Digital Commons Network^™

Extraterrestrial Resource Prospecting Using Particle Swarm Optimization And Conflict Based Search, Michael Andrew Johnson

Master's Theses and Capstones

Extraterrestrial prospecting missions will be an important first step in preparation of the harvesting and extraction of natural resources in space. Additionally, knowledge from a prospecting mission will allow the subsequent harvesting or mining mission to efficiently extract resources. Due to the risk and cost of manned space-flight, these prospecting missions will be robotic in nature, and will enable investors to weigh risk and return of a harvesting mission.

The research presented here explores a hypothetical automated prospecting mission on the Martian surface using landscapes simulated from the Mars Global Surveyor satellite. In this mission, a swarm of autonomous exploration …

Experimental Apparatus For Continuous-Bending-Under-Tension And Experiments On A6022-T4, Timothy John Roemer

Master's Theses and Capstones

An experimental technique called Continuous-Bending-under-Tension (CBT) can produce elongations over two times that of a standard tensile test by preventing the necking instability from occurring. This is achieved by superposing plastic bending on tension along the gauge length of the material using three rollers. The specimen is kept under tension as the rollers apply three-point bending while cyclically traversing the gauge length. This subjects the specimen to plastic deformation only in the region that is visited by the rollers. Details on the design of various subsystems of this unique CBT machine are presented. The results for a variety of CBT …

Design And Evaluation Of A Force Platform-Type Instrument To Measure Rate Change In Mass And Centroid Of An Ablating Body, Travis Paul Trottier

Master's Theses and Capstones

This study pertains to the design and evaluation of a force-platform type instrument comprised of three strain gauge load cells, intended to measure the rate of change in mass and centroid position of an object undergoing rapid ablation by heated flow of air. The strain gauges are affixed to a steel frame, oriented in a triangle beneath a 25 X 20 cm rectangular platform, into which is machined a 9 X 9 regular grid for the purpose of static calibration. An algorithm derived from first principles is used to convert the distribution of the applied load among the strain gauges …

Analytical, Experimental And Numerical Study On The Mechanical Behavior Of 3d Printed Auxetic Chiral Structures, Yunyao Jiang

Master's Theses and Capstones

A unique deformation mechanism of auxetic chiral structure was investigated via integrated analytical, experimental and numerical approaches. This unique deformation mechanism is the auxetic effect due to internal rotation. In this thesis, first, a rigid-rod-rotational-spring model was developed to capture the quantitative relation between the Poisson’s ratio and internal rotation of the cells in the auxetic chiral structure. It was concluded that the auxetic effects will be amplified with elevated internal rotation. Then, based on this concept, two new auxetic chiral structures were designed: (1) auxetic chiral structure with soft hinges at the corners, and (2) auxetic chiral structure with …

Modified Hybrid Modeling Technique For Flexible Spin-Stabilized Spacecraft Applied To Nasa's Magnetospheric Multiscale (Mms) Mission Tablesat Generation Ic (Tablesat Ic), Chris Hashem

Master's Theses and Capstones

This continued research uses a hybrid dynamic algorithm to mathematically model the attitude dynamics of a flexible spacecraft. While a full finite element model would be the most accurate model, it also would be a huge computational burden on MMS. This method is meant to be an accurate approximation while still being computationally reasonable for on-board, real-time calculations. The algorithm uses Euler’s Moment Equations to propagate the dynamics of the spacecraft hub while finite element analysis is used to calculate the flexible boom displacements and update the systems mass moment of inertia tensor. This algorithm is iterative and the FEM …

Ductility Of 304 Stainless Steel Under Pulsed Uniaxial Loading, Graham Webb Cullen

Master's Theses and Capstones

The enhanced ductility that 304 stainless steel is exhibited under pulsed loading (Zhang, 2009) is investigated here using a combination of experiments and analysis. The simplest loading case, i.e., uniaxial tension, was selected to avoid the complicating effects of multiaxial stress states and/or contact and friction with a rigid die. Three types of tensile tests were performed: monotonic, pulsed and hold. For a range of strain rates, the pulsed and the hold tests exhibited different elongation-to-fracture from the monotonic tests. Digital image correlation and infrared thermography were employed to further probe this behavior. It was discovered that since the pulsed …