Publications related to Fractography

An adaptive phase field approach to 3D internal crack growth in rocks

Alexandra Roma Larisa Kushnir, Tao Xu, Michael Heap

Modeling the 3D internal crack under compression entails complex fracture mechanics (mode I-II-III fracture), resulting in substantial computational costs and challenges in characterizing fracture morphology characterization for Phase Field Method (PFM) si ...

2024

Strain-based analysis on the influence of local undercut geometry on fatigue crack initiation life

Alain Nussbaumer, Heikki Tapani Remes, Abinab Niraula

The local undercut defects at the weld toe provide a potential initiation site for fatigue cracks and significantly impact the structure's fatigue strength. The influence of continuous undercut depth on fatigue performance is widely studied, but the resear ...

2024

CRACK SHIELDING MECHANISMS OF INTERLAYERED EPOXY MATERIALS UNDER QUASI-STATIC AND FATIGUE LOADING

Anastasios Vassilopoulos, Dharun Vadugappatty Srinivasan

This research explores the capability of PEI and PVDF thermoplastic interlayers to arrest cracks in epoxy materials modified with short-glass fibers and core-shell rubber particles. It also investigates the effect of interlayer position, the number of inte ...

Queen's University Belfast2023

Full Scale Experiments of a Composite Steel Moment Resisting Frame: Behavioral Insights and Implications on Seismic Design

Dimitrios Lignos, Hammad El Jisr

This paper discusses the cyclic performance of a heavily instrumented 2-bay full-scale composite-steel moment resisting frame (CMRF) sub-system from the onset of structural damage up until incipient collapse. The CMRF featured stiffened end plate bolted co ...

EEME2023

Determining crack kinematics from imaged crack patterns

Katrin Beyer, Bryan German Pantoja Rosero, Amir Rezaie, Ketson Roberto Maximiano Dos Santos

Determining the relationship between the cause of damage and the subsequent structural behavior of infrastructure systems requires an accurate characterization of the propagation of cracks, which represents the evolution of the damage state. When no inform ...

2022

Prediction of crack nucleation and propagation in porous ceramics using the phase-field approach

Arata Nakajo

The relevance of the phase-field approach to simulate the fracture in porous ceramics has been investigated. For this purpose, the conditions for the crack initiation using the phase-field model have been compared to the theoretical predictions of the coup ...

ELSEVIER2022

TOPO-Loss for continuity-preserving crack detection using deep learning

Pascal Fua, Katrin Beyer, Radhakrishna Achanta, Bryan German Pantoja Rosero, Doruk Oner, Fernando Perez Cruz

We present a method for segmenting cracks in images of masonry buildings damaged by earthquakes. Existing methods of crack detection fail to preserve the continuity of cracks, and their performance deteriorates with imprecise training labels. We address th ...

2022

Study on the internal crack network of the ASR-affected concrete by the tomography-based numerical model

Jean-François Molinari, Emil Gallyamov, Mahdieh Shakoorioskooie

In this paper, we present a novel finite element model to simulate alkali-silica reaction in a realistic concrete meso-structure. Application of the internal ASR loading leads to the evolution of multiple deviated cracks and corresponding macroscopic expan ...

Pergamon-Elsevier Science Ltd2022

Delayed Hydride Cracking in Irradiated and Unirradiated Zircaloy-2 Cladding

Aaron William Colldeweih

Zirconium alloys used in the nuclear industry are exposed to extreme conditions undergoing high levels of irradiation damage and corrosion. Zircaloy-2 is used as nuclear fuel cladding in boiling water reactors and for the encapsulation of the spallation ta ...

EPFL2022

Investigating the cracking of plastered stone masonry walls under shear–compression loading

Katrin Beyer, Amir Rezaie, Michele Godio

Cracks are the most important source of information about the damage that occurs to unreinforced masonry piers under seismic actions. To predict the structural state of unreinforced masonry piers after an earthquake, research models have been developed to ...

2021

Numerical modeling of two-dimensional delamination growth in composite laminates with in-plane isotropy

Thomas Keller, Anastasios Vassilopoulos, Congzhe Wang

The two-dimensional (2D) delamination growth in fiber-reinforced polymer (FRP) laminates with in-plane isotropy under Mode I loading condition was numerically investigated using finite element analyses. Two sizes of plate models were developed, focusing on ...

2021

Effect of water on sandstone's fracture toughness and frictional parameters: Brittle strength constraints

Marie Estelle Solange Violay, Corentin Jean-Marie Rémi Noël

Water presence causes a dramatic reduction of sandstone strength. Under compressive stress conditions, the strength of a rock sample is controlled by frictional parameters and the fracture toughness of the material. Here, we report fracture toughness, fric ...

2021

Predicting damage in aggregates due to the volume increase of the alkali-silica reaction products

Jean-François Molinari, Barbara Lothenbach, Emil Gallyamov

Volume increase between the reactants and the products of alkali silica reaction could reach up to 100%. Taking place inside the aggregates, ASR imposes internal pressure on the surrounding material. In the current paper, we study the possibility of crack ...

Pergamon-Elsevier Science Ltd2022

Combining active and passive acoustic methods to image hydraulic fracture growth in laboratory experiments

Brice Tanguy Alphonse Lecampion, Seyyedmaalek Momeni, Dong Liu

We combine active and passive acoustic measurements to improve the spatio- temporal imaging of hydraulic fracture growth performed under true triaxial confinement in the laboratory. 64 active piezo-electric transducers (54 P waves, 10 S waves) work in sour ...

IOP2021

Damage-driven strain localisation in networks of fibres: A computational homogenisation approach

Pablo Antolin Sanchez, Felipe Figueredo Rocha

In many applications, such as textiles, fibreglass, paper and several kinds of biological fibrous tissues, the main load-bearing constituents at the micro-scale are arranged as a fibre network. In these materials, rupture is usually driven by micro-mechani ...

2021

Meso-scale finite element modeling of Alkali-Silica-Reaction

Jean-François Molinari, Emil Gallyamov, Roozbeh Rezakhani

The Alkali-Silica Reaction (ASR) in concrete is a chemical reaction, which produces an expansive product, generally called “ASR gel”, and causes cracking and damage in concrete over time. Affecting numerous infrastructures all around the world, ASR has bee ...

2021

Microtensile failure mechanisms in lamellar bone: Influence of fibrillar orientation, specimen size and hydration

Johann Michler, Daniele Casari, Tatiana Kochetkova

A mechanistic understanding of bone fracture is indispensable for developing improved fracture risk assessment in clinics. Since bone is a hierarchically structured material, gaining such knowledge requires analysis at multiple length scales. Here, the ten ...

ELSEVIER SCI LTD2021

3D laser shock peening - A new method for improving fatigue properties of selective laser melted parts

Roland Logé, Christian Leinenbach, Nikola Kalentics, Manuel Ortega Varela De Seijas

Although Selective Laser Melting (SLM) currently revolutionizes the way parts are being manufactured, certain process inherent limitations such as accumulation of residual stresses and increased porosity content can lead to a decrease in fatigue life of pr ...

ELSEVIER2020

How Fast Cracks in Brittle Solids Choose Their Path

John Martin Kolinski

While we fundamentally understand the dynamics of simple cracks propagating in brittle solids within perfect (homogeneous) materials, we do not understand how paths of moving cracks are determined. We experimentally study strongly perturbed cracks that pro ...

2020

Detection and Measurement of Matrix Discontinuities in UHPFRC by Means of Distributed Fiber Optics Sensing

Eugen Brühwiler, Bartlomiej Wojciech Sawicki, Antoine Bassil

Following the significant improvement in their properties during the last decade, Distributed Fiber Optics sensing (DFOs) techniques are nowadays implemented for industrial use in the context of Structural Health Monitoring (SHM). While these techniques ha ...

2020