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Full-Text Articles in Engineering
Structural Behavior Of Inflatable, Reinforced, Braided, Tubular Members, Joshua Clapp
Structural Behavior Of Inflatable, Reinforced, Braided, Tubular Members, Joshua Clapp
Electronic Theses and Dissertations
The Hypersonic Inflatable Aerodynamic Decelerator (HIAD) system being developed by the National Aeronautics and Space Administration (NASA) is an inflatable structure composed of multiple, concentric, pressurized tori, load straps, and a thermal protection system. The HIAD overcomes limitations inherent with the use of rigid decelerators since the deployed diameter is much larger than the packed size, which makes it an enabling technology for new opportunities in space exploration. The HIAD is designed to decelerate and protect spacecraft during atmospheric re-entry. The objective of this research was to improve understanding of structural behavior of HIAD components through material testing, structural testing …
Six Degree Of Freedom Dynamic Modeling Of A High Altitude Airship And Its Trajectory Optimization Using Direct Collocation Method, Pradens Pierre-Louis
Six Degree Of Freedom Dynamic Modeling Of A High Altitude Airship And Its Trajectory Optimization Using Direct Collocation Method, Pradens Pierre-Louis
Electronic Theses and Dissertations
The long duration airborne feature of airships makes them an attractive solution for many military and civil applications such as long-endurance surveillance, reconnaissance, environment monitoring, communication utilities, and energy harvesting. To achieve a minimum energy periodic motion in the air, an optimal trajectory problem is solved using basic direct collocation methods. In the direct approach, the optimal control problem is converted into a nonlinear programming (NLP). Pseudo-inverse and several discretization methods such as Trapezoidal and Hermite-Simpson are used to obtain a numerical approximated solution by discretizing the states and controls into a set of equal nodes. These nodes are approximated …
Development And Implementation Of A Streamlined Process For The Creation And Mechanization Of Negative Poisson's Ratio Meso-Scale Patterns, Matthew Shuler
Development And Implementation Of A Streamlined Process For The Creation And Mechanization Of Negative Poisson's Ratio Meso-Scale Patterns, Matthew Shuler
Electronic Theses and Dissertations
This thesis focuses on the development a streamlined process used to create novel meso-scale pattern used to induce negative Poisson's ratio (NPR) behavior at the bulk scale. This process includes, the development, optimization, and implementation of a candidate pattern. Currently, the majority of NPR structures are too porous to be utilized in conventional applications. For others, manufacturing methods have yet to realize the meso-scale pattern. Consequently, new NPR meta-materials must be developed in order to confer transformative thermomechanical responses to structures where transverse expansion is more desirable than contraction. For example, materials at high temperature. Additionally, patterns that take into …
Timoshenko Beam Viscous Damping Model For Spacecraft Cabling Dynamics, Brandi Mcpherson
Timoshenko Beam Viscous Damping Model For Spacecraft Cabling Dynamics, Brandi Mcpherson
Electronic Theses and Dissertations
With the increasing data handling and power requirements of today's spacecraft, accurately modeling the effects of cabling on spacecraft structural dynamics has become an increasingly important part of the design process. During testing, spacecraft cabling produces a damping effect on the system dynamics; however, current models often overpredict this response in higher frequency modes and produce unrealistic damping values. Previous models incorporated structural and viscous damping terms into Euler-Bernoulli and shear beams; this thesis presents a viscous damping model for Timoshenko beams that can accurately capture the effects of both spacecraft wiring and harnesses during the design phase. Damping in …
Characterization Of Mechanical Properties In Nanoparticle Reinforced Hybrid Carbon Fiber Composites Using Photoluminescence Piezospectroscopy, Sanjida Jahan
Electronic Theses and Dissertations
Carbon fiber composites have become popular in aerospace structures and applications due to their light weight, high strength, and high performance. Hybrid carbon fiber reinforced polymer (HCFRP) composites with alumina nanoparticles reinforcement display improved material properties such as fracture toughness, resistance to crack propagation and improved fatigue life. However, homogeneous dispersion of nanoscale materials in the matrix is important for even distribution of the improved properties. Implementing silane coupling agents (SCAs) improves dispersion by acting as a bridge between organic and inorganic materials, which increases interfacial strength and decreases sedimentation by bonding the particulate filler to the fiber reinforcement. This …