This work presents an optimized adaptive semi-explicit/explicit time integration strategy to analyse elastodynamic models. The discussed methodology is based on two time-integration parameters, which are allowed to assume different values for each element of the adopted spatial discretization. The computation of the first parameter is designed to improve accuracy and to ensure the stability of the analysis, and it defines the so-called semi-explicit and explicit elements of the hybrid model. The evaluation of the second parameter, on the other hand, focuses on enabling an effective numerical dissipative algorithm, and it defines the so-called dissipative and non-dissipative elements of the model, which are relabelled at each time step of the analysis. These adaptive time-integration parameters are computed taking into account the physical and geometrical properties of the elements of the spatial discretization, the adopted time-step value, and local previous time step results. The resulting time-marching formulation is very accurate and highly efficient, providing a very attractive solution procedure. To further improve the effectiveness of the discussed technique, optimal time-step values are also here automatically evaluated, taking into account a particle swarm optimization algorithm, which allows to establish the most efficient distribution of semi-explicit and explicit elements along the model for solution. As a consequence, the proposed formulation becomes entirely automated, requiring no expertise, decision nor effort from the user to be applied, further improving its usability. Numerical results are presented at the end of the paper, illustrating the good performance of the optimized hybrid approach.
