Methods for the exclusion of the fibre bridging effect in composite structures under cyclic Mode I loading

In composite structures, delamination damage is typically the most common failure mechanism. Accurately characterizing the delamination behaviour of composite laminates is therefore crucial for predicting the fatigue safe-life of such structures. To this end, double-cantilever beam (DCB) composite specimens are used to measure the interlaminar...

Fatigue life prediction of composite marine propellers

Fiber reinforced composites have been increasingly used in the aerospace and automotive industry, due to their potential advantages for designing flexible, strong and lightweight structures. More recently they are also being considered for the manufacturing of marine propellers. Since they have the potential to lower the weight, lower the...

Fatigue Behavior of Multi-Spot Welded Joints in Thermoplastic Composites: Effects of Spot Arrangement in a Four-Spot Joint

Welding is a joining method for thermoplastic composites (TPCs) that offers multiple advantages over the more traditional methods of mechanical fastening and adhesive bonding. A particularly promising welding technique is ultrasonic welding, which features very short process times as a result of the high heating rates that can be achieved. This...

Online Prognostics of Remaining Useful Properties for Cross-Ply Composites in Early Fatigue Life: A Model-Based Machine Learning Approach

High performance continuous fiber-reinforced composites are becoming increasingly important in the aerospace industry. In these structures, internal damage is often created and propagated throughout the lifetime, having a negative impact on the structural properties. In order to allow for condition-based maintenance, there is a need for reliable...

Investigating energy dissipation for a methodology to fatigue master curves

A Progressive Blended Fatigue Framework for FRPs

In general, damage models for Fibre-Reinforced Polymers (FRPs) can be divided into two categories: Continuum Damage Models (CDMs) and Fracture Mechanics Damage Models (FMDMs). Damage models within each of these categories are advantageous for different type of failure mechanisms. Therefore, it is of interest to develop a unified framework in...

Durability of stiffened CFRP panels with initial delaminations

A numerical fatigue delamination model is validated by means of experimental tests. Delamination is initiated on the skin-stiffener interface which, under cyclic compressive loading and in the post-buckling regime, grows at a decreasing rate. A cohesive zone formulation is used to model the static and fatigue delamination growth, good agreement...

Fatigue life prediction of carbon fibre-reinforced epoxy laminates using a single S-N curve

Fatigue life prediction models, used in the design and analysis of cyclic loaded structures, often require experimental data in order to interpolate or extrapolate fatigue behaviour to different loading conditions. Due to scatter in fatigue life data, as well as model input requirements of several S-N curves, large numbers of experimental tests...

Predicting residual strength of composites after cyclic loading: A numerical, progressive damage analysis based approach

As the demand on new lightweight materials increases due to economic and environmental reasons, fiber reinforced plastics seem an interesting solution. In order to maximize their potential, ways have to be found to introduce damage tolerant designs. To this end, in the present exercise, the damage caused by cyclic loading is investigated.<br/...

Compression-Compression and Tension-Compression Fatigue of Textile Carbon-Epoxy Composites: Experimental Testing and Instrumentation

Efficient design of woven composite structures is limited by a knowledge gap in predictive modeling of their behaviour. Fatigue modeling in particular is difficult and limited by a lack of experimental data. For compression-compression (C-C) or tension-compression (T-C) fatigue, experimental results in literature are uncommon. In this master...