Failure Analysis Of Quasi-honeycomb Sandwich Structure Under Flexural And Torsional Loads

The quasi-honeycomb sandwich structure has excellent mechanical properties and energy absorption characteristics.In order to further reveal its important performance in crash resistance and failure and their correlation,it is urgent to carry out basic research on its failure mechanism and other aspects to improve its.Use reliability to provide theoretical and design basis.In this paper,the quasi-honeycomb sandwich structure is taken as the research object,and the method of combining theoretical derivation and simulation analysis is used to analyze the failure characteristics of the quasi-honeycomb sandwich structure under bending-torsion load.The main research contents are as follows:(1)Mechanical performance analysis of quasi-honeycomb sandwich structure.Based on the sandwich cell theory proposed by Gibson,the mechanical analysis of the quasi-honeycomb sandwich structure is carried out;the longitudinal equivalent elastic modulus and shear modulus of the quasi-honeycomb sandwich are derived using the material mechanics theory and the equivalent principle of strain energy,and then the whole The longitudinal equivalent elastic parameters of the honeycomb sandwich structure are numerically simulated,and the simulation results are compared with the theoretical data to verify the correctness of the mechanical model.(2)The failure mode of the quasi-honeycomb sandwich structure is analyzed.Based on the Engesser method formula,considering the transverse shear effect in the buckling analysis of the sandwich structure,the buckling load formula of the quasi-honeycomb sandwich structure under tensile and compressive loads is derived.Finally,the finite element simulation software is used for numerical simulation.By changing the number of cells,panel thickness and core height,the influence of these three structural parameters on the buckling capacity of the sandwich structure is analyzed.(3)Failure analysis of quasi-honeycomb sandwich structure under bending load.Theoretical research on the stiffness and strength of quasi-honeycomb sandwich structure under bending load is carried out,and the failure mode of quasi-honeycomb sandwich structure under bending load is analyzed.Based on bending deformation and shear deformation,the quasi-honeycomb sandwich structure is deduced at three points Disturbance response under bending load;the stress state of the panel and honeycomb sandwich layer under three-point bending load is analyzed,and the upper and lower panel crushing,upper and lower panel wrinkling,quasi-honeycomb wall crushing and quasi-honeycomb wall are derived Critical load corresponding to four failure modes of buckling;draw the failure mechanism diagram through the critical load calculation formula,and analyze the geometric parameters of the most mass-efficient quasi-honeycomb sandwich structure.(4)Failure analysis of quasi-honeycomb sandwich structure under torsional load.The mechanical behavior of quasi-honeycomb sandwich structure under torsional load was studied,and the torsional stiffness of quasi-honeycomb sandwich structure was derived.Based on the classic laminate theory,the disturbance response of quasi-honeycomb sandwich structure under torsional load was derived.The numerical simulation of the quasi-honeycomb sandwich structure under load is carried out,and the four-stage failure process of the quasi-honeycomb sandwich structure under torsional load is analyzed.(5)Failure analysis of quasi-honeycomb sandwich structure under bending-torsion load.The numerical simulation of the failure of the quasi-honeycomb sandwich structure under the action of bending-torsion load is carried out.The results show that: within the elastic deformation range,the applied bending load increases,and the ability of the quasi-honeycomb sandwich structure to withstand the torsional load gradually decreases.The point of failure load gradually decreases;when the bending load is large,the honeycomb wall buckling or collapse has already occurred within its elastic range,and it quickly enters the densification stage,thereby increasing the torsional strength of the structure.