Engineering Commons^™

Wolfpack Gear Inc. Composite Frame Firefighter Backpack, Gabriel Mountjoy, Blair Ridings, Carl Drummond Buchenroth

Mechanical Engineering

No abstract provided.

Empirical Modelling Of Force Profiles Produced During Drilling Of Carbon Composites, Christopher Cook, Gursel Alici, Marta Fernandes

Christopher Cook

No abstract provided.

Drilling Of Carbon Composites Using A One Shot Drill Bit. Part 2 Empirical Modeling Of Maximum Thrust Force, Marta Fernandes, Christopher Cook

Christopher Cook

In order to extend tool life and improve quality of hole drilling in carboncomposite materials, a better understanding of ‘oneshot’ hole drilling is required. This paper describes the development of an empirical model of the maximum thrust force and torque produced during drilling of carbon fiber with a ‘oneshot’ drillbit. Shaw's simplified equations are adapted in order to accommodate for tool wear and used to predict maximum thrust force and torque in the drilling of carboncomposite with a ‘oneshot’ drillbit. The mathematical model is dependent on the number of holes drilled previously, the geometry of the drillbit, the feed used …

The Effect Of A Low-Velocity Impact On The Flexural Strength And Dynamic Response Of Composite Sandwiches With Damage Arrestment Devices, Kodi A. Rider

Master's Theses

Impact strength is one of the most important structural properties for a designer to consider, but is often the most difficult to quantify or measure. A constant concern in the field of composites is the effect of foreign object impact damage because it is often undetectable by visual inspection. An impact can create interlaminar damage that often results in severe reductions in strength and instability of the structure. The main objective of this study is to determine the effectiveness of a damage arrestment device (DAD) on the mechanical behavior of composite sandwiches, following a low-velocity impact. A 7.56-lb_f crosshead …

Static Flexural Behaviour Of Fly Ash-Based Geopolymer Composite Beam: An Alternative Railway Sleeper, Wahid Ferdous

Wahid Ferdous

These days, the most commonly used materials for railway sleepers are timber, concrete and steel. High maintenance cost, installation issues, deterioration of materials, and environmental considerations are among the factors that prompt research and industry to seek a different and more efficient system. This research was undertaken with the aim of developing a material for sleepers which may overcome some of these problems. Through a comprehensive survey of the literature, it was decided to propose and investigate a sleeper system composed of fly ash-based geopolymer concrete and pultruded FRP profile composites. Although the engineering properties of fly ash-based geopolymer concrete …

Finite Element Modeling Of Ballistic Impact On A Glass Fiber Composite Armor, Dan M. Davis

Master's Theses

Finite Element Modeling of Ballistic Impact on a Glass Fiber Composite Armor

Dan Davis

Experiments measuring the ballistic performance of a commercially available fiberglass armor plate were used to guide the development of constitutive laws for a finite element model of the impact. The test samples are commercially available armor panels, made from E-glass fiber reinforced polyester rated to NIJ level III. Quasi-static tensile tests were used to establish material properties of the test panels. These properties were then used to create models in the explicit finite element code LSDYNA.

Ballistic impact testing of the panels was conducted using a …

Modal Analysis Of Composite Structures With Damping Material, Kellie Michelle Tremaine

Master's Theses

The purpose of this study is to develop an analytical solution for modal analysis of actively damped orthotropic composite plates in bending and to verify it with experimental analysis.

The analytical modal analysis solution for composite plate dynamics is derived using Euler theory. This analysis applies to structures with orthotropic lamina of uniform material properties at any lamination angle. The bending-extensional coupling can be neglected for plates that are symmetric or approximately symmetric, which allows an exact solution for natural frequency and mode shape to be obtained. An exact solution can be found for natural vibration and in general.

The …

Investigation Of The Fracture Phenomena During The Milling Process Of Inorganic Particulates And Brittle Fracture Of Polymer Composites Using Fractal Theory, Zheng Qian

Dissertations

This dissertation investigates the applicability and usefulness of applying Fractal mathematics and to the fracture of brittle particulates in Fluid Energy Mill devices, and in particular quantifying the resulting power law particle size distributions, examining the Surface Fractal Dimension of milled particulates, and relating the Izod Impact Strength values of composites of polypropylene and Calcium carbonate particulates which are large un-milled, small milled, as well as small and produced by the simultaneous milling and coating with nano-silica to the Surface Fractal Dimension of the impact fracture surfaces.

First, the dissertation examines the behavior of un-coated and micron-sized wax pre-coated particulates …

Method For The Simulated Layup Of Composite Fabrics, David M. Christensen

Theses and Dissertations

Due to the complexity of designing advanced composite parts, many software tools have been developed to aid the designer and reduce design cycle time. Draping is one of those tools and is used to predict the fiber angles throughout the part. This application of draping is to simulate the actual hand layup process that a technician would go through while creating a multi-layered laminate composite part. This method is the first to use plies as an underlying surface for draping instead of just using an offset mold surface. This method can visualize full 3D ply geometry taking into account the …

Feasibility Analysis For Electrically-Powered Hoverboard, Cameron Chan, Jason Cortez, Jay Lopez

Aerospace Engineering

Composite materials are engineered by combining two or more constituent materials with significantly different physical or chemical properties in such a way that the constituents are still distinguishable, and not fully blended. Due to today’s high rising prices of gasoline and aviation fuel costs, many manufacturers have turned to the use of lightweight composites in their designs due to the advantages of the composite material, which include outstanding strength, excellent durability, high heat resistance, and significant weight reduction that the composite material properties hold. The purpose of this project is to design and construct a composite structure for an electrically-powered …

Surface Roughness And Diametral Consistency Of Holes Drilled Into Ddgs/Phenolic Resin Blends, J. W. Shanafield, A. W. Otieno, R. A. Tatara, D. J. Schroeder, Kurt A. Rosentrater

Kurt A. Rosentrater

In this study, corn-based distillers dried grains with solubles (DDGS) has been utilized as a filler and blended with phenolic resin. The blends were compression molded into rectangular test specimens, into which holes have been machined using a standard 9.52 mm (3/8 in) diameter, two-fluted twist drill. A series of tests was then conducted to examine the effects of DDGS content, cutting speed, and feed rate upon the surface finish (roughness) of the interior hole slot, as well as the consistency of the drilled hole diameter. DDGS content was 0, 25, 50, and 75%, by weight. Cutting speed was 17, …

Graphene Wrapped Lifepo4/C Composites As Cathode Materials For Li-Ion Batteries With Enhanced Rate Capability, Yi Shi, Shulei Chou, Jia-Zhao Wang, David Wexler, Hui-Jun Li, Hua-Kun Liu, Yuping Wu

Faculty of Engineering - Papers (Archive)

To reduce the reaction time, electrical energy consumption, and cost, LiFePO₄/C/graphene has been synthesized by a rapid, one-pot, microwave-assisted hydrothermal method within 15 min at a temperature of 200 °C, followed by sintering at 600 °C for 2 h under a H₂/Ar (5:95, v/v) atmosphere. The microstructure and morphology of the LiFePO₄/C/graphene products were characterized by means of X-ray diffraction, Raman spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. The carbon coated LiFePO₄/C nanoparticles, around 200 nm in size, are thoroughly wrapped by crumpled micrometer-size graphene sheets. In this kind …

Failure Analysis Of Impact-Damaged Metallic Poles Repaired With Fiber Reinforced Polymer Composites, Robert Arthur Slade

Electronic Theses and Dissertations

Metallic utility poles, light poles, and mast arms are intermittently damaged by vehicle collision. In many cases the vehicular impact does not cause immediate failure of the structure, but induces localized damage that may result in failure under extreme service loadings or can promote degradation and corrosion within the damaged region. Replacement of these poles is costly and often involves prolonged lane closures, service interruption, and temporary loss of functionality. Therefore, an in situ repair of these structures is required. This thesis examines the failure modes of damaged metallic poles reinforced with externally-bonded fiber reinforced polymer (FRP) composites. Several FRP …

Combined Finite Element And Peridynamic Analyses For Predicting Failure In A Stiffened Composite Curved Panel With A Central Slot, Erkan Oterkus, Erdogan Madenci, Olaf Weckner, Stewart Silling, Philip Bogert, Alexander Tessler

US Department of Energy Publications

This study presents an analysis approach based on a merger of the finite element method and the peridynamic theory. Its validity is established through qualitative and quantitative comparisons against the test results for a stiffened composite curved panel with a central slot under combined internal pressure and axial tension. The predicted initial and final failure loads, as well as the final failure modes, are in close agreement with the experimental observations. This approach demonstrates the capability of the PD approach to assess the durability of complex composite structures.

Modulation Of Mesenchymal Stem Cell Behavior By Nano And Micro-Sized Beta-Tricalcium Phosphate Particles In Suspension And Composite Structures, Lekeith Terrell

LSU Master's Theses

Nano and micro particles have steadily grown in interest for synthetic bone composite structures. Nano and micro sized calcium phosphates especially are of interest because of the osteoinductive behavior of calcium phosphate. Engineered composites incorporating polymers and ceramics, such as poly l-lactic acid (PLLA)/β-TCP, for bone tissue regeneration have been well investigated for their proliferative and osteoinductive abilities. Limited research has been done to thoroughly investigate the effects of various sized β-TCP particles on human mesenchymal stem cell behavior. Foreign bodies are known to elicit an inflammatory and cytotoxic response and several nano-particles are known to elicit cytotoxic and pro-inflammatory …

Frp Stiffener Efficiency Coefficient For Sbs Shear Strengthening Applications, Hamed Babaizadehroshanfekr

LSU Master's Theses

The use of composite materials such as Fiber Reinforced Polymer (FRP) to strengthen concrete structures has surged during the past two decades as an alternative for conventional methods of structural strengthening and repair. FRP materials are light and relatively easy to install. They are noncorrosive, durable and less vulnerable to environmental conditions in comparison to other construction and retrofitting materials. The knowledge and applications of composites for strengthening steel structures are relatively smaller when compared to concrete strengthening applications. Strengthening-By-Stiffening (SBS) is a new strengthening alternative that was developed at Louisiana State University. SBS has proven to be a practical …

Processing And Evaluation Of Long Fiber Thermoplastic Composite Plates For Internal Fixation, Paul Benjamin Warren

All ETDs from UAB

The metallic plates used in internal fracture fixation may have up to ten times the elastic modulus of normal bone tissue, causing stress shielding-induced osteopenia in healed bone that can lead to re-fracture after plate removal and prolonged and painful recovery. Thermoplastic polymer matrix composites reinforced with long carbon fiber are promising alternative materials for internal fixation plates because they may be produced with relative ease and be tailored to have specific mechanical properties, alleviating the stress shielding problem. Long carbon fiber-reinforced polyetheretherketone (LCF PEEK) plates were produced using the extrusion / compression molding process. Static flexural testing determined that …

Advanced Ceramics And Composites Based On Rice Hulls, Peigen Zhang

LSU Doctoral Dissertations

As a by-product of the agricultural industry, rice hulls are available at large volume across the world. The disposal of the rice hulls itself is a big problem for the rice millers where the rice paddies are peeled off and rice hulls are produced. There have been many disposal methods developed, but the true value of the rice hulls would be more appreciated when they are employed to produce high value-added advanced ceramics. In this dissertation, advanced ceramics, such as AlN nanowires, SiC whiskers, mullite and SiC/Al2O3 nano-sized composites, were developed and studied based on the rice hulls. The SiC …