Composite materials are widely used in the aerospace industry because of their high strength-to-weight ratio. Although they have many advantages, their inhomogeneity and anisotropy pose problems. Because of these properties, machining of composites, unlike conventional metal working, needs more investigation. Conventional drilling of composites is one such field that requires extensive study and research. Among various parameters that determine the quality of a drilled hole, surface finish is of vital importance. The surface finish of a drilled hole depends on speed, feed-rate, material of the work piece, and geometry of the drill bit. This project studied the effect of speed and feed on surface finish and also the optimization of these parameters. Experiments were conducted based on Design of Experiment (DOE) and qualitative verification using Artificial Neural Network (ANN). Relevant behavior of surface finish was also studied. In this project, holes were drilled using a conventional twist drill at different cutting speeds (2,000 to 5,000 rpm) and feed rate was varied from 0.001 to 0.01 ipr for solid carbon fiber laminate (composite material). The other material drilled is BMS 8-276 form 3 (toughened resin system). Also five different drill bits were used to conduct experiments on BMS 8-276 form 3. Speed values were 5,000, 3,000, and 2,000 rpm and feed rates were 0.004, 0.006, and 0.01 ipr. The effect of speed, feed rate, and different drill geometries was analyzed with respect to surface finish in the drilled composites. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering. / "July 2006." / Includes bibliographic references (leaves 79-81).

Fiber reinforced polymeric (FRP) composites are beginning to find applications in constructing infrastructures such as bridges, railroads, etc. Composites may potentially be more durable replacements for steel and concrete, but their experience in these applications is minimal. Also, composite decks are susceptible to change in environmental conditions. Thus, the study of the behavior of composite material in elevated environmental conditions is necessary. This thesis is aimed at development and validation of Finite element methods used to analyze Fiber reinforced polymeric composite beam under moisture and elevated temperature change. The response of the composite beam subjected to various loads is analyzed under dry and moist conditions. It is assumed that only the matrix properties are adversely affected. The mechanical properties such as stiffness, strength, etc are degraded due to the combined effect of moisture and temperature change. The laminate properties are calculated using the rule of mixtures. A parametric study is carried out by varying the fiber volume fraction and by changing the fiber orientations and ply lay-ups in the laminate. From results it can be observed that the static and dynamic deflections increase due to the presence of moisture and increased temperature. The behavior of the beam is also influenced by the ply orientations and fiber volume fraction. Thus, for composite materials to reach their full potential in structural applications, it becomes quite imperative to consider factors such as moisture content, temperature, ply orientations and fiber volume during design and analysis. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

Unlike published shell theories, the main two parts of this thesis are devoted to the asymptotic construction of a refined theory for composite laminated shells valid over a wide range of frequencies and wavelengths. The resulting theory is applicable to shells each layer of which is made of materials with monoclinic symmetry. It enables one to analyze shell dynamic responses within both long-wavelength, low- and high-frequency vibration regimes. It also leads to energy functionals that are both positive definiteness and sufficient simplicity for all wavelengths. This whole procedure was first performed analytically. From the insight gained from the procedure, a finite element version of the analysis was then developed; and a corresponding computer program, DVAPAS, was developed. DVAPAS can obtain the generalized 2-D constitutive law and recover accurately the 3-D results for stress and strain in composite shells. Some independent works will be needed to develop the corresponding 2-D surface analysis associated with the present theory and to continue towards full verification and validation of the present process by comparison with available published works.

No description available.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 154-158). Also available via the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 230-235). Also available on the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 286-307). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.) in Forest Resources--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 143-148).

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Dr. Steve Johnson; Committee Member: Dr. Andrew Makeev; Committee Member: Kyriaki Kalaitzidou. Part of the SMARTech Electronic Thesis and Dissertation Collection.