Session: MF-22-01 3D Crack Growth Simulation Using FEA

Paper Number: 106211

106211 - 3d Mesh Regeneration Along With Crack Propagation 

AI-FEM(Advanced Iterative-Finite Element Method) is iterative method to simulate crack propagation based on FEM. AI-FEM process is to overcome limitation of conventional crack propagation analysis methods. It repeats calculation of fracture toughness using FEM model with updated crack front to predict crack propagation more precisely. To do so, mesh regeneration is necessary to consider crack growth at every iteration. In this study, mesh regeneration process is developed and implemented by Abaqus/CAE that enable to create geometry and mesh.

Process begin with input data including crack plane and coordinates of points to represent arbitrary shape of crack front using cubic spline interpolation. Obtaining accurate contour integral results at given interpolated points require detailed focused meshes, which is a typical meshing technique having layers of elements in rings around the crack tip. To create such a spider web like mesh, tube shaped geometry is made using an additional partition. All the loads and boundary conditions are reallocated, then simulation can be run.

Based on the stress intensity factor along with the crack front, incremental crack growth for all crack front nodes can be evaluated. Direction of crack propagation is assumed to be perpendicular to cubic spline. Propagated crack front can be composed of relocated nodes on crack front with given direction and growth. After that newly updated FEM model is generated by prescribed method. Repeat above process until the number of iterations reaches the value specified by user or fail to generated focused mesh due to geometric limitation.

Most of geometric limitations occur when incremental growth of crack is too large. If updated crack front is twisted or the curvature of spline is too small, fail to create tube shaped geometry. To deal with those cases, crack front correction methods such as using additional node and substitution of problematic nodes are also developed.

In this study, developed mesh regeneration process is automated by Abaqus python language, and applied to evaluation of fatigue crack growth (FCG) and stress corrosion crack (SCC) growth of pipelines

Presenting Author: Sunghoon Park VENG Co., Ltd.

Presenting Author Biography: Sunghoon Park is a research engineer at VENG.

Authors:

Sunghoon Park VENG Co., Ltd.
Noh-Hwan Park VENG Co., Ltd.
Jun Park VENG Co., Ltd.