v.A. Krab et al. Composites Science and Technology 61(2001)1561-1570 1563 measured the displacements on the edge of the speci- Applied load, CMOD, strain gage output and load-line men,as shown in Fig. 2. Longitudinal strains ahead of displacement(8)were recorded continuously as a func the notch tip were measured using standard foil strain tion of time during all tests gages 0.8 mm in gage length and 1.6 mm in width Ultrasonic C-scans of the specimens were recorded Typical gage locations are shown in Fig. 2. before and after testing. A schematic of the C-scan set Heating of the test specimen was achieved with closed- up is shown in Fig 3. The C-scans were obtained using loop controlled, four zone quartz lamps. Slotted windows a through transmission, reflector plate scanning techni- in the center of the quartz lamps allowed for visual que described elsewhere [10, 11]. A 12.7 mm diameter, 10 inspection of the surface matrix crack during testin ng. MHz, 76 mm spherically focused transducer produced Further details of the test equipment have been described by kB Aerotech was used to emit and receive the ultra elsewhere [14, 15 sonic energy. A Panametrics model 5052 pulser/receiver, fracture tests were conducted under load-line displace- Le Croy model TR 8828C 200 MHz digitizer, and a ment control at a rate of 0.001 mm/s. After reaching the CalData 5 axis scanning system were used to acquir desired maximum load, test specimens were removed from ultrasonic C-scan data. The data acquisition and scan- the test machine for ultrasonic and optical evaluation. ning control was accomplished using in-house software water tank transducer(sends and scan axes in the receives ultrasound) y plane of the specimen stainless steel reflector plate (a) pulser/receiver 5 axis scanning system synch RF signal out transduc servo-motion 8 bit digitizer digital data movement controller 200 MHz commands IEEE-488 data acquisition motion control computer Fig 3. Schematic of the ultrasonic C-scan set-up(a)reflector plate scanning technique(b)equipment schematic.measured the displacements on the edge of the speci￾men, as shown in Fig. 2. Longitudinal strains ahead of the notch tip were measured using standard foil strain gages 0.8 mm in gage length and 1.6 mm in width. Typical gage locations are shown in Fig. 2. Heating of the test specimen was achieved with closed￾loop controlled, four zone quartz lamps. Slotted windows in the center of the quartz lamps allowed for visual inspection of the surface matrix crack during testing. Further details of the test equipment have been described elsewhere [14,15]. Fracture tests were conducted under load-line displace￾ment control at a rate of 0.001 mm/s. After reaching the desired maximum load, test specimens were removed from the test machine for ultrasonic and optical evaluation. Applied load, CMOD, strain gage output and load-line displacement (
) were recorded continuously as a func￾tion of time during all tests. Ultrasonic C-scans of the specimens were recorded before and after testing. A schematic of the C-scan set￾up is shown in Fig. 3. The C-scans were obtained using a through transmission, reflector plate scanning techni￾que described elsewhere [10,11]. A 12.7 mm diameter, 10 MHz, 76 mm spherically focused transducer produced by KB Aerotech was used to emit and receive the ultra￾sonic energy. A Panametrics model 5052 pulser/receiver, LeCroy model TR 8828C 200 MHz digitizer, and a CalData 5 axis scanning system were used to acquire ultrasonic C-scan data. The data acquisition and scan￾ning control was accomplished using in-house software. Fig. 3. Schematic of the ultrasonic C-scan set-up (a) reflector plate scanning technique (b) equipment schematic. V.A. Kramb et al. / Composites Science and Technology 61 (2001) 1561–1570 1563