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Your search for ETD Contributor Cairns, Douglas S. (committee chairperson) resulted in 13 match(es).

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Application of Energy Methods to Modeling Failures in Composite Materials and Structures: Author: Ritter, William Joseph; Date: 2004-08-15; Program: Mechanical Engineering; Abstract: Characterizing the mechanical properties of composite materials is difficult and expensive. There is a legacy for the scale up from basic materials testing to final structures in compositeS. Each material architecture and manufacturing technique potentially represents a different mechanical response in a structure. Hence, as new composite material forms and manufacturing techniques become available, a need exists to streamline the characterization procesS. In this study, a new methodology for characterization of composite materials and structures is presented. It has its roots in fracture mech...; Download File | View full details

Feasibility in developing smart structures for use in wind turbine blades: Author: Blockey, James Craig; Date: 2008-08-15; Program: Mechanical Engineering; Abstract: Recently the use of wind as an alternative energy source has developed quickly. The length of the blades is a leading factor in the power output of a wind turbine and as a result, blade length has grown at a similar pace to the growth of the industry. The rapid expansion in use and size of wind turbines is not without its problems, though. As the industry has changed and grown, the overall design of the blades has remained relatively stagnant. This is evident in two primary areas, power control and health monitoring. Power control mechanisms are generally unchanged, utilizing either pitch cont...; Download File | View full details

Simulation and Testing of Resin Infusion Manufacturing Processes for Large Composite Structures: Author: Mastbergen, Daniel Blair; Date: 2004-08-15; Program: Mechanical Engineering; Abstract: The use of composite materials in large primary structures such as wind turbine blades and boat hulls has dramatically increased in recent yearS. As these structures get larger, new manufacturing processes are required to make them possible. Larger parts also require more expensive tooling, and a higher cost for scrapped partS. This may prohibit the trial and error approach that has been used for many yearS. The need for accurate process modeling in the design of tooling is becoming essential. Unfortunately, as the processes become more complex so do the modelS. Although there are several pote...; Download File | View full details

Use of Pultruded Carbon Fiber / Epoxy Inserts as Reinforcement in Composite Structures: Author: Bundy, Bryan Charles; Date: 2005-05-15; Program: Mechanical Engineering; Abstract: As polymer matrix composite based structures such as wind turbine blades get larger in span, the required stiffness is usually supplied by the increasing thicknesS. The fabrication of current composite thicknesses is expensive in terms of labor, mechanical components and fabrication time. The problems are compounded for very long spanS. Thermosetting resins are injected into these fiber pre-forms under very high pressures so the resin can completely encase the fibers before the resin hardenS. These pressures can induce waviness into the fibers that significantly reduces the critical compressio...; Download File | View full details

A Validation Study of the Montana State University In-Plane Loader: Author: Collett, Aaron Bruce; Date: 2006-08-15; Program: Mechanical Engineering; Abstract: Characterizing a polymer composite material's response to loading beyond the elastic region is less well defined than it is for other structural materials such as metalS. The Naval Research Laboratory has developed a method that uses dissipated energy as a metric to facilitate this characterization. The method relies on empirical data from material strength tests as well as finite element analysis data to make the prediction. A substantial amount of empirical data from different loading conditions is needed to characterize a material. This warrants a testing machine that can apply several load...; Download File | View full details

Progress and Challenges in Non-Linear Constitutive Modeling for Composite Material: Author: Booth, Eric Jason; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: In this paper is outlined a technique for determining the non-linear constitutive properties of an orthrotropic laminated material such as a fiber reinforced composite. The Characterization of Composites is difficult because of the anisotropic stiffness properties of the material and also because of the complex manner in which they accumulate internal damage and eventually fail. Presented here are techniques for determining the mechanical properties of a material by solving what is known as the Inverse Problem. In such a problem, the response of a material system to an external stimulus is mea...; Download File | View full details

Fused Deposition Modeling with Localized Pre-Deposition Heating using Forced Air: Author: Partain, Seth Collins; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: Rapid prototyping (RP) systems have been used for several years to produce design prototypes without expensive tooling costS. As these systems have matured, there has been increasing interest in using them to produce actual end-use partS. Fused deposition modeling (FDM) is an RP technology that has been identified by many as having strong potential for this transition from rapid prototyping to rapid manufacturing, due primarily to its capability of using a wide array of high performance materialS. FDM creates parts layer-by-layer, extruding semi-molten material "roads" through a comp...; Download File | View full details

Internal Damage Characterization for Composite Materials under Biaxial Loading Configuration: Author: Smith, Jay David; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: This thesis contains the results of a composite material database developed for fiber glass laminates using test data from the in-plane loader (IPL). The IPL is a unique multi-axial test machine developed at Montana State University. The research was completed with the aim to improve the reliability of composite materials, namely fiber glass for use in wind turbine bladeS. An energy method was used to characterize strain-induced damage in fiber glass couponS. The energy dissipated by internal failure mechanisms was employed as a metric of internal damage. Thus, by means of a deconvolution proc...; Download File | View full details

Modeling of In-Plane and Interlaminar Fatigue Behavior of Glass and Carbon Fiber Composite Materials: Author: Wilson, Timothy James; Date: 2007-05-15; Program: Mechanical Engineering; Abstract: This thesis presents the results of a modeling study of the fatigue behavior of fiberglass and carbon fiber reinforced epoxy composite materials intended primarily for wind turbine bladeS. The modeling effort is based on recent experimental results for infused glass fiber laminates typical of current blades, and hybrid carbon prepreg laminates of potential interest for future bladeS. There are two focus areas: in-plane performance represented by stress-life (S-N) curves, and out-of-plane ply delamination at details including ply drops and joints, based on fracture mechanicS. In-plane fatigue m...; Download File | View full details

Damage initiation and post-damage response of composite laminates by multiaxial testing and nonlinear optimization: Author: Schmitt, James Tyler; Date: 2008-12-15; Program: Mechanical Engineering; Abstract: Fiber reinforced plastics are increasingly being used in the construction of primary structures in the aerospace and energy industrieS. While their elastic behavior and fatigue response have been the subject of considerable research, less is known about the performance of continuous fiber composites following initial damage. Several competing models for the post-damage response of orthotropic composite materials are explored in this thesiS. Each of these models includes only the in-plane loads experienced by the material and characterizes damage based on the local state of strain. Starting wit...; Download File | View full details

Development and implementation of a low cost image correlation system to obtain full-field in-plane displacement and strain data: Author: Parker, John Wesley; Date: 2009-05-15; Program: Mechanical Engineering; Abstract: When using multi-axial testing, obtaining in-plane strain and displacement data can be difficult and costly. Montana State University's In Plane Loader (IPL) can apply any number of loads in the X and Y axes and as rotation but can only provide the displacement data at the gripS. This project uses a Canon consumer-model digital single lens reflex camera and a series of matlab codes to provide in-plane displacement and strain data at as many points on the surface of the loaded specimen as required using Digital Image Correlation. The system has been successfully used to measure surface and boun...; Download File | View full details

Smart composites: evaluation of embedded sensors in composite materials: Author: Palmer, Nathan Reed; Date: 2009-08-15; Program: Mechanical Engineering; Abstract: As an emerging form of renewable energy, horizontal wind turbines have experienced advancements in improving efficiency and reliability. These advances have pushed the limits of current technology used in wind turbineS. Smart blades have been proposed as a method of addressing these limitationS. Sensor integration within blade construction is the first step in development of smart bladeS. Thus, several low cost sensors were chosen, 1 axis strain gages, polyvinylidene fluoride films (PVDF), and single mode fiber optics either coated in acrylate or polyimide. To ensure successful bonding between...; Download File | View full details

Integration of actuators and sensors into composite structures: Author: Ehresman, Jonathan David; Date: 2009-08-15; Program: Mechanical Engineering; Abstract: The need for more efficient wind turbine blades is growing in our society. One step in accomplishing this task would be to make wind turbines blades into smart structureS. A smart structure is one that incorporates sensors, complete control systems, and active control devices, in order to shed, or redistribute the load placed on the structure. For wind turbine blades this means changing the shape of the blade profile as it encounters different wind conditionS. In order to have active control surfaces functioning on wind turbine blades, the existing blades would have to be retrofitted, and the ...; Download File | View full details

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