Mechanical Engineering Commons^™

Isoparametric Finite Elements For Axisymmetric Solids, Ramanand R. Shetty

Theses

The finite element formulation of axisymmetric plane stress analysis is used to develop a computer program for numerical implementation. The basic relations used to derive the finite element equations for a solid continum are reviewed in the thesis. The programming organization is summarized and program list is given in Appendix.

The program portion for isoparametric elements are borrowed from Numerical Methods in Finite Element Analysis by K. J. Bathe and E. L. Wilson, and various other subroutines are used from Mr. Huang's thesis on Micropolar elasticity analysis. Mr. Huang's computer program is based on the work done by Dr. Nakamura …

On Radial And Rotational Spring Constants Of Piping With Square Tubing Attachment, Hson-Chih Sun

Theses

Numerical values and analytical expressions for spring constant in the radial direction, and rotational spring constants in the circumferential and longitudinal directions of piping with square structural tubing attachment are presented.

Following Bijlaard's approach, the double Fourier series solution for the thin shell equation are used to express these spring constants as a function of internal pressure, q, and pipe-structural tubing parameters, such as alpha (piping length/radius), beta (tube size/pipe dia.), gamma (pipe radius/thickness) and thickness of the structural tubing. Numerical results of these spring constants are presented in tabulated form. These Tables include a set of eight standard square …

Chebyshev Approximate Solution For Stiff Problems, Kwo-En Hoh

Theses

Chebyshev polynomial and collocation methods are adapted to solve general ordinary differential equations ( initial-value problems and boundary-value problems ). Approximate solutions of initial-value problems are obtained in step-by-step fasion. the solutions have minimax absolute error in the interval and correct values at the end points. The approximate solutions of boundary-value problem will be continuous on the whole domain and have piecewise Chebyshev approximation characteristics in each subinterval of the chosen partition.

Discontinuity Stresses Analysis In Pressure Vessel, Jan-Joo Liu

Theses

In this paper, the ANSYS general purpose finite element computer aided design program was used to perform a series of stress analyses for shells with heads of various shapes.

The analysis included maximum discontinuity stresses, stress contours and displacements induced in axisymmetrical shells subjected to internal pressure loading; especially at the junction of the cylinder and heads of various shapes.

CONICAL SHELL finite elements and TWO-DIMENSIONAL ISOPARAMETRIC finite elements were used in the analysis. The results of the analyses compared very favorably with solutions derived from membrane and bending theory solutions for pressure vessels.

The effect of longitudinal and hoop …

On Torsional Spring Constants At The Juncture Of Piping-Nozzle, Shean-Juinn Chiou

Theses

Numerical results of torsional spring constants at the juncture of piping-nozzle are studied in this thesis by using the "ANSYS" program and run on VAX computer. These results are presented in tabulated form for a piping-nozzle vessel with constant thickness of 0.375 in. Plot for the torsional spring constants in terms of beta (nozzle radius/pipe radius), gamma (pipe radius/thickness) and alpha (pipe length/radius) are also presented in this thesis. These data are under zero piping internal pressure with beta ranging from 0.1 to 0.8, and gamma ranging from 10 to 150. A numerical example with verification is also given.

A Closed Form Image Force Function For Deposition Of Particles In A Cylindrical Tube, Hsi-Chung Chiou

Theses

This study investigated the behavior of charged particles suspended in a laminar steady incompressible flow in a cylindrical tube under the influences of image , inertia , viscous and gravitational forces. A new expression for the image force was obtained by introducing an approximate potential energy function. The velocity profiles employed in the analysis were uniform and parabolic.

The governing equations derived were based on Newton's second law of motion and were solved by a Runge-Kutta numerical method. The results were obtained for different values of Q, a dimensionless inertia-charge parameter. For a value of Q equal to zero the …

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.

Identification Of Material Constants Of Human Bone Using Finite Element Method For Micropolar Elasticity, Sajid Mannan Sayed

Theses

Bone differs from most engineering materials in the composition of its structure. The classical theory of elasticity fails to correctly predict the stress concentration effects in bones with precracked or notched surfaces, and can be applied only to those materials which exhibit more homogeneity and isotropicity than bone. Therefore, generalized continuum theories, which have addditional degrees of freedom, must be used to determine the stress concentration effects in human bone, especially in regions of high strain gradient, such as a hole or an interface.

In this thesis, efforts have been made to identify the material constants of human bone since …

Development Of Dynamic Analysis Program Mini-Dymac, Shang-Rou Shien

Theses

The computer program DYMAC developed by B. Paul automatically generates and numerically integrates the equations of motion of closed loop multi-body mechanical systems. The theory behind this program is Larange's form of d'Alembert's principle. However, it is not an easy task for the beginners to understand this program completely. If there is a simplified version of the program, it will be of great help for those people to understand the essential organization of the program.

Using the same theory of DYMAC, computer program MINI-DYMAC is developed in this thesis and hoped to serve as an educational version of DYMAC. For …

Graphic Display Of Robot Kinematics, Ramamurthy Vishwanathan

Theses

This thesis uses the HOUIE.BYLI graphics software package to simulate the kinematics of a six degree of freedom, MAKER I robot. The coordinate frames for the various links of the robot were established. The kinematic equations for the manipulator were developed snd solved using the techniques of inverse geometric transformations and transformations of objects in 3D space. A program was also developed to calculate the joint variables of the manipulator given any point on, and the orientation of, an object. These variable values are used to direct the robot end effector to the given point. This can be seen in …

On Natural Frequency Of The Stiffened Hvac Ducts, Jin-Lian Ha

Theses

This thesis employs ANSYS program to calculate the natural frequency of a stiffened HVAC duct and to investigate the affect of these stiffeners to the values of the natural frequency.

Investigation through this thesis shows that increases in the number of transverse stiffeners mould increase the natural frequency of the HVAC duct and the installation of the axial stiffener mould also increase the duct natural frequency.

Simulation Of A Microprocessor Controlled Drill Press, Arun J. Ayyagari

Theses

The concept of flexible manufacturing systems has ushered new dimensions into machine tool design. The power of this new technique is that a high degree of flexibility in a machine tool can be easily achieved by developing a software based control system as against conventional hard wired systems in existence.

To demonstrate this point, a microprocessor based control system is developed, in this thesis, to control the automated drill press. The Motorola MC6808 8-bit microprocessor is chosen as an example.

The microprocessor first evaluates the optimum cutting parameters for the given cutter size, work material and operation. It then uses …

Analysis And Evaluation Of The Developments In The Use Of Coal, Farid Najib Elkheshen

Theses

This thesis is a survey and evaluation of the developments in the use of coal. It deals with the social, economic, physical, and biological impacts of such a shift. It examines the complete coal system, from extraction to combustion, including the key steps and policy initiatives. The United States, with 6% of the world's population, consumes about 33% of its commerical energy supply - while the available reserve coal is about 80% of total energy in the United States, with coal use representing only 17%, oil and gas about 78% at present.

Technologies under development that might reduce costs, increase …

Computational Method For Solving The Kinematics Of Mechanisms Using Matrix Methods, Rajat Pardal

Theses

This thesis deals with the computational methods for kinematics of mechanisms using matrix methods. The method is particularly suited to the complex mechanism problems for which hand calculations are difficult. The thesis first reviews the matrix methods on which the program IMP is based. A computer program developed by Ve Tung using the same theory is enhanced in this thesis. By using this revised program, comparison between the non-linear algebraic approach and the matrix methods developed in this thesis has been made by the help of suitable examples. Further, it has been proved that the Integrated Mechanisms Program does not …

Optimum Design Of Structures Subject To Buckling Constraints, Thomas G. Looby

Theses

This thesis describes the optimal design of bar type planar truss structures subject to stress and buckling constraints. All of the structures considered are modeled using the direct stiffness finite element approach. A mathematical programming method incorporating a feasible directions routine is utilized to develop least weight designs for these conditions. The existing structural optimization programme CADOS which has successfully solved stress and deflection problems for this class of structures is adapted herein to treat local stability constraints based on Euler bucking criteria.In addition the optimization routine is modified to more effectively treat, infeasible starting designs. These modifications were tested …

Finite Element Analysis Of The Prosthetic Acetabular Region, Katkuri Venkat Rammanohar Reddy

Theses

Femoral component loosening and prosthetic stem fractures have renewed interest in conservative alternatives to conventional total hip replacements. The objective in this study is to get interfacial stresses of a acetabular surface replacement cup. This is done by performing finite element analysis of the model. A solid three - dimensional model with a grid of 3D isoparametric solid elements is generated using ANSYS, a powerful finite element analysis package. The stiffness is considered to be linearly proportional to the stress in the acetabular region. The stresses are determined by performing iterative finite element analysis. Stresses arp computed using two different …

Laminar Flow Through A Porous Annulus With Surface Suction, Stelios C. Nicolaides

Theses

A theoretical investigation was conducted to obtain the velocity, pressure and shear stress distributions for incompressible, steady, fully developed, laminar flow through an annulus, with a uniformly porous inside tube wall. Suction at the walls is a result of the pressure difference across the porous wall.

The continuity equation, momentum equation and the Darcy's law for suction velocity are analysed with an integral method. The resulting differential equations were solved using a numerical technique.

For the same radii ratio, dimensionless inlet pressures on both sides of the porous wall and dimensionless porous resistance, the dimensionless length required to reach zero …

Computer Analysis On Discontinuity Of Cylindrical Pressure Vessels With Various Heads, Ku-Shiang Sheu

Theses

This thesis uses FORTRAN programs to compute the maximum shear stresses of the cylindrical pressure vessel with various heads. They are cylindrical, spherical, ellipsoidal, flat and conic shapes. Also the maximum shear stresses for the bimetallic joints at the vessel wall and away from the vessel wall are analyzed. Numerical examples are given for each case to facilitate the applications.

A Survey Of The Literature On Moisture In Building Construction, Lawrence Charles Tiboldo

Theses

The aim of this thesis was to evaluate the literature on moisture in buildings for its usefulness in the understanding of the theory involved in moisture transfer in buildings. Because analysis of the effects of moisture migration and development of condensation control strategies in structures depends on the knowledge of heat and moisture transfer theory as well as on the documented data on building material properties, evaluation of the usefulness of the reference material will serve as an indication of the availability of pertinent information.

To fulfill this objective, the literature listed as references to Chapter 21 of the 1985 …

Buckling Of Some Grooved Columns, Clovis Georges Baaklini

Theses

Columns with two types of transverse grooves are analyzed: a one-sided groove whose bottom is parallel to a vertical plane and cross-section is constant, and a concentric uniform groove. Then, for illustration and to be more specific, round columns are selected such that the cross-section becomes partially circular, for one-sided grooves and totally circular for a concentric groove. The columns are simply supported at both ends and subjected to a compressive eccentric load P at eccentricity e. The static equilibrium of such columns is studied via two types of solutions: the solution to three-segment column and a substantially simpler but …

Skyline Technique For Least Square Temporal Finite Element Method, Ying-Woei Hu

Theses

Skyline technique is known to be one of the most efficient numerical methods for solving symmetric and positive definite simultaneous linear algebraic equations whose coefficient matrix is banded and sparse. This technique considers non-zero elements below the skyline only and manipulates Gaussian elimination process efficiently.

In recent years, the finite element methods applied to discretize the space domain has been successfully extended to time domain discretization. This new technique, temporal finite elements, makes it possible to numerically solve initial value problems in a manner similar to boundary value problems.

This thesis introduces skyline technique to one of the temporal finite …

Experimental Investigation Of Heat Transfer From An Array Of Air Jets Impinging Normally On A Flat Plate, Deniz Metin Kaya

Theses

Heat transfer from submerged, turbulent, circular and axisymmetric array of air jets impinging normally on a hot flat plate has been studied experimentally. Jets issued from an array of five nozzles 6.35 mm (0.25 in.) in diameter. The ratio of nozzle center-to-center distance to the nozzle diameter, given by C_n/D, of 2, 3 and 4 were considered. Nozzle exit Reynolds Numbers 14000, 26000 and 54000 were employed. The ratio of distance between the test plate and nozzle diameter (Z_n/D) varied from 5 to 15.

Two experimental arrangements, one with a segmented brass plate heated by a …

Optimal Design Of A Dynamic Structural System, Azhar Imtiyaz Khan

Theses

This Thesis studies optimal design of structural dynamics, based on the State Space approach which uses the Design Sensitivity Analysis and the Adjoint Variable Technique. As a numerical example, optimal design of a multistory structure subjected to a dynamic response, similar to that of an earthquake, is chosen. The equations of motion of the structural system are constructed using the Finite Element method, treating the cross-sectional area of each story as a design variable. To solve the equations a package program DE is used. A program is developed based on the State Space Algorithm and the cost function, constraints and …

Evaluation Of Pressure Capacity Of Rectangular Hvac Duct Plates, Ming-Tui Liu

Theses

The purpose of this thesis is to evaluate the pressure capacity of the duct plates for HVAC design as recommended by Sheet MeLal and Air Conditioning Contractors' National Association, Inc, 1980, whose code is based on the theories of both one-dimensional and two-dimensional analysis. Various sizes of duct width and stiffener spacing for rectangular plates are investigated, Charts and plots are Provided to facilitate the HVAC desidn. A BASIC language program and disc for personal computer is also provided.

Computer Simulation Of Drop Weight Impact Tests On Plastic Parts Or Sheeting, Upendra V. Patel

Theses

The ASTM D3029 drop weight test on plasic parts or sheeting is simulated in this thesis. The simulation is accomplished by using the Bruceton staircase method or the Up-and-Down method and the normal distribution theory. The "Probit" method is also analyzed.

The simulation programs are done in FORTRAN computer language. First, the random number generator is used to find the probability value between 0 and 1.0. Then, the cumulative probability distribution formula is used to find the absolute standard normal value. This absolute standard normal value is converted in to X normal value using given input values of mean and …

Axisymmetric Air Jet Impinging On A Hemispherical Convex Plate, Salahuddin Qureshi

Theses

This experimental study was carried out on an axisymmetric air jet impinging normally on a smooth, hemispherical convex plate. Three different nozzles of diameters 0.5in.(12.7mm), 0.375in.(9.525mm) and 0.25in.(6.35mm) were used and the nozzle exit Reynolds number varied from 14,000 to 80000.

The impingement hemispherical plate was made of brass and had a nominal outer diameter of 7.48in (189.99mm).

Calibrated Pitot tubes, U-tube manometer and a micromanometer were used for pressure and velocity measurements. The Pitot tubes were mounted on Precision position mechanisms permitting the accurate traversing in any direction in space. The test air flow rate was measured with calibrated …

Free Convection Boundary Layer Heat Transfer Analysis Of Isothermal Horizontal Square Plates, Konstantinos E. Tsouras

Theses

The theoretical study presented here examines free convective boundary layer flow and heat transfer over isothermal horizontal square plates.

The boundary layer equations subjected to the appropriate boundary conditions were solved by using Von Karman's approximate integral technique. The analysis was performed by considering an axisymmetric boundary layer because the analyzed phenomenon is three-dimensional in nature. Three-dimensional boundary layer analysis, however, is complicated and the work involved is rather tedious. Consequently, the axisymmetric boundary layer offers a useful alternative. Unfortunately, it was found that this type of analysis is applicable to the case of an upward-facing heated plate only; for …

The Effects Of Ultrasonic Excitation Of A Hydrocarbon Fuel On The Performance Characteristics Of A Spark Ignition Engine, Michael John Kooman

Theses

A six cylinder, 200 cu. in. spark ignition engine, model 1-AC-100-200 manufactured by Ford was tested by means of a Clayton dynamometer, model 8-200. The purpose of the test was to establish a reference base and to determine the effects of ultrasonic excitation on performance and combustion characteristics of the internal combustion engine. Variable load tests were performed at full throttle, 90% throttle, 60% throttle, and 40% throttle for the standard carburetor and the carburetor modified for ultrasonic excitation. Power was supplied by a Firbra-Sonics, model G-100 Mark 3, Ultrasonic generator. Exhaust gas concentrations were measured by means of a …

Development Of Robotic Arm Models Using The Integrated Mechanisms Program, Mohan J. Somnay

Theses

The purpose of this thesis is to study the broad concepts and applications of robots in industry and to evaluate the Integrated Mechanisms Program (IMP) for the development of models to suit the requirements of an industrial robot.

IMP is a programmed system for the computer-aided-design and analysis of mechanisms. The use of IMP to analyse and design mechanisms is done through a related problem oriented language which allows a variety of joints to be used.

This thesis describes a general procedure for designing robotic arms. Two mechanisms are modelled using IMP; the first is a jointed arm robot executing …

On Circular Hvac Duct Design Through Stress Analysis, Chien-Chung Lee

Theses

In this thesis, comprehensive studies through stress analysis of the circular HVAC ducts are made. The ducts are made of thin gaged steel sheet, and reinforced by stiffeners that are made of hot-rolled steel sections of L or C shapes. The ducts are loaded with pressure, its own weight and the possible seismic accelerations. A comprehensive FORTRAN program is developed as an aid Lo achieving the optimum design of circular ducts, i.e. duct thickness, stiffener spacing, stiffener size and seismic span length, Several stress analysis tables and a design parameter plot arc, provided in this thesis Lo facilitate design optimization.