Interlaminar Fracture Toughness And Impact Response Of A Novel Fiber Metal Laminate

Interlaminar delamination and fracture in Metal Fiber Laminate(FML)is a common form of damage which will cause severe reductions in strength and stiffness as well as may lead to catastrophic failure of a whole structure.This research aims at the improvements of interlaminar fracture toughness and impact properties of AZ31 B magnesium alloy based FML laminates(Mg-based FMLs)reinforced with carbon fiber/polymer composite(CFRP)prepregs through a new bonding process.Combined with double cantilever beam(DCB)and three point end-notched flexure(3ENF)experiments,the interface mechanical properties of the Mg-based FMLs bonded with a new solder alloy have been determined by an intelligent algorithm;On this basis,the improved tensile and impact properties as well as strengthening mechanism of the fiber/magnesium alloy hybrid laminates were further investigated.In addition,a micromechanical model of grapheme nanoplates(GNPs)reinforced epoxy matrix composites was developed with considering the agglomeration distribution of GNPs,and the mechanism of anti-debonding performance of GNPs reinforced interface under dynamic loading was numerically studied.Finally,the reasons why the Mg-based hybrid laminates have improved interfacial fracture toughness and excellent low-speed impact resistance were analyzed systematically.Carbon fiber woven fabric/AZ31 B Mg alloy laminates bonded by epoxy resin and Mg alloy solder were first prepared by vibration-assisted hot pressing technique.The interlayer strength of the Mg-based FMLs was tested by DCB and 3ENF experiments.At the same time,the tensile properties of the Mg-based FMLs were also tested.Compared with the resin bonded FMLs,the FMLs bonded with hybrid adhesives has higher interlayer strength.The tensile strengths of the two FMLs both increase with the increase in the fiber volume fraction,but the tensile strength for the latter increases in a larger amplitude.When the volume fraction of carbon fiber/polymer increases from 29.5% to 38.9%,the tensile strength of the hybrid laminate increases from 313.5 MPa to 448.7 MPa.Compared with the traditional resin binder,the interlaminar fracture strength of the hybrid laminate is also significantly improved,the?-type fracture toughness is increased by 179.3%.Secondly,in order to extract cohesive zone model(CZM)parameters for interfacial bonding layer of the hybrid laminate,inversion analysis of the bond layer parameters was carried out based on the DCB experimental data and optimization algorithm improved by using genetic algorithm and simulated annealing algorithm.Finally,the inversion parameters are used for finite element simulation,and the simulation results are in good agreement with the experimental data,which verifies the correctness of the inversion parameters.Based on the above research,the impact response of the novel Mg-based hybrid FMLs with different configurations under impact loading was studied.The low-speed impact response and failure mode of the FMLs were studied by means of experiments and simulations,and the performance comparisons between the two Mg-based FMLs bonded with different adhesives were conducted.In addition,the dynamic debonding behavior of the Mg-based hybrid laminates induced by impact was evaluated.Finally,we have tried to improve the interface strength by adding GNPs into the resin matrix as interface adhesive,and develop a three-dimensional RVE modeling program with considering the distribution of GNPs.The mechanical properties of GNPs/epoxy resin adhesive are predicted on the basis of micro-mechanics,and the effects of GNPs on dynamic debonding properties of the Mg-based FMLs was analyzed.