Explicit-implicit time-stepping for non-uniformly meshed models

When computing the dynamic response of a finite element model of a structure, explicit or implicit time-integration procedures can be applied. Implicit time integration are usually unconditionally stable so that the time-step can be chosen large, but each time-step requires solving a static-like problem. Explicit schemes are conditionally stable and require using very small time-steps corresponding to the highest eigenfrequency in the model and therefore determined by the smallest element. The cost of one time-step using explicit schemes is however very small. In this research we investigate the possibility to filter-out high frequency modes in order to apply explicit time-integration with a time-step larger than what is possible with standard explicit time-integration. We illustrate the efficiency of the method with an example of wave propagation in a rod and with the transient analysis of a truss frame.