Materials Science and Engineering Commons^™

An Experimentally Generated Constitutive Model For Peak Stress (Σ_Peak) In Compression Samples, Kevin Mathew Lopez Galang

Master's Theses

The hot working behavior of AISI 1018 steel was studied by hot-compression deformation tests on the Gleeble 1500 thermo-mechanical simulator at true strain values of -0.143 and -0.405, true strain rate values of 0.01 and 0.1, and working temperatures of 900^°C and 1000°C. The tests show that a lower working temperature and lower true strain value results in a greater maximum compressive force. The apparent activation energy Q_app was calculated by using the Zener-Hollomon parameter combined with the low stress law. Q_{app ­}was calculated to be 311 kJ mol^-1 K^-1.

The Application Of Advanced Composites For The Construction Of Commercial Transport Aircraft, Mark D. Severson

Graduate Student Works

This individual Capstone project examined and evaluated current industry methods of testing, certification, and maintenance of advanced composite materials for the construction of commercial transport aircraft and the FAA regulations governing their use. The project critically compared and contrasted existing FAA standards and regulations governing the testing, certification, and maintenance of advanced composites for commercial transport aircraft structural applications with current industry practices to determine whether there were any areas of conflict between the two in order to accept or reject that current testing, certification, and maintenance procedures for advanced composites used in primary and secondary commercial transport aircraft structures …

Analysis Of Bolted Joints Under Medium And High Impact Loading, Deepak Sankar Somasundaram, Mohamed Trabia, Brendan J. O'Toole

College of Engineering: Graduate Celebration Programs

• Develop test fixture for medium impact study on bolted joints
• Create FEA model that can replicate the experiment
• Develop test fixture for high impact loading
• Create FEA model and select material properties that can produce results that
  closely match experiments.
• Compare different modeling techniques for high impact loading

Vulnerability Of Progressive Collapse In Reinforced Concrete Flat-Plate Buildings, Jinrong Liu

College of Engineering: Graduate Celebration Programs

• Progressive collapse is the spread of initial local failure, causing partial or
  even total collapse of a building.
• Flat plate structure is widely used for office and residential buildings.
• There is a large inventory of older flat plate building without continuous slab bottom reinforcement through columns.
• Limited knowledge exists regarding the risk of disproportionate collapse in
  older flat-plates under sudden column removal during abnormal events.
• Reliable mechanical model is needed for structural evaluation.

Plastic Deformation Of Astm A36 Steel Using Two-Stage Light Gas Gun, Shawoon Kumar Roy

College of Engineering: Graduate Celebration Programs

To characterize material deformation in high velocity impact. To validate material models for computation simulation purposes.

This ongoing research is an attempt to study the plastic deformation of A36 steel plate (0.5” thick) under hypervelocity impact. Plastic deformation of the target plate was simulated using finite element software LS-DYNA.

An Examination Of The Potential Of Building Information Modelling To Increase The Efficiency Of Irish Contractors On Design And Build Projects, Charles Anthony Mitchell, Myles Keaveney

Conference papers

Competition between Irish contractors is more aggressive than ever before. In the current economic climate an ability to construct with greater efficiency could ensure a company’s survival. The purpose of this research was to determine the extent to which efficiency benefits could be realised by contractors on design and build projects as a result of implementing a revolutionary process referred to as Building Information Modelling (BIM). After a critical analysis on all aspects of BIM in the literature review, questionnaires were sent to establish the success of this system in the US and also in the comparatively few Irish firms …

Quantum Man, Julian Voss-Andreae

The Transdisciplinary STEAM+ Journal

According to quantum physics, the world is fundamentally quite different than it seems. Drawing inspiration from the underlying nature of reality, former quantum physicist Julian Voss-Andreae created an image of a walking human as a quantum object. Made up of parallel sheets of steel, the sculpture is a metaphor for the counter-intuitive world of quantum physics. Symbolizing the dual nature of matter with the appearance of classical reality on the surface and cloudy quantum behavior underneath, the sculpture seems to consist of solid steel when seen from the front, but dissolves into almost nothing when seen from the side.

Numerical Modeling And Characterization Of Vertically Aligned Carbon Nanotube Arrays, Johnson Joseph

Theses and Dissertations--Mechanical and Aerospace Engineering

Since their discoveries, carbon nanotubes have been widely studied, but mostly in the forms of 1D individual carbon nanotube (CNT). From practical application point of view, it is highly desirable to produce carbon nanotubes in large scales. This has resulted in a new class of carbon nanotube material, called the vertically aligned carbon nanotube arrays (VA-CNTs). To date, our ability to design and model this complex material is still limited. The classical molecular mechanics methods used to model individual CNTs are not applicable to the modeling of VA-CNT structures due to the significant computational efforts required. This research is to …

Rapid Repair Of Severely Damaged Rc Columns With Different Damage Conditions: An Experimental Study, Ruili He, Lesley Sneed, Abdeldjelil Belarbi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Characterization Of And Controlling Morphology Of Ultra-Thin Nanocomposites, Guy C. Laine

Theses and Dissertations--Chemical and Materials Engineering

Ultrathin film nanocomposites are becoming increasingly important for specialized performance of commercial coatings. Critical challenges for ultrathin film nanocomposites include their synthesis and characterization as well as their performance properties, including surface roughness, optical properties (haze, refractive index as examples), and mechanical properties. The objective of this work is to control the surface roughness of ultrathin film nanocomposites by changing the average particle size and the particle volume fraction (loading) of monomodal particle size distributions. This work evaluated one-layer and two-layer films for their surface properties. Monodispersed colloidal silica nanoparticles were incorporated into an acrylate-based monomer system as the model …

Flexural Rigidity Characterization Of Retrofitted Frp Plates, Steven J. Makonis Jr., Stella B. Bondi, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

Presented herein is a procedure and numerical results for flexural rigidity characterization of Fiber Reinforced Polymer (FRP) plates retrofitted with various types of fabrics. The FRP plates were retrofitted with Kevlar® 49 (Aramid), Carbon Fiber (Harness-Satin H5), and Unidirectional Carbon Fiber (T700 Aerospace Grade) fabrics, respectively. The FRP plate flexural rigidity values were calculated with a central finitedifference iterative scheme while utilizing the experimental load-deflection relations based on bending tests. The tests were performed on each plate by applying a concentrated load at the center. A fourth-order partial differential equation of plate equilibrium was adopted to estimate the plate flexural …

Prediction Of The Thermomechanical Behavior Of Particle-Reinforced Metal Matrix Composites, Yi Hua, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this paper was to predict the thermomechanical behavior of 2080 aluminum alloy reinforced with SiC particles using the Mori–Tanaka theory combined with the finite element method. The influences of particle volume fraction, stiffness, aspect ratio and orientation were examined in terms of effective Young’s modulus, Poisson’s ratio and coefficient of thermal expansion (CTE) of the composite. The microstructure induced local stress and strain field was obtained through the numerical models of the representative volume element. Results suggested that particle volume fraction had significant impact on the effective Young’s modulus, Poisson’s ratio and CTE of the composite. Stiffer …

Review Of Anchorage Systems For Externally Bonded Frp Laminates, Stephen V. Grelle, Lesley Sneed

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Implementation And Validation Of Fault-Rupture Response Spectrum Analysis Procedure In Csibridge For Bridges Crossing Earthquake Fault Ruptures, Jennifer Evelyn Tures

Master's Theses

This thesis evaluates the application of a simplified analysis procedure as implemented in version 16 of CSiBridge^TM for design of bridges crossing earthquake fault ruptures. The fault-rupture response spectrum analysis (FR-RSA) approximation method has been proved adequate for both straight and curved ordinary bridges, but lacked a comfortable interface to accommodate the method users. Computers and Structure, Inc. has implemented the FR-RSA procedure into CSiBridge^TM, a user-friendly integrated 3-D bridge design software, as an added seismic design feature. By combining the response of the bridge due to the quasi-static displacement from the fault strike-slip rupture and the …

Kinetics And Mechanisms Of Titanium Wire Oxidation, Tanmay P. Engineer

Boise State University Theses and Dissertations

The kinetics and mechanisms of oxidation of titanium wire were assessed using a large test matrix in Ar-20% O₂ at 800 to 1200°C, and N₂-20% O₂ at 1000°C, for 0.5 to 24 hours. The effects of geometry on oxidation were evaluated by investigating the behavior of six high purity Ti wires with diameters varying from 50 to 2000 μm, with an objective of producing hollow TiO₂ tubes.

Oxidation behavior was characterized by measuring oxide thicknesses and morphology by optical microscopy, and the phases were characterized using a combination of SEM and TEM. The kinetics was …

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

Mechanical Engineering

No abstract provided.

A Resistance Based Structural Health Monitoring System For Composite Structure Applications, Dennis N. Boettcher

Master's Theses

This research effort explored the possibility of using interwoven conductive and nonconductive fibers in a composite laminate for structural health monitoring (SHM). Traditional SHM systems utilize fiber optics, piezoelectrics, or detect defects by nondestructive test methods by use of sonar graphs or x-rays. However, these approaches are often expensive, time consuming and complicated.

The primary objective of this research was to apply a resistance based method of structural health monitoring to a composite structure to determine structural integrity and presence of defects.

The conductive properties of fiber such as carbon, copper, or constantan - a copper-nickel alloy - can be …

Effects Of Annealing/Solution Treating And Aging On Longitudinal And Transverse Properties Of Ti-6al-4v Forgings, Blake Reller

Materials Engineering

Forty-eight subsize round-bar tensile samples (ASTM E8) were machined from 3-in-thick forgings of Ti-6Al-4V. Half of these samples were cut so the axis aligned with the longitudinal (LG) direction of the forging, the other half were cut to align with the transverse (LT) direction. Four samples from each direction were subjected to one of six heat treatments so that a total of eight samples received each treatment. Annealed samples were held at 1350°F for two hours, then air cooled. Solution treated and aged (STA) samples were solution treated at one of five temperatures between 1785°F and 1435°F for one hour …

Fabrication And Characterization Of Torsional Micro-Hinge Structures, Mike Madrid Marrujo

Master's Theses

ABSTRACT

Fabrication and Characterization of Torsional Micro-Hinge Structures

Mike Marrujo

There are many electronic devices that operate on the micrometer-scale such as Digital Micro-Mirror Devices (DMD). Micro actuators are a common type of DMD that employ a diaphragm supported by torsional hinges, which deform during actuation and are critical for the devices to have high stability and reliability. The stress developed within the hinge during actuation controls how the actuator will respond to the actuating force. Electrostatically driven micro actuators observe to have a fully recoverable non-linear viscoelastic response. The device consists of a micro-hinge which is suspended by two …

Biaxial & Twist Testing Of Composite Carbon-Fiber Sandwich Panels For Automotive Racing Vehicles, Erik Eckberg

Materials Engineering

Composite sandwich panels were constructed with 4-ply plain weave carbon-fiber/epoxy face sheets in the 0^o/45^o/0^o/45^o orientation and 1/8^th inch Nomex honeycomb core. The panels were cut into 5-inch square test plates for mechanical testing. All testing was done on a fixture designed and fabricated by Pratt & Miller Engineering and installed on an Instron testing system at Cal Poly. The twist test was performed by supporting diagonal corners of the plate while simultaneously loading the opposite two corners at a crosshead rate of .06 in/min (ASTM 3044-94R11). Out of 10 panels tested, …

Effects Of Alternate Cementitious Materials On Compressive Strength And Environmental Impacts Of Cement Mix Designs., Mitchell R. Bush

Materials Engineering

Specific proportions of Portland cement, fly ash, and blast furnace slag cement mixtures where chosen by a ternary phase diagram to be investigated. By experimental testing and company data history fly ash was limited to not exceed 30% and contribution of Portland cement must be over 50%. Ten chosen mix designs were batched by following ASTM C305-94 and cured for twenty-eight and forty-two days, the extended cure length allows the reaction of pozzolanic material with calcium hydroxide to complete. Compressive strength testing at forty-two days yielded low strength for mix designs with 20% or less Portland cement compared to our …

Discontinuous Grain Boundaries Of Forged René 41, Steven Crump

Materials Engineering

Forged components must pass a grain size specification (grain size, distribution) for acceptance in an application. The varying amounts of plastic deformation during forging can lead to abnormally large recrystallized grain sizes in certain regions of the part, which will not pass specification. The question exists whether these abnormally coarse grains are truly comprised of poly crystalline fine grains with grain boundaries resistant to etching techniques. To investigate this abnormal grain size effect, a cross section of a forged René 41 nickel-based superalloy aircraft engine ring was cut and sectioned into six segments. Those segments were then prepared for microstructural …

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 …

Investigation Of Negative Differential Resistance Phenomena In Quantum Well Heterostructures, Nazariy Andrushchak

Graduate Theses and Dissertations

Increasing interest in entirely new possibilities for quantum mechanical description of carriers transport is becoming more evident with the developing advancements in epitaxial growth technique. Consequently, molecular beam epitaxy (MBE) technique is considered to be the most precise technique that allows the growth of ultra-thin layers of different compositions.

Those structures can be designed to investigate the wave-nature of carriers, which broadens the possibilities in device design and fabrication for a specific area. In this thesis the fundamental study of the real space charge transfer (RST) mechanism that took place in quantum well heterostructures and led to the negative differential …

Nano-Silica For Enhanced Greener Concrete, Mohamed S. Zeidan

College of Engineering: Graduate Celebration Programs

Colloidal nano-silica was added to normal and fly ash concretes with different rates to examine the its effect on different concrete performance aspects. The main objectives of the study is to determine the effect of adding nano-silica on:

• The rate hydration and the reactivity of cement and pozzolans.

• The mechanical properties and strength gain rate (especially for fly ash concrete).

• Durability.

• Microstructure and Porosity.

The Influence Of Heterogeneous Meninges On The Brain Mechanics Under Primary Blast Loading, Linxia Gu, Mehdi S. Chafi, Shailesh Ganpule, Namas Chandra

Department of Mechanical and Materials Engineering: Faculty Publications

In the modeling of brain mechanics subjected to primary blast waves, there is currently no consensus on how many biological components to be used in the brain–meninges–skull complex, and what type of constitutive models to be adopted. The objective of this study is to determine the role of layered meninges in damping the dynamic response of the brain under primary blast loadings. A composite structures composed of eight solid relevant layers (including the pia, cerebrospinal fluid (CSF), dura maters) with different mechanical properties are constructed to mimic the heterogeneous human head. A hyper-viscoelastic material model is developed to better represent …

Peridynamic Model For Dynamic Fracture In Unidirectional Fiber-Reinforced Composites, Wenke Hu, Youn Doh Ha, Florin Bobaru

Department of Mechanical and Materials Engineering: Faculty Publications

We propose a computational method for a homogenized peridynamics description of fiber-reinforced composites and we use it to simulate dynamic brittle fracture and damage in these materials. With this model we analyze the dynamic effects induced by different types of dynamic loading on the fracture and damage behavior of unidirectional fiber-reinforced composites. In contrast to the results expected from quasi-static loading, the simulations show that dynamic conditions can lead to co-existence of and transitions between fracture modes; matrix shattering can happen before a splitting crack propagates. We observe matrix–fiber splitting fracture, matrix cracking, and crack migration in the matrix, including …

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 …

Introducing Fly Ash Into Lsi's Recipe, Andrew Mathias Beckrich

All Graduate Theses, Dissertations, and Other Capstone Projects

There has been published data that states that concrete producers can use Fly Ash as an alternative to Portland cement and still generate similar or better strength properties. By applying these principles to our industry and products, what new processes will need to be put in place and followed? What is the correct combination/portion of Fly Ash that will produce similar and better results as well as the adjusted new recipes? What type of cost is associated with the introduction of this new ingredient? Lastly, how does this affect the quality and reputation of the product?

Numerical Simulation Of Natural Convection In Rectangular Enclosures Of Varying Aspect Ratios And Its Feasibility In Environmental Impact Management Studies, Charles R. Walker

College of Graduate Studies: Theses & Dissertations

Author's abstract: Numerical simulation was used to investigate natural convection in horizontal and vertical enclosures with and without an internal heat source. Natural convection in rectangular enclosures is found in many real-world applications. Included in these applications are the energy efficient design of buildings, operation and safety of nuclear reactors, solar collector design, passive energy storage, heat transfer across multi-pane windows, thermo-electric refrigeration and heating devices, and the design-for-mitigation of optical distortion in large-scale laser systems. Considering all these applications, especially controlling heat transfer in nuclear power plants, knowledge and research results of natural convection in enclosure play a vital …