Quasi-static and Fatigue Strength of Helically Wrapped Structures

A Helically wrapped structure is a hollow pipe structure that is made from a metal strip and the overlapping interfaces are adhesively joined. It is yet unknown how to determine the quasi-static strength and predict the fatigue life of this structure. A method was developed to determine whether either the adherend or the adhesive is critical to...

Evaluation of Grid-Stiffened Structures For Applications on Drones

The use of Grid-stiffened structures has been increasing in the space industry over the last decade. Thanks to it is high specific mechanical properties and excellent damage tolerance characteristics, researchers also started looking into the potential of using them for aeronautical applications. However, not much has been done to investigate...

A Fibre-Path Generation Algorithm for Fibre-Steered Variable Stiffness Laminates

The development of novel materials has been of great interest to the aerospace industry in the pursuit of efficiency and cost reduction. Fibre-steered variable stiffness laminates have promising characteristics due to the ability to better tailor designs for expected loading, as the fibre orientation can be varied within a layer. This thesis was...

Buckling performance improvement in 3d printed variable stiffness composite laminates: Analyzing effect of steering curvature in performance of laminates

Over the past decades, fibre-reinforced composite structures have been increasingly adopted into mainstream manufacturing over conventional metals owing to their higher performance attributes, such as superior strength-to-weight ratios. Composite structures offer the unique advantage of tailoring reinforcements in correspondence with design load...

Microstructural characterisation of recycled carbon fibre reinforced polymer composites: Application and evaluation of the method of ellipses

Carbon fibre reinforced polymer (CFRP) composites are well-known for their specific strength and stiffness properties. For the past two decades, various industries have increasingly used these materials to improve performance and reduce emissions. This increased use has caused a problematic growth in both production and end-of-life CFRP waste....

Design and optimisation of a type IV composite pressure vessel

Due to an ever-growing demand for sustainable transportation, there is an increased need for the development of hydrogen as an energy carrier. Based on mass, hydrogen contains about three times as much energy as conventional gasoline. However, the volumetric energy density, which is the amount of energy per volume unity, is much lower for...

Modelling Skin-Stringer Separation in a Post-Buckled Composite Stiffened Panel through Single Stringer Specimens

The collapse of composite stiffened panels in compression is complex and involves the interactions of many different failure modes. However, when the panel is allowed to enter the post-buckling regime, skin-stringer separation due to the interaction of the post-buckling deformations with the skin-stringer interface is often the critical failure...

Disassembly of fusion bonded thermoplastic composite joints aided by induction heating: Effects of induction heating on disassembly force and damage patterns

Disassembly of fusion bonded joints aided by induction heating was investigated. Single-lap shear experiments were performed while heating the joint with an induction coil to research the effect on force required and damage inflicted during disassembly. Co-consolidated CF/PEEK samples with and without a metal mesh susceptor and ultrasonically...

Topology optimization, variable stiffness design and staggered optimization for laminated composite structures: a comparative study

The demand for efficient lightweight structures grows rapidly in the aerospace sector. Topology optimization, introduced in the late 80s, is a method capable of producing such structures and has been mainly studied for isotropic materials. On the other hand, the performance of composite structures, which are already widely employed in the...

Effect of Rapid Laser Deconsolidation on Intimate Contact Development

L-AFP is able to place composite tapes in very precise directions, thereby allowing tailored stiffness designs. The laser is used to heat the thermoplastic matrix material to temperatures above its melting point. CF/PEEK is a popular choice for aerospace grade structures due to the high structural performance and high glass transition and...

Multi-Objective Optimisation of Variable Stiffness Cylindrical Shells: An Artificial Intelligence Approach

The structural properties of a composite laminate can be tailored by allowing the fibres to vary their orientation within the individual plies. This class of composites is termed variable stiffness and they are able to enhance the structural performance over traditional laminates by redistributing the internal load of the structure. Therefore,...

A Study of Free Edge Stresses and Delamination Initiation in Fibre Reinforced Composite Laminates

Near free edges of fibre reinforced composite laminates modelled with homogeneous layers, the presence of high gradient interlaminar stresses has been found theoretically. Over a span of nearly 50 years, various methods, including numerical and analytical have been employed for analysis of the high gradient stresses which sometimes exist to an...