A methodology to reproduce postbuckling in composite panels to study skin stringer separation

A building block pyramid is designed used to evaluate a composite aircraft structure, combining tests and analyses, using stiffened panels, single-stringer specimens and coupons. Failure in these structures can be caused by postbuckling-induced skin-stringer separation, which is complex, involving matrix cracks, fibre bridges, and delamination...

Analysis of thermoplastic composites and conduction welded joints

Thermoplastic composites enable new manufacturing techniques such as conduction welding to make the aviation industry more sustainable, while at the same time, provide great benefits to cost-efficient high-volume production. One of the benefits of welding is that it reduces the amount of mechanical fasteners required. Fastener-free joining also...

Transonic Wing and Control Surface Loads Modelling for Aeroservoelastic Analysis

The exponential growth of the aviation sector combined with environmental and energy supply challenges have led companies to innovate to reduce aircraft fuel consumption. Among the many areas currently under research, this thesis investigates the possibility of making aircraft wings lighter thanks to flight load alleviation systems and more...

Buckling, Post-buckling and Vibrations of Composite Plates under Combined Thermomechanical Loads

A big technological leap in Carbon Fibre Reinforced Plastics (CFRP's) has brought to the market materials that are able to operate under severe thermomechanical loading conditions and yet remain lightweight. This is of high interest for new developments in aerostructures, such as supersonic airliners or the hydrogen aircraft. A continuous need...

Simultaneous Optimisation of Composite Wing Structures and Control Systems for Active and Passive Load Alleviation

Future composite aircraft wing designs will exploit anisotropic material properties by aeroelastic tailoring and include active control methods for manoeuvre and gust load alleviation. The research focuses on the simultaneous optimisation of aeroelastically tailored wing structures with active manoeuvre and gust load alleviation as well as the...

Dynamic aeroelastic optimization of composite wings including fatigue considerations

The COVID-19 pandemic had a significant impact on the aviation industry with more than 60% reduction in the passenger traffic in the year 2020 compared to year 2019. The passenger traffic which is now expected to reach the 2019 level only around the year 2024 will still continue to grow but at a lower pace compared to the pre pandemic levels....

Aeroelastic Tailoring of Composite Aircraft

The process of designing an aircraft is generally divided in three phases, namely the conceptual, preliminary and detailed. The whole process is one that involves various disciplines and is subject to multiple constraints. Traditionally the different aspects of the design process are tackled separately by different departments within a company....

Optimal Design of Structures and Variable Stiffness Laminates with Strength and Manufacturing Constraints

Reducing weight and improving strength of structures have always been major design goals in the aerospace industry since its inception. In particular, strength directly affects the safety and serviceability of an airplane and is therefore of great importance in structural design. Improving the strength of an airframe can effectively increase its...

High-Fidelity Load and Gradient Corrections for Static Aeroelastic Tailoring of Composite Wings

Multi-disciplinary design optimization (MDO) is a field that has gained traction in recent years. It can be distinguished as a methodology that promotes a simultaneous change in design features associated to multiple disciplines in order to achieve the best possible design of a coupled multi-disciplinary problem. A typical application in...

Towards Geometrically Consistent Aerostructural Optimisation of Composite Aircraft Wings

Modelling fracture and healing in particulate composite systems

Research in the field of self-healing materials gained significant attention in the last decade owing to its promise of enhanced durability of the material components in engineering applications. Though the research has led to several successful demonstrations, extensive experimental tests will be required for a successful demonstration. Further...

Aeroelastic Modelling and Design of Aeroelastically Tailored and Morphing Wings

In order to accommodate the growth in air traffic whilst reducing the impact on the environment, operational efficiency is becoming more and more important in the design of the aircraft of the future. A possible approach to increase the operational efficiency of aircraft wings is the use of aeroelastic tailoring, by taking advantage of the...

Design Optimisation of Practical Variable Stiffness and Thickness Laminates

The use of composite materials in airplanes has been increasing over the last decades, mainly due to the high strength-to-weight and stiffness-to-weight ratio of composites. Traditionally, the possible fibre angles are often restricted to 0°, ±45° and 90°, referred to as conventional laminates. However, with the rise of fibre placement machines,...

Delamination Analysis of A Class of AP-PLY Composite Laminates

A recently developed fiber placement architecture, AP-PLY, has been shown to give significantly improved damage tolerance characteristics of composite structures. The behavior of delaminations resulting from low speed impact damage is of particular concern. Major attention has been paid to expand current knowledge on the delamination response of...

Isogeometric Shape Optimization for Quasi-static and Transient Problems

The recently developed isogeometric analysis (IGA) was aimed, from the start, at integrating computer aided design (CAD) and analysis. This synthesis of geometry and analysis has naturally led to renewed interest in developing structural shape optimization. The advantages of using isogeometric analysis in shape optimization are embodied in its...

Isogeometric analysis for thin-walled composite structures

The conceptual ideas behind isogeometric analysis (IGA) are aimed at unifying computer aided design (CAD) and finite element analysis (FEA). Isogeometric analysis employs the non-uniform rational B-spline functions (NURBS) used for the geometric description of a structure to approximate its physical response in an isoparametric sense. Due to the...