Mechanical Engineering Commons^™

Effect Of Center Of Gravity Location On Optimum Performance Of Random Vibratory Vehicle Suspension, Daniel Mahar

Theses

This study provides the analysis for the optimal design of a conventional vehicle suspension system, consisting of a sprung mass (vehicle body) and two unsprung masses (wheel frame), accentuated by the implementation of a damped absorber to the unsprung masses. Further, the effect of the c.g. (center of gravity) location of the vehicle body is investigated. A two dimensional, four degrees of freedom linear model is chosen. Randomly profiled terrain is assumed to impart hyperbolically distributed stationary vertical random displacements to the front and rear wheels. For generalization, nondimensional design parameters are selected. Criteria for optimization include the tire-terrain normal …

A Tracheoesophageal Puncture Voice Prosthesis, Georghios Makris

Theses

A voice prosthesis was developed that allows verbal communication of laryngectomised patients. The prosthesis requires a superiorly directed tracheoesophageal puncture in which the periscope mounted on the tracheal stoma vent is introduced. The prosthesis is operated by air injection through the periscope. Air injection is achieved by pulmonary pressure after the occlusion of the stoma vent. Stoma vent occlusion can be achieved either by the patient's finger or by the designed cover valve mounted on the prosthesis. The cover valve allows free breathing, hand-free prosthesis use, and it can release excess pressure during coughing. Periscope valve air resistance tests have …

Three-Dimensional Elastic-Plastic Finite Element Analysis Of Fatique Crack Growth And Closure, Rahmatollah G. Chermahini

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of this study was to develop a three-dimensional, elastic-plastic, finite element analysis to investigate crack extension and closure under cyclic loading. The initial study concentrated on the behavior of a straight through crack in a finite-thickness plate subjected to tensile loading (middle-crack tension specimen). The finite element model was composed of 8-noded (linear-strain) isoparametric elements. In the analysis, the material was assumed to be elastic-perfectly plastic. Zienkiewicz's "initial-stress" method, von Mises' yield criterion, and Drucker's normality condition, under small-strain assumptions, were used to account for plasticity. The three-dimensional analysis is capable of extending the crack and changing boundary …

An Analytical And Experimental Study Of Clearance And Bearing-Bypass Load Effects In Composite Bolted Joints, Rajiv Vikas Arun Naik

Mechanical & Aerospace Engineering Theses & Dissertations

A combined analytical and experimental study is conducted to determine the effects of clearance and bearing-bypass loading for mechanically fastened joints in composites. A simple method of analysis is developed to account for the nonlinear effects of bolt-hole clearance. The nonlinear load-contact variations for clearance-fit fasteners are also measured using specially instrumented fasteners. For a quasi-isotropic graphite/epoxy laminate, results show that the contact arc as well as the peak stresses around the hole and their locations are strongly influenced by the clearance. After a slight initial nonlinearity, the peak stresses vary linearly with applied load. The typical clearance levels are …

Circular Plate Analysis Using Finite Element Method, Shyh-Rong Chiu

Theses

The ANSYS computer program is the application of finite element methods to large-scale engineering problems. In this work the ANSYS program has been employed to solve the circular plate under uniformly loaded with various boundary conditions as follows: (1) clamped along entire edge, (2) simply supported along entire edge, (3) clamped at several points along the boundary, (4) simply supported at several points along the boundary, and (5) simply supported 36 points with 4 points clamped..

The results obtained from the ANSYS program illustrated that the finite element method has no boundary conditions constraints and presents good approximations to the …

Introductory Guide To Bridgeport Series I Cnc Milling, Drilling And Boring Machine, Apurva Vinodchandra Doshi

Theses

This thesis is intended to serve as an easy introductory guide on how to work with Bridgeport Series I CNC Milling, Drilling and Boring machine. An attempt has been made to make the subject matter simpler to give the reader a good start in programming and operating this machine

The spectrum of technological implementation of CNC machine tools is extremely broad,. Companies utilizing advanced technologies such as computer graphics, DNC and Group Technology are in this field for some time. Even small shops are getting equipped with CNC machine tools. The present CNC systems, which are less costly, more reliable …

Modal Analysis Of A Cantilever Plate, Ohseop Song

Theses

This thesis discusses the vibration of a thin, flat cantilever aluminum plate. Results are based on both an analytical finite element method using the ANSYS program and an experimental analysis using a digital Fast Fourier Transform (FFT) analyzer. The FFT analyzer permits extraction of modal parameters (natural frequency, damping, mode shape) for the plate.

Substructuring Analysis For Impact Dynamics Using Ansys Finite Element Package, Chang Ho Cho

Theses

This thesis is intended to serve as an introductory guide to ANSYS finite element package for the analysis of impact dynamics. Substructuring technique has been used to reduce the degrees of freedom.

Finite element method is essentially a numerical technique to calculate elastic deformations. However, by introducing some techniques like gap element, the technique can be easily extended to rigid body dynamic analysis. To solve the equation of motion both for rigid body and elastic deformations, direct integration technique is used in this thesis, i.e., Houbolt method.

ANSYS is a large scale general purpose computer program for finite element analysis. …

Analysis Of Compliant Pins Subjected To Plastic Deformation, Lincoln Miller

Theses

An experimental/numerical analysis of two types of compliant pins is presented: dynamic retention pins and cantilever pins. It is shown that there is a trade-off between the performances of both types of pins. For the same range of retention force, the cantilever pin, with a smaller stiffness, is more forgiving and gives a broader range of deflection. The dynamic retention pin is shown to be more reliable with time and replacement frequency, since it exhibits less plastic deformation for the same range of retention force.

Two And Three-Dimensional Isoparametric Finite Elements For Axisymmetric Micropolar Elasticity, Fuang-Yuan Huang

Dissertations

Finite element analysis program for isotropic and orthotropic axisymmetric micropolar (Cosserat) elastic solids are developed in this thesis. Isoparametric elements of 8- and 20- node are used to solve general three-dimensional problems, arid both 4- and 8-node elements are used for two-dimensional cases. Three-dimensional finite element formulation for cylindrical coordinate system is derived. Corresponding Fortran programs are then developed. Patch tests are performed for two-dimensional cases to verify the applicability of the finite element method to non-rectangular geometries. Several two-dimensional and three- dimensional problems for micropolar elastic solids are solved to verify the formulations arid computer program.

Good agreements were …

Deposition Of Suspensions In Convergent Channels Due To Electrostatic Image Forces, Kwok Wah Hui

Dissertations

The deposition of suspensions for uniform flow in convergent channels under the combined influences of inertia, viscous and electrostatic image forces was studied theorectically. The fluid phase was assumed to be two-dimensional, steady, uniform, incompressible and laminar while the particle phase was assumed to be uniform, steady, dilute and with negligible gravity effects.

Since the image force equations for convergent channels have not been derived, it becomes one of the main purposes of this study to perform the derivation of the image force equations. The lengths of the channels were chosen in a way that the exit area is only …

Deposition Of Particles In Tubes Due To Gravity And Electrostatic Charges, Win-Chung Chen

Dissertations

The deposition of particles in a parallel-plate channel and a circular tube under the influence of inertia, fluid viscosity, gravity and electrostatic image forces was studied by analytical and numerical methods. A laminar flow with uniform and parabolic velocity profiles was investigated with a particle initial velocity of zero as well as that of the local fluid velocity.

The governing equations were solved by the Lagrangian approach to obtain the particle trajectories from which the fraction of deposition was calculated. Closed form solutions for particle trajectory and a complete deposition of particles in a finite length of the flow passage …

Computer Aided Stress Analysis Of Long Bones Utilizing Computed Tomography, Shlomo Asher Marom

Dissertations

A computer aided analysis method, utilizing computed tomography (CT) has been developed, which together with a finite element program determines the stress-displacement pattern in a long bone section. The CT data file provides the geometry, the density and the material properties for the generated finite element model.

A three-dimensional finite element model of a tibial shaft is automatically generated from the CT file by a pre-processing procedure for a finite element program. The developed pre-processor includes an edge detection algorithm which determines the boundaries of the reconstructed cross-sectional images of the scanned bone. A mesh generation procedure then automatically generates …

Transient Response Of A Packed Bed For Both Sensible And Latent Thermal Energy Storage, Shi-Hong Ji

Doctoral Dissertations

The present work was undertaken to provide a model which accurately predicts the performance of a packed bed energy storage system utilizing spherically encapsulated phase-change material (PCM). Two models were developed which are referred to as the first-order and second-order models. Both models involve modeling of the phase-change material as a conduction problem with both sensible and latent energy storage and include consideration of the temperature gradients in both phases. Both models include the solution of the energy equation for the fluid passing through the packed bed. In the second-order model, both the intra-particle conduction and the dispersion effects in …

The Analytical Modeling Of The Thermometric Performance Of Total Temperature Thermocouple Probes, Leroy Bertram Butler

Open Access Dissertations

A total temperature thermocouple probe immersed in a moving gas stream undergoes thermal energy exchange by means of forced convection between the thermocouple wires and the flowing gas stream, conduction along the thermocouple wires to the probe mount, and radiation between the thermocouple junction wires and any surrounding structure. In general, the thermocouple junction does not indicate the true (stagnation) temperature of the gas stream, thus necessitating the calibration of total temperature probes to obtain correct temperature measurements.

Two models are developed to predict the temperature indicated by a total temperature probe (utilizing type K thermocouple wire) for a given …

A Performance Comparison Of Solar Radiation Predictive Models For Both Fixed And Tracking Surfaces, William F. Marion

Retrospective Theses and Dissertations

Accurate performance prediction for a system utilizing solar energy requires accurate estimates of the solar radiation received by the collector surface. This thesis compares the performance of five different diffuse solar radiation models in estimating the diffuse radiation received by a tilted surface in the warm, humid climate of Central Florida.

The following models were studied: Isotropic Model, Temps and Coulson Model, Klucher Model, Hay Model, and Perez Model. The models were evaluated for both a fixed south facing surface and for three different tracking schemes suitable for photovoltaic applications. Model estimates were then compared to the solar radiation data …

Investigation Of Vscous/Inviscid Interaction In Transonic Flow Over Airfoils With Suction, Chadra S. Vemuru

Mechanical & Aerospace Engineering Theses & Dissertations

The viscous/inviscid interaction over transonic airfoils with and without suction is studied. The streamline angle at the edge of the boundary layer is used to couple the viscous and inviscid flows. The potential flow equations are solved for the inviscid flow field. In the shock region the Euler equations are solved using the method of integral relations. For this the potential flow solution is used as the initial and boundary conditions. An integral method is used to solve the laminar boundary-layer equations. Since both methods are integral methods, a continuous interaction is allowed between the outer inviscid flow region and …

Recommendations For Amelioration Of Legal And Environmental Concerns About Mining Of Deepsea Deposits Of Polymetallic Sulfides, Michael P. De Luca

Dissertations, Theses, and Masters Projects

No abstract provided.

Commercial Design Of Four Indirect-Fired Fluidized Bed Gasifer Systems, Eoin Myles Clancy

Masters Theses

"This thesis deals with the design and cost analysis of four scaled up gasification plants. Reactor outputs range from 10 to 40 million Btu/hr (heating value of gas). Scale-up design parameters are based on data obtained from a 20 inch indirectly heated steam fluidized bed gasifier. This produces a medium Btu gas (450 Btu/ft³). The gas may be burnt on site or used as a chemical feedstock.

The plant designs consider reactor sizes, steam plant dimensions, specifications for feedhoppers, cyclones, conveying equipment, internal firetube heat exchangers, and drying plants.

The economic analysis deals with the cost of the …

Post-Buckled Performance Of Partially Restrained And Intermediately Supported Steel Angles, Perumal Radhakrishnan

Dissertations and Theses

The post-buckled performance of cross-braced single angles was experimentally determined. The results of this study will be used by the Bonneville Power Administration for the analysis of member performance in transmission towers.