Andres Galvis

University of Portsmouth · School of Mechanical and Design Engineering

Recent growth in the aeronautical and oil industries has increased the demand for efficient repair techniques that offer shorter maintenance periods, greater durability, and reduced costs. Bonded composite repairs have emerged as an excellent solution, enabling the restoration of components without compromising structural integrity. By the first at...

This paper explores the mechanical behaviour of the composite materials used in modern lithium-ion battery electrodes. These contain relatively high modulus active particle inclusions within a two-component matrix of liquid electrolyte which penetrates the pore space within a viscoelastic polymer binder. Deformations are driven by a combination of...

Modelling lithium-ion battery behavior is essential for performance prediction and design improvement. However, this task is challenging due to processes spanning many length scales, leading to computationally expensive models. Reduced order models have been developed to address this, assuming a “separation of scales” between micro- and macroscales...

A numerical and experimental framework is proposed for an uncoupled thermoelastic analysis of anisotropic cold-rolled steel alloys Fe-3%Si to explore the influence on the material strength when subjected to thermal and inertial loads. Following the stationary thermoelasticity formulation of the boundary element method (BEM), this model focuses on t...

Phenomena involving bubble flow play a significant role in numerous industrial, natural, and scientific systems. Thus, liquid–gas interfaces must be considered the influence of surface tension and buoyancy. This work analyzes a complete numerical study for bi-fluid flow problems in the deformation evolution of two bubbles coalescing in a viscous li...

Severe bone fractures are often treated by appending internal fixations. In unhealthy or osteoporotic patients, post-implantation bone fractures can occur due to external impact (e.g. from a fall), day-to-day activities in highly-osteoporotic cases and mismatches in the stiffness of bone and the implant’s biomaterial, since this causes stress conce...

Phenomena involved with bubble and droplet flow play a significant role in numerous applications, e.g., mixing, separation, selection, and cooling. An alternative to the bi-phases droplets/bubbles flow simulation is to employ the Navier-Stokes equations in a Lagrangian formalism using Smoothed Particle Hydrodynamics (SPH) method and the Continuum S...

This work presents a numerical study of the simulation of bi-phasic flow for a bubble rising in the viscous liquid. A 2D model is employed via Smoothed Particle Hydrodynamics (SPH). The liquid/bubble capillary interaction must be taken into account, implementing adequate properties of density, viscosity, and surface tension at the interface. Likewi...

This paper presents a multiscale approach to model the dynamic transition between macro, micro, and homogenized atomistic scales in 2D polycrystalline materials. At the macroscale, the material is assumed as an isotropic homogeneous medium. The material at the microscale, in contrast, is characterized by anisotropic grains with stochastic morpholog...

BESLE is the first available parallel open-source code to analyse the mechanical behaviour of heterogeneous materials using the boundary element method (BEM) in 3D and in both an elastostatic and elastodynamic setting. Unlike all the other codes that are presently available, the software presented here is capable of simulating both isotropic and an...

A multiscale approach to investigate the influence of the grain boundary (GB) lattice structures on the dynamic intergranular failure in polycrystalline materials is proposed. The model comprises the meso- and atomistic scales using the boundary element method (BEM) and molecular dynamics (MD), respectively. At the mesoscale, stochastic grain morph...

The use of adhesive bonding in the industry has been increasing significantly in recent years, especially in technical applications, e.g., bonded repairs and doublers in aircraft structures. This growth is due to its advantages when compared with traditional joining methods. The main advantages of adhesively bonded joints are: i) reduced average st...

A general procedure is applied to analyze fatigue crack propagation in isotropic materials under mixed mode conditions, the Paris law modified by a closure concept. The dual boundary element method (DBEM) provides an stress and strain analysis on the solid, with reliable results for the mechanical fields in the region near to the crack tip. For val...

Phenomena involving bubble flow have an important role in numerous applications such as mixing, separation, filtration and cooling. When two different phases are treated as liquids–gas, the surface tension and buoyancy must be taken into account. An alternative is proposed to simulate flow for two or more phases, using bubbles formation and the Nav...

This paper presents a multi-scale approach to analyze failure in laminated composites. First, at the continuum mesoscale, the boundary element method (BEM) is used with the anisotropic 3D fundamental solution based on double Fourier series. The dynamic effects in the continuum media are included owing to the application of high-rate boundary condit...

This thesis presents a multiscale approach to analyze the dynamic intergranular failure in 3D polycrystalline materials. The model comprises the meso and atomistic scales using the boundary element method (BEM) and molecular dynamics (MD), respectively. A detailed polycrystalline structure is considered in the mesoscale, where stochastic grain morp...

Bone health conditions are treated with prosthesis and implant fixations. Despite being there to assist the patient, the difference between the elastic properties of these artificial medical solutions and the treated bone region may lead to a new fracture. One strategy to circumvent that problem, reducing the gap between the elastic properties, is...

In this paper, a multiscale dynamic transition is analyzed for metallic materials. The boundary element method (BEM) is used in order to model macro and micro domains, being considered isotropic and anisotropic properties respectively. To connect both scales, a displacement field is obtained from the macroscale, and it is imposed to a micro domain....

In this work, the dynamic failure of 2D crystal aggregate structures is analyzed using the boundary element method (BEM) and the multiscale cohesive zone model (MCZM). To describe the transient approach, the dual reciprocity method (DRM) is considered. Regarding the microscopic modeling, anisotropic properties are randomly fitted. Furthermore, the...

This work presents the use of an explicit-form Green’s function for 3D general anisotropy in conjunction with the dual reciprocity boundary element method and the radial integration method to analyse elastodynamic problems using BEM. The latter two schemes are to treat the inertial loads in the time-domain formulation of the dynamic problem. The di...

A new computational framework to analyse the microscale dynamic behaviour of three-dimensional polycrystalline materials with different lattice structures is presented. The absence of analytical solutions for these stochastic materials has been a challenge in validating the numerical results. In macroscale analysis, when the number of crystal aggre...

This work presents the analysis of three-dimensional polycrystals in the microscale with different lattice structures, hexagonal closed package (HCP) and face centered cubic (FCC). In these materials, the grained medium is considered as a continuum elastic body. An artificial polycrystalline structure is modeled using the Voronoi tessellation to ge...

Composite materials are usually treated as homogeneous when carrying out structural design. However, failure in these materials often originated at their heterogeneous microstructure or constituents; hence, the different materials should be considered in the analysis. The use of composite materials has increased considerably over the years due to t...

Bone is a self adaptative material capable of reduce inertial loads due to its lightweight and also has a remarkable strength and stiffness for body support purposes. These particular mechanical properties arise mainly from its complex hierarchical structure organization. Computational studies using Finite Elements Method have sought to understand...

This work analyses the mechanical behaviour and dynamic intergranular fracture of polycrystalline materials, combining the mesoscale to consider the heterogeneities and anisotropy of the elastic material properties and the atomistic scale to include atomic separation effects. The Dual Reciprocity Boundary Element Method is used to evaluate the dyna...

The analysis of the intergranular fracture in polycrystalline materials demands a very detailed study of the structure and behaviour of these materials, taking into account its lattice structure, irregularities and anisotropic properties in the microscale. In order to include these physical effects, it is proposed the multiscale cohesive zone model...

This work analyses the mechanical behaviour of polycrystalline structures with intergranular cracks, leading to a reduction of stiffness and material strength. The 2D polycrystalline structure is generated using an average grain size through the Voronoi tes- sellation method and simulated with random crystalline orientation. Polycrystalline materia...

Este trabalho apresenta uma análise numérica de falha dinâmica em materiais policristalinos usando modelagem multiescala. O problema foi descrito em duas escalas, a escala micro ou mesoescala e a escala atômica. A estrutura policristalina (mesoescala) é gerada usando o diagrama de Voronoi com diferentes níveis de tamanho de grão homogêneo. As equaç...

Over recent years the rapid evolution of the computational power has motivated the development of new numerical techniques to account for engineering solutions. The Boundary Element Method (BEM) has shown to be a powerful numeric tool for the analysis and solution of many physical and engineering problems. However, BEM fully populated and non-symme...

Polycrystalline structures are present on metal alloys. Therefore, it is necessary to understand and model the mechanical behavior of this media. Usually , this is accomplished by the use of different numerical methods. However, the analysis of polycrystalline materials leads to other type of problems, such as high computational requirements genera...