Environmental degradation of adhesively-bonded composite joints

Test method to assess interface adhesion in composite bonding

This paper introduces a new type of peel tests dedicated to composite bonding: Composite Peel Tests. This test is inspired on the standard floating roller peel test widely used for metal bonding. The aim of this study is to investigate the potential of the Composite Peel Test to assess interface adhesion in composite bonded structures. To this...

Resistance Welding of Thermoplastic Composites: Process and Performance

Compared to thermoset composites, thermoplastic composites are drawing more and more attention by aircraft industries not only due to their excellent material properties but also due to their potentials to reduce cycle time and structure cost by using low-cost manufacturing technologies such as welding. Resistance welding has been regarded as...

Static Aeroelastic Optimization of Composite Wings with Variable Stiffness Laminates

The application of composite material in load carrying structural components of an aircraft is rapidly gaining momentum. While part of the reason for this can certainly be attributed to an increasing confidence of designers in the new material as a result of growing experience, two other crucial points can be made. One, the continuous...

Delamination and debonding failure of laminated composite T-joints

Composites are increasingly being used in aerospace, automotive and other industries. The T-joint (also named stringer stiffened skin) is a typical connection, broadly used in thin-walled structures, such as the wing and fuselage of aircraft. This thesis presents the analysis of the delamination and debonding failure of laminated composite T...

Fibre Placement Architectures for Improved Damage Tolerance

Composites are notorious for their poor impact behaviour. Delaminations seriously decrease the compressive strength of the material after impact. Laminates made from woven fabric show in general more beneficial impact behaviour than laminates with unidirectional layers, but their manufacturing process is harder to automate. The new fibre...

Stiffness and Layout Tailoring of a Morphing High-lift System with Aeroelastic Loads

Lamb wave detection in prepreg composite materials with fibre Bragg grating sensors

This paper demonstrates that existing Structural Health Monitoring (SHM) techniques have potential during the production phase in addition to their application for maintenance and for in-flight monitoring. Flaws occur during composite fabrication in industry, due to an imperfect process control and human errors. This decreases production...

Optimization of sandwich composites fuselages under flight loads

The sandwich composites fuselages appear to be a promising choice for the future aircrafts because of their structural efficiency and functional integration advantages. However, the design of sandwich composites is more complex than other structures because of many involved variables. In this paper, the fuselage is designed as a sandwich...

Novel routes to liquid-based self-healing polymer systems

Inspired by the current state-of-the-art and the progressing advancements in the field of self-healing materials, this thesis addresses several novel routes to advance the concept of liquid-based self-healing polymer systems. This thesis presents the concept and characterisation of a one-component solvent-based healing mechanism for...

Usage of fiber Bragg grating sensors in low earth orbit environment

It is widely known that materials exposed to the severe low earth orbit (LEO) environment undergo degradations. For the evaluation of fiber Bragg grating (FBG) sensors in the LEO environment, the reflective spectrum change and the Bragg wavelength shift of FBG sensor were measured during aging cycles simulating the LEO environment. The LEO...

Materials and manufacturing processes of the Superbus

The Superbus is a new public transportation non polluting, fast, economic, and appealing vehicle developed in The Netherlands as proof of concept for the implementation of a new transportation system which includes totally new infrastructure and logistics. This new vehicle is sustainable, can transport passengers and goods from point to point...

Multilevel design optimization of composite structures with blended laminates

This research work deals with the design and optimization of a large composite structure. In design of large structural systems, it is customary to divide the problem into many smaller independent/semi-independent local design problems. The use of composite necessitates the inclusion of ply angles as design variables. These design variables are...

Fatigue life prediction and strength degradation of wind turbine rotor blade composites

Wind turbine rotor blades are subjected to a large number of highly variable loads, but life predictions are typically based on constant amplitude fatigue behaviour. Therefore, it is important to determine how service life under variable amplitude fatigue can be estimated from constant amplitude fatigue behaviour. A life prediction contains...