Applied Mechanics Commons^™

Viscoelasticity Of Ptfe-Based Face Seals, Bo Tan

Theses and Dissertations--Mechanical and Aerospace Engineering

PTFE-based materials are widely used in areas of tribology, particularly in seal and bearing applications because of their outstanding self-lubricating properties. Often in dynamic seal applications there is a need for ultra-low mechanical friction loss between the sealing surfaces. Due to its extremely low friction coefficient, there is interest in employing Polytetrafluoroethylene (PTFE) materials in such applications. One challenging aspect of employing PTFE is that these materials are viscoelastic and plastic. This dissertation concentrates on the modeling of viscoelastic material response when used as mechanical face seals with a focus on PTFE-based materials. First, the viscoelastic characteristics are measured through …

Effective Modulus Of Cracked Bodies: A Finite Element Analysis, Alan Thomas Varughese

Theses and Dissertations--Mechanical and Aerospace Engineering

This thesis considers how cracks in an elastic body can alter the body’s elastic properties. In the present study the elastic property of note is the elastic or young’s modulus. It is desired to investigate to what extent the number and orientation of cracks can cause a reduction in the elastic modulus. Because of the complex nature of the elastic fields resulting from multiple cracks interacting together in a finite geometry an analytical solution is not possible or considered. Rather the Finite Element Method is used to determine the elastic response to a body with many cracks. This provides a …

Atomistic Continuum Simulations For Nano-Indentation And Compression Of Multi-Layer Graphene, Ashwini Nikumbh

Dissertations, Master's Theses and Master's Reports

Graphene has attracted a great share of research interest due to its extraordinary electrical, thermal, mechanical, and physical properties. Such spectacular properties of graphene open a wide range potential of applications in electronics, energy storage, composites, and biomedical fields. The mechanical properties of graphene can have a huge impact on its performance in graphene-based devices and thus it is important to study them. But the difficulties in experimental characterization and computational limitations to simulate large graphene sample consisting of billions of atoms makes it a challenging task. Thus, accurate and efficient simulation tools to predict the complex deformation of large …

Investigation Of A Machine-Plant Interface For Extracting Rooted Invasive Aquatic Plants, Brad Baas

Dissertations, Master's Theses and Master's Reports

The current solutions for managing rooted aquatic invasive plants are time consuming, have negative environmental impacts, or are cost-limiting for management organizations. The most effective treatment method is hand pulling, but hand pulling is not a feasible solution for a whole lake. A new device, the invasive aquatic plant extractor, aims to replace human divers who hand pull plants with a mechanical system. The device implements a machine-plant interface that resembles the tines of a fork. These tines will be pushed linearly through the substrate, and then raised from the substrate with the plant caught in the tines. The primary …

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 …

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 …

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 …

Dual Motor Drive System For Formula Sae Electric Race Car, Bryan D. Neill, Jackson T. Mcfaul, Cole T. Andrews, Isaiah D. Penzell

Mechanical Engineering

This paper serves as the Final Design Report (FDR) for the senior project developed by our team. This FDR builds on our CDR, in which the main deliverable was the detailed design of a planetary gearbox delivering a 5:1 reduction to be mated to an Emrax 188 motor. This planetary gearbox would allow for the possibility of implementing a dual-motor torque-vectoring rear-wheel-drive system in Cal Poly Racing’s electric FSAE car, which has demonstrated in simulation to yield significant performance gain over the current single motor/mechanical LSD system. As this project’s scope is purely mechanical, the intent is for the Cal …

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 …

The Development Of A Wearable Device For Relieving The Lower Leg Muscles Fatigue, Warawarin Nitirojntanad

Chulalongkorn University Theses and Dissertations (Chula ETD)

Standing is considered one of the most practical working postures since our limbs have the greatest range of motion. Standing yields plenty of benefits, however, prolonged standing could lead not only to discomfort but also to musculoskeletal disorders (MSDs). This study aims to design and develop a device that could help relieve muscle fatigue in the lower leg as the effects of prolonged standing as well as to evaluate the proposed device. The basics of fatigue, the consequences of prolonged standing and walking, and a review of the existing interventions to cope with muscle fatigue are used in designing the …

Design For Additive Manufacturing (3d Printing), Michael O'Donnell, Michael J. Levy

Williams Honors College, Honors Research Projects

The goal of this project is to study the performance of a 3D printed mechanical part subjected to topology optimization. A part that is somewhat complex in its load bearing and geometry will be selected. That part will then be designed, finite element analysis will be performed on it to optimize its topology, and then it will be 3D printed and tested. The goal of topology optimization is to either save material cost and/or part weight due to the ability of 3D printing to manufacture parts with complex and obscure geometry.

Smart Home Pet Feeder, Andrew Markja, Simona Zdravev, Timothy Zubek, Christian Jackson

Williams Honors College, Honors Research Projects

The goal of this project was to design a Smart Home Pet Feeder that will allow the owner to feed their pet using 4 different methods. The methods are: manually, scheduled, app/url, Alexa/Google. The advantages of this design are that it will become convenient for pet owners who are busy and unable to make it back to their house to feed their pets remotely or for those who enjoy the use of technology from within their home for no-trouble feeding.

Chainless Bike Drive, Dominic Apisa, Bradley Powell, Garrett Colvin, John Monsour

Williams Honors College, Honors Research Projects

The focus of this project was to design a drive system that could replace the conventional chain drive system, improving on both the efficiency and reliability, in addition to being low cost and lightweight. This report will provide background into why this group chose this as the subject of their project, as well as challenges faced throughout the design process. The design developed was a drive shaft driven by a system of pinions and gears, with a freewheel mechanism that allowed the system to coast when not pedaling. Due to cost and time constraints, only a prototype was created, with …

Door Barricade, Alex Cerino

Williams Honors College, Honors Research Projects

My senior capstone project will be a door barricade. The main idea for the use of the door barricade is for schools in the case of an intruder. The barricade that I will be designing is a solution to the inefficient barricades that I saw at my high school. It could also be used at businesses and homes. My design would be easy to use and have a fail-safe option. The two areas of mechanical engineering technology that my capstone project will focus on are stress analysis and electronics. Every part for my door barricade is drawn in SolidWorks. All …

Additive Manufactured Formula Sae Brake Caliper, Auston Obringer, Robert Kucera, Steven Massarelli, Jared John, Michael Finer

Williams Honors College, Honors Research Projects

In a world where innovation has become the new norm, automobiles can often be found at the forefront of that movement. Each and every year there are new innovations and concepts that push modern day technology to the edge of what is physically possible. This can be seen from every aspect of these automobiles ranging from the conceptual stage all the way to production.

Most of these advancements have been made possible with the new technology that has become available on the manufacturing side of the designs. Instead of being constrained by what is possible on your average 3 to …

Combined Puncture And Cutting Of Soft-Coated Fabrics By A Pointed Blade: Energy, Force, And Stress Failure Criteria, Ennouri Triki, Chantal Gauvin

Études primaires

Soft elastomer-coated fabrics are widely used in engineering and protective applications. Puncture cutting by sharp-tipped objects is one of the most common failure modes of protective gloves made of coated fabrics. In order to investigate the puncture-cutting process of soft elastomer-coated fabrics, we studied the mechanisms and mechanics of pointed-blade insertion into specimens cut out from four protective gloves. Experimental and analytical analyses showed that total energy and critical puncture-cutting force calculated analytically are both able to predict the puncture-cutting resistance of soft elastomer-coated fabrics measured experimentally. Total energy is obtained from the relationship between the puncture-cutting work and the …

Hydraulic Vehicle Challenge, Jacob Steiner, David Kotovets, Evan Blitz, Luke Fetherston, Alex Colucy

Williams Honors College, Honors Research Projects

The target goal of this project is for a team of students to design a vehicle which is based on human power as the primary mover of the system and achieves vehicle propulsion through the required use of hydraulics and pneumatics. In summary, the rider will power a pump that will generate pressure in order to move the fluid that drives the motor. This will result in the powered rotation of the wheels. As there are many possible designs, naturally, this means that the final design for the vehicle will have specific limitations such as weight and the required use …

Golf Ball Mark Repair Tool, Peter Gildea, Jacob Cunningham, Simon Aramouni, Michael Buckley, Andrew Perez

Williams Honors College, Honors Research Projects

Golf is a unique sport because the players consist of various ages. Inexperience and old age are two factors that cause issues on the course for others, such as improperly repaired divots. Divots are “craters” in the ground caused by the golf ball landing with high velocity on the greens. Older players encounter body limitations that make it difficult for them to bend over in order to properly fix the divots on every hole. This device will be created to properly repair divots to keep the greens in good playing condition for all players and to keep the older players …

Elastic Bending Behaviour Of Sandwich Composite Structures With Abs Cores By Using Additive Manufacturing, Dechawat Wannarong

Chulalongkorn University Theses and Dissertations (Chula ETD)

Maintaining the lightweight performance of sandwich structures while achieving good bending strength and stiffness is difficult. Core materials for these programmable sandwich constructions are 3D printed with hexagonal honeycomb, re-entrant honeycomb, and circular honeycomb topologies with varying core densities. The bending stiffness and strength of these sandwich structures are determined by a three points bending test including an Acrylonitrile Butadiene Styrene core and a unidirectional carbon fibre reinforced polymer face sheet. The sandwich composite with the greater relative core density displays greater bending strength and stiffness than the composite with the lower relative core density. The sandwich composites beam with …

Effectiveness Of The New Ambulance Air Exhaust System In Reducing Aerosol Particle Concentration, Vasutorn Petrangsan

Chulalongkorn University Theses and Dissertations (Chula ETD)

The objective of this work is to assess the effectiveness in reducing airborne particles of the Camfil® CC410-concealed air exhaust system, that is installed in the ER-1 ambulance (a King Chulalongkorn Memorial Hospital ambulance). This is done by diffusing aerosols into the cabin at the patient’s face position for an injection period (IP) of 1 minute and measuring the aerosol concentration inside the cabin over time. The experiment is conducted for 2 ventilation conditions, when the exhaust system is off (Minimal Ventilation: MV) and at maximum speed (High Ventilation: HV). Density of the aerosol is interpreted in terms of its …