Acoustic Emission and Damage Monitoring During Fatigue of C/SiC Composites at Room Temperature Dr. Gregory Morscher OAl at NASA Glenn Research Center MS 106-5, Cleveland, OH 441 35 Phone: (216 ) 433-551 2 & Fax: (21 6) 433-5544 g mor scher @ g rc.n asa.g ov Fatigue experiments were performed at room temperature for C-fiber reinforcedc hemical vapor infiltrated (CVI Sic) matrix and melt-infiltrated( MI) matrix composites. The goal was to associate some nondestructive parameter or acoustic emission characteristic with the processes that lead to fatigue failure. Failure only occurred at loads very close to the ultimate. However, correlations between the acoustic data and the eventual failure of the composites could be made. These will be presented with respect to health monitoring of these types of composites. 89 a, I m c) 2 m 0 CmI II E 8 E 0 m 0 A - a, n 0 'EJ C U a, m S t .- m Lc E .CI I S v, L L 0 c a0) v, m- S 0 I-I m- a, u> cn a 0 cn E a m- tn E a, Q) 3 I- S 0 W 0 W v, I 0 c) 0 cn c) -m a, > S m- a, 0 0 2 € u L =- a, a, I v) I 0 a, cn CI > 0 3 i) a, 0 I 0 m a, t m L1. S a' cu II 0 a, 0 II I m - U a a> s v) m m- E 3 - II a, m II 3 - U I S 3 a, > 0 0 F 0 a, 0 I cn a, > 0 I U U & a, U a, cn a, v) I -cn E S 3 S I a m U L cn m S i= a, Q 3 v) 0 a, S cn a, 0) > I I. E 0 a, U m S a, 0 U a, m- c m - > r) 1 cn 2 j a, t) a, a, S IL m- E 23 a, > v) L m ' a, m- E I 2 a, U I a, n 0 - - 5 0 t m a , U U S 6 m cn cn a, L X I cn S m- zL I x a, m I a, Q I $ a, h cn a, I X m I aj L1 S 0 a, a, 0 S b 3 X m- I - 0 W c) S U m- U 0 a, Im m- & Clf Im c L m- I 0 0 I C 0 + - .I a, L S m 0 U 0 6 a, 0 > a, CI nii 2 cn t> 0 a, 0 1c-r m m L U a, L .- I cn .- a, In 2 v, m I 6 In cn 0 0 v, 1c-r a, (0 0 S a, I 0 a, + a, m- u> + v> a, n 0 0 v, E d- v, za, m > II a. 0 cn L 0 v, U a, a, S N c1 C0I +vL, I am aL, X cn x 0 0 +S a, m T- U m0 W Q a, II 3 a. LL >s II I I I I I N 0 0 0 0 CCI L E E v) -Q) E E S v) 3 ul v) v) n cy) cy) E, S 0 I a, a, U in m I cn m u 3 cn 0 0 0 0 0 0 0 0 0 0 v) d c3 (OY r n CII h! m- c r 0 r + 0 S 2 0 x 2 3 0 d- b 00 (D cv I u5 c6 0 I b m m m cn in n 0 3 cn a, U Lo m Lo m p1 00 00 7 00 00 7 0 0 0 0 0 0 a, E 0 0 0 0 0 0 m- d- (D (D d- m m t a, in Q a, a, a, a, S a, a, S W rr, 0 0 rr, rr, 0 m m 4 m m d rr, rr, I rr, I rr, 0) 0, U U 0 U U 0 a, a, m a, a, rn 0 0 0 0 3 3 3 U U 2 2 6 7 q ca v> 0 I -- E E E E v) v) cy3 c') 0 E Q) m =.c, L 0 E k Q) C L .I 0 L 'EJ 3 Q Q) 0 tn S 0 .I Q) 0 E L L c & 0 0 0 0 c, .cI c, +.r t!Q) Q) E" .8I3 3 o * c S 8 c, 0 + S .I Q>) ca, Q>) - 0 m Q) 0 3 S 4 m