the edge of insert 36 this is not an exact representation since the dye layer approaches zero thickness at this point and its location cannot be determined with precision however as stated above it appears to coincide with the edges of insert 36 and the debond appeared to not progress beyond insert 36 there is a buildup of dye at the top edge of the insert implying that the patch overlaid the top edge of the insert even though the top edge of the patch coincided with the top edge of the insert this is caused by the fact that during the cure cycle the adhesive initially becomes thin and watery it travelled along the top edge of the patch by capillary action then hardened to form a dye retaining seal the same holds true for the buildup of dye at the lower part of the left side of the insert none of these specimens showed any evidence of debonds initiating from the barriers but debonds were evident under the inserts unfortunately the debond opening displacement approaches zero at the debond front so there was insufficient contrast to conclusively determine the location of the debond front thus although there was no evidence that any debond penetrated past an adhesive layer barrier or an insert the resolution was insufficient to definitively state that the debonds grew to the barriers and stopped or that debonding was not initiated by the inserts the adhesive layer in the fiberglass epoxy specimens experienced strains similar to the adhesive layer in the aluminum specimens but none of the 64 barriers on these 8 specimens initiated a detectable debond by itself thus it appears that adhesive layer barriers would not induce any significant additional damage during at least.