Redesign of a composite sports car to accommodate a battery electric powertrain for type approval in the European Union

The goal of this research was to get a better understanding of the consequences of the integration of a battery electric powertrain on the chassis layout and its type approval in the European Union. The Roding Roadster was used as reference throughout this research. Based on the legislation for type approval within the European Union,...

Online non-destructive evaluation in automated fibre placement

The strict quality requirements for aerospace composite structures give rise to costly quality control procedures. In automated fibre placement (AFP) these procedures rely heavily on manualwork and inspection. This research aims at performing preventative non-destructive evaluation of composite laminate quality based on an online geometric...

Prediction of Buckling-Induced Delamination Growth Onset in Composite Laminates

A one-dimensional analytical solution to predict buckling-induced delamination growth was developed toward an efficient and effective engineering application. The postbuckling solution for a composite beam was first obtained with nonlinear deflection approximations based on 'thin film' assumption. An interlaminar stress analysis method was then...

Acoustic emission monitoring of fatigue damage progression in composite ship structures: A constitutively-informed approach to acoustic emission source classification

AE-based structural integrity monitoring of composite structures potentially offers the means to gain knowledge on in-service damage accumulation, as well as mitigation of some of the risks associated with in-service damage. However, validation of any identified classes of AE events with regard to their underlying source mechanics is generally...

A strain invariant criterion for open hole failure in quasi-isotropic composite structures

In aerospace industry, composites structures are widely used because of their high stiffness to weight ratio. To ease the manufacturing process, components are assembled together using fasteners which leads to introduction of holes in composites. The failure of these composite structures is affected the high stress concentration region around...

Modelling Delaminations in Composite Panels: Including Novel Theories for Post-Buckling and Delamination Growth

Even though composite materials are being applied more and more often, these materials are often not used to their full potential. In particular, composite materials are very sensitive to Compression-After-Impact (CAI), typically leading to knockdown factors in the order of 0.65. Many researchers have tried to predict the effects of Compression...

Welding of thermoplastic to thermoset composites through a thermoplastic interlayer

Research into the fusion bonding of joints containing thermoplastic and/or thermoset composites. A thermoplastic interlayer is co-cured with the thermoset that provides a fusible surface. Depending on the type of materials the interlayer can form an adhesive interface or a gradient interphase with the thermoset. Welding of thermoset composite to...

Investigation into the weight saving potential of multi-spar torsion-bending boxes

This thesis continues the work performed by Ferreira and Almeida on the topic of weight and cost reduction of composite multi-spar torsion-bending boxes. The goal is to find the influence of changes to the structural configuration on the resulting weight of said torsion-bending boxes. Using analytical methods, combined into the BoxSolver MATLAB...

Design of a lightweight FRP T-boom for an offshore gangway, and development of a fatigue model for prediction of its service life

The high stiffness to weight ratio of fibre reinforced composites have been utilized in improving the performance of various structures conventionally designed using metals. One such application is the gangway of the Ampelmann system used to transfer personnel safely from and to the offshore platform in sea. In the current work, a preliminary...

Thermal Characterization of Structure-Integrated Thermal Subsystems based on the MASCOT Landing Module

Accurate thermal characterisation of composite structures can help structural designers in predicting thermal paths in a spacecraft structure and assessing the effect of modifying materials on the structure’s overall thermal performance. Existing spacecraft thermal analysis software lack the ability to model anisotropic thermal properties of...

Predicting Onset of Damage in Special Class of Laminates under Tension

In design with composite materials, the capability of tailoring the properties of the structure with respect to the specific load requirements in each direction, allowed by their anisotropic nature, is coupled with the development of interlaminar stresses transferred through the thickness. Specifically, at the free edge of the laminate, due to...

Spatial variability of stiffness in fiber reinforced composites in short beam shear test specimens

Modern and future aerospace structures make increasing use of fiber reinforced composite materials to optimize structural performance. Yet, characterizing the composite material properties is very expensive and time consuming. Parameters like non-linear shear and their interactions with stresses perpendicular to the fiber direction are hardly...

Preliminary fatigue analysis of anionic polyamide-6 composites

Thermoplastic blades offer a variety of advantages to the wind energy industry, but also a few major drawbacks. One of these is the weak fiber to matrix bond in traditional melt processed thermoplastic composites. Because fatigue is dependent on a strong interface, and it is a driving requirement for wind turbine blades, research has been...