An Interface-enriched Topology Optimization for Mitigating the Effect of Surface Flaws in 3D Brittle Structures

In this 3D fracture-based topology optimization framework, the author extended the 2D framework on tailoring fracture resistance for brittle materials (Zhang et al., 2022) to 3D. In the optimization, the topology is described by radial basis functions interpolated level set function, and the problem is solved by the Interface-enriched...

A discontinuous Galerkin based enriched finite volume method

In this report a new enriched finite volume method is introduced. This method will be particularly useful for fluid-structure interaction problems. In engineering many problems are in the domain of fluidstructure interaction. Examples of these are water in sea locks, blood flowing in vessels and sailing ships. Fluid problems are usually solved...

An interface-enriched finite element method for immersed contact under large deformation kinematics

Historically, contact analysis has been an important design tool for various applications such as vehicle crash analysis or manufacturing. It is also becoming increasingly more relevant in newer fields such compliant mechanism or metamaterial design. Even though contact has been a topic of discussion for decades, there are still challenges that...

A Generalized Finite Element Method with Spread and Discrete Enrichments for Capturing High Thermal Gradients in Composites

The demand for composites is rising in industries for instance, in aircraft and automobile engines. In these applications, composites encounter high thermal gradients service condition, and composites exhibit material discontinuous gradient field. It is essential to study how high thermal gradients and material discontinuities influence on the...

Autoencoder enabled global optimization

High-dimensional optimization problems with expensive and non-convex cost functions pose a significant challenge, as the non-convexity limits the viability of local optimization, where the results are sensitive to initial guesses and often only represent local minima. But as the number of expensive cost function evaluations required for a full...

Origami for tunable vibration isolation

It is relevant for various applications to seek a material that could be used for the active control of wave propagation. In this study, we explore tunablemetamaterials based on foldable origami sheets where the size of the bandgap can be tuned by the rigid folding along predefined crease lines. A combination of out-of-plane components and a...

A Discontinuity-enriched Finite Element Method for Dynamic Fracture in Brittle Materials

The computational modeling of crack propagation is important in aerospace and automotive industries because cracks play a significant role in structural failure. In comparison with the quasi-static case, inertial effects are significant in dynamic crack propagation. The classical numerical tool for modeling dynamic crack propagation is the...

Modelling Discrete Dislocation Dynamics with Discontinuity-Enriched Finite Element Analysis

Discrete Dislocation Dynamics concerns the analysis of microplasticity in which the dislocations, a line defect in the crystallographic periodicity, are treated as separate moving entities inside an elastic continuum. This analysis at the mesoscale can give valuable insights in the nature of dislocations and the behaviour of macroscopic...

Locking free discontinuous nonlinear thin-walled structures

The demand for using thin-walled composite structures for instance, in aircraft and ships are rising in the industry. These structures contain material interfaces, and at these interfaces, the structure exhibits non-smooth field behavior which is known as weak discontinuity. It is essential to study the effects of such discontinuities on the...

Towards high-order discontinuity-enriched finite element method

The computational study of discontinuous problems becomes increasingly important due to industrial needs, such as the application of natural or artificial composites and the understanding of damage and fracture processes of materials. The discontinuity-enriched finite element method (DE-FEM) and interface-enriched generalized finite element...

Pareto Set Extrapolation method: an efficient solving technique for multi-objective optimization problems

When considering techniques for producing the Pareto front of a <i>Multi-Objective Optimization Problem</i> (MOOP), there exists a trade-off between the effectiveness of the method in obtaining the Pareto front and the computational cost required to achieve that. For a method to be effective, the generated solutions must result in a true...

Finite element based analysis and validation for nonlinear structural dynamics

Analysing nonlinear vibrations of any finite element model containing a considerable number of degrees of freedom requires extensive computational resources. For a time-dependent nonlinear analysis, numerous iterations and time increments are required to compute steady statesolutions....

A NURBS-enhanced Discontinuity-Enriched Finite Element Method

Generalized finite element methods have proved a great potential in the mesh-independent modeling of both weak and strong discontinuities, such as the ones encountered when treating materials with inclusions or cracks. By removing the constraint of a conforming mesh, more freedom is offered to modeling exact geometries by means of splines....

A stress recovery procedure for 3-D linear finite elements

In this thesis, a stress recovery procedure for 3-D linear finite elements is presented. The formulation is based on a modified version of the Hu-Washizu variational principle, in which the recovered stresses are calculated by minimizing the error with respect to the directly-computed stresses, and ensuring that the recovered stresses satisfy...

Feasibility of Alternative Finite Element Formulations within Topology Optimization

In this work, topology optimization is used to obtain optimal designs with minimal compliance as the objective. The checkerboard problem, refers to a resulting optimal topology where the material is distributed in regions of alternating solid and void elements. It has been shown that these regions emerge due to higher stiffness of the...

Modeling of Fiber Kinking in Composite Laminates

Recent advancements in computational methods has led to improvements in the computational modeling of tensile failure of composite laminates. Models for compressive failure however, have not yet reached the same level of maturity. Particularly in the case of fiber kinking there is a need for improved modeling techniques. Fiber kinking occurs...