DCM-2 DCPD CRACK GROWTH MONITOR
Capable of reversing DCPD*.
Sophisticated filtering options. The unit has advanced sampling and
High Current O/P, up to 50A. Variable in steps of 10mA.
Built in scan controller*, for direct control of high current scanners.
Pulsed DCPD as standard.
Advanced triggering*, including peak, trough, and mid-point of load cycle
Variable DC offsets for the removal of standing voltages.
Two channels as standard, reference and specimen.
Slow crack growth
Dynamic crack growth studies
Crack closure studies
Fatigue crack initiation
Stress corrosion testing
The DCM-2 is a modern microprocessor based instrument for measuring crack depth in metals undergoing
materials testing. Building on the success of the DCM-1 this unit takes on board customer comments and
suggestions, as shown in its impressive features list.
It utilises the pulsed current potential drop method (DCPD) which is an established technique also covered
by the ASTM 647 standard. The technique involves passing a constant 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.
DCPD is generally regarded as easier to set-up than ACPD, but care is required to attain comparable
crack depth resolutions due to the extra opportunity for experimental noise.