The Use of Damping to Mitigate Violent Snap-Through of Bistable Systems

The energy release associated with the snap-through phenomena when bistable systems transition from one stable equilibrium state to another leads to large transient oscillations which may often be unacceptable in morphing and other applications. This study, based on a bistable von-Mises truss, considers the role of damping in mitigating the transient oscillations as well as its impact on the snap-through behavior. The study also examines the energy transfer from potential to kinetic energy, and its dissipation, to understand the effect of load duration and amplitude on the behavior of bistable systems. The addition of damping was shown not to change the nature of whether or not the system will exhibit bistability. Increasing levels of damping result in the quicker decay of transient oscillations and settling of the system in the second equilibrium position, but also increase the time duration required for the system to snap-through. Damping levels in the range of 10–20% appear to result in a quick decay of the transient oscillations without causing the snap-through to become too sluggish. If the applied load is removed very quickly after snap-through there is still sufficient energy in the system to jump the energy barrier between the two equilibrium conditions and the system could settle in either position. Maintaining the load for a slightly longer duration allows the energy to dissipate (due to damping in the system), and the system is then unable to jump the energy barrier and remains in the second stable state. The applied load level determines the maximum amount of energy in the system, irrespective of how long the load is maintained. Increasing the applied load level results in additional energy in the system appearing as kinetic energy.