A strongly coupled partitioned approach for fluid‐structure‐fracture interaction

Abstract

Summary We present a novel method to model large deformation fluid‐structure‐fracture interaction, which is characterized by the fact that the fluid‐induced loads lead to fracture of the structure and the fluid medium fills the resulting crack opening; the mutual interaction between the crack faces and the surrounding fluid contributes substantially to the overall dynamics. A mesh refitting approach is used to model the quasi‐static fracture of the structure, and a robust embedded interface formulation is used to solve the fluid flow equations. The proposed method uses a strongly coupled partitioned scheme with Aitken's Δ2 method as convergence accelerator. Selected numerical examples of increasing complexity are presented to evaluate the performance of the proposed fluid‐structure‐fracture coupling algorithm. The most difficult simulation of the reported examples involves a number of complex phenomena: mixed‐mode crack propagation through the structure, fluid starts to fill the crack opening, complete fracture of the structure into two pieces of which one is carried away by the flow.

Mesh refitting approach: a simple method to model mixed-mode crack propagation in nonlinear elastic solids

“…However, in FSFI applications, fluid loads are acting on the crack faces, and as a result an additional term appear in the computation of J -integral. This is explained further in [1].…”

“…The objective of this work is to devise a simple procedure to achieve the required mesh modifications, which enables us to model complex crack paths through nonlinear elastic solids. The present work is motivated by our interest in developing computational methodologies for fluidstructure-fracture interaction (FSFI) [1] that model the following phenomenon: when a flexible structure interacts with the fluid flow, the fluid loading induces elastic deformation as well as fracture failure of the structure, and the fluid medium fills the crack opening. The first step of extending fluid-structure-interaction (FSI) methods to handle FSFI is to equip the structural analysis with a fracture mechanics solver.…”

A fully Lagrangian formulation for fluid-structure interaction problems with free-surface flows and fracturing solids

“…In [55], similar problems were analyzed considering also the fragmentation of the structure due to the cracks propagation. In [63], free-surface flows were also considered using a coupled Smoothed Particle Hydrodynamics -Discrete Element Method (SPH-DEM) model.…”

On the role of (weak) compressibility for fluid‐structure interaction solvers

“…This can be due to overall weak compressibility effects in some cases or local compressibility effects when strong pressure differences appear locally, eg, in scenarios of fluid-structure-fracture interaction. 8 In such cases, including weak compressibility in the fluid formulation could both be a better physical approximation and might also be beneficial with regards to the coupled solver performance. This is why we propose such a formulation in this paper and study its influence on widely used coupling schemes.…”

“…Hence, in some situations, one has to pay a price for using a model that is not even the most appropriate one. This can be due to overall weak compressibility effects in some cases or local compressibility effects when strong pressure differences appear locally, eg, in scenarios of fluid‐structure‐fracture interaction . In such cases, including weak compressibility in the fluid formulation could both be a better physical approximation and might also be beneficial with regards to the coupled solver performance.…”