An efficient multi-time-step implicit-explicit method to analyze solid-fluid coupled systems discretized by unconditionally stable time-domain finite element procedures

The numerical modelling of interacting elastodynamic solids and acoustic fluids by time-domain finite element procedures is discussed here. In this study, the global model is divided into solid and fluid sub-domains and each sub-domain is analyzed independently, as an uncoupled model. The interaction between the different sub-domains is accomplished by interface forces. In order to improve the efficiency, accuracy and flexibility of the methodology, a multi-time-step method is also considered, allowing optimal time-steps to be selected for each sub-domain of the model. At the end of this paper, numerical applications illustrate the performance and potentialities of the proposed techniques.