Study On Mechanical And Displacement Self-sensing Properties Of Metal Rubber With Large Volume

In the early stage,metal rubber materials were mainly used in machinery,aerospace and other fields,and their application research in civil engineering is still in the preliminary stage.At present,the theoretical and experimental research of metal rubber is still mainly focused on specimens with small wire diameter and small volume,and their actual output and energy consumption are small,which can not meet the service conditions of large structures in civil engineering.In addition,in recent years,with the rise of intelligent construction and intelligent civil engineering structure,functional structural materials have been highly valued and developed rapidly.Metal rubber is a kind of porous metal material,which is braided and pressed by metal wire turns.It has good electrical conductivity,and the macro density of metal rubber will change during the loading process,which will change its related electrical parameters and have certain self-sensing characteristics.However,there are few researches on the self-sensing characteristics of metal rubber at present.In view of this,this paper mainly studies the molding process of metal rubber with large wire and large volume diameter,studies its mechanical properties and electromechanical sensing characteristics theoretically and experimentally,and verifies and evaluates its self-sensing characteristics under static and dynamic loads.The main contents of this paper are as follows:(1)Based on the traditional preparation process,the preparation process of metal rubber with large wire diameter and large volume is improved,and the effects of process parameters and material parameters on the mechanical properties of large volume metal rubber are studied experimentally;By introducing the pinch function and the improved Bouc-Wen model,the macro mechanical constitutive model of metal rubber material was established.The parameters of the model are identified based on the least square method,and the constitutive model is verified.(2)The influence of nominal density,wire diameter,height and other parameters on the electromechanical properties of ring metal rubber under uniaxial compression and multi working condition cyclic loading is analyzed.The sensitivity and applicability of metal rubber resistance to its output and displacement change are clarified.The correlation between mechanical properties and electromechanical properties of metal rubber is studied.(3)Based on the test data of electromechanical properties,the electromechanical model of metal rubber was established.The accuracy of the model is verified by identifying the resistance,force and displacement of metal rubber under different loading conditions.Based on the pyramid contact pair model and contact resistance model,the parameters such as wire diameter,wire turn diameter,contact pair layer number and wire turn segment number are introduced to establish the meso electromechanical properties analysis model of metal rubber,and the influence of metal rubber parameters on the electrical contact logarithm is studied.(4)Through the drop weight impact test of metal rubber and the simulation analysis of vertical single degree of freedom system(SDOF)under earthquake excitation,the correctness of the electromechanical model and macro mechanical model of metal rubber are compared and verified,and the engineering application feasibility of self-sensing characteristics of metal rubber is studied and evaluated.