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Spacecraft pyroshock attenuation in three parts

58th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2017

Babuska, Vit B.; Gomez, Steven P.; Hammetter, Christopher H.; Smith, Scott A.; Murphy, Dylan

Satellites are subject to pyroshock events that come from the actuation of separation and can be damaging events for satellites. The damage risk is mitigated by the fact that shock intensity is attenuated by the spacecraft structure. NASA and MIL handbooks and standards, which were developed from extensive tests performed in the 1960’s, provide guidelines for estimating the attenuating effects of distance, joints, and other structural features in the load path between the shock source and the shock sensitive component. Anecdotal evidence suggests that these rules are not always conservative while sometimes they are grossly over-conservative. The first part of the paper summarizes and interprets the attenuation rules-of-thumb. The second part presents a case study in which attenuation factors developed for a satellite are compared to attenuation factors measured in a pyro-shock test of the satellite. The third part looks at the feasibility of using 21st century computational tools to predict shock attenuation through a simple jointed structure. Such tools have the potential to recreate satellite specific shock attenuation factors that could provide greater confidence in the predicted loads on shock sensitive components by reducing, and perhaps eliminating, the over-under conservatism issue; however they are surprisingly difficult to use.

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TYPE Conference Poster YEAR 2017
DOIDOIOSTIOSTIScopusScopus

Energy based representations of mechanical shock for failure characterization

57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

Babuska, Vit B.; Sisemore, Carl; Booher, Jason

The relationship between the damage potential of a series of relatively low level shocks and a single high level shock that causes severe damage is complex and depends on many factors. Shock Response Spectra are the standard for describing mechanical shock events for aerospace vehicles, but are only applicable to single shocks. Energy response spectra are applicable to multiple shock events. This paper describes the results of an initial study that sought to gain insight into how energy response spectra of low amplitude shocks relate to energy response spectra of a high amplitude shock in which the component of interest fails. The study showed that maximum energy spectra of low level shocks cannot simply be summed to estimate the energy response spectra of a high level, failure causing single shock. A power law relationship between the energy spectra of a low amplitude shock and the energy spectra of the high amplitude shock was postulated. A range of values of the exponent was empirically determined from test data and found to be consistent with the values typically used in high-cycle fatigue S-N curves.

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TYPE Conference Poster YEAR 2015
DOIOSTIScopus
Results 26–50 of 67
Results 26–50 of 67