CHAPTER 12: Adaptive Magnetorheological Energy Absorbing Mounts for Shock Mitigation

Analysis of an adaptive energy absorbing mount is addressed in this study to protect payloads against drop-induced shocks. The adaptive capabilities of the energy absorbing mount is enabled by the implementation of a magnetorheological energy absorber (MREA) mounted between the base of the mount and a rigid payload. The problem is formulated as a single degree of freedom initial velocity problem, where the control objectives are achieved using terminal trajectory optimal control. The non-dimensional Bingham number, defined as the ratio of the controllable field dependent MREA yield force to the MREA viscous force, is used as the control variable. The optimal Bingham number was determined as that Bingham number required to achieve a soft landing, that is, the payload comes to rest after utilizing the available MREA stroke. The optimal Bingham number is computed knowing the drop velocity, payload mass, and viscous damping, and enabled the payload to simultaneously utilize available MREA stroke and minimize stroking load. The optimal responses for different MREA design configurations and drop velocities are illustrated.