Research On Performance Of Rotary Damper And Its Reinforced Concrete Shear Wall

Magnetorheological fluid is a kind of smart material.Magnetorheological effect occurs under the action of external magnetic field.It can be converted from high fluidity and low shear strength Newtonian fluid to the high shear strength semi-solid in millisecond time.Magnetorheological damper based on magnetorheological fluid properties is an excellent semi-active control device with advantages of large output,good adjustability,rapid response,stable performance and low energy consumption.In this paper,the preparation and performance of magnetorheological fluid,the magnetic circuit and structure design of rotary magnetorheological damper,the performance of magnetorheological damper and the influence of damper on the seismic performance of shear wall are studied.The main research contents are as follows:(1)A new type of structure combining rotary magnetorheological damper and shear wall is proposed.Rotary magnetorheological damper is installed inside the shear wall.When the shear wall is deformed,the damper can work together.Increase the energy consumption of the shear wall and reduce the damage of the seismic energy to the shear wall.(2)According to the composition and rheological mechanism of magnetorheological fluid,a magnetorheological fluid with high shear yield stress is prepared,and the rheology of magnetorheological fluid under different magnetic field strength and shear rate is prepared.The properties are tested and the effects of magnetic field strength and shear rate on the shear yield stress and apparent viscosity of magnetorheological fluid are investigated.(3)Based on the Bingham model,the calculation model of the output damping torque of the MR damper is proposed.Through the size and magnetic circuit design of the MR damper,the reasonable damper structural parameters are obtained,and make a rotary magnetorheological damper with high damping torque.(4)The pseudo-static loading test is carried out on the produced rotary magnetorheological damper.Under the triangular wave displacement input,the relationship between the damping torque and the current and angular amplitude of the damper at low speed is studied.The test results show that the damping torque increases with the increase of current,and the torque-angle curve is full,which is approximately rectangular,and the angular amplitude has little effect on the damping torque.(5)The dynamic loading test of the rotating magnetorheological damper is carried out.Under the sine wave displacement input,the influence law of current,frequency and angular amplitude on the damping torque of the MR damper is studied.The test results show that the damper works stably,the adjustable range is large,the damping torque increases with current,and the frequency and angular amplitude have little effect on the damping torque.(6)The ABAQUS is used to analyze the three-dimensional nonlinear finite element analysis of the shear wall specimen with additional damper under monotonic loading.The influence of the applied damping force on the bearing capacity,stiffness and ductility of the shear wall is obtained.The results show that with the increase of the applied damping force,the bearing capacity and initial stiffness of the shear wall increase,and the ductility is almost unchanged.