Numerical Modelling of Skin-Stringer Separation in Thermoplastic Composite Stiffened Panels

This thesis project focuses on the evaluation of the Extended Finite Element Model (XFEM) for modelling skin-stringer separation in thermoplastic composite stiffened panels. The study uses test results from a reference study in the literature on a PEKK-FC carbon composite panel with three stringers joined to the skin using a short-fibre...

Sustainability Integration in Engineering Practice: A Comparative Life Cycle Assessment Study for the Case Study of a Wing Rib

Having seen exponential growth in demand for air travel, the aviation industry has found itself trying to find a balance between economic growth, technological development, and environmental sustainability. This saw a shift in attention towards materials such as fiber reinforced composites, predominantly thermoset in the past with higher...

Development and Testing of a Tailored Resistance Heating Element for Resistance Welding with the Aim to Achieve Temperature Uniformity at the Welding Interface

Numerical and experimental study on post-buckling skin-stringer separation in butt-joined stiffened thermoplastic panels

So far thermoset based composites have been used in primary aircraft structures, owing to their good performance and vast research on the subject. Recently thermoplastic based composites also gained an increased attention and there is a push towards adopting these for primary aircraft structures as well. This interest for thermoplastic...

In vitro evaluation of a PEKK and poly-carbonate-urea-urethane implant for the treatment of osteochondral defects

Cartilage repair remains a major challenge and treatment of osteochondral defects generally results in inferior quality fibrous repair tissue. This study aims to elaborate on the work of Korthagen et al. who developed a thermoplastic polyurethane and polyetherketoneketone implant to treat osteochondral defects. Although promising results were...

Influence of induction welding on PEKK crystallization: Computational, analytical and experimental investigation

Current studies about crystallization kinetics of polymers are aimed at Differential Scan- ning Calorimetry (DSC), characterized by constant conditions of temperature, cooling and heating rate. This is of limited use to industry, as non constant cooling/ heating rates occur during most manufacturing processes. This research is aimed at predict-...

Induction heating of uni-directional carbon-fibre PEKK composites: Multiphysics modelling

The usage of carbon-fibre reinforced composite materials in the aerospace industry has been steadily increasing due to their light weight solution with respect to their metal counterparts. Using thermoplastic resins gives rise to induction heating as a joining technique. Induction heating can be applied by utilising the inherent material...

Critical Parameters in Mode I Interlaminar Fracture Toughness Testing of Thermoplastic Composite Materials

The goal of the thesis (executed for Fokker Aerostructures) was to further the understanding of critical parameters in the DCB test method for thermoplastic composites. The influence of fiber bridging, specimen thickness, insert film thickness, crack length and crack opening rate are investigated by means of experimental DCB tests for...

Optimising Ultrasonic Welding of Carbon Fibre PEKK Composites

The interest of the aerospace industry in thermoplastic composites has increased over the last years. One of the advantages of using thermoplastics over thermosets is the possibility to use thermoplastic welding as a joining technique. Ultrasonic welding is considered one of the most promising variants: it is very fast, results in high-quality...