Validation of Force Limited Vibration Testing at NASA Langley Research Center

Validation of Force Limited Vibration Testing at NASA Langley Research Center

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-06-20

Total Pages: 36

ISBN-13: 9781721573219

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Vibration tests were performed to develop and validate the forced limited vibration testing capability at the NASA Langley Research Center. The force limited vibration test technique has been utilized at the Jet Propulsion Laboratory and other NASA centers to provide more realistic vibration test environments for aerospace flight hardware. In standard random vibration tests, the payload is mounted to a rigid fixture and the interface acceleration is controlled to a specified level based on a conservative estimate of the expected flight environment. In force limited vibration tests, both the acceleration and force are controlled at the mounting interface to compensate for differences between the flexible flight mounting and rigid test fixture. This minimizes the over test at the payload natural frequencies and results in more realistic forces being transmitted at the mounting interface. Force and acceleration response data was provided by NASA Goddard Space Flight Center for a test article that was flown in 1998 on a Black Brant sounding rocket. The measured flight interface acceleration data was used as the reference acceleration spectrum. Using this acceleration spectrum, three analytical methods were used to estimate the force limits. Standard random and force limited vibration tests were performed and the results are compared with the flight data. Rice, Chad and Buehrle, Ralph D. Langley Research Center NASA/TM-2003-212404, L-18280, NAS 1.15:212404


Force Limited Vibration Testing Monograph

Force Limited Vibration Testing Monograph

Author: T. D. Scharton

Publisher: CreateSpace

Published: 2014-04-15

Total Pages: 118

ISBN-13: 9781499162974

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The work described in this paper was carried out by the Jet Propulsion Laboratory, California Institute of Technology under a contact with the National Aeronautics and Space Administration. The support of the NASA Headquarters Office of Chief Engineer for the development and documentation of the force limited vibration testing technology described in this monograph is gratefully acknowledged.


Spacecraft Structures

Spacecraft Structures

Author: J. Jaap Wijker

Publisher: Springer Science & Business Media

Published: 2008-01-08

Total Pages: 503

ISBN-13: 3540755535

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Space flight is a comprehensive and innovative part of technology. It encompasses many fields of technology. This monograph presents a cross section of the total field of expertise that is called "space flight". It provides an optimal reference with insight into the design, construction and analysis aspects of spacecraft. The emphasis of this book is put on unmanned space flight, particularly on the construction of spacecraft rather than the construction of launch vehicles.


Application of the Semi-Empirical Force-Limiting Approach for the Connect Scan Testbed

Application of the Semi-Empirical Force-Limiting Approach for the Connect Scan Testbed

Author: Lucas Staab

Publisher: BiblioGov

Published: 2013-06

Total Pages: 38

ISBN-13: 9781289091453

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The semi-empirical force-limited vibration method was developed and implemented for payload testing to limit the structural impedance mismatch (high force) that occurs during shaker vibration testing. The method has since been extended for use in analytical models. The Space Communications and Navigation Testbed (SCAN Testbed), known at NASA Glenn Research Center (GRC) as, the Communications, Navigation, and Networking re-Configurable Testbed (CoNNeCT) project utilized force-limited testing and analysis following the semi-empirical approach. This presentation presents the steps in performing a force-limited analysis and then compares the results to test data recovered during the CoNNeCT force-limited random vibration qualification test that took place at NASA Glenn Research Center (GRC) in the Structural Dynamics Laboratory (SDL) December 19, 2010 - January 7, 2011. A compilation of lessons learned and considerations for future force-limited tests is also included.


Application of the Semi-Empirical Force-Limiting Approach for the CoNNeCT SCAN Testbed

Application of the Semi-Empirical Force-Limiting Approach for the CoNNeCT SCAN Testbed

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-05-22

Total Pages: 38

ISBN-13: 9781719390699

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The semi-empirical force-limiting vibration method was developed and implemented for payload testing to limit the structural impedance mismatch (high force) that occurs during shaker vibration testing. The method has since been extended for use in analytical models. The Space Communications and Navigation Testbed (SCAN Testbed), known at NASA as, the Communications, Navigation, and Networking re-Configurable Testbed (CoNNeCT), project utilized force-limiting testing and analysis following the semi-empirical approach. This paper presents the steps in performing a force-limiting analysis and then compares the results to test data recovered during the CoNNeCT force-limiting random vibration qualification test that took place at NASA Glenn Research Center (GRC) in the Structural Dynamics Laboratory (SDL) December 19, 2010 to January 7, 2011. A compilation of lessons learned and considerations for future force-limiting tests is also included. Staab, Lucas D. and McNelis, Mark E. and Akers, James C. and Suarez, Vicente J. and Jones, Trevor M. Glenn Research Center IMPEDANCE; VIBRATION TESTS; DYNAMIC STRUCTURAL ANALYSIS; RANDOM VIBRATION; MATHEMATICAL MODELS; DYNAMIC RESPONSE; LESSONS LEARNED; SPACE COMMUNICATION; PAYLOADS; NAVIGATION


Investigation of the Semi-empirical Method for Force Limited Vibration Testing

Investigation of the Semi-empirical Method for Force Limited Vibration Testing

Author: Vijayamohan Rao Dharanipathi

Publisher:

Published: 2003

Total Pages: 0

ISBN-13:

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Conventional vibration testing of aerospace hardware is normally performed by controlling the acceleration input to the base of a test item to the specifications, namely the envelope of the acceleration peaks of the flight environment. In the nineties, NASA JPL led the development and implementation of an improved method called Force Limited Vibration (FLV) testing. In addition to controlling the input acceleration, the FLV testing measures and limits the reaction forces between the test item and the shaker. This force limiting technique results in acceleration notching at predominant natural frequencies of the test item. Due to its partly empirical nature, the crucial coefficient, C 2, still requires some judgment for its selection. Although the semiempirical method is very powerful and has been implemented successfully on several space missions, there is still some work required to realize it and make it acceptable to everyone. The objective of this study is to present a comprehensive and complete analytical and experimental investigation on the semi-empirical method.