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Full-Text Articles in Mechanical Engineering

Marangoni Propulsion Of Active Particles, Saeed Jafari Kang Jan 2021

Marangoni Propulsion Of Active Particles, Saeed Jafari Kang

Dissertations, Master's Theses and Master's Reports

We study the surfing motion of active particles located at a flat liquid-gas interface. The particles create and maintain a surface tension gradient by asymmetrically discharging a surface tension-reducing agent. We employ theory and numerical simulation to investigate the Marangoni propulsion of these active surfers. First, we use the reciprocal theorem to establish a relationship between the propulsion speed and the release of the active chemical. This theoretical relation is utilized to examine the effect of wall confinement and geometry on the Marangoni-driven motion of active particle when the inertial effects are negligible and when the transports of the released …


Thermomechanical Mechanisms That Cause Adhesion Of Aluminum High Pressure Die Castings To The Die, Alex Monroe Jan 2021

Thermomechanical Mechanisms That Cause Adhesion Of Aluminum High Pressure Die Castings To The Die, Alex Monroe

Dissertations, Master's Theses and Master's Reports

In high pressure die casting (HPDC) of aluminum, cast material adhering to die is a significant defect. Adhesion occurs in two primary ways. The casting may stick preventing its removal from the die. Aluminum can also adhere to the die and buildup in local areas on the die surface with additional casting cycles. This second form of adhesion is called soldering. Lubricant is the best technology to control all forms of adhesion, but it comes at the cost of casting porosity, blisters, reduced die life, and increased die casting machine wear. New strategies to prevent adhesion are desired to eliminate …


Phase-Field Fracture Modeling For Interlocking Micro-Architectured Materials, Shubham Sinha Jan 2021

Phase-Field Fracture Modeling For Interlocking Micro-Architectured Materials, Shubham Sinha

Dissertations, Master's Theses and Master's Reports

It is fascinating to see how natural materials like teeth enamel, bone and nacre possess a very high stiffness and strength in spite of the fact that they are composed of minerals mostly. Studies have shown the reason for this aberration as the presence of weaker interfaces with intricate interlocking architectures at microscopic levels in these materials. Inspired by the architecture of these materials, micro-architectured sutures with jig-saw like geometry is being studied in this research study. The main focus of this study is to examine the effects of friction co-efficient and interlocking angles of the jig-saw tabs on pullout …


Studying The Effects Of Initial Crack Angle On The Crack Propagation In Graphene Nano-Ribbon Through Molecular Dynamics Simulations, Vijay Kumar Pathak Jan 2021

Studying The Effects Of Initial Crack Angle On The Crack Propagation In Graphene Nano-Ribbon Through Molecular Dynamics Simulations, Vijay Kumar Pathak

Dissertations, Master's Theses and Master's Reports

In this research, we have worked on the brittle fracture of graphene nano-ribbon to explore the behavior of crack propagation at different crack angles. We have performed classical Molecular Dynamics simulations using LAMMPS at ten different crack angles between 0 degrees and 45 degrees, in an increment of 5 degrees to observe the parameters that dominate the crack path. The graphene nanoribbon is loaded in the zigzag direction by pulling it in the armchair direction with a pre-existing crack in the center. We have used OVITO for the visualization of the simulation. AIREBO potential is employed in this work because …