Repair of mirage III aircraft using the BFRP crack-patching technique

Composite repairs to bridge steels demystified

“…Indeed the results of the boron epoxy repairs to the Mirage III [31], where the patch reduced the stress intensity factor by more than 90% 4 [32] and hence was indeed beneath the long crack threshold, and the C-141 repair program [33] show that such repair designs can be very effective. However, as noted in ASTM 647-13a any analysis/design (repair assessment) of a composite repair to an operational structure should use valid da/dN versus ΔK small crack data.…”

Bonded Composite Patch Repairs on Cracked Aluminum Plates: Theory, Modeling and Experiments

“…Composite patches, bonded on cracked or corroded metallic aircraft structures, have shown to be a highly cost effective method for extending the service life and maintaining high structural efficiency (Baker & Jones, 1988;Baker, 1993;Molent et al, 1989;Baker et al, 1984;Torkington, 1991;Bartholomeus, 1991). Damage tolerant and fail-safe design of aircraft, aerospace and civil structures requires a substantial amount of inspection and defects-monitoring at regular intervals.…”

The effects of size and stacking sequence of composite laminated patch on bonded repair for cracked hole

“…(2) Note that S varies with the polar angle 0 only and the coefficients aij are given by 16Gall = (3 -4u -cos 0) ( l + cos 0)…”

“…To increase the fatigue life of the aircraft components, many studies have been published on developing techniques for bonded repairs to damaged components. Over the last decade, composite patches and/or steel sleeves have been adopted to repair the cracked holes [1][2][3][4][5]. Undoubtedly, the use of a patch changes the load path and bypasses the crack.…”