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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Evaluation and analysis of DDG-81 simulated athwartship shock response /

Petrusa, Douglas C. January 2004 (has links) (PDF)
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Young S. Shin. Includes bibliographical references (p. 69-70). Also available online.
2

Health monitoring for damage initiation & progression during mechanical shock in electronic assemblies

Choudhary, Prakriti, Lall, Pradeep. January 2007 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references.
3

OPTIMIZING FLIGHT SHOCK AND VIBRATION MEASUREMENT BY RF LINKS

Walter, Patrick L. 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Acquiring shock and vibration data from flight vehicles through rf telemetry links has numerous associated challenges. Yet, these measurements are important to establish environmental specifications to provide a basis for system or component design and testing. The principal limitation in acquiring these measurements is the frequency bandwidth available for data transmission. This limited bandwidth is often responsible for invalid data being accepted as valid. This work provides a brief review of time and frequency division multiplexing to identify the potential error contributors to shock and vibration measurements. Its focus is on the design of acceleration measurement systems to eliminate these errors and optimize individual measurement channel performance.
4

FILTERING CONSIDERATIONS WHEN TELEMETERING SHOCK AND VIBRATION DATA

Walter, Patrick L. 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The accurate measurement of shock and vibration data via flight telemetry is necessary to validate structural models, indicate off-nominal system performance, and/or generate environmental qualification criteria for airborne systems. Digital telemetry systems require anti-aliasing filters designed into them. If not properly selected and located, these filters can distort recorded time histories and modify their spectral content. This paper provides filter design guidance to optimize the quality of recorded flight structural dynamics data. It is based on the anticipated end use of the data. Examples of filtered shock data are included.
5

Explicit dynamic analysis of computer motherboards subjected to mechanical shock

Jain, Priyank P. January 2005 (has links)
Thesis (M.S.)--State University of New York at Binghamton, Department of Mechanical Engineering, 2005. / Includes bibliographical references (p. 78-80).
6

Prediction of surface ship response to severe underwater explosions using a virtual underwater shock environment /

Schneider, Nathan A. January 2003 (has links) (PDF)
Thesis (Mechanical Engineer and M.S. in Mechanical Engineering)--Naval Postgraduate School, June 2003. / Thesis advisor(s): Young S. Shin. Includes bibliographical references (p. 161-162). Also available online.
7

Evaluation and analysis of DDG-81 simulated athwartship shock response

Petrusa, Douglas C. 06 1900 (has links)
Approved for public release; distribution is unlimited / In 2001 the USS WINSTON CHURCHILL (DDG-81) was subjected to three underwater explosions as part of a ship shock trial. Using the actual trial data from experiment and three-dimensional dynamic models of the ship and surrounding fluid very successful comparisons of the vertical motion have been achieved. On average, the magnitude of the vertical motion is three to four times the magnitude of athwartship motion. Previous simulations of this athwartship motion have been less accurate than the vertical motion simulations. This thesis examines recent efforts attempted to improve the simulation results of the athwartship motion including shock spectra analysis, and the reasons behind the disparities that exist between the simulated values and the actual trial data. / Lieutenant, United States Coast Guard
8

Optomechanical Analysis And Experimental Validation Of Bonding Based Prism And Mirror Mounts In A Laser System

Unal, Ugur 01 March 2012 (has links) (PDF)
In this thesis, different optomechanical design and adhesive configurations for mounting mirrors and prisms used in a laser system are investigated. Maintaining stability and strength of optical components of a laser device is difficult especially if the system is to be used in military environment. In order to determine the strength of prism mounts to high acceleration levels, mathematical correlations derived by Yoder are used. By use of these mathematical correlations, safety factor of different prism mounts and adhesive configurations are calculated for an acceleration level of 40g. So as to decide most stable mirror mount and adhesive configuration, several experiments are conducted. For the experiments, 5 different optomechanical mounts are designed. Then, 25 mirrors are bonded to the designed mounts with 5 different adhesives. These experiments are done to simulate harsh military environmental conditions such as thermal shock, mechanical vibration and mechanical shock. In the experiments, angular movement of mirrors due to adhesive cure, thermal shock, mechanical vibration and mechanical shock are monitored. Thermal shock is applied between -40&ordm / C and 70&ordm / C with a temperature change of 22&ordm / C/min. On the v other hand, mechanical vibration of 14 grms and mechanical shock of 40g for 6 ms is applied in the experiments. Shortly, this study is done for determination of the most stable mirror and prism mount design and adhesive combination of a laser system subjected to extremely harsh environments.
9

Parametric studies of DDG-81 ship shock trial simulations

Didoszak, Jarema M. 03 1900 (has links)
Approved for public release, distribution is unlimited / Evaluations, otherwise known as ship shock trials, have been conducted in order to determine the seaworthiness of each new class of ship commissioned in the U.S. Fleet. While beneficial in determining the overall survivability of a ship and its mission essential equipment in a severe shock environment, these Navy-mandated tests pose serious danger to the crew, ship and environment. As an alternative to these labor intensive, costly and time consuming at-sea tests, the recent advances in computer processing power have made it possible to employ finite element methods involving complex geometries in the modeling and simulation of shock response for the ship and surrounding fluid. This thesis examines the accuracy of shock simulation predictions as compared to the ship shock trials conducted on USS WINSTON S. CHURCHILL (DDG-81). An investigation of the effects of sensor location, damping and shot geometry is presented as validation of the Naval Postgraduate School modeling and simulation methodology. / Lieutenant, United States Navy

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