach, aprogressive damage model is proposed to predict the impact force andenergy response of the laminates subjected to low velocity impact. Thetypical failure modes were simulated by employing damage mode-basedfailure criteria. Irreversible damage variables and computing method of internal energy were defined in order to quantify damage associated with thegradual stiffness reduction and energy dissipation. A good agreement wasfound between the FEM model and experimental results.