Investigation on surface roughness of piston in mini-magnetorheological damper using dissipative particle dynamics modeling

摘要

Mini-magnetorheological damper is modeled using dissipative particle dynamics method, as a molecular modeling technique by applying various arrangement patterns of rough sections on the surface area of piston as four proposed scenarios of A, B, C, and D to obtain optimal damper performance. Modeling is developed to achieve 10-N damping force utilized in micro-machines and compared to experimental results that show good conformity. Weierstrass-Mandelbrot function is used to apply rough surface profile on the piston, and bounce back boundary condition is utilized as no-slip boundary condition. Results of modeling show that 140-CG magnetorheological fluid is suitable as the agent fluid. Also, it is observed that by increasing fractal dimension of roughness profile, damping force has an initial enhancement and then trends to a constant value. Results shown by utilizing Bouc-Wen model and genetic algorithm method and fractal dimension of roughness profile of 1.5 using at the beginning and the end of the piston as presented in scenario B; by applying 20% magnetic field strength, considered damping force of 10 N is achieved within 2 s, while under conventional conditions, using the smooth surface area of piston, more damping time is needed and more electrical energy is used than the developed model.