Research Activities

In this program, we seek to design new materials, structures, and manufacturing processes that allow us to control failure at both material and structural levels, and ultimately improve material and system performance in a variety of applications. Particularly, we employ different machine learning and deep learning toolboxes in all aspects of our projects to explore the processing-microstructure-property-failure-performance relationships, coupling with advanced experimental (e.g., dynamic testing, ultra-high-speed imaging) and computational mechanics (e.g., multi-scale and multi-physics modelling). Examples of research projects that are currently being pursued include:

• Design of next-generation lightweight materials via advanced manufacturing (e.g., laser additive manufacturing) for multi-functional structures and applications
• Study of high-rate failure and fragmentation of novel materials for exploring their performance under dynamic environments 
• Evaluation of fatigue and corrosion behavior of alloys for oil & gas and aerospace applications
• Design of coating materials via advanced manufacturing techniques (e.g., cold spray) to mitigate wear failure of machines in the oil & gas industry

A range of experimental and computational mechanics research topics are derived from these main themes. The Natural Sciences and Engineering Research Council of Canada, the Canada Foundation for Innovation, Natural Resources Canada, and many industry partners are thanked for their support in these projects.

Highlights of Multi-Scale Testing and Modelling Research

 

Schematic of Research Activities on Design of Materials and Structures for Extreme Environments

 

In this research thrust, we focus on understanding the deformation and failure mechanisms that govern the dynamic behavior of brittle materials fabricated via different processes (e.g., hot pressing as a conventional technique, and additive manufacturing). Materials include: advanced ceramics (e.g., alumina, silicon carbide, boron carbide), ceramic-ceramic composites, transparent ceramics, and rocks. The overarching objective is to develop multi-functional ceramic-based materials and structures for harsh environments in various applications (e.g., thermal barrier, impact shield). During experiments, we study damage accumulation, fracture, and fragmentation phenomena using an ultra-high-speed Shimadzu HPV-X2 camera with digital image correlation capabilities. We do this for intact, cracked, and granular forms of brittle materials. Material microstructures and failure features are characterized using X-ray tomography, scanning electron microscopy (SEM) and tools, transmission electron microscopy (TEM), and automated particle size analysis using the Malvern Morphologi G3. The characterization and experimentation work is used as inputs for mechanism-based models developed within the group and by partners. This includes micromechanical, phase-field, and phenomenological models describing failure mechanisms at different length scales. Both open-source and commercial software packages are used.

In this research thrust, we focus on understanding the strain-rate-dependent failure of ductile materials. This includes shear banding and grain recrystallization in HSLA naval and railway steels, grain re-orientation and fracture in cermets, void growth and fracture in metal-matrix compositions and thin metallic films, and dynamic fracture and microstructural evolution in medium and high entropy alloys. In addition, we have developed projects to investigate the fatigue and corrosive behavior of industrial steels (e.g., for pipelines). We use ultra-high-speed and high-resolution thermal cameras to visualize deformation in situ during experiments. Electron back-scattered diffraction (EBSD), scanning electron microscopy (SEM) tools, and transmission electron microscopy (TEM) are used to study deformation mechanisms post-experiment. This information serves as inputs into mechanism-based models describing material behavior developed within the group and by partners. Specifically, the group has developed one of the most comprehensive ceramic-metallic composite micromechanical models in the literature that is being used to inform the design of advanced cermet structural materials, coatings, and thin films.

In this research thrust, we focus on understanding the dynamic failure mechanisms in soft materials. Materials primarily include foams and composites used in helmet and armor applications. The foam materials include D30, Hybrid Polyurethane Elastomer, Microcellular Urethane, Vinyl Nitrile, Expanded Polypropylene, Expanded Polystyrene, and Low-Density Polyethylene. The composite materials generally comprise fiber-reinforced composites (e.g., CFRP, para-aramid (Kevlar), woven glass fiber laminates). We study pore collapse and localization during experiments using ultra-high-speed and high-resolution thermal cameras. X-ray computed tomography scans of the porous microstructures are analyzed using Matlab-based image processing algorithms developed within the group. This reveals insights into the important microstructure length scales (e.g., pore size, ligament thickness) that influence the dynamic failure of these soft materials. Both empirical and thermo-mechanical models can be developed using these inputs to describe material behavior and failure.