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Reliability-Based Optimization Of Fiber-Reinforced Polymer Composite Bridge Deck Panels, Michel D. Thompson, Christopher D. Eamon, Masoud Rais-Rohani
Reliability-Based Optimization Of Fiber-Reinforced Polymer Composite Bridge Deck Panels, Michel D. Thompson, Christopher D. Eamon, Masoud Rais-Rohani
Civil and Environmental Engineering Faculty Research Publications
A reliability-based optimization (RBO) procedure is developed and applied to minimize the weight of eight fiber-reinforced polymer composite bridge deck panel configurations. The method utilizes interlinked finite element, optimization, and reliability analysis procedures to solve the weight minimization problem with a deterministic strength constraint and two probabilistic deflection constraints. Panels are composed of an upper face plate, lower face plate, and a grid of interior stiffeners. Different panel depths and stiffener layouts are considered. Sensitivity analyses are conducted to identify significant design and random variables. Optimization design variables are panel component ply thicknesses while random variables include load and material …
Homogenization And Field Concentrations In Heterogeneous Media, Robert Lipton
Homogenization And Field Concentrations In Heterogeneous Media, Robert Lipton
Faculty Publications
A multiscale characterization of the field concentrations inside composite and polycrystalline media is developed. We focus on gradient fields associated with the intensive quantities given by the temperature and the electric potential. In the linear regime these quantities are modeled by the solution of a second order elliptic partial differential equation with oscillatory coefficients. The characteristic length scale of the heterogeneity relative to the sample size is denoted by ε and the intensive quantity is denoted by u ε. Field concentrations are measured using the L p norm of the gradient field ||∇u ε||L p(D) for 2 ≤ p < ∞. The analysis focuses on the case when 0 < ε ≪ 1. Explicit lower bounds on lim inf ε→0 are developed. These bounds provide a way to rigorously assess field concentrations generated by the microgeometry without having to compute the actual field u ε. © 2006 Society for Industrial and Applied Mathematics.
Tensile Property Of Hand Lay-Up Plain-Weave Woven E-Glass/Polyester Composite:Curing Pressure And Ply Arrangement Effect, Mohd Aidy Faizal Johari, Kiam Beng Yeo, Mohd Noh Dalimin
Tensile Property Of Hand Lay-Up Plain-Weave Woven E-Glass/Polyester Composite:Curing Pressure And Ply Arrangement Effect, Mohd Aidy Faizal Johari, Kiam Beng Yeo, Mohd Noh Dalimin
mohd aidy faizal johari
This paper describes an experimental study on the tensile properties of hand lay-up plain-weave woven GFRP panels. Tests are conducted on the GFRP specimens fabricated at different curing pressure of 35.8kg/m2, 70.1kg/m2, 104kg/m2 and 138.2kg/m2. Two types of woven GFRP lay-up are designed with symmetrically and non-symmetrically arrangement at the center-plane of the composite are also investigated. The rectangular straight sided tensile samples are fabricated and tested with reference to British Standard. Uni-axial tensile deformation behaviors are then investigated with respect to the different curing pressures and lay-up arrangements. The results obtained have demonstrated the convergence of both elastic tensile …
Modeling Fracture In Z-Pinned Composite Co-Cured Laminates Using Smeared Properties And Cohesive Elements In Dyna3d, Jason K. Freels
Modeling Fracture In Z-Pinned Composite Co-Cured Laminates Using Smeared Properties And Cohesive Elements In Dyna3d, Jason K. Freels
Theses and Dissertations
The purpose of the present research was three-fold: 1) gain a more sophisticated understanding of the response of co-cured composite joints with and without through-thickness reinforcement (TTR), 2) compare the behavior of specimens reinforced with various sizes and densities of reinforcement, and 3) use experimental data to verify the existing DYNA3D smeared property model. Double cantilever beam, end-notch flexure and T-section specimens reinforced with 0.011" diameter z-pins at 2% and 4% volume densities were tested to determine the mode I, mode II and mixed mode (I and II) behavior. Results were added to preliminary research in which tests were conducted …
Some Aspects Of The Mechanical Response Of Pmr-15 Neat Resin At 288°C: Experiment And Modeling, Christina M. Falcone
Some Aspects Of The Mechanical Response Of Pmr-15 Neat Resin At 288°C: Experiment And Modeling, Christina M. Falcone
Theses and Dissertations
The mechanical response of PMR-15 neat resin was investigated at 288?C. Monotonic loading/unloading tests performed at several constant stress rates revealed considerable rate dependence, especially on the unloading path. Effect of prior stress rate on creep behavior was evaluated in creep tests preceded by uninterrupted loading to a target stress. Creep response was dependent on the prior stress rate. Effect of loading history was studied in stepwise creep tests, where specimens were subjected to a constant stress rate loading followed by unloading to zero stress with intermittent creep periods during both loading and unloading. Comparison of creep strains accumulated during …
Characterization Of Functionally Graded Materials, Benjamin D. Chapman
Characterization Of Functionally Graded Materials, Benjamin D. Chapman
Theses and Dissertations
The purpose of this study was to characterize the behavior of a functionally graded material through experimentation and analytical modeling. Functionally graded materials are a ceramic metal composite which transitions from metal on one face to ceramic on the opposite face. Creating reliable models required verifying the material properties. This was accomplished through the use of a static modulus of elasticity test as well as a dynamic ping test. The natural frequencies from the dynamic test were compared with finite element models to determine which material properties most accurately represented the functionally graded material. It was found that the material …
Application Of Spline Variational Analysis Method In The Modeling Of Composite Repairs, Brian M. Fredrickson
Application Of Spline Variational Analysis Method In The Modeling Of Composite Repairs, Brian M. Fredrickson
Theses and Dissertations
The purpose of this thesis is to apply a non-commercialized spline-based (BSpline Analysis Method or BSAM) computer program to model and predict strain fields in two composite repairs, a scarf joint and a stepped-lap joint, subjected to static tensile loading. Test specimens with scarf and stepped-lap joints are fabricated using quasiisotropic sixteen ply panels made from IM6/3501-6 prepreg with a [+452/02/-452/902]s lay-up. The panels were bonded together with FM-300M (0.05psf), a 176°C cure film adhesive, under positive pressure. A total of five coupons of each joint type are made. Two of …
Creep-Rupture And Fatigue Behaviors Of Notched Oxide/Oxide Ceramic Matrix Composite At Elevated Temperature, Mark A. Sullivan
Creep-Rupture And Fatigue Behaviors Of Notched Oxide/Oxide Ceramic Matrix Composite At Elevated Temperature, Mark A. Sullivan
Theses and Dissertations
Oxide/oxide composites are being considered for use in high temperature aerospace applications where their inherent resistance to oxidation provides for better long life properties at high temperature than most other ceramic matrix composites (CMCs). One promising oxide/oxide CMC is Nextel 720/A (N720/A) which uses an 8-harness satin weave (8HSW) of Nextel 720 fibers embedded in a porous alumina matrix. Possible aerospace applications for N720/A will likely require inserting holes into the material for mounting and cooling purposes. The notch characteristics must be understood to ensure designs using the material are sufficient for the desired application. This research effort examined the …
Multiferroic Properties Of Pb(Zr,Ti)O3∕Cofe2o4 Composite Thin Films, N. Ortega, P. Bhattacharya, R. S. Katiyar, P. Dutta, A. Manivannan, M. S. Seehra, I. Takeuchi, S. B. Majumder
Multiferroic Properties Of Pb(Zr,Ti)O3∕Cofe2o4 Composite Thin Films, N. Ortega, P. Bhattacharya, R. S. Katiyar, P. Dutta, A. Manivannan, M. S. Seehra, I. Takeuchi, S. B. Majumder
Faculty & Staff Scholarship
No abstract provided.
Structural Design Of Hollow Extruded Wpc Sheet Piling, Melissa Kahl
Structural Design Of Hollow Extruded Wpc Sheet Piling, Melissa Kahl
Electronic Theses and Dissertations
In marine environments, materials are exposed to a number of harsh environmental factors. Traditional retaining wall materials experience severe degradation as a response to these factors. To address these degradation issues, wood plastic composite (WPC) materials can be used in marine sheet pile applications. WPC materials are both lightweight and durable. This research focuses on developing a sheet pile design that utilizes the material benefits of extruded wood plastic composites with a voided z section sheet pile geometry. The objectives are to develop a more efficient structural design in terms of both material and geometry as compared to the polyvinylchloride …
Structural Testing And Analysis Of Hybrid Composite/Metal Joints For High-Speed Marine Structures, Jean Paul Kabche
Structural Testing And Analysis Of Hybrid Composite/Metal Joints For High-Speed Marine Structures, Jean Paul Kabche
Electronic Theses and Dissertations
The implementation of composite materials in engineering applications has observed a rapid increase over the last few decades. The U.S. Navy currently has an objective to enhance its future naval capabilities by developing hull-forms with advanced materials, including composites. Speed can be increased by reduction in weight and by incorporating innovative shaping of the hull-form, which can potentially be achieved with composites. Any naval vessel using composite materials for structural components will require hybrid connections of some sort, where composite sections are joined to metallic sub-structures. Joints are critical regions in the design of hybrid systems, as failures typically occur …