국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Composite Stress Rupture: A New Reliability Model Based on Strength Decay
저자	Reeder, James R.
Keyword	COMPOSITE STRUCTURES;; COMPOSITE WRAPPING;; CREEP RUPTURE STRENGTH;; FAILURE;; PRESSURE VESSELS;; PROVING;; RELIABILITY;; RELIABILITY ANALYSIS
URL	http://hdl.handle.net/2060/20120008181
보고서번호	NASA/TM-2012-217566
발행년도	2012
출처	NTRS (NASA Technical Report Server)
ABSTRACT	A model is proposed to estimate reliability for stress rupture of composite overwrap pressure vessels (COPVs) and similar composite structures. This new reliability model is generated by assuming a strength degradation (or decay) over time. The model suggests that most of the strength decay occurs late in life. The strength decay model will be shown to predict a response similar to that predicted by a traditional reliability model for stress rupture based on tests at a single stress level. In addition, the model predicts that even though there is strength decay due to proof loading, a significant overall increase in reliability is gained by eliminating any weak vessels, which would fail early. The model predicts that there should be significant periods of safe life following proof loading, because time is required for the strength to decay from the proof stress level to the subsequent loading level. Suggestions for testing the strength decay reliability model have been made. If the strength decay reliability model predictions are shown through testing to be accurate, COPVs may be designed to carry a higher level of stress than is currently allowed, which will enable the production of lighter structures.