Characterisation of Fatigue Crack Growth in Adhesive Bonds

Modeling fatigue-driving delamination using a thick level set interface model

This paper presents a new discontinuous damage model for simulating fatigue-driven delamination in composites. Fatigue models commonly describe crack growth using the Paris law which provides the link between the energy released due to delamination and the crack growth rate. A core issue in implementing the Paris law is to accurately compute the...

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...

Online Remaining Fatigue Life Prognosis for Composite Materials Based on Strain Data and Stochastic Modeling

The present study utilizes a state-of-the-art stochastic modeling with structural health monitoring (SHM) data derived from strain measurements, in order to assess the remaining useful life (RUL) online in composite materials under fatigue loading. Non-Homogenous Hidden Semi Markov model (NHHSMM) is a suitable candidate with a rich mathematical...

On Dynamic Fatigue Loads on Composite Downlines in Offshore Service

Offshore oil & gas production is an industry where breaking records has become a necessity. So-called unconventional oil in ultra-deep water (2000 m+) requires rethinking of current production techniques, as steel tubing begins to buckle under its own weight. Other problems arise from corrosion of pipelines at all depths, requiring expensive...

Multiaxial Fatigue due to Wave Induced Accelerations in a Flex-lay Tower Structure

Marine and offshore structures are continuously exposed to different loading types. Cyclic loads results in cyclic stresses in structural components, which may result in degradation of the structural integrity. This process is called fatigue. Fatigue damage of structural components usually occurs without any —global— visible sign. Ultimately,...

Stress Intensity Factors for Fatigue Crack Growth Analysis

Fatigue loads and failures in metallic structures are a well-known technical problem. Commonly, the fatigue life of the steel elements is determined by an analytical calculation using S-N curves as design resistance to periodic action. However, the technological improvements in almost all structures continuously stretch the limits of acceptance...

Static and fatigue performance ofthick laminates test design and experimental compression results

The aim of this work is to study the thickness effect in static and fatigue tests of glass-fibre unidirectional compression coupons. For this purpose, the self-heating effect, the effect of specimen geometry, and the influence of the manufacturing processes have been minimized. A scaled thickness compression coupon has been designed with the...

Low Cycle Corrosion Fatigue in the North Sea Environment

Low cycle corrosion fatigue is an interesting issue in civil Engineering because it may effect the lifetime of structures in negative and unexpected ways. However, analysis of design codes has revealed that low cycle corrosion fatigue is not a major issue in the design of offshore structures because these structures are designed with a global...

Multi-Scale Modelling of Fatigue of Wind Turbine Rotor Blade Composites

In this research, extensive fatigue tests were performed on single glass fibres and composite coupons. Comparison of the test results shows that there is a significant difference between the fibre and composite fatigue behaviour. In order to clarify this difference, a multi-scale micro-mechanical model was developed. This model predicts fatigue...

Characterization and Identification of Bituminous Materials Modified with Montmorillonite Nanoclay

Montmorillonite (Mt) nanoclay is a layered silicate mineral with a 2:1-type layer structure, two tetrahedrals sandwiching one octahedral. In recent decades, it is successfully introduced into polymer systems to form polymer-clay nanocomposites (PCN) in which the silicate layers of the Mt are randomly and homogeneously dispersed at a molecular...

Stress concentration factors for multiplanar joints in RHS

Hollow sections are most suitable for welded connections between members. The welding procedure is fairly straightforward in RHS, because they do not require profiling which is necessary for circular hollow sections. Although many multiplanar and uniplanar joints in structures are present, limited evidence is available for the fatigue behaviour...

High temperature gas turbine materials

The requirements and problems of high temperature materials in gas turbines are reviewed, with specific reference to turbine discs, blades, vanes and combustion cans. The mechanical and environmental property requirements of these components are discussed, followed by an overview of the types of materials used. Lastly, there is a summary of the...