Performance Of SMA-MR Vibration Isolation System With Semi Active Vibration Control

Metal rubber(MR)is a kind of elastic porous material,which has the dual characteristics of rubber and metal.The vibration isolator made of MR is used to solve the vibration problem under special working conditions.Metal rubber components made of shape memory alloys(SMA)have the characteristics of stiffness changing with temperature.However,the mechanism of shape memory effect of SMA micro element spring in metal rubber is not clear,and the influence of temperature on dynamic response of SMA metal rubber isolator is not clear,There are few studies on the technology of adjusting the performance of vibration isolator by controlling the internal temperature.In this paper,the semi-active control technology for the vibration isolation performance of memory alloy metal rubber isolator is studied.Firstly,based on the shape memory effect,a new type of metal rubber component was developed by combining shape memory alloy coil spring and carbon fiber heating wire;According to the Ni Ti shape memory alloy micro element spring,the stiffness test under different temperature environment is carried out,and the rule that the stiffness of Ni Ti shape memory alloy micro element spring changes with temperature is obtained;On the basis of mastering the temperature characteristics of micro element spring,the static mechanical experiments of sma-mr specimens are carried out,and the influence of temperature on its average stiffness,energy dissipation coefficient and nonlinear stiffness is analyzed.Secondly,the heat transfer characteristics of metal rubber porous materials are analyzed,and the thermal conductivity model of metal rubber materials is established by using the minimum thermal resistance rule,and the calculation formula of the equivalent thermal conductivity of metal rubber is derived;The effects of metal rubber density,wire diameter and coil diameter on its thermal conductivity were analyzed;The sma-mr temperature control system is built by using temperature sensor and controller to realize the automatic control of internal temperature of sma-mr;The temperature stability of sma-mr is analyzed,and the relationship between temperature response and input power is obtained.Finally,the sma-mr semi-active vibration isolation system is built by using sma-mr isolator,DC power supply and semi-active controller;The sinusoidal frequency sweep test of sma-mr isolator is completed,and the influence of temperature on the first resonance frequency,acceleration transmissibility and working frequency band is obtained;The random vibration test of sma-mr isolator is carried out,and the influence of temperature on resonance frequency and damping ratio is analyzed;The impact test of sma-mr isolator is used to analyze the influence of temperature on the impact isolation coefficient;The above results provide a basis for the establishment of adjustment method of dynamic response performance of sma-mr isolator.