List of Titles

Slope stability analysis considering fully saturated poro-elasto-plasticity by an image-based scaled boundary finite element approach

- Wijesinghe, Dakshith, Dyson, Ashley, You, Greg, Khandelwal, Manoj, Natarajan, Sundararajan, Chan, Andrew, Ooi, Ean Tat

Authors: Wijesinghe, Dakshith , Dyson, Ashley , You, Greg , Khandelwal, Manoj , Natarajan, Sundararajan , Chan, Andrew , Ooi, Ean Tat
Date: 2024
Type: Text , Journal article
Relation: Engineering Analysis with Boundary Elements Vol. 158, no. (2024), p. 160-181
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Description: Open pit mines are large geotechnical structures. Their stability is an important consideration in the mining industry. The deformations of geotechnical structures often involve the coupled interaction between the pore fluid pressure and the nonlinear deformation of soil, characterised by poro-elasto-plastic behaviour. This paper develops the scaled boundary finite element method (SBFEM) to address poro-elasto-plastic in slope stability problems. It builds upon a previously developed elasto-plastic formulation to consider the effect of pore fluid pressure and its interaction with the nonlinear deformation within the soil. The pore pressure field introduces an additional variable in the governing equations that is similarly discretised using SBFEM shape functions. The SBFEM is implemented together with a pixel-based quadtree mesh generation technique, enabling automatic meshing directly from digital images. This leads to efficient automation when modelling problems with iterative changes in the geometry such as in optimisation of construction processes during the rehabilitation of slopes. The formulation is validated first using a standard numerical benchmark. Application of the developed technique in construction applications in slopes where the stability and effect of pore water pressure is considered e.g., tailings dam construction and optimisation of backfilling process is demonstrated in three examples to demonstrate feasibility. © 2023 The Authors

Dynamic fracture modeling of concrete composites based on nonlocal multiscale damage model and scaled boundary finite element methods

- Jiang, Shouyan, Lin, Anbang, Ooi, Ean Tat, Gao, Jia, Sun, Liguo, Du, Chengbin

Authors: Jiang, Shouyan , Lin, Anbang , Ooi, Ean Tat , Gao, Jia , Sun, Liguo , Du, Chengbin
Date: 2024
Type: Text , Journal article
Relation: Engineering Analysis with Boundary Elements Vol. 167, no. (2024), p.
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Description: Dynamic fracture is a critical concern in the design and reliability assessment of concrete structures. This study presents a numerical prediction of dynamic fractures in concrete composites using a nonlocal multiscale damage model and the scaled boundary finite element method (SBFEM). The nonlocal multiscale damage model accurately captures the damage behavior of concrete materials by considering the nonlocal effects and predicting fractures under dynamic loading conditions. The SBFEM combined with quadtree meshes, efficiently models and discretizes concrete composites, enhancing computational efficiency, and capturing local details. The concrete mesostructure consists of aggregates, mortar matrix, and interface transition zone. The random aggregates are generated using the popular Monte Carlo simulation and take-and-place methods. By slightly offsetting the boundaries of the generated aggregates, a virtual thickness interface is obtained to approximately characterize the weakest regions. This study extensively investigates the effects of loading rate, aggregate content and shape, and interface thickness on fracture properties. The loading rate significantly influences crack morphology, with low rates suppressing crack branching, and higher rates resulting in crack branching. Moreover, an increased aggregate content in the concrete results in greater maximum reaction force. Additionally, the range of the maximum reaction force is higher when polygonal aggregates are used as compared to circular aggregates. This study examines the impact of the interface thickness on the fracture characteristics. Increasing the interface thickness makes the interface region more fragile, resulting in additional minimally damaged areas alongside the completely damaged cracked sections. This behavior can be attributed to the energy degradation functions employed in the model, thereby decreasing the load-bearing capacity of these regions. These findings contribute to a better understanding of the dynamic fracture phenomena and aid in optimizing the design and improving the reliability of concrete structures. © 2024 Elsevier Ltd

On the semi-analytical framework for Cosserat continuum

- Suvin, V., Ooi, Ean Tat, Natarajan, Sundararajan

Authors: Suvin, V. , Ooi, Ean Tat , Natarajan, Sundararajan
Date: 2024
Type: Text , Journal article
Relation: Engineering Analysis with Boundary Elements Vol. 159, no. (2024), p. 352-363
Full Text: false
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Description: In this paper, a semi-analytical method is employed to model a Cosserat continuum. The spatial discretization is based on quadtree decomposition, a hierarchical structure. The hanging nodes as a result of quadtree decomposition are naturally handled by the scaled boundary finite element framework without requiring additional constraints/shape functions. The accuracy and convergence properties of the proposed framework is demonstrated with four numerical examples of varying complexity. From the numerical study, it is opined the framework yields accurate results. The influence of characteristic length

Fitted meshes on an unfitted grid based on scaled boundary finite element analysis

- Suvin, V., Arrutselvi, M., Ooi, Ean Tat, Song, Chongmin, Natarajan, Sundarajan

Authors: Suvin, V. , Arrutselvi, M. , Ooi, Ean Tat , Song, Chongmin , Natarajan, Sundarajan
Date: 2024
Type: Text , Journal article
Relation: Engineering Analysis with Boundary Elements Vol. 166, no. (2024), p.
Full Text: false
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Description: Traditional domain based discretization techniques (both mesh based and meshless methods), require a conforming discretization to capture the boundary/interfaces present in a structure. This increases the computational burden when the boundary/interface is complex and when the morphology of it changes with time. In this paper, we present a ‘simple’ technique to generate fitted meshes on an unfitted background grid. The salient features of this technique are: (a) direct enforcement of boundary/interface conditions without using Lagrange multipliers/Nitsche's approach and (b) does not require polynomial/non-polynomial enrichment functions to capture the boundary/interface. A structured background mesh consisting of 8-noded linear elements are used and the scaled boundary finite element method is used to compute the bilinear/linear form. The robustness and the accuracy is demonstrated with a few examples from scalar and vector valued problem with stationary and moving boundaries/interfaces. © 2024 Elsevier Ltd

Scaled boundary finite element based two-level learning approach for structural flaw identification

- Thananjayan, Pugazhenthi, Natarajan, Sundararajan, Ooi, Ean Tat, Ramu, Palaniappan

Authors: Thananjayan, Pugazhenthi , Natarajan, Sundararajan , Ooi, Ean Tat , Ramu, Palaniappan
Date: 2024
Type: Text , Journal article
Relation: Engineering Analysis with Boundary Elements Vol. 166, no. (2024), p.
Full Text: false
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Description: A comprehensive framework that combines classification and regression techniques through machine learning (ML) algorithms to address the inverse problem of flaw identification and quantification is proposed. The framework uses the scaled boundary finite element method (SBFEM) and quadtree (octree mesh in 3D) to compute displacements for various flaw shapes and specified boundary conditions. The flaw data, such as their numbers, location, and size, along with the displacement data, serve as the input for ML models. A random forest model is used to predict the number of flaws, while an artificial neural network (ANN) employing a fully connected multi-layer perceptron is utilized to predict flaw locations and sizes. The framework underwent rigorous testing to identify the number and location of multiple flaws (circular and elliptical) in 2D structures. The accuracy of the classification and regression models for flaw detection, ranging from one to four circular flaws, is observed to be 98%. As an extension of its capabilities, the proposed model successfully identifies multiple flaws and their features in 3D structures as well with 98% accuracy, demonstrating the robustness of the proposed approach. © 2024 Elsevier Ltd

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