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CGM-7 ACPD CRACK GROWTH MONITOR |
FEATURES |
Continuously variable frequency output from 10Hz to 500kHz in 1Hz increments. Advanced filtering capabilities with 3 user selectable ranges (and out). 10 pre-set gains built in. User selectable from 1000 to 30000. Two channels as standard on all models. |
High output currents up to 5 amps. Continuously variable in 1mA increments. User selectable offsets. Variable from -4v to +4v. Resistive and inductive components simultaneously displayed. Pre-amplifiers provided as standard for each channel for superior SNR. |
APPLICATIONS |
Slow crack growth Crack sizing Dynamic crack growth studies Crack closure studies |
Crack initiation Fatigue crack initiation Condition monitoring Stress corrosion testing |
OVERVIEW |
The CGM-7 is a modern microprocessor based instrument for measuring crack depth in metals undergoing materials testing. Building on the success of the CGM-5R this unit improves upon the CGM-5R specification by offering two channel operation, higher frequency and current outputs, full computer control and a variety of expansion options. It utilises the alternating current potential drop method (ACPD) which is an established technique covered by the ASTM 647 standard. The technique involves passing an alternating current through the metal under test and measuring the resultant voltage drop that is created across the specimen. The presence of a growing defect will alter this voltage and by suitable calibration, a measure of the defect depth can be obtained. |