Investigation into the mechanical behaviour of bio-cemented sands using the discrete element method

Bio-mediated methods, such as microbially induced carbonate precipitation (MICP) and enzyme induced carbonate precipitation (EICP), have gained considerable attention as alternatives to invasive ground improvement techniques. MICP and EICP use biogeochemical processes to drive carbonate precipitation and bind soil grains, thereby improving the...

RILEM TC 277-LHS report: properties of lime-based renders and plasters—discussion of current test methods and proposals for improvement

Renders and plasters have significant functions in buildings. Their functionality is closely related to their properties, which depend on the mortar itself, the application technology, the interaction with the environment and the substrate. There are many basic characteristics that influence the performance of renders and plasters; however,...

Local control of microstructure and mechanical properties of high-strength steel in electric arc-based additive manufacturing

Additive manufacturing offers a significant potential for producing metallic parts with distinctly localised microstructures and mechanical properties, commonly known as functional grading. While functional grading is generally accomplished through compositional variations or in-situ thermo-mechanical treatments, variation of process...

Mechanical behaviour and energy evolution of polyurethane-mixed ballast under revised bonding constitutive model

The bonding contact presents complex modes in polyurethane-mixed ballast. The commonly used parallel bond model is revised and four different contact models are developed including Ballast-Ballast Contact Bonding, Ballast-Ballast Noncontact Bonding, Ballast-Sleeper Contact Bonding, and Ballast-Sleeper Noncontact Bonding. The mechanical...

Mechanical Behaviour of PA2241FR used in Selective Laser Sintering

This research focuses on the possible causes of variation in the tensile strength and stiffness of witness specimens that are used in the manufacturing of aerospace grade selective laser sintered parts. Using specimens and data obtained from Materialise of the PA2241FR samples, the crystallinity and porosity of the samples was determined. The...

Hydrogen Storage in Salt Caverns: Prediction of the Elasto-viscoplastic Behaviour of Rock Salt

A transition towards more renewable energy sources such as wind- and solar energy is underway. These sources can be unpredictable with regard to energy production and therefore energy storage has become a major concern. A promising technique, Underground Hydrogen Storage (UHS), converts excess energy into hydrogen and stores it underground,...

Multi-spot ultrasonic welding of thermoplastic composite single-lap joints: Effect of spot spacing and number of spots on weld strength

Thermoplastic composite spot welded joints are more well-suited for carrying shear load rather than peel load. However, peel load is difficult to be eliminated in single-lap joint configuration. In this paper, a series of mechanical tests were carried out to study the effects of the spot spacing and the number of welded spots on the secondary...

Micro-scale computational analysis of Fused Filament Fabricated Materials: Experimentally-validated Finite Element Analyses of Representative Volume Elements

This work aims at predicting the elasto-plastic and fracture behavior of ABS polymers obtained by Fused Filament Fabrication (FFF). The strategy adopted is to characterize the microstructure of Representative Volume Elements (RVEs) of the material, as well as the mechanical properties of the polymeric filament used in the FFF process and then...

In vitro evaluation of a PEKK and poly-carbonate-urea-urethane implant for the treatment of osteochondral defects

Cartilage repair remains a major challenge and treatment of osteochondral defects generally results in inferior quality fibrous repair tissue. This study aims to elaborate on the work of Korthagen et al. who developed a thermoplastic polyurethane and polyetherketoneketone implant to treat osteochondral defects. Although promising results were...

The effect of post process treatments on biomechanical properties of Ti6Al4V metamaterials and spinal cage implants manufactured by selective laser melting

Selective laser melting (SLM) is an additive manufacturing technique, which is currently on the rise of being used for manufacturing bone implants. Spinal cage, dental and hip implants can for example be manufactured using SLM. Ti6Al4V lattice structures, categorised as metamaterials, can be printed by SLM with mechanical properties close to...

Assessment of demountable steel-concrete composite flooring systems

Sustainability concerns steer the construction sector towards adopting a circular economy philosophy. Steel-concrete composite beams are extensively used in multi-story buildings and bridges due to their competitive construction and efficient material use. Currently the composite action is mainly achieved by headed shear connectors welded to the...

Sequential ultrasonic spot welding of thermoplastic composites: An experimental study on the welding process and the mechanical behaviour of (multi-)spot welded joints

The popularity of thermoplastic composites (TPCs) has been growing steadily in the last decades in the aircraft industry. This is not only because of their excellent material properties, but also owing to their fast and cost-effective manufacturing process. Fusion bonding, or welding, is a typical joining method for TPCs due to the intrinsic...

Towards high-quality multi-spot-welded joints in thermoplastic composite structures

Ultrasonic welding is a promising assembly technique for thermoplastic composites and it is well-suited for spot welding. In this study, two typical welding process control strategies, i.e. displacement-controlled and energy-controlled welding, were selected to manufacture spot-welded joints. The influence of different boundary conditions,...

Laminated connections for structural glass components: a full-scale experimental study

The use of glass material for structural components has drastically increased in the last decade. Among others, a laminated connection is a type of adhesive joint that makes use of foil interlayer adhesive to transfer forces between glass and metal parts. In this work, the use of embedded laminated connections is studied as connection between...