Study On Dual Synergistic Control Damping Characteristics For Magnetorheological-shear Thickening Damper

Intelligent fluid dampers,such as magnetorheological dampers and shear thickening fluid dampers,are widely used in the field of vibration reduction as one of the most important components in semi-active control devices.However,both of them have many shortcomings.The former has excellent active control characteristics,but its response to vibration amplitude and frequency is weak.For the latter,the response of vibration amplitude and frequency is very good,but the active control of damping force cannot be realized.Different from the first two magnetorheological shear thickening fluid dampers,the magnetorheological shear thickening fluid dampers have the characteristics of dual cooperative control of magnetorheological and shear thickening damping.Its vibration damping characteristics are different from those of magnetorheological damper and shear thickening fluid damper.In order to systematically study the dual control characteristics of magnetorheological truncated thickening fluid damper,this paper carries out the study from three aspects,namely,the fluid-rheological characteristics,the structure of the damper and the mechanical model of the damper.The main contents are as follows(1)The magnetorheological shear thickened fluid samples with different iron powder mass fraction and silica particle size were prepared,and the rheological test of the magnetorheological shear thickened fluid was carried out.The distribution of iron powder in the magnetorheological shear thickening fluid was observed by scanning electron microscopy,and the rheological law and mechanism of the fluid under different iron powder mass fraction,silica particle size and magnetic field were analyzed.By analyzing the relationship between fluid viscosity and shear rate in rheological test,the Ostwald-de Wale model and Cross model were used to model the rheological characteristics of the fluid,and the Levenberg-Marquardt algorithm was used to fit and calculate the rheological data.The accurate fluid mathematical model is obtained,and the fluid characteristics are described by the model.(2)Cross model was used to characterize the viscosity function of the fluid,and the design of MRSTF damper structure was carried out.Accroding to the mathematical model of the fluid and the structure of the double-rod damper,the relationship between the damping force and the fluid viscosity and the structural parameters of the damper was deduced.Combined with the structure and fluid continuity characteristics of the damper,the mathematical model of the damping force including the vibration frequency and amplitude of the piston and the shear rate of the fluid was established.The structural design and material selection of the damper were completed through the structural design,strength checking and magnetic conductivity characteristics of the material.The magnetic circuit of the damper was designed and optimized by using magnetic circuit Ohm’s law,and the magnetic circuit was simulated and verified by Ansoft Maxwell.A prototype of magnetorheological shear thickening damper has been developed successfully.(3)By applying sinusoidal loads to the prototype of the magnetorheological shear thickening damper,the relation curve between damping force and displacement and velocity was tested.By analyzing the variation characteristics and principles of damping force under different iron powder content,frequency,amplitude and particle size of thickening phase,a linear model,a nonlinear model,a Bouc-Wen model and a modified model were proposed.Based on the Levenberg-Marquardt algorithm and the Simulink module,the four models are fitted to the experimental data under different magnetic fields,frequencies and amplitude-and the comparative study shows that the nonlinear model can well represent the mechanical properties of the magnetorheological shear thickening damper.