Control of corrosion-fatigue in NGV fuel cylinders. Topical report, January 1987-August 1989

Technical Report · Thu Feb 01 00:00:00 EST 1990

OSTI ID:5483420

Hudak, S J; Birring, A S; Bartlett, M L; Hanley, J J

Natural gas vehicle (NGV) fuel cylinders are periodically recertified using hydrostatic testing. However, the procedure is costly, and of questionable value for the detection of corrosion-fatigue cracking, the most serious form of cylinder degradation. The present program examines the feasibility of an improved recertification procedure based on in-service acoustic emissions (AE) monitoring of cracks during cylinder refueling, combined with fracture mechanics testing and analysis to determine the optimum inspection period, the level of detectability required, and the cylinder retirement criteria. Laboratory experiments were used to measure the corrosion-fatigue and fracture resistance of several cylinder steels, as well as to provide basic information on AE sources. A comparison of the latter information with the background noise obtained during cylinder refueling was used to demonstrate the feasibility of the AE procedure. An analytical fracture mechanics model for corrosion-fatigue crack growth in the cylinders was also developed and used, together with the measured materials' properties, to predict cylinder life as a function of crack size, operating pressure, and environment. Conditions for leak-before-break of the cylinder were also examined. Areas requiring additional work are defined, including the important task of determining the minimum AE-detectable crack size in actual cylinders.

• Research Organization: Southwest Research Inst., San Antonio, TX (United States)
• OSTI ID: 5483420
• Report Number(s): PB-91-178749/XAB; CNN: GRI-5086-252-1440
• Resource Relation: Other Information: Sponsored by Gas Research Inst., Chicago, IL
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
36 MATERIALS SCIENCE
03 NATURAL GAS
GAS CYLINDERS
CORROSION FATIGUE
NATURAL GAS
COMBUSTION
STEELS
VEHICLES
ACOUSTIC EMISSION TESTING
CERTIFICATION
CRACK PROPAGATION
CRACKS
FEASIBILITY STUDIES
FRACTURE MECHANICS
FUEL SYSTEMS
IN-SERVICE INSPECTION
LEAK DETECTORS
LEAKS
LOADING
MATHEMATICAL MODELS
PRESSURE DEPENDENCE
SERVICE LIFE
SIZE
ACOUSTIC TESTING
ALLOYS
CHEMICAL REACTIONS
CONTAINERS
ENERGY SOURCES
FATIGUE
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
INSPECTION
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS HANDLING
MATERIALS TESTING
MECHANICAL PROPERTIES
MECHANICS
NONDESTRUCTIVE TESTING
OXIDATION
TESTING
THERMOCHEMICAL PROCESSES
420500* - Engineering- Materials Testing
360105 - Metals & Alloys- Corrosion & Erosion
034000 - Natural Gas- Combustion