Deterioration of concrete bridge decks has become a serious problem in the past few decades. Fortunately, non-corrosive, light-weight Fiber Reinforced Polymer (FRP) material provides an excellent alternative. More than 117 bridges in the USA have been built or repaired with FRP. In Canada, no FRP bridge deck has been used in the field, yet. However, Wardrop Engineering Inc., Faroex Ltd., and ISIS Canada have successfully designed, manufactured, and patented the filament-wound Glass Fiber Reinforced Polymer (GFRP) bridge deck. Since there is no design code for FRP bridge decks, a finite element method, labeled “L&D”, is proposed in this thesis to help bridge engineers better understand the structural behavior of FRP bridge decks. The L&D method is validated by comparing the analysis results with the experimental results of three filament-wound GFRP bridge decks. This L&D method is also applicable for analyzing FRP bridge decks manufactured by other processes.

The non-corrodible nature of FRP bars along with their high strength, light weight and ease of installation made it attractive as reinforcement especially for structures exposed to aggressive environment. In addition, the transparency of FRP bars to magnetic and electrical fields makes them an ideal alternative to traditional steel reinforcement in applications sensitive to electromagnetic fields such as magnetic resonance imaging (MRI) units. Continuous concrete beams are commonly-used elements in structures such as parking garages and overpasses, which might be exposed to extreme weather conditions and the application of de-icing salts. In such structures, using the non-corrodible FRP bars is a viable alternative to avoid steel-corrosion problems. However, the linear-elastic behaviour of FRP materials makes the ability of continuous beams to redistribute loads and moments questionable. The objective of this research project is to investigate the flexural behaviour of continuous concrete beams reinforced with FRP and their capability of moment redistribution. An experimental program was conducted at the University of Manitoba to realize the research objectives. Ten full-scale continuous concrete beams were constructed and tested to failure in the laboratory. The specimens had a rectangular cross-section of 200×300 mm and continuous over two spans of 2,800 mm each. The main investigated parameters were the amount and material of longitudinal reinforcement, the amount and material of transverse reinforcement and the spacing of used stirrups. The experimental results showed that moment redistribution in FRP-reinforced continuous concrete beams is possible if the reinforcement configuration is chosen properly, and is improved by increasing the amount of transverse reinforcement. A finite element investigation was conducted using ANSYS-software. A 3-D model was created to simulate the behaviour of continuous beams reinforced with FRP. The model was verified against the experimental results obtained from the present study. This verified model was used to investigate the effect of the concrete compressive strength, longitudinal reinforcement ratio, midspan-to-middle support reinforcement ratio and the amount of transverse reinforcement on the behaviour of FRP-reinforced beams. The analytical results of this parametric investigation along with the experimental results were used to propose an allowable limit for moment redistribution in FRP-reinforced continuous concrete beams.

This thesis studies the application of a multi-objective niched Pareto genetic algorithm on the design optimization of an electric field mill sensor. The original sensor requires resonant operation. The objective of the algorithm presented is to optimize the geometry eliminating the need for resonant operation which can be difficult to maintain in the presence of an unpredictable changing environment. The algorithm evaluates each design using finite element simulations. A population of sensor designs is evolved towards an optimal Pareto frontier of solutions. Several candidate solutions are selected that offer superior displacement, frequency, and stress concentrations. These designs were modified for fabrication using the PolyMUMPs abrication process but failed to operate due to the process. In order to fabricate the sensors in-house with a silicon-on-glass process, an anodic bonding apparatus has been designed, built, and tested.

Use of an inflatable/rigidizable wing is explored for Mars airplane designs. The BIG BLUE (Baseline Inflatable-wing Glider Balloon Launched Unmanned airplane Experiment) project was developed at the University of Kentucky, with an objective to demonstrate feasibility of this technology with a flight-test of an high-altitude glider with inflatable/rigidizable wings. The focus of this thesis research was to design and analyze the wing for this project. The wings are stowed in the fuselage, inflate during ascent, and rigidize with exposure to UV light. The design of wings was evaluated by using aerodynamic and finite element software and wind tunnel testing. The profile is chosen based upon aerodynamic results and consideration of manufacturability of the inflatable wing structures. Flow over prototypes of inflatable/rigidizable and ideal shaped wings were also examined in the wind tunnel. Flow visualization, lift and drag measurements, and wake survey testing methods were performed. Results from the wind tunnel testing are presented along with suggestions in improving the inflatable/rigidizable wings aerodynamic efficiency and use on a low Reynolds number platform. In addition, high altitude wing deployment tests and low altitude flight tests of the inflatable/rigidizable wing were conducted.

Bending loss in silicon-on-insulator rib waveguides was calculated using conformal mapping of the curved waveguide to an equivalent straight waveguide. Finite-element analysis with perfectly matched layer boundaries was used to solve the vector wave equation. Transmission loss was experimentally measured as a function of bend radius for several SOI waveguides. Good agreement was found between simulated and measured losses, and this technique was confirmed as a good predictor for loss and for minimum bend radius for efficient design.

The neutron Electric Dipole Moment Experiment at the Spallation Neutron Source requires an overall magnetic shielding factor of order 105 to attenuate external background magnetic fields. At present, the shielding design includes an external (room-temperature) multi-layer μ-metal magnetic shield, a cryogenic (4 Kelvin) Pb superconducting shield, and a cryogenic (4 Kelvin) ferromagnetic shield composed of Metglas ribbon. This research determined how to construct a Metglas shield using minimal material that produced axial and transverse shielding factors of ~267 and ~1500. In addition, the μ-metal and Metglas shields were modeled using finite element analysis. The FEA model includes external coils and their effect on the residual magnetic fields. This study will help with the design of the shielding.

Oral bisphosphonate drug therapy is a common and effective treatment for osteoporosis. Little is known about the long-term effects of bisphosphonates on bone quality. This study examined the structural and mechanical properties of trabecular bone following 0-16 years of bisphosphonate treatment. Fifty-three iliac crest bone samples of Caucasian women diagnosed with low turnover osteoporosis were identified from the Kentucky Bone Registry. Forty-five were treated with oral bisphosphonates for 1 to 16 years while eight were treatment naive. A section of trabecular bone was chosen from a micro-computed tomography (Scanco µCT 40) scan of each sample for a uniaxial linearly elastic compression simulation using finite element analysis (ANSYS 14.0). Morphometric parameters (BV/TV, SMI, Tb.Sp., etc.) were computed using µCT. Apparent modulus, effective modulus and estimated failure stress were calculated. Biomechanical and morphometric parameters improved with treatment duration, peaked around 7 years, and then declined independently of age. The findings suggest a limit to the benefits associated with bisphosphonate treatment and that extended continuous bisphosphonate treatment does not continue to improve bone quality. Bone quality, and subsequently bone strength, may eventually regress to a state poorer than at the onset of treatment. Treatment duration limited to less than 7 years is recommended.

Traumatic brain injuries (TBIs) are a major health and socioeconomic problem throughout the world, with an estimated 10 million deaths and instances of hospitalization annually. Numerical methods such as finite element (FE) methods can be used to study head injuries and optimize the protection, which can lead to a decrease in the number of injuries. The FE head models were initially evaluated for biofidelity by comparing with donated corpses experiments. However, there are some limitations in experiments of corpses, including material degradation after death. One feasible alternative to evaluating head models with living human tissue is to use reconstruction of real accidents. However, the process of accident reconstruction entails some uncertainties since it is not a controlled experiment. Therefore, a deeper understanding of the accident reconstruction process is needed in order to be able to improve the FE human models. Thus, the aim of this thesis was to evaluate and further develop more advanced strategies for accident reconstructions involving head injuries. A FE head model was used to study head injuries in accidents. Existing bicycle accident data was used, as were hypothetical accident situations for cyclists and pedestrians. A FE bicycle helmet model having different designs was developed to study the protective effect. An objective method was developed based on the Overlap Index (OI) and Location Index (LI) to facilitate the comparison of FE model responses with injuries visible in medical images. Three bicycle accident reconstructions were performed and the proposed method evaluated. The method showed to have potential to be an objective method to compare FE model response with medical images and could be a step towards improving the evaluation of results from injury reconstructions. The simulations demonstrated the protective effect of a bicycle helmet. A decrease was seen in the injurious effect on both the brain tissue and the skull. However, the results also showed that the brain tissue strain could be further decreased by modifying the helmet design. Two different numerical pedestrian models were compared to evaluate whether the more time-efficient rigid body model could be used, instead of a FE pedestrian model, to roughly determine the initial conditions as an accident reconstruction involves some uncertainties. The difference, in terms of the head impact location, rotation and velocity, attributable to the two models was in the same range as differences due to uncertainties in some of the initial parameters, such as vehicle impact velocity. / <p>QC 20150414</p>

Thermally bonded nonwovens are low-price substitutes for traditional textiles. They are used in many areas including filtration, automotive and aerospace industries. Hence, understanding deformation behaviours of these materials is required to design new products tailored for specific applications in different areas. Because of their complex and random structure, numerical simulations of nonwoven materials have been a challenging task for many years. The main aim of the thesis is to develop a computational modelling tool to simulate the effect of design parameters on structural behaviour of low-density nonwoven materials by using a finite element method. The modelling procedure is carried out with a parametric modelling technique, which allows a designer to run a series of analyses with different design parameters and observe the effects of these parameters on the mechanical behaviour of nonwoven materials. The thesis also presents the study of rate dependent behaviour of nonwoven fibres. Novel test and data-interpretation procedures are proposed to determine the creep behaviour of fibres in the nonwoven structure. Some case studies are presented to demonstrate the effectiveness of the model. The developed computational tool allows macro and micro-scale structural investigation of nonwoven materials. Two additional studies are presented, performed with the developed tool. In the first study, the effect of design parameters on tensile stiffness of nonwovens was determined by performing numerical analyses with various nonwoven models. In the second one, strain distribution in fibres is studied thoroughly together with factors affecting the distribution. The models, developed in the thesis can also be employed in further studies of nonwovens, such as investigation of their damage and fracture behaviour.

Biofidelity of finite element head model (FEHM) includes geometric and material aspects. A FEHM with inhomogeneous material properties was proposed to improve material biofidelity. The proposed FEHM was validated against experimental data and good agreements were observed. The capability of the proposed model in simulating large tissue deformation was also demonstrated. Influences of inhomogeneous material properties on the mechanical responses of head were investigated by comparing with homogeneous material model. The inhomogeneous material properties induce large peak strains in head constituents, which are probably the cause of various brain injuries. Helmets are effective in preventing head injuries. Parametric studies were conducted to investigate how changes in helmet shell stiffness, foam density and pad thickness influence the performance of a helmet in protecting the brain. Results showed that strain energy absorbed by foam component, contact stress on the interfaces and intracranial responses are significantly affected by foam density and pad thickness.