Modelling fatigue transition behaviour of FRP in mode I block loading

According to experiments the fatigue damage behaviour of fibre reinforced polymers (FRP) experiences a load sequence effect. In this report the ability of the cohesive fatigue damage model of Dávila (2020) to simulate the behaviour after a load amplitude change is investigated. For this a double cantilever beam (DCB) with fictitious material...

Evaluating and predicting fatigue behavior in adhesively bonded joints

The fatigue behavior of an adhesively bonded joint is of key importance to its long-term structural integrity. However, the complex stress distribution inside a bonded joint does not make it easy to evaluate the fatigue behavior. This chapter discusses the various approaches that have been developed for predicting the fatigue behavior of...

Modelling fatigue crack propagation in coped beams using XFEM

In the past years, the safety of steel railway bridges has been questioned due to the coped beam connection sensitivity to fatigue and fatigue crack appearance. To ensure the safety of these railway bridges, the propagation of the fatigue crack needs to be analysed by performing regular inspection on the bridges. The frequency of these is...

Measurement of damage growth in ultrasonic spot welded joint

Ultrasonic spot welding is a joining technique for thermoplastic composites with great potential regarding processing speed and cost. To investigate the damage tolerance and possible inherent damage arresting behavior of multi-spot welded joints, a technique is necessary to measure damage growth in the joints under cyclic loading. Visual...

A stiffness independent Interfacial Thick Level Set method: A modified approach for crack analysis

Crack growth is an important failure mechanism in many engineering materials. Numerical models for crack growth have been developed within the framework of damage mechanics. All these models aim for the same goal, obtaining accurate results for crack growth under various loading conditions. Many damage models are based upon the cohesive crack...

Fracture Mechanics: Application on Orthotropic Steel Decks

In the course of this thesis, a research has been conducted to the application of fracture mechanics on an othotropic steel deck (OSD). Obtaining accurate predictions of crack path and fatigue life assessment were the main objectives for this thesis. As 3D crack propagation modelling in orthotropic steel decks is an arduous task, simpler studies...

Prediction of Fatigue Crack Growth and Damage Directionality in Non-Conventional Fibre Metal Laminates

This thesis presents a model that is able to predict fatigue crack growth and damage directionality in non-conventional Fibre Metal Laminates (FMLs) in CentreCracked Tension (CCT) specimens. Non-conventional FMLs encompass all FMLs other than standardised ones such as GLARE. FMLs can be made non-conventional by using multiple fibre types, any...

Delamination fatigue growth in polymer-matrix fibre composites: A methodology for determining the design and lifing allowables

The introduction, originally in 2009, by the FAA of a ‘slow growth’ approach to the certification of polymer-matrix fibre composites has focused attention on the experimental data and the analytical tools needed to assess the growth of delaminations under cyclic-fatigue loads. Of direct relevance is the fact that fatigue tests on aircraft...

Using acoustic emission to understand fatigue crack growth within a single load cycle

Current methods for prediction of fatigue crack growth are based on empirical correlations which do not take the crack growth behaviour within a single cycle into account. To improve these prediction methods, more understanding of the physical mechanisms of crack growth is required. In this research the acoustic emission technique was used to...

Acoustic Emission-Based Methodology to Evaluate Delamination Crack Growth Under Quasi-static and Fatigue Loading Conditions

The aim of this study was to investigate the applicability of acoustic emission (AE) technique to evaluate delamination crack in glass/epoxy composite laminates under quasi-static and fatigue loading. To this aim, double cantilever beam specimens were subjected to mode I quasi-static and fatigue loading conditions and the generated AE signals...

Committee III.2: Fatigue and Fracture

Concern for crack initiation and growth under cyclic loading as well as unstable crack propagation and tearing in the ship and offshore structures. Due attention shall be paid to the suitability and uncertainty of physical models and testing. Consideration is to be given to practical application, statistical description and fracture control...

Fatigue behaviour of a welded I-section under a concentrated compression (wheel) load

This paper deals with the evaluation of fatigue cracks under a concentrated compression (wheel) load in an I-section with full penetration welds between the web and flange. The objective is to investigate whether cracks stop or nearly stop when they have grown through the residual tensile stress field. These experimental investigations are...

On the Development of a Volumetric Acoustic Emission Fatigue Crack Monitoring System

Research into multi-axial fatigue requires knowledge on the through time and thickness development of the propagating crack front. In order to provide this knowledge methods must be developed to monitor crack initiation and growth during a fatigue test. The acoustic emission method has been recognised as a possible means to this end. <br/...

Fatigue behaviour of a welded I-section under a line load in compression

This paper is part of an evaluation of fatigue cracks in a crane runway girder with full penetration welds between the web and flange. The fatigue analysis of this actual crane runway girder is described in [1]. The investigation described in this paper deals with additional experimental tests on equivalent welded I sections on scale of...

Characterisation of Fatigue Crack Growth in Adhesive Bonds

How proper similitude can improve our understanding of crack closure and plasticity in fatigue

The appropriateness of some common similitude principles with respect to describing and predicting fatigue damage propagation is discussed. Linear elastic fracture mechanics have provided a basis to describe damage growth using stress intensity factors or strain energy release rates, both related to the work of Griffith and Irwin. The fatigue...