Numerical and experimental investigation of a highly effective single-sided vibro-impact non-linear energy sink for shock mitigation

In this paper a highly asymmetric, lightweight, vibro-impact non-linear energy sink (NES) leading to very efficient passive non-linear targeted energy transfer (TET) is investigated. To this end, a two degree-of-freedom linear system (the primary structure) is coupled to a single-sided vibro-impact (VI) attachment with highly asymmetric impact non-linearity (the VI NES). The proposed NES passively absorbs and rapidly dissipates a considerable amount of the impulse energy induced into the linear structure, leading to very effective shock mitigation compared to a double-sided (symmetric) VI NES. We find that appropriate selection of the weak linear stiffness that couples the non-linear VI attachment to the linear structure plays a significant role in the proposed design. Moreover, in contrast to the double-sided VI NES which has optimal performance for a narrow range of input energies, the proposed single-sided asymmetric VI NES maintains a high level of performance over a broad range of high input energies. Hence, the proposed design is especially suitable for severe shock mitigation in infrastructure. To quantify the enhanced shock mitigation performance of the asymmetric VI NES we employ measures of effective damping and stiffness developed in previous works to demonstrate that the primary structure with attached NES possesses drastically increased effective damping and stiffness compared to its nominal properties when no NES is attached. A series of experimental results fully validates the theoretical predictions.