Dynamic Mechanical Properties Of TB6 Titanium Alloy Materials And Impact Resistance Of It's Typical Structure

TB6 titanium alloy is a type of near ? titanium alloy with high strength.Because of its property of high strength in light weight and great fracture toughness,it is widely used in the aerospace vehicle,especially in the area of landing gear,air inlet and engine.Since modern times on,birds impacting on aircraft has occurred frequently.Inlet and engine parts are the hot spots area of bird impacting.The dynamic mechanical properties of materials under high strain rate must be taken into account because of the high speed of flight,large impact force and short loading time in the process of bird impact.In this paper,the dynamic mechanical properties of TB6 titanium alloy at high strain rate are studied,and the bird impact test and numerical calculation of TB6 titanium alloy plate are carried out.The contents and conclusions of this paper are as follows:In this paper,the quasi-static and dynamic experiments of TB6 titanium alloy have been carried out,and studied the mechanical properties of TB6 titanium alloy with conducted four types of tests,i.e.uniaxial compression,uniaxial tension,pure shear and combined shear-compression under the condition of high strain rate loading.The results show that the yield strength of TB6 titanium alloy is asymmetric in tension and compression;the yield strength of TB6 titanium alloy increases with the increase of strain rate;the stress of TB6 titanium alloy under uniaxial compression at high strain rate appears thermal softening,while the stress under pure shear and combined shear-compression does not appear the phenomenon of thermal softening.The temperature softening term of J-C dynamic constitutive equation was modified by adiabatic temperature rise,and the stress-strain curves of TB6 titanium alloy under uniaxial compression and pure shear loading were successfully fitted.Based on von Mises yield criterion,a modified yield criterion which could consider the asymmetry of tension and compression is established,and a modified plastic flow constitutive model of TB6 titanium alloy is established according to the plastic flow theory.Subsequently,secondary exploration of constitutive model ofABAQUS/Explicit module is realized by the modifying plastic flow constitutive model in this paper.The accuracy and validity of the VUMAT subroutine are verified by simulating quasi-static and dynamic experiments.In order to investigate the impact resistance of TB6 titanium alloy plate during bird impact,the experiments were carried out.It is found that,the critical failure speed of TB6 titanium alloy plate under the bird impact test is 167 m/s,and the failure model of TB6 titanium alloy plate is shear failure,which indicates the poor shear resistance of TB6 titanium alloy.At last,using the modified constitutive model presented in this paper,the finite element numerical calculation of bird impact on TB6 titanium alloy plate was carried out inABAQUS.