Study On The Multi-field-coupling Self-sensing Properties Of Bearing Based On The Modified Magnetorheological Rubber

Signal monitoring and sensing ability in complex environment(coupling of force,magnetism,displacement and electric field)is the precondition for intelligent equipment system(vehicle,mechanical equipment system,etc.)to achieve fast adaptive protection.It has important research value in the fields of health monitoring and vibration/shock protection.Vibration isolation system based on the Magnetorheological elastomer(MRE)has been widely studied and applied because of its controllable stiffness and damping under magnetic field.Previous studies have shown that MRE exhibits anisotropic electrical properties and is sensitive to external stimuli such as magnetic field,force or temperature.It has potential as a sensor.However,in the face of complex environment,there is no effective solution on how to take into account the sensing and fast adaptive response ability of MRE vibration isolation system.Therefore,this thesis will explore the realization of self-sensing vibration control system on MRE sensing capability,which is expected to provide theoretical method and experimental support for fast adaptive protection in complex environment.MRE is a kind of composite material,and its sensing characteristics are also affected by the execution state.It involves the key scientific and technical problems such as the piezoresistive/magnetoresistive effect of the force-magnetic coupling,the exploration of macro-micro sensing mechanism,and so on.It has important academic value and engineering reference significance.Therefore,the comprehensive effect of sensing and execution functions under multi-field coupling is explored combined with basic theory,simulation and experiment.The main research work is as follows:1.The important academic value and engineering significance of MRE for vibration control research are elaborated,and the research status of MRE in the field of vibration isolation and sensing is summarized.Then,the application prospects and urgent needs of self-sensing technology for intelligent equipment systems under vibration environment are clarified,and the main research work of this paper is proposed.2.In view of the theoretical problem that the sensing mechanism of MRE bearings under complex multi-field coupling conditions is not clear,the sensing mechanism of MRE bearings from the perspective of multi-field coupling is analyzed by the macro-micro-scale methods of "structure-bearing-foundation".Furthermore,amacro-micro multi-field coupling self-sensing model of MRE bearing is established,which provides theoretical guidance for the design of MRE and bearing structure with self-sensing and self-adaptive function.3.Studying and improving the sensing performance of MRE with low volume fraction of iron powder is the key to realize the integration of sensing and execution of MRE vibration isolation bearing.By improving the preparation method of MRE,the composite effect of MRE and multi-wall carbon nanotubes(MWCNTs)materials was explored.By adjusting the volume fraction of MWCNTs,the resistance of MRE can be reduced from close to insulation to less than 1k?,and the maximum change of resistance of modified MRE can reach 90% under the pressure(0~60kPa),and the stiffness can be adjusted under the magnetic field.MWNCTs can greatly improve the sensing performance of MRE without destroying the vibration isolation performance,which lays a foundation for the realization of self-sensing MRE bearings.4.Based on the design requirements of mechanics and electromagnetism,the design of self-sensing vibration isolation bearing is put forward.The influence of structural parameters on the performance parameters of sensing and vibration isolation is theoretically expounded.Furthermore,COMSOL multi-field coupling software is used to simulate,and the structural optimization model considering sensing and vibration isolation is established.The prototype structure of MRE bearings with self-sensing and self-adaptive function is designed,which provides a new idea for the structural design and optimization of self-sensing actuators.5.In order to verify the feasibility of the perception and execution of the modified MRE bearing in complex environment,multi-angle force and magnetoresistance response tests were carried out.The results show that the modified MRE bearing still has good resistance change rate and linearity.When the pressure changes from 0N to 160 N,the resistance change rate is about 65%.It has continuous,stable and completely reversible dynamic resistance signal with good repeatability.Based on the formula of multi-field coupling self-sensing characteristic of MRE bearing,the displacement of adaptive vibration isolation system is reduced by 20%~31% compared with the uncontrolled state.It provides experimental support for the self-sensing technology of intelligent equipment system in complex environment and has broad application prospects.