Research On The Influence Of Temperature On The Static Strength Of Composite Material-metal Mechanical Connection Structure

With the in-depth application of composite materials in the aerospace field,metal-composite connection structures are inevitable.Bolted connections are widely used in connection structures because of their high reliability,easy disassembly,and reusability.In the service process of bolted connections,high-temperature working conditions will inevitably appear,and temperature has a particularly obvious influence on composite materials.Therefore,research on the static mechanical properties of composite-metal bolted connections at different temperatures will improve the reliability of the connection structure.It is particularly important to extend the application conditions of the connection structure.This paper takes the composite material-metal bolt connection structure as the research object,conducts experiments and finite element numerical simulations on the connection structure at different temperatures,and studies the effect of temperature on the static mechanical properties of the connection structure.The main research contents are as follows:First,starting from the theory of composite materials,through the classical laminate theory and thermal stress theory,explore the thermal s tress generation mechanism of the connection structure;explore the theory of progressive damage analysis of composite materials,including finite element calculation of stress process,failure criterion and stiffness degradation method.Secondly,the quasi-static tensile test of the composite material-aluminum alloy and titanium alloy bolt connection structure under normal temperature and high temperature environment is carried out,and the load-displacement curve of the connection structure under different temperature environments and the strain near the bolt hole are obtained,and the experimental research is carried out.The effect of temperature on the static mechanical properties of the connection structure of two metals and composite materials is discussed.Finally,based on the progressive damage analysis of composite materials,a finite element numerical model of composite material-aluminum alloy and titanium alloy connection structure was established using finite element software,the load-displacement curve of the connection structure was obtained,the damage failure mode of the connection structure was analyzed,and the connection structure was calculated.Thermal stress,combined with the results of experiments and finite element calculations,proves the accuracy of the finite element model,analyzes the effect of temperature on the static mechanical properties of the connection,and provides data support for the practical application of the connection structure.