Engineering Mechanics Commons^™

Development Of Curved-Plate Elements For The Exact Buckling Analysis Of Composite Plate Assemblies Including Transverse-Shear Effects, David Michael Mcgowan

Mechanical & Aerospace Engineering Theses & Dissertations

The analytical formulation of curved-plate non-linear equilibrium equations including transverse-shear-deformation effects is presented. The formulation uses the principle of virtual work. A unified set of non-linear strains that contains terms from both physical and tensorial strain measures is used. Linearized, perturbed equilibrium equations (stability equations) that describe the response of the plate just after buckling occurs are then derived after the application of several simplifying assumptions. These equations are then modified to allow the reference surface of the plate to be located at a distance z_c, from the centroidal surface. The implementation of the new theory into the …

Development Of Vibration And Sensitivity Analysis Capability Using The Theory Of Structural Variations, Ting-Yu Rong

Mechanical & Aerospace Engineering Theses & Dissertations

In the author's previous work entitled "General Theorems of Topological Variations of Elastic Structures and the Method of Topological Variation," 1985, some interesting properties of skeletal structures have been discovered. These properties have been described as five theorems and synthesized as a theory, called the theory of structural variations (TSV). Based upon this theory, an innovative analysis tool, called the structural variation method (SVM), has been derived for static analysis of skeletal structures (one-dimensional finite element systems).

The objective of this dissertation research is to extend TSV and SVM from one-dimensional finite element systems to multi-dimensional ones and from statics …

Development Of A Model Updating Technique For Controls-Structures Integrated Design Optimization, Angela Georges

Mechanical & Aerospace Engineering Theses & Dissertations

A model updating technique is developed with the intent of providing an efficient means of improving the accuracy of the modelling of the vibrational qualities of a large, flexible structure as it undergoes an integrated controls-structures design optimization. The proposed technique utilizes eigenvalue/eigenvector sensitivity information, two different model reduction methods which assign weights of importance to the vibrational modes of the structure, and modal switching based upon the modal weights determined by the model reduction methods. Issues associated with the numerical implementation of the proposed technique, such as discontinuities induced by modal switching, are also addressed.

The proposed model updating …

Finite Element Frequency Domain Solution Of Nonlinear Panel Flutter With Temperature Effects And Fatigue Life Analysis, David Yongxiang Xue

Mechanical & Aerospace Engineering Theses & Dissertations

A frequency domain solution method for nonlinear panel flutter with thermal effects using a consistent finite element formulation has been developed. The von Karman nonlinear strain-displacement relation is used to account for large deflections, the quasi-steady first-order piston theory is employed for aerodynamic loading and the quasi-steady thermal stress theory is applied for the thermal stresses with a given change of the temperature distribution, ΔΤ (x, y, z). The equation of motion under a combined thermal-aerodynamic loading can be mathematically separated into two equations and then solved in sequence: (1) thermal-aerodynamic postbuckling and (2) limit-cycle oscillation. The Newton-Raphson iteration technique …

Numerical Investigation Of A Non-Newtonian Material Through A Sudden Pipe Expansion, V. G. Masanja

Tanzania Journal of Engineering and Technology (TJET)

A numerical method for solving two dimensional elliptic boundary-value problems of fourth order is used for finding stationary solutions of the equations of motion for a laminar flow through a sudden pipe expansion of an incompressible non-Newtonian fluid with a constitutive equation of the Reiner-Rivlin (R-R) type. Results for the Newtonian fluid, which is a special case, are in excellent agreement with those by previous investigators and they demonstrate the reliability, superiority and accuracy of the method. Results for the non-Newtonian cases could be of value for fixing ideas about visco-elastic behaviour although the R-R fluid allows only inelasticity: this …

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 …

Application Of Shape Sensitivity Analysis For Computation Of Transient Free-Surface Flows, Frank Nicolas Michel

Mechanical & Aerospace Engineering Theses & Dissertations

Shape sensitivity analysis is introduced into a numerical scheme simulating a transient free-surface flow and applied to the case of a fluid advancing through a bed of cylinders. For this incompressible Newtonian flow, viscous forces are dominant. A penalty function finite element formulation is used to solve the problem. Coordinates of nodes on the moving boundary are chosen as design variables and an analytical formulation of the gradient of the finite element algebraic system, with respect to these variables, is derived.

In a numerical example, the results obtained with and without sensitivity analysis are compared. The efficiency and accuracy of …

A Reiner-Rivlin Fluid Flow Through Entrance Region Of A Circular Pipe, V. G. Masanja

Tanzania Journal of Engineering and Technology (TJET)

The flow of a Reiner-Rivlin fluid with two viscosity coefficients through the entrance region of a circular pipe has been studied numerically. In particular the growth of the entrance length as a function of the Reynolds number and the non-Newtonian parameters has been examined. Where comparison could be made, the results have been compared with existing experimental -and numerical data as well as the limited theoretical work available.

Coupled Bending-Torsion Steady-State Response Of Pretwisted, Nonuniform Rotating Beams Using A Transfer-Matrix Method, Carl E. Gray Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Using the Newtonian method, the equations of motion are developed for the coupled bending-torsion steady-state response of beams rotating at constant angular velocity in a fixed plane. The resulting equations are valid to first order strain-displacement relationships for a long beam with all other nonlinear terms retained. In addition, the equations are valid for beams with the mass centroidal axis offset (eccentric) from the elastic axis, nonuniform mass and section properties, and variable twist. The solution of these coupled, nonlinear, nonhomogeneous, differential equations is obtained by modifying a Hunter linear second-order transfer-matrix solution procedure to solve the nonlinear differential equations …

An Apparatus For Measuring The Thermal Conductivity Of Cast Insulation Materials, Christine A. Wilkins, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

A steady-state apparatus has been developed for measuring the thermal conductivity of cast materials. The design has employed a novel thermal symmetry arrangement which can permit total electrical isolation of the test material from its surroundings. © 1980 American Institute of Physics

Effect Of Compliant Wall Motion On Turbulent Boundary Layers, Dennis M. Bushness, Jerry N. Hefner, Robert L. Ash

Mechanical & Aerospace Engineering Faculty Publications

A critical analysis of available compliant wall data which indicated drag reduction under turbulent boundary layers is presented. Detailed structural dynamic calculations suggest that the surfaces responded in a resonant, rather than a compliant, manner. Alternate explanations are given for drag reductions observed in two classes of experiments: (1) flexible pipe flows and (2) water-backed membranes in air. Analysis indicates that the wall motion for the remaining data is typified by short wavelengths in agreement with the requirements of a possible compliant wall drag reduction mechanism recently suggested by Langley. Copyright © 1977 American Institute of Physics.

Australian Tractor Test Report No. 58 : Massey-Ferguson 165, G H. Vasey, W. T. Brown

Journal of the Department of Agriculture, Western Australia, Series 4

THE Massey-Ferguson 165 is a general purpose farm tractor. The test tractor gave 50 drawbar h.p. with 59 h.p. at the P.T.O. at rated engine speed it comes within Class 5 of the Australian Standard Classification of Wheeled Tractors for Agricultural Purposes, AS Dl 0-1967. It is equipped with 18.4 x 28 in. pneumatic tyres. It has a threespeed gear box with a ratio change giving 6 forward and reverse speeds.

Australian Tractor Test Report No. 55 : Nuffield 4/65, G H. Vasey, W. F. Baillie

Journal of the Department of Agriculture, Western Australia, Series 4

THE Nuffield 4/65 is a general purpose farm tractor of 49 drawbar horsepower.

With 54 h.p. at the P.T.O. at rated engine speed it comes within Class 5 of the Australian Standard Classification of Wheeled Tractors for Agricultural Purposes, AS D10-1967. I t is equipped with 18.4 x 30 pneumatic tyres.

It has a five speed gear box with a High and Low ratio change giving 10 forward and 2 reverse speeds.