Blast Response of Single-Degree-of-Freedom Systems including Fluid-Structure Interaction

The state of the practice for the blast-resistant design of structures uses a simplified single-degree-of-freedom (SDOF) analysis and estimates the blast loads assuming reflection from an unyielding rigid surface. Past studies showed that the interaction between the blast wave and the structure might influence the response depending on the blast characteristics and the structural properties. This study proposes a new fluid-structure-interaction (FSI) model and investigates its influence on the blast response of SDOF systems. Phenomena and model characteristics that are expected to influence the FSI response are investigated, and the limitations of past FSI models are addressed. The model includes the effects of aerodynamic damping, structural damping, and the damping caused by FSI that can significantly influence the displacement response. The model can be used to predict the blast response of a SDOF system for a range of shock strengths. The proposed FSI model is verified and validated with other FSI models and experimental studies and shown to predict the FSI response with considerable accuracy. The FSI effects are found to be more dominant in lightweight and flexible members relative to heavy and rigid systems. The study concludes that FSI effects are more significant at smaller-scaled distances (Z) at which stronger shocks are encountered. New charts are proposed that can be used to estimate the dynamic response of SDOF systems, including the effects of FSI. © 2020 American Society of Civil Engineers.