An integrated computational methodology for coupling in-crack physics with the adjacent environment: With an application on Solid-State Batteries

This thesis introduces a new computational methodology to solve partial differential equations within cracked domains, focusing on coupling in-crack physics with the adjacent environment. The crack is represented discretely, allowing to describe explicitly the crack opening, which is a key parameter in the description of the in-crack physics....

A Novel Approach to Modeling Arbitrary Damage in Composite Structures through a Discontinuous Galerkin Cohesive Zone Model

Finite Element Methods (FEMs) are widely employed for damage simulation in composites, with the Cohesive Zone Model (CZM) being particularly favored for its robustness and scalability. Despite the CZM's mesh-dependent nature, the Discontinuous Galerkin Cohesive Zone Model (DG/CZM) formulation allows for relatively arbitrary crack propagation...

Multiscale microstructure-based modelling of cleavage in high strength steels

The need for more accurate cleavage modelling is particularly acute for a new generation of high-strength steels because they obtain their favourable properties through complex, multi-phase microstructures. One of the challenges in cleavage modelling is the strong sensitivity to material characteristics at the microlevel. This thesis proposes a...

Fracture and Failure of Adhesives

This article presents an overview of methods for analyzing the facture and failure of adhesives. Special attention is given to stress analysis in adhesive bonds, as the difficulty of performing an accurate stress analysis is a major limitation of many failure analysis methods. The article also covers the effect of manufacturing and...

Methodology for the prediction of the strength of naturally aged glass based on surface flaw characterization

Flat glass is a material which is used extensively in almost all the buildings, mainly as infill for windows or facade panels. However, neither glass production nor its recycling are sustainable processes, as both incorporate the use of gas furnaces, which produce high amounts of CO2 emissions. Thus, the re-use of glass seems the only way to...

Enhancement of mode I fracture toughness of adhesively bonded secondary joints using different layup patterning of CFRP

Delamination growth in fibre reinforced polymer composites is generally evaluated with experiments that have been standardized for quasi-static load conditions. These tests characterize unidirectional delamination growth in mode I (DCB), mode II (ELS or ENF) of mixed mode conditions (MMB). However, little attention is paid in literature to the...

Do standard delamination tests relate to planar delamination growth?

Delamination growth in fibre reinforced polymer composites is generally evaluated with experiments that have been standardized for quasi-static load conditions. These tests characterize unidirectional delamination growth in mode I (DCB), mode II (ELS or ENF) of mixed mode conditions (MMB). However, little attention is paid in literature to the...

Higher order adaptively integrated cohesive element

Cohesive Element (CE) is a well-established finite element for fracture, widely used for the modelling of delamination in composites. However, the computational time of CE-based method is prohibitive. This is because the steep and non-smooth stress gradient in the cohesive zone requires a very fine mesh. In this context, a new type of CE is...

Three-dimensional Mixed-Mode Crack Propagation Calculations based on a Submodel Technique

Damage tolerant designs are necessary for the continuous operation of aircraft engines which are subjected to harsh environmental influences during operation (e.g. large temperatures, foreign object damage of airfoils). One important aspect of damage tolerance is crack propagation which can be investigated via 3D numerical software. This Master...

A Comparative Study of Thermo-Mechanical Fatigue Performance of Different Grades of SiMo Nodular Cast Iron

This thesis is a comparative study of the Thermo-Mechanical Fatigue (TMF) performance of different grades of SiMo nodular cast iron for heavy-duty diesel engine exhaust gas manifold applications. The TMF performance of the current SiMo variant used to manufacture exhaust manifolds - SiMo 5.10 (C-3.25Si-4.45Mo-0.76), is compared with that of the...

Load sequence effects on fatigue crack growth: A variable amplitude fatigue model in the framework of the Thick Level Set method

Recently a new framework to predict fatigue crack growth has been developed based on the Thick Level Set method. The aim of this thesis is to extend this framework to allow for realistic loading spectra. First, a calibration method for this framework is presented. This method decouples crack growth, defined by a Paris like equation, from the...

Thermo-Mechanical Fatigue-Lifetime Determination of Diesel Engine Exhaust Manifolds

The start-up and shut-down cycling of a heavy-duty truck engine leads to temperature and mechanical strain variations in the exhaust manifold, subjecting it to thermo-mechanical fatigue (TMF) damage. For the automotive manufacturers, it is essential to accurately predict the TMF lifetimes of the exhaust manifolds under service conditions. The...