Double-screw vehicles have been developed to operate in soft, wet terrains such as marsh, snow, and water. Their exceptional performance in soft and wet terrains is at the expense of performance on rigid terrains such as pavement. Furthermore, turning can be difficult because the method of turning varies depending on the terrain. Therefore, in this …
Tag Archive: Mechanical
Mar
13
High strain rate studies of armor materials
This thesis focuses on the high strain rate behavior of Maraging steel 300, High Hardness Armor HHA) and Aluminum 5083 — H131 Alloy. These materials are used by the Department of National Defense DND) of Canada as armor plate materials in military applications. The aim of the research is to investigate the dynamic shear-strain response …
Mar
12
An uncoupled multiphase approach towards modeling ice crystals in jet engines
A recent series of high altitude turbofan engine malfunctions, characterized by flameout and sudden power losses have been reported in recent years. The source of these incidents has been hypothesized to be due to the presence of ice crystals at high altitudes. Ice crystals have been shown to have ballistic trajectories and consequently enter the …
Mar
12
Isotropie des manipulateurs paralleles a nacelle articulee de classe H4
This thesis presents the isotropic conditions for the H4 topological class of parallel manipulators with articulated travelling plate and four degrees of freedom. First, a kinematic model of this class of manipulators is developed, then we impose isotropic conditions on the jacobian matrix. From the newly obtained equations, design constraints and a design procedure permitting …
Mar
12
Wave scattering and propagation in porous media with excitations from multiple wave sources
The research in this dissertation intends to investigate wave scattering, wave propagation in porous media saturated by fluids and multiphase flow in small tube. The scattering SH-wave field is studied in a half-space containing a semi-cylindrical hill and a subsurface horizontal hole. The “division-conjunction” concept, the complex function and a moving-coordinate method are employed in …
Mar
12
The influence of austempering temperature on the microstructure and mechanical properties of a high carbon high silicon steel
In this investigation a new bainitic steel with high strength and exceptionally high fracture toughness has been developed. This steel has been synthesized using the concepts from Austempered Ductile Cast Iron ADI) technology. The influence of austempering temperature on the microstructure and mechanical properties of this steel at room temperature and ambient atmosphere has been …
Mar
12
Etude et caracterisation des phenomenes d’eclatement et d’explosion des pneus de camion
This thesis presents the results of research activities on heavy vehicles tire blowout and explosion phenomena. Produced jointly by the Institut de Recherche en Sante et en Securite du Travail IRSST) in Montreal, Canada and Ecole Polytechnique de Montreal, it allows an update of knowledge on these two kinds of events, explains their causes and …
Mar
12
Changes in the Mechanical Properties of the Plantar Soft Tissue with Diabetes
A serious complication of diabetes is plantar ulceration, affecting several million diabetic Americans and often resulting in amputation of the afflicted limb. Plantar ulceration may be caused by a combination of factors including peripheral neuropathy resulting in insensate feet that are susceptible to mechanical trauma, poor vascular supply resulting in diminished healing, and aberrant plantar …
Mar
12
Evaluation of SI-HCCI-SI Mode-Switching Using Conventional Actuation on a CNG Engine
Homogeneous Charge Compression Ignition HCCI) operation is desirable for its high thermal efficiency and low emissions of NOx and particulates. Difficulty with cold starting and maximum achievable speed/load highlight the desire for mode-switching to traditional spark ignition SI) operation. Mode-switching between SI and HCCI is investigated using only actuation of throttle, CNG injector pulse width, …
Mar
12
Macro/Micro-Feature Development for Improved Hydrodynamic Performance at the Mechanical Seal Interface via Laser Surface Texturing
Mechanical Seals are used throughout the world as the principle method whereby fluid containment may be achieved between a rotating shaft and the shaft housing. As a key component in fluid transportation, storage, and containment, the reliability and performance of mechanical seals is very important. This paper deals with the design, development, and optimization of …