Mechanical testing and quantification of crack healing in self-healing yttria-stabilized zirconia thermal barrier coating

Thermal barrier coatings (TBC) are often applied to hot components of modern turbojet engines. These coatings increase the performance of the engine and enhance the lifetime of its structural components. Thus, improving the TBC lifetime is related with a reduction of maintenance costs and increased reliability. As an alternative to conventional...

Active corrosion protection of aluminium AA2024-T3 with corrosion inhibitor loaded electrospun nanofibres: An exploratory study and proof of concept

Aluminium AA2024-T3 is a high strength aluminiumalloy widely used in aerospace. The strengthening copper-rich intermetallic phases, however, make the material very susceptible to aqueous corrosion and severe pitting. To protect the metal, coatings loaded with corrosion inhibitors are typically used. Traditionally, highly efficient CrVI-based...

A study on the temporal evolution of bainitic ferrite in medium Mn steels using in-situ HT-LSCM

Bainite is an interesting solid-state transformation in steels and a detailed understanding of the mechanism and phase transformation kinetics is of fundamental interest as well as technological importance. In this study, the kinetics of austenite to bainitic ferrite is studied through in-situ high temperature laser scanning confocal microscopy ...

Magnetically Driven Healing of Self-Healing Polymers

Damage in materials and structures is unavoidable, leading to the time deterioration of its functional properties (e.g. barrier, load bearing, aesthetics) and ultimate repair or replacement. Lifetime extension can be achieved by using materials with initially higher performance or using materials that can repair themselves (self-healing). The...

Micromechanical Modelling of Fracture Behaviour in Self-Healing Thermal Barrier Coatings

Crack initiation and propagation in composite structures exists as a prominent knowledge gap in computational fracture mechanics. Prior to the development and implementation of fracture modules in FEM solvers, most studies were constrained to simple geometries and load cases. The set of parametric studies that constitute this thesis aims to...

Effects of Thermal Degradation on Carbon Reinforced PEEK Composites

The application of fibre reinforced thermoplastic composites in aerospace industry has increased drastically in the last decade. Carbon fibre/Polyether-ether-ketone (C/PEEK) is one of the high-performance thermoplastic composites and is replacing metallic and thermosetting counterparts in various aircrafts components. Parts made from such...

Three Phase Piezoelectric Composites for Energy harvesting applications

Piezoelectric materials have found application in wide range of devices from accelerometers to energy harvesters. They have proven their potential and versatility in aerospace, automotive, electronics and biomedical industry. Piezoelectric ceramics are not suitable for energy harvesting applications due to its brittleness and low strain levels,...

On the use of Laser Speckle Imaging to study local polymer dynamics

Optimization of Cantilever-Shaped Piezoelectric Energy Harvester: with the Application of Mechanical Stoppers

Energy harvesting has become a popular topic for battery substitution in recent years. In particular, mechanical vibrational energy, one of the most common energy sources, has been intensely studied. Piezoelectric materials play a crucial role in vibrational energy harvesting as they can directly convert the mechanical energy to the desired...

Design of actively controlled semi- permeable trailing edge inserts for aeroacoustic noise reduction

An experimental study is conducted on the design of actively controlled semi-permeable inserts for mitigating turbulent boundary layer noise originating from the trailing edge of an airfoil. Two sets of perforated inserts with hole diameter: 0.8 mm and hole spacing: 1.5 mm & 3 mm, are considered. The inserts are 3-D printed with a middle...

The Effects of Polymer Architecture on Dry Adhesion

Unlike traditional wet-adhesives, dry adhesives are bioinspired solid polymers that owe their adhesion to hierarchical structures. Gecko’s are the most recognizable living creatures relying on this concept to climb walls. A close look at the gecko’s fingers reveals a hierarchical system of micro-and nanoscale filaments. These ensure excellent...

Uncertainty quantification of the lifetime of self-healing thermal barrier coatings based on surrogate modelling of thermal cyclic fracture and healing

Improving the sensitivity of piezoelectric composites by adding porosity

Piezoelectric materials have the ability to convert mechanical to electrical energy (direct effect) and vice versa. They are readily used in the aerospace, automobile, telecommunication industry etc. as both sensors and actuators. For this work the focus is on the sensor application, which utilizes the direct piezoelectric effect. With the...

Creating Structural Material From Martian Regolith Using Spark Plasma Sintering: Understanding the effect of additives and the possibility to lower the energy requirement

In order to establish a sustained extra-terrestrial presence, habitats need to be built on the Moon and Mars using novel materials made from local resources. Several material processing methods can be applied to transform the locally abundant regolith into materials suitable for structural purposes. One promising method is sintering. This...

Self-Healing Behavior in 12Cr Steels

Self-healing of creep-induced damage in newly designed 12Cr self-healing ferritic steels is studied. The damage healing is achieved by the segregation of supersaturated solute atoms at the free surface of the creep-induced cavities, and in this research, the healing phase is the W-riched Laves phase. Two kinds of self-healing steel with...