Development of novel magnetorheological dampers with low-speed sensitivity for flying car suspensions

Abstract

As urban traffic environments continue to grow in complexity, there is an urgent need for a versatile mode of transportation that seamlessly transitions between terrestrial and aerial mobility. In these conventional magnetorheological damper (CMRD), the magnetorheological (MR) fluid flowing through the narrow annular gap between the piston and cylinder in CMRD results in a damping force directly proportional to velocity. As velocity increases, the damping force rises sharply, posing a significant risk to the vehicle's mechanical structure and passenger safety. This velocity sensitivity restricts their applications primarily to standard commercial vehicle suspension systems. They face significant challenges when it comes to high-speed impact scenarios. To overcome this limitation, enhance the shock-absorbing capacity of flying cars, ensure passenger safety, and improve passenger comfort during the landing phase, this study introduces a novel magnetorheological damper (NMRD) with unique internal channel structure embedded in a circular permanent magnet. In road travel mode, flying cars equipped with NMRD can maintain a broad dynamic range. During the landing process with high-speed impact, the specialized channel activates to reduce the peak impact force effectively. This feature greatly expands the application range of magnetorheological dampers (MRD). The researches included simulations of the electromagnetic induction phenomenon within the piston, followed by numerical analyses and impact tests to compare the velocity sensitivity of these two distinct impact dampers. Experimental evaluations were conducted using a material testing system (MTS), the peak force and peak acceleration experienced by the two dampers during impact were tested using a dedicated drop hammer apparatus. These tests demonstrate that the NMRD exhibits superior impact resistance performance compared to CMRD. This highlights the promising potential for the NMRD's application within the suspension systems of flying cars.