A Novel Micro-Indentation Based Method for Local Mechanical Property Characterization

Micro-indentation testing has shown great promise in extracting local mechanical properties of ductile metal materials. Although the relevant contact physics has been well revealed since the 19th century, interpreting the indentation data still poses many challenges at the application level. Regarding one of the mainstream methodologies for...

In-Situ Appraisal and Classification of Concrete Structures Prior Demolition: Chemical Composition Analysis Using Handheld X-ray Fluorescence Analyzer with Cement Type-Driven Separation

Recycled concrete aggregates (RCA) have been recognized as a sustainable solution to satisfy the demand and address the environmental impacts of the concrete industry. However, construction engineers and contractors still have reservations about RCA due to their heterogeneous origin and lower quality compared to natural aggregates. It is...

Characterization of Mixed-Mode Fracture Behaviour of Thermoplastic Composite Materials by Mandrel Peel Test

Delamination is a significant failure mode that has been the subject of extensive research in laminated structures. The interface in assembly structures often represents the susceptibly weak link and necessitates careful consideration to guarantee structural stability. It is of utmost significance to understand the behaviour of the delamination...

Identification of the cement type at the concrete surface with ordinary Portland cement and supplementary cementitious materials with a handheld X-ray Fluorescence analyser

This master's thesis provides knowledge on non-destructive testing of cement and supplementary cementitious materials composition in concrete with a handheld X-ray Fluorescence analyser. <br/><br/>Today, concrete production is responsible for 8% of the world’s CO2 emissions. Recycling concrete material can directly contribute to the reduction of...

Joining techniques for internal bonding of components into carbon fibre-reinforced polymer structures with limited access

Hall spars, a leading innovator in the composite mast-building industry with a long history of successful projects, provided a challenge which is the inspiration of this thesis. This thesis aims to contribute to the challenge: Joining techniques for the internal bonding of carbon fibre-reinforced polymer components into carbon fibre-reinforced...

Hydrogen-Enhanced Fatigue of Pipeline Steels and Their Welds

Hydrogen as an alternative energy source has risen in popularity due to increased environmental awareness. Existing natural gas infrastructure is considered as a means to transport hydrogen, due to practicality and financial aspects. However, hydrogen can deteriorate the fatigue behaviour and thus induce premature failure. Since fatigue is a...

Effect of isoparametric grain refinement on mechanical properties and cleavage fracture toughness in high strength steels

In recent decades, high strength steels in thick sections have been increasingly used in offshore structures where they are subjected to harsh service conditions such as freezing temperatures and high static/dynamic loading. At these conditions they are susceptible to a transition from ductile failure to a dangerous brittle (cleavage)...

Effect of microstructure on the degradation of 3D printed Mg-4Zn porous scaffolds

Many manufacturing industries have been impacted by the innovation of additive manufacturing (AM), and biomaterials manufacturing is no exception. One group of biomaterials impacted by the innovation of 3D printing are degradable biomaterials. Degradable biomaterials could eliminate the need for surgery to remove the implant. 3D printed porous...

Effect of Heat Treatment on Microstructure and Mechanical Behavior of Additively Manufactured Nitinol Shape Memory Alloys

Nitinol shape memory alloys (SMAs) have a unique combination of shape memory capability, making it an attractive material for various engineering and biomedical applications. Additive manufacturing (AM) by laser powder bed fusion (L-PBF) allows to produce Nitinol net shape parts, which broadens its applications. Due to the high heating and...

Retained austenite in silicon-containing bainitic spring steels for trucks

Bainitic steels are the type of steels which are widely in use, especially in automotive industries, for its good mechanical behavior, i.e., with coexistence of strength, ductility and fatigue resistance. A better understanding on the mechanism and transformation kinetics of bainite are necessary in order to improve the performance of the...

Fatigue Crack Propagation in Additively Manufactured and Functionally Graded Inconel 718

Additive Manufacturing (AM), commonly known as 3D printing, exemplifies the recently emerging processing methodologies that aim to substitute the conventional routes, such as to produce parts with complex geometries and eliminate expensive tooling. AM also allows high degree of freedom and rapid prototyping for functional part optimization. This...

Glass production from desert sand: Proof of concept and characterisation

For in-­situ resource utilisation start-up Maana Electric, an investigation was undertaken to determine whether a cover glass for solar panels can be produced using only desert sand as the raw material. During this investigation, the composition of desert sand, melt formation, processing temperatures, and mechanical and optical properties were...

Void Formation in Cu/Sn Interconnections in Flip Chip Package

The sporadic occurrence of voids within intermetallic compounds during microelectronic soldering is a key factor affecting the reliability of electronic solder joints. This study aims to understand the void formation mechanisms and investigate different soldering effects. Cu/Sn solder joints in flip chip packages were examined at 190°C after...

Electrolytic Plasma Cleaning of Advanced High Strength Steels

The most commonly used material in the automotive industry is steel. Steel used in making Body-In-White (BIW) for cars are broadly classified as Advanced High Strength Steels (AHSS). These AHSS are produced by a well-defined alloying and specific annealing procedure. However, external oxidation of the constituent alloying elements from the steel...

Architectured MIcrostructures: The effect of localized laser heat treatment on the microstructure of a FeCNi steel

Laser surface treatments offer interesting prospects for the creation of architectured microstructures formed by distinct phases in metastable austenitic steels. In the present study, a laser-based localised heat treatment was developed to locally create an austenitic region in a quenched Fe25Ni0.2C martensitic microstructure. The highly...

Research on the Applicability of Metal Foam Based Sandwich Materials for Friction Stir Welded Ship Structures with Sufficient Fatigue Life Time

Research to analyse and/or develop novel materials and techniques is necessary to address competition and safeguard craftmanship in shipbuilding. In this master thesis, two new approaches to reduce the production and maintenance costs are studied: {metal foam core, metal face sheet} sandwich materials and corner adstir fillet stationary shoulder...