Low-velocity Impact Response Analysis Of Composite Laminates

The composite material began to emerge in the late 20 th century.As a rising star in material field,it was widely concerned by construction industry,aerospace,ship structure and other fields because of its excellent corrosion resistance,fatigue resistance and shock absorption.At present,the main load-bearing components of the aircraft developed at home and abroad are all composite materials,especially on the wings and fuselage.Although composite materials have advantages of light weight and high strength,they are also extremely vulnerable to impact.The impact damage of the composite structures would lead to a substantial decrease in strength,which seriously threatens the quality and reliability of the aircraft.Specifically,low-velocity impact often causes damage to the laminates in combination modes such as matrix cracking and delamination.This damage is not easy to be directly observed,and usually regarded as the most dangerous damage situation.Therefore,it is necessary to study the low-velocity impact response of composite laminates.In addition,this article will also analyze the structural stability to obtain the ultimate bearing capacity of the structure.Based on the ABAQUS finite element software platform,this paper established an impact damage model of HTS40/977-2 carbon fiber/epoxy composite laminates according to the twodimensional Hashin failure criterion and the bilinear stiffness degradation scheme.The calculated results of the model with cohesive element have a good corresponding relationship with the experiment.Based on the finite element model with cohesive elements,using the method of controlling variables,by changing the ply angle and impact energy,analyze its influence on the parameters of the impact response,and find the critical impact energy of the laminate under this working condition.By establishing finite element model of impact on T-shaped composite stiffened panels,and changing the distance between the rib and the punch,explore the influence of impact location on impact damage.Besides,analyze the stability of composite laminates and stiffened composite panels.And the ultimate load-bearing capacity of the structure is obtained through the pre-buckle analysis step and the post-buckle Riks analysis step.