Accession Number : ADP005008

Title :   Results Obtained during Acoustic Emission Monitoring of Impact Damage Graphite/Epoxy Pressure Vessels,

Corporate Author : HERCULES INC MAGNA UTAH

Personal Author(s) : Gardiner,D. S. ; Gorman,M. R. ; Rytting,T. H. ; Sakai,K.

Report Date : NOV 1984

Pagination or Media Count : 17

Abstract : Acoustic emission (AE) sensors were used to monitor subscale graphite/epoxy pressure vessels that were subjected to increasing levels of impact damage. Impact damage was inflicted after each vessel had undergone a pressure proof test. Proof pressure is defined as 80 percent of ultimate. AE activity was then monitored throughout a series of successively higher pressure cycles ranging from 13 to 60 percent of ultimate. Each cycle included a ramp to pressure followed by a four minute hold period and pressure unload. Four sensors were used to cover the vessel surface and two additional sensors were used to monitor the impact damage site. This paper presents the AE event versus load history of these tests and demonstrates the ability of the technique to monitor the growth of damage and to estimated damage criticality (i.e. effect on ultimate strength). When significant damage was present, a noticeably higher number of events was low, indicating its insignificance to performance. The events that occurred during the pressure holds proved to be a reasonable estimator of vessel performance. Good correlations between the number of events during hold and burst pressure were obtained. (Author)

Descriptors :   *PRESSURE VESSELS, *COMPOSITE STRUCTURES, *IMPACT STRENGTH, *DAMAGE ASSESSMENT, ACOUSTIC EMISSIONS, DETECTORS, MONITORING, GRAPHITE, EPOXY COMPOSITES, IMPACT TESTS, HIGH PRESSURE, ROCKET ENGINE CASES, MODELS

Distribution Statement : APPROVED FOR PUBLIC RELEASE