A quadtree-polygon-based scaled boundary finite element method for crack propagation modeling in functionally graded materials
- Authors: Chen, Xiaojun , Luo, Tao , Ooi, Ean Tat , Ooi, Ean Hin , Song, Chongmin
- Date: 2018
- Type: Text , Journal article
- Relation: Theoretical and Applied Fracture Mechanics Vol. 94, no. (2018), p. 120-133
- Full Text: false
- Reviewed:
- Description: This paper presents a method to improve the computational efficiency of the scaled boundary finite element formulation for functionally graded materials. Both isotropic and orthotropic functionally graded materials are considered. This is achieved using a combination of quadtree and polygon meshes. This hybrid meshing approach is particularly suitable to be used with the SBFEM for functionally graded materials because of the significant amount of calculations required to compute the stiffness matrices of the polygons/cells in the mesh. When a quadtree structure is adopted, most of the variables required for the numerical simulation can be pre-computed and stored in the memory, retrieved and scaled as required during the computations, leading to an efficient method for crack propagation modeling. The scaled boundary finite element formulation enables accurate computation of the stress intensity factors directly from the stress solutions without any special post-processing techniques or local mesh refinement in the vicinity of the crack tip. Numerical benchmarks demonstrate the efficiency of the proposed method as opposed to using a purely polygon-mesh based approach. © 2018 Elsevier Ltd
Modeling the particle breakage by using combined DEM and SBFEM
- Authors: Luo, Tao , Ooi, Ean Hin , Chan, Andrew , Fu, Shaojun
- Date: 2017
- Type: Text , Conference proceedings , Conference paper
- Relation: 7th International Conference on Discrete Element Methods, DEM7 2016; Dalian, China; 1st-4th August 2016; published in Springer Proceedings in Physics Vol. 188, p. 281-288
- Full Text: false
- Reviewed:
- Description: A novel computational method is developed in this study through the coupling of the discrete element method (DEM) and the scaled boundary finite element method (SBFEM). The objective of the developed technique is to model the particle breakage phenomenon in granular materials. This method models individual grains as single star-convex arbitrary sided polygons. The DEM is used to resolve the dynamics of each grain whereas the SBFEM is used to determine its corresponding stress state after a DEM analysis. The flexibility of both the SBFEM and DEM enable the grains to be formulated on arbitrary sided polygons so that the morphology of each grain to be replicated using only a single polygon. Grain breakage condition is determined if the stress state in a polygon satisfies a mechanically driven criterion e.g. the Hoek-Brown criterion is used. Once the breakage condition is detected, the resulting grain is split into two separate polygons. The resulting new polygons are directly modelled by the DEM and SBFEM without any change to the formulation. The feasibility of the developed method is demonstrated using a numerical example. © Springer Science+Business Media Singapore 2017.
- Description: Springer Proceedings in Physics