Materials Science and Engineering Commons^™

An Investigation Of The Influence Of Tightening Torque And Sea Water On Pultruded Gfrp Composite Bolted Joints, Satish Devara

Mechanical & Aerospace Engineering Theses & Dissertations

Pultruded glass fiber-reinforced polymeric matrix composites are candidate materials for ever-increasing structural applications due to their continuous production capability, light weight and excellent properties. In this investigation an extensive experimental study has been carried out to understand their structure, basic mechanical properties, and influence of fiber orientation on the unnotched, notched and pin-loaded tensile strength. Furthermore, the effects of sea water and tightening torque separately and together on the failure loads and failure modes of the bolted joints are also studied. It is shown that blockshear failure mode is also a principal mode of failure in the bolted joints of …

Effects Of Elevated Temperature On The Physical Aging Of A High Temperature Thermoplastic Resin And Composite, Mark Feldman

Mechanical & Aerospace Engineering Theses & Dissertations

Development of a High Speed Civil Transport is considered by the commercial aviation industry to be one of the next big challenges for our national aircraft industry. Critical to the success of this aircraft is the development of advanced polymeric composites for both the primary and secondary structures and the predictive methodology necessary for assessment of long term durability. While polymeric composites offer an excellent strength to weight ratio a key disadvantage is the time dependent properties exhibited by the polymer matrix which can age and ultimately effect the resultant stiffness of a laminate.

Experimental studies were performed to determine …

A Comparison Of Tool Life Of Two Coated Carbide Inserts Under Identical Conditions And At Different Cycle Times, Garold Zander

Graduate Research Papers

Coated hardmetals have brought tremendous increases in productivity since 1969, when they were first applied to cutting materials. These coatings are extremely hard and are very abrasion resistant. Typical coatings are alumina oxide, silicon nitride with metal oxides, titanium carbonnitrides with metal carbides, titanium nitride, titanium carbonitride, and zirconium oxide. This study examined two different coated cutting inserts to determine which would maximize performance for lathe operators.

The two chemical vapor deposition (CVD) coated indexible inserts examined were Carboloy CMNA 543 TP 100, and Carboloy CNMA 543 TP 10. Both cutting inserts were multi-coated with alumina (Al2O3 ), titanium nitride …

Threaded-Nail Fasteners - Research And Standardization Needs, B L. Wills, S G. Winistorfer, D A. Bender, David Pollock

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Threaded nail fasteners are commonly used in agricultural and commercial post-frame structures, yet there has been insufficient research to fully understand the effect of threads on withdrawal and lateral load resistance. The objective of this article is to review technical information on threaded nail fasteners and to identify problems facing manufacturers, designers, and users of threaded nail fasteners for engineering applications. Recommendations are given concerning research and standardization needs.

An Investigation Into The Use Of Expanded Polystyrene Patterns With The Loose-Sand, Vacuum Assisted Counter Gravitational Casting Process, John B. Vandersall

Graduate Research Papers

"Considered for years as a metal casting renegade, Expendable Pattern Casting (EPC) is believed by some to be tomorrows long-term casting future. Others, however, see it as an unproven headache-ridden process that makes the simple art of metal casting unnecessarily complex." (Lessiter, 1994, p. 36). The complexity of this process has been largely due to the lack of knowledge surrounding the interaction of the metal front and the dissipating polystyrene pattern.

Since the discovery of EPS as a pattern material, numerous applied research projects have been performed to gain a better understanding of the thermal breakdown characteristics of the material. …

Window-On-Europe, S. R. Leclair, A. G. Jackson

Mechanical and Materials Engineering Faculty Publications

This report covers a three week visit to the following locations: 1.) A.A. Baikov Institute of Metallurgy of the Russian Academy of Science, Moscow, Russia; 2.) Institute for Applied Informatics, of the Ukrainian Academy of Science, Kiev, Ukraine; 3.)Engineering Design Center.Cambridge University, Cambridge, England- and 4) Artificial Intelligence Department, University of Edinburgh, Edinburgh, Scotland. The visits involved sites whose current research involved either empirical methods for the design of materials and resultant products and/or the development of empirical methods of potential benefit in automating empirical research of materials and/or processing. The report address, for each site, 1) a brief overview …

Relationship Of The Second Order Nonlinear Optical Coefficient To Bandgap In Inorganic Non-Centrosymmetric Crystals, A. G. Jackson, M. Ohmer, S. R. Leclair

Mechanical and Materials Engineering Faculty Publications

The purpose of this paper, is to provide a means of estimating and comparing the wavelength conversion efficiency (figure of merit, FOM) of new nonlinear materials knowing only their bandgap. The approach for the estimates is trend analysis of existing data^1-28 for the second order nonlinear coefficient, x⁽²⁾ijk, or d_ij =x⁽²⁾ijk^/2, the index of refraction n, and the bandgap E. No underlying physical basis for the result will be presented. The result of this trend analysis, in the form of plots of x⁽²⁾ vs E and FOM vs E …

An Analysis Of The Disposition Of Used Foundry Sand With Thermal Reclamation, Douglas Miller

Graduate Research Papers

The purpose of this study was to identify the economic and environmental concerns for the disposal, reuse, or reclamation of used foundry sand and show how foundries have developed options to landfills. The sand type and the reclamation processes available are the factors to use in determining whether disposal, reuse, or reclamation is appropriate. The continued use of landfills for disposal of used sand strongly indicates that reclamation and reuse techniques were either not understood or not as economical as disposal. Public concerns and new environmental laws demand that alternate means of disposal for used foundry sand should be developed …

The Development Of A Method To Extract High Purity Oxygen From The Martian Atmosphere, Dongchuan Wu

Mechanical & Aerospace Engineering Theses & Dissertations

A glow-discharge in an ambient Mars atmosphere (total pressure of 5 torr, composed of 95% carbon dioxide) results in the dissociation of carbon dioxide molecules into carbon monoxide and oxygen. If the glow-discharge zone is maintained adjacent and close to a silver membrane, operated at temperatures above 400°C, atomic and molecular oxygen, produced by the glow-discharge, can be separated from the other species by atomic diffusion through the membrane to an ultrahigh vacuum region where the desorbed O₂ is then collected. Experiments have been conducted to study the behavior of the glow discharge in both molecular oxygen and carbon …

Long-Term Effects Of Neutron Absorber And Fuel Matrix Corrosion On Criticality, William Culbreth, P. Zielinski

Mechanical Engineering Faculty Research

Proposed waste package designs will require the addition of neutron absorbing material to prevent the possibility of a sustained chain reaction occurring in the fuel in the event of water intrusion. Due to the low corrosion rates of the fuel matrix and the Zircaloy cladding, there is a possibility that the neutron absorbing material will corrode and leak from the waste container long before the subsequent release of fuel matrix material. An analysis of the release of fuel matrix and neutron absorber material based on a probabilistic model was conducted and the results were used to prepare input to KENO-V, …

Evaluation Of Photodiode Arrays For Use In Rocket Plume Monitoring And Diagnostics, Dallas Snider, M. Keith Hudson, Robert B. Shanks, Reagan Cole

Journal of the Arkansas Academy of Science

The spectroscopic analysis of plume emissions is a non-intrusive method which has been used to check for fatigue and possible damage throughout the pumps and other mechanisms in a rocket motor or engine. These components are made of various alloys. Knowing the composition of the alloys and for which parts they are used, one can potentially determine from the emissions in the plume which component is failing. Currently, Optical Multichannel Analyzer systems are being used which utilize charge coupled devices, cost tens of thousands of dollars, are somewhat delicate, and usually require cooling. We have developed two rugged instruments using …

Superplastic Forming System Design, Keith Bain

Honors Capstone Projects and Theses

No abstract provided.

Fiber Enhanced Viscoelastic Damping Polymers And Their Application To Passive Vibration Control, Houchun Xia

Mechanical & Aerospace Engineering Theses & Dissertations

A new composite damping material is investigated, which consists of a viscoelastic matrix and high elastic modulus fiber inclusions. This fiber enhanced viscoelastic damping polymer is intended to be applied to light-weight flexible structures as surface treatment for passive vibration control. A desirable packing geometry for the composite material is proposed, which is expected to produce maximum shear strain in the viscoelastic damping matrix. Subsequently, a micromechanical model is established in which the effect of fiber segment length and relative motion between neighboring fibers are taken into account. Based on this model, closed form expressions for the effective storage and …

Study Of Single-Fiber Fiber Optic Lever Microphone, Trung Duc Nguyen

Electrical & Computer Engineering Theses & Dissertations

Fiber optic sensors are widely used in today's technological applications, providing many advantages that conventional sensors lack. In particular, there is a demand in hypersonic applications to develop microphones to measure acoustic pressure that performs in high temperature and noisy surroundings. This thesis analyzes fiber optic lever microphones (FOLM), since they perform at high temperatures. An FOLM system is an intensity modulated sensor, which is simple to implement and is small in size. Two models of the FOLM have been fabricated and calibrated. The first model uses a seven-element fiber array while the second uses a single-fiber to transmit and …

A Technical Paper On Automated Pouring And The Selection Process Used By One North American Foundry, R. Stanley Weaver

Graduate Research Papers

This report on automated pouring focuses on the selection process used by one North American iron foundry. The problem facing this facility and any operation wishing to implement this technology lies in the number of variables which must be addressed in their quest for a suitable system.

Silicon Carbide/Electroless Nickel Composite Plating For Aluminum Substrates, Ben Charbit

Masters Theses

The effectiveness of producing a composite coating by suspending micron-sized particles in an electroless nickel bath while plating a 2024T4 aluminum alloy part was studied. The variation in the count of particles trapped in the nickel coating due to changes in the particle size, concentration of the particles in the bath, and the substrate surface texture was also studied. Particle sizes of 1 micron and 10 microns, concentrations of 15 gr/lt and 30 gr/lt, and polished and blasted textures were used. It was found that this technique is an effective way to produce composite coatings rendering a high number of …

Measurement Of The Coefficient Of Thermal Expansion Of Superconducting Thin Films Using Powder X-Ray Diffraction, Biju Chandran, R. Calvin Goforth, S. Nasrazadani

Journal of the Arkansas Academy of Science

The High Density Electronics Center (HiDEC) at the University of Arkansas, Fayetteville is developing the technology for High Temperature Superconductor Multi-Chip Modules (HTSC-MCM's). As part of this work, we are looking at the mechanical properties of HTSC materials. An important mechanical property which influences the mechanical integrity of the hybrid MCMis the coefficient of thermal expansion (CTE) of the HTSC films. As a first step in developing a procedure for the determination of the CTE of HTSC materials, the lattice parameters and the CTE of an alpha-alumina substrate have been determined by powder x-ray diffraction technique. An extension of this …

Micromechanics Of Granular Materials And Its Relation To Wave Velocity, Tarun K. Agarwal

Civil & Environmental Engineering Theses & Dissertations

The macro characters of the granular materials depend upon micromechanical parameters such as the void ratio, particle shape, contact force distribution, and initial state of the fabric of the assembly. Since it is difficult to evaluate these internal parameters from laboratory experiments, a macro measure is desired which depends directly on these internal parameters. One such measure has been shown to be dynamic shear modulus but it was incomplete in predicting directional changes in the internal parameters. Therefore, it is hypothesized here that the complete elastic moduli matrix will have more direct information about the internal parameters, especially the dynamic …

Finite Element Analysis Of Structures With Constrained Viscoelastic Layer Damping, Yung Chen

Mechanical & Aerospace Engineering Theses & Dissertations

It has been demonstrated that constrained viscoelastic layer damping treatments provide an effective means of passive control for structural vibration. These treatments dissipate vibrational energy by inducing shear strain in a thin layer of viscoelastic material. Our interest is in adding passive damping to a structure as an augmentation to active control. For such applications it is desirable to achieve high damping performance in a given frequency range with a minimum of added weight. Most damping treatments employ spatially continuous constraining layers over the entire viscoelastic layer. Plunkett and Lee have shown that the effectiveness of the damping treatment can …

A Systematic Procedure For The Analysis And Design Of Deployable Space Structures, Praveen Kumar

Mechanical & Aerospace Engineering Theses & Dissertations

An integrated graph theory and a symmetry-based approach have been developed for the type synthesis of deployable truss structures. Using this systematic approach, a bay of a deployable structure may be looked upon as being built around an axis or a plane of symmetry, including anti-symmetry. By providing a fictitious joint along this axis, the problem of structural design and analysis can be reduced to the study of one plane or face of the given structure. Each face is considered to be an assemblage of structural links connected by joints which form a closed kinematic chain. The conventional graph representation …

Behavior Of Ductile Materials Under Impulsive Loading, M. Y. Brunner

Tanzania Journal of Engineering and Technology (TJET)

Ductile materials under dynamic loading are known to be able to absorb energy and thereby delay or even prevent structural failure. This paper is concerned with such behaviour in the case of impulsive loads of short duration. It is shown that even when the feared, unstable, labile condition is attained, failure may not necessarily occur. This behaviour is particularly impressive for structures with large mass, because it is essentially the mass which slows down the attainment of the failure strains. If the impulsive load dies away quickly enough, the constant plastic resistance will be adequate to bring the increasing deformations …

Relationship Between Magnetic Ageing, Metallographic Evidence Of Ageing And Composition For Cold Rolled Si-Fe Electrical Sheets, J .V .Tesha

Tanzania Journal of Engineering and Technology (TJET)

The cold rolled Si-Fe sheets used for the production of the current cores for electricity meters suffer from ageing which causes an irreversible change in the magnetic properties. The ageing process is due to the precipitation of mixed iron silicon carbides in the microstructure. There exists already a thermal treatment and magnetic properties measurements method to detect the susceptibility to ageing. This requires a minimum of 1000 hours. In order to find the correlation between magnetic ageing, composition and metallographical evidence of ageing, different Si-Fe sheet compositions were investigated using the optical microscope to observe the time to appearance of …

Effect Of The Variations Of The Mobile Dislocation Density On The Thermally Activated Cyclic Deformation Behavior, J. S. Mshana

Tanzania Journal of Engineering and Technology (TJET)

The application of the transition state theory of rate processes to describe tension-tension, strain controlled cyclic deformation BEHAVIOUR was extended to describe the effect of the variations of the mobile dislocation density on the cyclic deformation BEHAVIOUR. It was shown from the derived constitutive relation that due to the net increase in the mobile dislocation density during strain controlled cyclic deformation the stress change per cycle (or in function of time) increases.

Elasto-Composition Waves In Inhomogeneous Solids, R. C. Batra, Manfred Wuttig

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Structural Self-Shadowing And Its Effects On The Thermal-Structural Behavior Of Orbiting Trusses, Jack Mahaney

Mechanical & Aerospace Engineering Theses & Dissertations

The determination of structural shadowing is described. The computation of environmental heat loads for slender structural members in earth orbit is described, and two methods for finite element thermal analysis are described . The effects of self-shadowing on the thermal structural behavior of single truss members and two different trusses are presented. In each case the shadowing produces a noticeable effect on the temperature distributions on truss members, and on the deformations of the trusses.

Desirable Combinations Of Electrode And Flux For Submerged Arc Welding Of Low Carbon Steel, James A. Husmann

Graduate Research Papers

The major purpose of this study was to provide information about desirable combinations of welding electrode and appropriate fluxes for submerged arc welding of low carbon steel. Other purposes were to:

1. Test a variety of combinations of available submerged arc welding electrodes and fluxes in welding low carbon steel.

a. Prepare specimens for tensile tests.

b. Conduct tensile tests.

c. Calculate tensile strength, yield point, break point, percent of elongation, and percent reduction of area.

2. Determine the most desirable combinations of electrode and flux for companies presently using or planning to use submerged arc welding for low carbon …

Measurement Of Neck Development In Tensile Testing Using Projection Moire, Raghavan Srinivasan, C. S. Hartley, C. Raju, J. Clave

Mechanical and Materials Engineering Faculty Publications

The projection moire technique affords an accurate method of measuring the geometry of the necked region in a tensile specimen. Corrections to the measured stress, necessary to account for the triaxiality introduced by the neck, require values for the radius of curvature of the specimen at the minimum section. The spacing of fringes resulting from the interference between a grating projected on the specimen surface and a master grating not only provide information which permits calculation of the radius but also demonstrates any changes in symmetry resulting from plastic deformation. Results obtained by testing specimens of copper and mild steel …

Kentucky Building Code 1980, Kentucky Library Research Collections

Research Collections

Kentucky Building Code (KBC) is the official referenced standards to ensure that a building is constructed in accordance with the approved construction documents.

Materials Testing And Consultancy For The Tanzanian Industry, H. Fallenbach

Tanzania Journal of Engineering and Technology (TJET)

Abstract

Investigation Of Corrosion And Weathering Phenomena In Tropical Marine Environment, K. P. Stormer

Tanzania Journal of Engineering and Technology (TJET)

Abstract