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TITLE AND SUBTITLE:
Feasibility of Various NDE Techniques to Assess and Monitor Damage in Ceramic Composites at Elevated Temperatures
AUTHOR(S):
Tiwari, Anil; Henneke, Edmund, G., II
REPORT DATE:
1998-03-01
FUNDING NUMBERS:
WU-523-21-13-00
PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES):
Engineering Science and Mechanics Department Virginia Polytechnic Institute and State University Blacksburg, Virginia 24061-0001
PERFORMING ORGANIZATION REPORT NUMBER:
E-11011
SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration Lewis Research Center Cleveland, Ohio 44135-3191
REPORT TYPE AND DATES COVERED:
Conference Publication
SPONSORING/MONITORING AGENCY REPORT NUMBER:
NASA/CR-1998-206315
SUPPLEMENTARY NOTES:
Project Manager, George Y. Baaklini, Structures Division, NASA Lewis Research Center, organization code 5920, (216) 433-6016.
ABSTRACT:
Custom made ovens were integrated with Instron type load frame to test ceramic matrix composites at 1600 °C. A Lab View program was written to monitor the area under the histeresis loop to evaluate damage progression in composites at elevated temperatures. Dynamic stiffness was also calculated throughout the test and used as a damage parameter. It was demonstrated that acoustic emission signals with 0.5 to 3 MHz in frequency are generated due to fiber fracture and matrix cracking in SiC/CAS-II. This damage was beyond the detection capabilities of stress waves by a laser based Ometron system and a stress pattern analysis by thermal emission (SPATE) approach. It was concluded that1) hysteresis loop and dynamic stiffness can be used to monitor damage in ceramic matrix composites at elevated temperatures, and 2) more work is needed to establish laser-based acousto-ultrasonic for damage monitoring during high temperature loading of ceramic composites.
SUBJECT TERMS:
NDE; Acousto-ultrasonics; Ceramic composites; Damage monitoring; SiC/CAS
NUMBER OF PAGES:
16
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