Dynamic Impact And Fatigue Properties Of GLARE Laminates

GLARE laminate is a lightweight hybrid composite material,which is prepared by is prepared by curing with alternating glass fiber prepreg and aluminum alloy in a certain order.Compared with aluminum alloys,it has better fatigue resistance and damage tolerance,and higher strength and impact resistance than glass fiber.It combines all performance advantages of two matrix materials and has good designability to meet the needs of different properties.GLARE laminates are regarded as the ideal skinning material for lightweight structures,especially in aircraft structures.In potentially long-service conditions,fatigue damage and random impact are inevitable.It is important to explore the mechanical behaviors and their intrinsic mechanisms for wider engineering applications.In this paper,the dynamic responses of GLARE laminates under low-velocity impact are studied based on experimental test and finite element analysis.Considering the effects of impact energy and the punch shape,impact damage of laminates are characterized by indentation characteristic parameter and interlayer morphology,employing the image gray processing and metal chemical etching technology.The variation trend and damage difference of impact damage are revealed.The numerical simulation of low-velocity impact adopts three-dimensional composite Hashin failure criterion and Cohesive viscous contact surface treatment.The failure of fiber matrix and interlayer damage of GLARE layer are considered,and the simulation results are compared with the test results to verify the reliability of the simulation model.SPH algorithm is used to analyze the bird impact resistance behavior of GLARE laminate,revealing the impact response and internal damage evolution process subjected to random impact angle.The interlayer damage is characterized by the characteristic parameters of impact pits and deviation of impact center,and the energy change in the impact process is obtained.Combined with the potential application of GLARE plate in aircraft skin structure,considering the effect of internal supporting ribs,the anti-bird impact behaviors of the leading edge structure of aircraft wing are explored.The SPH impact attitude of bird body and the stress state of skin material in the impact process are obtained,and the influences of different impact positions on structural damage are revealed.The fatigue experiments of GLARE laminates are carried out to reveal the fatigue response under different stress ratios.Considering that inevitably open-holes for aircraft structures,such as structural openings and tightening holes,the fatigue property degradation trends of GLARE laminates with different center holes are explored.The open-hole behavior and fatigue damage mechanism of GLARE laminates are researched.Based on the fatigue life prediction model,the S-N curves are obtained based on the fatigue test data.In order to satisfy the actual engineering application,considering the statistical characteristics of fatigue life,the P-S-N fatigue life models are developed under different survival rates.