Material Testing: Monitoring Metal Fatigue Crack Growth

ADwin-Gold Real-Time Data Acquisition System
CHESTERLAND OH—March 5, 2012

CAS DataLoggers recently supplied the data acquisition and control solution for a prominent manufacturer of material used in the aviation and aerospace industries. Characterizing the growth rate of cracks in metal samples under repeated cyclical stress was critical to the customer: typically, a material test system incorporating a closed loop servo-hydraulic system was employed to apply a repetitive stress to the sample while the growth rate was monitored by one of several methods. Variable amplitude-loading, conventional closed-loop servohydraulic systems using simple PID control were employed but became very difficult to tune to handle varying test conditions. Read the entire article on our applications note page.