Gokul Murali

Project description

Shape-memory structures have a wide scope of potential application ranging from deployment of satellites to drag reduction in aircraft. There are several studies taking place worldwide that are investigating the capability of shape memory composites for such applications. Traditionally, shape memory composites are made of at least one specialised shape memory material thus increasing their complexity and decreasing their feasibility. This project will focus on the development of shape memory composites without any shape memory constituents in an attempt to make a commercially viable product.

The aim of this project is to develop and optimise ‘intrinsically heated’ shape memory composites for satellite applications. This project will build upon the earlier works of Prof Paul Robinson (Imperial College London), who will be supervising it. The scope of this project includes the development of the composite, optimisation of structure, and modelling of this phenomenon.


PhD Researcher at Imperial College London (2019-Present)

M.Sc., Aerospace Engineering, Delft University of Technology, (2016-2018)

Research interests

High-performance composites, materials characterization techniques, NDT, functional materials, and adhesives technology.

Personal note

Outside of my academic life, I love travelling, personal fitness, watching movies, and reading fantasy fiction books. I also love cooking, and would always be up for a coffee and meeting new people.

Latest publications by this author

Improving the performance of pseudo-ductile hybrid composites by film-interleaving [OPEN ACCESS]

Salvatore GiacomoMarino, GergelyCzél

Improvement of the interfacial fracture toughness of the layer interfaces is one way to increase the performance of interlayer hybrid laminates containing standard thickness carbon/epoxy plies and make them fail in a stable, progressive way. The layer interfaces were interleaved with thermoset 913 type epoxy or thermoplastic acrylonitrile–butadienestyrene (ABS) films to introduce beneficial energy absorption mechanisms and promote the fragmentation of the relatively thick carbon layer under tensile loads. Carbon layer fragmentation and dispersed delamination around the carbon layer fractures characterised the damage modes of the epoxy film interleaved hybrid laminates, which showed pseudo-ductility in some cases. In the ABS film interleaved laminates, a unique phase-separated ABS/epoxy inter-locking structure was discovered at the boundary of the two resin systems, which resulted in a strong adhesion between the fibre-reinforced and the thermoplastic layers. As a result, the delamination cracks were contained within the ABS interleaf films.

Effect of Plasma-Treatment of Interleaved Thermoplastic Films on Delamination in Interlayer Fibre Hybrid Composite Laminates [OPEN ACCESS]

Salvatore Giacomo Marino, Florian Mayer, Alexander Bismarck and Gergely Czél

Safe, light, and high-performance engineering structures may be generated by adopting composite materials with stable damage process (i.e., without catastrophic delamination). Interlayer hybrid composites may fail stably by suppressing catastrophic interlayer delamination. This paper provides a detailed analysis of delamination occurring in poly(acrylonitrile-butadiene-styrene) (ABS) or polystyrene (PS) film interleaved carbon-glass/epoxy hybrid composites. The ABS films toughened the interfaces of the hybrid laminates, generating materials with higher mode II interlaminar fracture toughness (GIIC), delamination stress (σdel), and eliminating the stress drops observed in the reference baseline material, i.e., without interleaf films, during tensile tests. Furthermore, stable behaviour was achieved by treating the ABS films in oxygen plasma. The mechanical performance (GIIC and σdel) of hybrid composites containing PS films, were initially reduced but increased after oxygen plasma treatment. The plasma treatment introduced O-C=O and O-C-O-O functional groups on the PS surfaces, enabling better epoxy/PS interactions. Microscopy analysis provided evidence of the toughening mechanisms, i.e., crack deflection, leading plasma-treated PS to stabilise delamination.

Understanding the mechanical response of glass and carbon fibres: stress-strain analysis and modulus determination

Rajnish Kumar, Lars P Mikkelsen, Hans Lilholt and Bo Madsen

Accurate characterization of fibres is crucial for the understanding the properties and behaviour of fibre-reinforced composite materials. Fibre properties are key parameters for composite design, modelling and analysis. In this study, characterization of mechanical properties of glass and carbon fibres has been performed using a semi-automated single-fibre testing machine. Based on a sample set of 150 glass and carbon fibers fibres, engineering and true stress-strain curves are analyzed. Different modulus determination methods are discussed based on true stress-strain and tangent modulus-strain relationships. For glass fibres, the true stress-strain based tangent modulus is found to be independent of applied strain, whereas for carbon fibres, a tendency of tangent modulus to increase with applied strain is observed. The modulus of glass fibres is found to be independent of fibre diameter, whereas carbon fibres with smaller diameter show higher modulus compared with carbon fibres with larger diameters.