Design And Performance Study Of Magnetoheological Damper With Single-action Type

The energy of modern aircraft landing gear shock absorber is absorbed by oil flows through the orifice to shock, but the damping performance of modern aircraft landing gear is not ideal in the case the load changes large. In addition, the vibration control method to output damping force for the changing external load of shock absorber of oil and gas is passive,which reduces the buffer performance and the scope of its application. IF the magnetorheological technology is applied to aircraft landing gear shock absorbers, it can enable the performance with low energy consumption, low output quality and adjustable and controllable damping force, which can solve the problems that adjust mechanically the size of the hole and filling parameters to improve the performance of shock absorber.To analyze the structure type of existing oil and gas shock absorbers, based on the size of the landing gear of a certain type of unmanned aerial vehicle, and to combine with the design method of the magnetic structure and the structure type of magnetorheological, a landing gear single-acting magnetorheological damper structure is designed. To model the magnetic circuit structure of magnetorheological damper by using the ANSYS parametric programming language(APDL), the optimization analysis is carried out. The analysis results show that the magnetic flux density of the optimized structure in the damping channel is enhanced to 0.32 times than before, and the distribution is more uniform. After optimized, the volume of the magnetic structure is reduced by 7% than before, which makes the magnetic circuit structure more compact.After machining and assembling the landing gear shock absorber, static damping performance test and design landing shock test are processing, and the figures of the quantity of work is plotted by extracting and processing the test data under the corresponding test.Static damping characteristics results show that: under the same amplitude and frequency,the damping force of the shock absorber increases with the increase of the load current. With the sinusoidal excitation frequency and amplitude increases, the figure of work quantity the damper turns to full. When the load current is between 0.5A-2A, the shock absorber dampingforce changes significantly, and the maximum power adjustable multiples reach more than 2times. It proves the magnetic circuit design of shock absorber is reasonable.The design landing shock test results show that: when the current is zero, the stroke value of the shock absorber strut is the maximums. With the load current increases, the shock absorber strut stroke value decreases, and the vertical load increases. With served to increase the height of the shock absorber strut, the load and stroke of the damper also increase. When the load current is 0.6A and the throwing height is 165 mm, 318 mm, and 474 mm, the shock absorber strut stroke decreased than that without current 3.9mm, 2.9mm, 5.4 mm respectively;In the case of any test, the efficiency of the shock absorber is between 70%~75%.It proves the global design of landing gear shock absorber is correct and the cushioning performance is good, and it has practical value.