Thesis (Ph.D.) -- McMaster University, 2001. / Includes bibliographical references (leaves 244-254). Also available via World Wide Web.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xi, 157 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 96).

Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 1998 / However, studies were also conducted for the buckling of composite laminates involving temperature distribution. Chen and Chen (1991) studied thermal buckling of laminated plates under uniform and nonuniform temperature distribution using the eight-node Serendipity finite element. Mathew, Singh and Rao (1992) investigated thermal buckling of antisymmetric cross-ply composite laminates with a onedimensional furite element having two nodes and six degrees of freedom. Chandrashekhara (1992) accounted for transverse shear flexibility by using the thermo-elastic version of the first-order shear deformation theory. This will also be the case in this report. Literature on buckling and laminated composites abounds. Brush and Aimroth (1975) published a book on Buckling of Bars, Plates, and Shells, while Bushnell (1985) surveyed the Methods and Modes of Behaviour in Static Collapse. The foundation for the study of composite materials was based on the references [8], [10], [15] and [18]. The use of the Finite Element Method to analyse the buckling behaviour of laminated structures comes from references [I], [4]. [I2]. [16], [24] and [32]. Reference [14] provided the basis for the formulation of the variation of the governing equations. Most of the ideas in this report are based on these publications and references. Chapter I of this report introduces the concept of a composite. the formation of a composite and a brief overview of the elements of a composite material. This chapter also presents the concept of buckling that will form the basis of the development of this project. At the end of this chapter the choice of the element that is used in this study is justified. Chapter 2 provides the fundamentals of elasticity that relate to the deformation of a loaded body. In this Chapter the stresses and strains are defined and the temperature terms are introduced. In Chapter 3 the Mindlin plate theory is presented with a view to laying the foundation for the analysis of laminated plates, and as a starting point in the formulation of thermal buckling behaviour of laminated plates. In Chapter 4 the elements of a composite material are discussed and the constitutive equations of a laminated composite plate are built. Also the idea of lamination is introduced and the various simplifications that can be introduced as a result of lamination are discussed. The non-linear equilibrium equations and the stability analysis of a composite plate are formulated in Chapter 5 using the conventional anal}1ical method. The resulting equations justify the use of the Finite Element Method as introduced in Chapter 6 and it is the method by which the governing equations will be solved in ABAQUS computer analysis. The results for various computer runs are presented for a normal plate, a plate with a square hole, and the plate ""ith a circular cut-out in Chapter 7. Also in chapter 7 a comparison is made between the laminate "ith a central hole and a normal plate to study the effect of a cut-out on a critical buckling temperature. Appendices A deals the transverse shear in plates, and Appendix B deals with the transformation of the laminate elastic constants form the principal material direction to the general Cartesian co-ordinates. Also in Appendix B the laminate stiffness matrices and these matrices are briefly evaluated analytically. Appendix C is about the governing equations of laminated composites, while Appendix D gives a full representation of the abbreviated finite element equations of Chapter 6. Appendix E presents the list of ABAQUS input files that were used in the computer simulation of Chapter 7.

A three-month study evaluated composting of cross laminated timber (CLT) sawdust amended with 10% and 20% chicken litter. Moisture was provided by rainwater or deionized water depending on the precipitation. The contents in the containers were mixed once or twice a week for aeration. Samples were collected at 0, 45, and 90-day intervals to measure weight loss, moisture content, pH, compost maturity, microbial count, and carbon-to-nitrogen ratio. Results indicated that composted CLT with 20% chicken litter had much higher weight reduction than others at day 45 and 90. Treatments with 10% and 20% chicken litter had a higher initial pH than controls and showed a slow increase near to neutral 7 by day 90. The germination rate of radish seeds to measure the compost maturity showed that composted CLT with 20% chicken litter had significantly higher germination rate than the others at days 45 and 90. A greenhouse study of composted material showed also that the 20% treatment could be used as soil amendment due to its excellent C/N ratio but appears to be unsuitable for container media. Longer composting time is suggested for CLT sawdust to be cured and used for potting media.

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Many commercial finite element programs support piezoelectric modeling and composite modeling to some extent. The popular program ABAQUS, however, has piezoelectric modeling capabilities only for continuum and one-dimensional truss elements. In situations where aspect ratio constraints and computational inefficiencies become a significant issue, such as modeling very large thin structures, alternate modeling techniques are sometimes required. Much of the focus of this thesis was to introduce equivalent methods for modeling laminated piezoelectric beams and plates. Techniques are derived based on classical beam and plate theory, classical lamination theory, and the linear theory of piezoelectricity. Finite element approximations are used with the principle of minimum potential energy to derive the static equilibrium equations for piezoelectric laminated structures. Equivalent loading techniques are derived based on the constitutive equations of piezoelectricity to simulate actuation forces within the piezoelectric layers. Finite element models using equivalent modeling techniques as well as equivalent loading techniques for piezoelectric laminated structures are developed and compared to ABAQUS models using piezoelectric elements to evaluate the error in theoretical assumptions. The analysis will prove that equivalent structural models and equivalent loading techniques provide excellent means for simplifying the analysis of thin piezoelectric laminated structures. / Master of Science

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A change in laminate thickness due to terminating internal plies acts as a stress riser for both intralamina and interlaminar stresses. This laminate configuration is referred to as a ply drop. The linear elastic, three-dimensional stress distributions in the vicinity of a ply drop are determined for a graphite-epoxy laminate subject to axial tension and compression by a finite element analysis. It is shown that the interlaminar stresses have a maximum magnitude at the ply drop-off, and decrease proceeding away from the drop-off. Two modes of failure initiation are analyzed. In the pure resin regions surrounding the dropped plies, the maximum stress criterion is assumed to govern failure. The Tsai-Wu criterion is used for intralamina failure prediction. The influence of two laminate lay-ups and a variety of ply drop geometries on the response and failure are presented. / M.S.

ABSTRACT EXPERIMENTAL ANALYSIS OF CURVED LAMINATED GLASS BEAM Uzhan, Tevfik M.S., Department of Engineering Sciences Supervisor: Prof. Dr. M. Z&uuml / lf&uuml / ASik May 2010, 33 Pages In this thesis, experimental studies are carried out on curved laminated glass beams to form a database for the scientists who may like to test their mathematical models. Beams which are only free to rotate and constrained in radial direction at both ends are tested to make the data available for further calculations. Test setup is prepared to minimize error that could occur due to test setup and data readings. Material testing machine and 4 channel data collecting machine are used to measure the signals at the strain gauges located over the glass beam. Within the range of force applied to the specimens, laminated curved beam shows linear behavior without any fracture. Data collected from the specimens are in conformance with each other. Results obtained from experiments are compared with the results obtained from the mathematical model developed by ASik and Dural (2006). As it is observed from the graphs presented, experimental results from the tests and numerical results from the mathematical model are in good agreement.