Experimental Study On The Mechanical Property Of Bonded Joint Subjected To Combined Thermal And Constant Loading

One of the main ways to achieve lightweight is to apply lightweight and high-performance materials.With the increasing use of various lightweight new materials on the vehicle body,the connection between heterogeneous materials has become an urgent problem for lightweight technology.Compared with the traditional connection:welding,riveting and bolting,the structural bonding technology has the advantages of high bearing capacity,uniform stress distribution,corrosion resistance,and the material requirements of the connecting materials are not high,it can solve the above problems very well.In addition,the bonded structure will be affected by unfavorable factors such as load,temperature,salt spray and moisture.The service behavior in the coupled environment will be more complicated,especially the combined thermal and constant loading environment.Therefore,the combined thermal and constant loading environment is critical to the mechanical properties of adhesives and single lap joints.In this paper,the AL-CFRP single lap joint structure composed of Araldite~?2015adhesive,aluminum and Carbon Fiber Reinforced Plastic was selected as the research object,The ageing behavior of adhesives was studied by ageing experiments in the combined thermal and constant loading environments,and the influence of it on the strength degradation behavior of AL-CFRP single lap joint was analyzed.Firstly,the loading jig and calibration equipment required for the ageing test were designed.Then the ageing test of Araldite~?2015 adhesive was carried out.By measuring the creep elongation,and the creep characteristic parameters of the adhesive were obtained.The quasi-static tensile test of the adhesive was also carried out,and the ageing behavior of the adhesive was obtained.Secondly,the ageing test of AL-CFRP single lap joint was carried out.Then the quasi-static tensile test of single lap joint specimen was carried out.The influence of the combined thermal and constant loading environment on the strength degradation behavior of AL-CFRP single lap joints was obtained.Through the mechanical properties analysis of the adhesive and AL-CFRP single lap joint,the results showed that:first,the influence of temperature condition on the strength degradation behavior of the specimens is insignificant,whereas that of constant loading coupled with temperature condition on the strength degradation behavior is significant;second,the single lap joint and the adhesive had the same trend in strength degradation:the failure strength increases with ageing time increases under the condition of temperature only,the strength first increased and then decreased with ageing time increases under the combined thermal and constant loading environment.