For the same specimen, conventional eddy current and ultrasonic testing failed to provide any indications of cracks, and fluorescent liquid penetrant detected only an inconclusive spot indication.
Even with much refined meshes no indication of crack surface folding is found here.
Comparisons between the AE results and the video gauge-based crack propagation data strongly suggest that the AE energy vs time curve is a much clearer indication of crack initiation than is the widely used AE hit count vs time curve.
European Committee for Standardisation, 1998.] and some indication of accelerated crack growth for short cracks was found.
Combining these results with those from a previous study, it is shown that the wedge indentation test is capable of accurately measuring the interface toughness of low-k films, and a pop-in event in the load penetration curve can be used as an early indication of interface crack initiation.
There were no indications of environment induced cracking, neither creep nor stress corrosion cracking.
The methodology is based on a combination of (i) a unit cell crystal plasticity model of Ti 6Al 4V, (ii) a frictional contact model of an experimental fretting wear configuration, and (iii) implementation of a microstructure-sensitive fatigue indication parameter for prediction of crack nucleation.
The most likely support movement scenarios identified from these comparisons are then validated with visual indications of damage, such as crack location and size, and other geometric quantities, such as the change of the bedding joint elevations along the bridge.
From Tables 3 and 4, we can see that, whether with the transverse or the longitudinal laser stripe, our method can detect the location and width of crack accurately, the indication error is not greater than 1mm. Figure 17 Accuracy experiment of crack detection (a) gauge block (mm) (b) experimental image.
For the crack velocity measurements, timing wire system with the required circuitry capable of giving the precise temporal indication of the propagating crack was designed and employed.
