Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Preload (2)
- A286 (1)
- Anaerobic Adhesive (1)
- Cavity Effect (1)
- Computational Fluid Dynamics (1)
-
- Countermeasures (1)
- Cubesat (1)
- DARPA (1)
- Distributed control (1)
- Ductility Index (1)
- Fastener (1)
- Finite-time control (1)
- Heat Transfer (1)
- Joint Diagram (1)
- Kalman Filter (1)
- Kinematics (1)
- Kinetics (1)
- Locknut (1)
- Model reference adaptive control (1)
- Multiagent systems (1)
- NASA (1)
- Prevailing Torque (1)
- Removal Torque (1)
- Reuse (1)
- Reuse Life (1)
- Seated (1)
- Space (1)
- Spacecraft (1)
- Stability and performance guarantees (1)
- Stabilization (1)
Articles 1 - 7 of 7
Full-Text Articles in Mechanical Engineering
Investigation Of Navigation Systems For Size, Cost, And Mass Constrained Satellites, Omar Awad
Investigation Of Navigation Systems For Size, Cost, And Mass Constrained Satellites, Omar Awad
USF Tampa Graduate Theses and Dissertations
The feasibility of using radically inexpensive micro-electromechanical system (MEMS) technology for navigation of a nanosatellite is investigated with a focus on attitude estimation. Typically, larger satellites are equipped with star cameras, sun sensors, or Earth horizon sensors for attitude estimation. These sensors can provide very accurate attitude measurements. A nanosatellite is highly size, power, and cost constrained and cannot readily accommodate these sensors. Our mission is to design, build, and operate a radically inexpensive nanosatellite system. While there is no consensus on what constitutes a "radically inexpensive" satellite, our goal is a maximum cost of $10,000 per unit. This precludes …
Control Of Uncertain Dynamical Systems With Spatial And Temporal Constraints, Ehsan Arabi
Control Of Uncertain Dynamical Systems With Spatial And Temporal Constraints, Ehsan Arabi
USF Tampa Graduate Theses and Dissertations
The overarching objective of this dissertation is the development of feedback control frameworks for uncertain dynamical systems that are subject to spatial and/or temporal constraints. These spatiotemporal constraints usually arise from the physical and/or performance characteristics associated with a considered dynamical system in safety-critical applications, where synthesis and analysis of feedback control laws are not trivial. Specifically, the proposed control architectures in this dissertation mainly contribute to the model reference adaptive control and finite-time control literature. In particular, unlike existing model reference adaptive control approaches that are not capable of enforcing user-defined performance guarantees without an ad-hoc tuning process, the …
Simulation Of Radiation Flux From Thermal Fluid In Origami Tubes, Robert R. Bebeau
Simulation Of Radiation Flux From Thermal Fluid In Origami Tubes, Robert R. Bebeau
USF Tampa Graduate Theses and Dissertations
Spacecraft in orbit experience temperature swings close to 240 K as the craft passes from the shadow of the Earth into direct sunlight. To regulate the craft’s internal energy, large radiators eject unwanted energy into space using radiation transfer. The amount of radiation emitted is directly related to the topology of the radiator design. Deformable structures such as those made with origami tessellation patterns offer a mechanism to control the quantity of energy being emitted by varying the radiator shape. Three such patterns, the Waterbomb, Huffman Waterbomb, and Huffman Stars-Triangles, can be folded into tubes. Origami tubes offer greater control …
Developing Motion Platform Dynamics For Studying Biomechanical Responses During Exercise For Human Spaceflight Applications, Kaitlin Lostroscio
Developing Motion Platform Dynamics For Studying Biomechanical Responses During Exercise For Human Spaceflight Applications, Kaitlin Lostroscio
USF Tampa Graduate Theses and Dissertations
In future human spaceflight missions, with prolonged exposure to microgravity, resistive and aerobic exercises will be countermeasures for bone loss, muscle loss, and decreased aerobic capacity. Two of the exercises of interest are squats and rowing. The cyclic forces produced during these exercises are at relatively low frequencies which are likely to excite structural resonances of space vehicles. Vibration Isolation Systems (VIS) are being designed to be paired with future exploration exercise devices in order to prevent these cyclic exercise forces from impacting the space vehicle. The VIS may be configured such that a platform supports the human and exercise …
Ductility And Use Of Titanium Alloy And Stainless Steel Aerospace Fasteners, Jarrod Talbott Whittaker
Ductility And Use Of Titanium Alloy And Stainless Steel Aerospace Fasteners, Jarrod Talbott Whittaker
USF Tampa Graduate Theses and Dissertations
The main purpose of this thesis is to investigate the ductility and application of titanium alloys, like titanium 6Al-4V, when used in aerospace fasteners compared to more conventional stainless steel aerospace fasteners such as A286. There have been concerns raised about the safe usability of titanium 6-4 in the aerospace industry due to its lack of strain hardening. However, there is a lack of data pertaining to this concern of safe usage which this thesis aims to address. Tensile tests were conducted to find the ductility indexes of these fasteners which quantify the amount of plastic to elastic elongation. From …
Use Of Anaerobic Adhesive For Prevailing Torque Locking Feature On Threaded Product, Alan Hernandez
Use Of Anaerobic Adhesive For Prevailing Torque Locking Feature On Threaded Product, Alan Hernandez
USF Tampa Graduate Theses and Dissertations
The purpose of this research is to determine if anaerobic adhesive can be used as a prevailing torque locking feature. Maintaining preload in critical joints is the usual standard that anaerobic adhesives are held to in aerospace and other industry. To test if anaerobic adhesive can be used as a prevailing torque locking feature a test procedure was developed and implemented to measure the removal torque of threaded fasteners after an allotted cure time. In total, 191 threaded fasteners of different material and coatings were tested in the unseated and seated states with various strengths and varieties of anaerobic adhesive. …
Prevailing Torque Locking Feature Wear-Out, Adam Joseph Charles Zimandy
Prevailing Torque Locking Feature Wear-Out, Adam Joseph Charles Zimandy
USF Tampa Graduate Theses and Dissertations
This thesis provides much needed representative sample data for reuse life of fully seated and torqued locknuts. Most national requirements for prevailing torque locking fasteners only specify unseated reuse life. This could create a potentially dangerous situation if unseated is misinterpreted for seated. This thesis provides comparative data for seated verses unseated configuration. Six aerospace, 3 all-metal and 3 nylon insert, and one non-aerospace locknuts were tested at preloads levels of unseated, 66%, 75%, and 85% of yield of bolt. The locknuts tested are MS21043-4, NAS1291-4, NAS1805-4, MS17825-4, MS21044D4, NAS1021N4, and Grade 8. A fixture was created in order to …