Engineering Commons^™

Characterization Of Fiber Bragg Grating Based, Geometry-Dependent, Magnetostrictive Composite Sensors, Edward Lynch

Theses and Dissertations

Optical sensors based on geometry dependent magnetostrictive composite, having potential applications in current sensing and magnetic field sensing are modeled and evaluated experimentally with an emphasis on their thermal immunity from thermal disturbances. Two sensor geometries composed of a fiber Bragg grating (FBG) embedded in a shaped Terfenol-D/epoxy composite material, which were previously prototyped and tested for magnetic field response, were investigated. When sensing magnetic fields or currents, the primary function of the magnetostrictive composite geometry is to modulate the magnetic flux such that a magnetostrictive strain gradient is induced on the embedded FBG. Simulations and thermal experiments reveal the …

Seismic Tensile Force On Steel Girder-Concrete Wall Connections In High-Rise Composite Building Structures, Yuchen Hui

Theses and Dissertations

Composite steel frame – reinforced concrete (RC) core wall structures are often used in high-rise buildings. It is commonly assumed that reinforced concrete walls carry lateral loads such as earthquake loads, while steel frames carry gravity loads. As a result, lateral loads are directly applied to wall elements during a typical structural analysis. This design based on this simplification can be adequate for most structural members except the connections between steel girders and RC walls. This study focuses on the tensile loads on girder-wall connections for composite building structures in earthquakes.

Computer models were created for a 28-story composite structures …

Phase Sensitive Thermography Of Magnetostrictive Materials Under Periodic Excitations, Peng Yang

Theses and Dissertations

The use of giant magnetostrictive materials in actuator and sensor applications is still relatively new. Giant magnetostrictive materials, such as Terfenol-D, are unique in producing large deformation under a magnetic field. Applications of these materials in solid state actuators and transducers may require more knowledge on the interaction between geometry and material properties for a specific design. In order to gain more understanding of the magnetostriction mechanism, phase sensitive or lock-in thermography has been used to study Terfenol-D. Thermography is useful in that it allows for full field measurement of the surface of an object with a relatively simple setup. …

Characterization Of Carbon-Fiber Reinforced Polyetherimide Thermoplastic Composites Using Mechanical And Ultrasonic Methods, Mohannad A. Alhaidri

Theses and Dissertations

Continuous fiber-reinforced thermoplastics (CFRT) have the potential for being a mass-produced material for high-performance applications. The primary challenge of using CFRT is achieving fiber wet-out due to the high viscosity of thermoplastics. This results in higher temperatures and pressures required for processing the composites. Co-mingling thermoplastic fibers with a reinforcing fiber, potentially, can enable better wetting by reducing the distance the matrix needs to flow. This could result in shorter cycle times and better consolidation at lower temperatures and pressures. In this study, a polyetherimide (PEI) fiber was comingled with carbon fibers (CF). The resultant fibers were woven into fabrics …

Analysis Of Multi-Directional Recycled Jute Fiber Composite Behavior Using Experimental, Numerical, And Analytical Methods, Patrick Severson

Theses and Dissertations

Composite materials are increasing in popularity as a material of choice in many engineering applications. Major industries using composites include automotive, construction, and sports equipment. Most of the knowledge, research, and technology that will help decrease the cost of composite materials have been aimed at developing synthetic fibers as the reinforcing constituent.

This thesis characterizes jute fibers obtained as a byproduct from the coffee industry to determine if they can be viable in composite manufacturing. Experimental analysis, finite element analysis, and analytical modeling are used to characterize jute fiber based composites. Experimental analysis consists of jute fiber bundle tensile testing …