The Preparation And Mechanical Property Research Of Negative Poisson's Ratio Material

Because of the good mechanical property,the negative poisson's ratio material is applied to the aviation,spaceflight and automobile field and so on.Since the professor Lakes has successfully prepared negative poisson's ratio foam material with concave structure,many scholars began to study the foam material.Now most preparation of the foam matel is rule model,which is much different from the actual structure of the foam metal.This paper researched the preparation of two-dimension random negative poisson's ratio material with the finite-element numerical simulation method,and studied the mechanical property and energy absorption.At the same time,our reseach group has found In-Sn alloy metal with negative poisson's ratio and isotropic properties,but the microscopic structure;mechanism and mechanical characteristics of the metal are still unclear.So,this paper did not only prepare to the alloy metal,but also studied mechanical property and observed microstructure.At first,this paper established the two-dimension random Voronoi model,while controlling the size and density of hole by random number in the model.The model was imported to ANSYS/LS-DYNA software by APDL.This paper didn't only study the relation between poisson's ratio and area compression ratio with the finite-element numerical simulation method,but also discussed that thickness,holes amount,random number and squeezing velocity which effected on the poisson's ratio.Second,this paper researched the energy absorption of the random and different area compression ratio model under different velocity with Reid theory.This paper discussed that thickness and holes amount effected energy absorption of models,not only on by plateau stress and stress plateau,but also by normalized peak stress and normalized energy per unit.At the same time,this paper discussed the difference energy absorption among the first thickness model,concave hexagon model and convex hexagon model with same density ratio.Finally,this paper researched the poisson's ratio of In-Sn alloy metal by Resonant ultrasound spectroscopy(RUS)and the finite-element numerical simulation method,while studying the relation between the full range of poisson's ratio(from-1 to +0.5)and resonant frequency ratio.And then,this paper observed the microstructure of negative poisson's ratio In-Sn alloy metal by light microscope,X-ray diffraction(XRD),transmission electron microscope and scanning electron microscope and so on.