A coupled Lagrangian framework for modelling multi-fracturing structures in natural hazards scenarios
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This work presents a novel numerical methodology for modelling fracturing processes in protective structures induced by the impact of natural hazards, such as tsunami waves and debris flows. The formulation is based on a fully Lagrangian approach involving a fluid-structure interaction between free-surface water flows and multi-fracturing structures. The fracture of the solid part is simulated by using a FEM-DEM formulation [1,2] that combines the Finite Element Method and the Discrete Element Method. This methodology takes into account the geometrical and constitutive non-linearities in the solid part and, additionally, prevents the indentation between crack faces by computing the frictional contact forces between the discrete elements placed at the nodes of the erased finite elements. The fluid part is solved via the Particle Finite Element Method [3,4,5]. The fluid domain is remeshed at each time step and is capable of adapting to the changing boundary due to the fracturing of the solid part. The fluid-structure interaction analysis is done via a partitioned strong coupling between the two solutions (fluid and solid solvers) including a relaxation technique as a convergence accelerator, especially for problems involving added-mass effects. We present examples of the efficiency of the coupled PDFEM formulation for problems of free surface fluid flows impacting against solid structures such as walls, harbors and dikes, among others.
