32
sets of ACPD probes were installed around the chord–brace intersections
near corner C4, as shown in Fig. 10. The probes were placed at
equal intervals of 10 mm along the weld toe, making a total monitored
length of 320 mm. The plan views of the ACPD probe locations for both
specimens are shown in Fig. 11 (with the final crack paths recorded).
During fatigue tests, crack depth data were recorded automatically by
the control software at an interval of 10 min which is equivalent to
200 cycles of loadings for Specimen I and 300 cycles for Specimen II.