Performance Analysis And Design Of Magneto-Rheological Fluids Drives Based On Variable Surfaces

At the beginning of the 21 st century,the application of smart materials has gradually come to the forefront of people’s minds.Among them,magnetorheological fluid and shapememory alloy,as two kinds of relatively new smart materials,their physical properties have attracted the attention of the majority of scientific researchers,and researchers have carried out a lot of research and analysis.Based on the mechanical properties of magnetorheological fluid and shape-memory alloy itself,this paper proposes a temperature-controlled variable surface transmission method,which uses brush slip rings to electrically heat the electrothermal shape-memory alloy spring to drive the displacement of the driving disk,so as to achieve a double-sided magnetorheological fluid transmission.By passing different current to the electro-thermal shape-memory alloy spring,flexible control can be realized under different working conditions.This method can not only compensate for the torque drop at high temperature,but also greatly improve the transmission efficiency.Based on the basic methods of mechanical principles and mechanical design,the working structure and schematic diagram were designed,a mathematical model was established,the transmission principle,transmission performance and transmission equations were designed,and the parameters generated were tested,analyzed and studied through the electromagnetic finite element simulation techniques,and the optimized geometric model was obtained.In order to obtain an intelligent composite transmission device with stable transmission torque,fast response,flexible regulation and superior performance,the following research work has been done in this paper:(1)Introduce the basic composition of magnetorheological fluids,the research status on its transmission,specific application techniques,magnetorheological effects brought about by their own chain mechanism,the analysis of the shear yield stress generated in terms of transmission performance,and study the effect of temperature on the viscosity and rheological properties of magnetorheological fluids.(2)Introduce the basic composition of shape memory alloys,specific development and application technology of shape memory alloys;Through the shape memory effect and its phase transition characteristics,the electro-thermal shape memory alloy spring was designed,and its thermodynamics,mechanical energy and driving performance were analyzed.(3)Introduce a temperature-controlled variable surface magnetorheological compound transmission device,describe its working principle and characteristics,analyze mechanically the transmission torque provided by the magnetorheological fluid in the transmission device,analyze the torque generated in the working process,and establish a theoretical model between the transmission torque generated and the current,magnetic field intensity,temperature and specific structural parameters under the compound transmission.(4)Design the structure of the temperature-controlled double-faced magnetorheological drive driven by an electrothermal shape-memory alloy spring,optimize the key dimensions,design and analyze the magnetic circuit.The magnetic field simulation analysis was carried out by Ansys-Maxwell,the magnetic induction intensity and nephogram of distribution of magnetic force line in three and two dimensions before and after changing the surface were obtained,and the optimized nephogram of magnetic field distribution of each node in the process of changing the surface was analyzed.And the transmission torque generated on one and two sides was analyzed simultaneously,it is finally concluded that increasing the working clearance can greatly improve the torque of the whole transmission device.(5)The electro-thermal shape memory alloy spring driving experiment was carried out to determine mechanical parameters such as the material,winding number and calorific value of the spring.The relationship between the actual extrusion pressure generated by the electro-thermal shape memory alloy spring and the current,temperature,displacement and other parameters was verified by the experiment.The fitting value was analyzed and compared with the experimental value,and the driving characteristics could meet the requirements of surface changing.