The Phase I research proposed herein provides for using the tremendous energy and pressure generated by embedded detonating cord (EDC) to not only sever an acrylic canopy but, more importantly, create and propagate cracks that weaken and fracture the canopy. The approach is firmly based on the use of fracture mechanics principles combined with tailored experimental testing to confirm important hypothesis. Prior experience of Anamet and our consultant, Dr. George C. Sib, with the fragilization of Navy canopies and the redesign of the Navy F-18 canopy and mechanical breakers has provided a good understanding of how stretched acrylic canopies fracture. During the early part of the Phase I work, experimental testing to determine the critical strain energy density will be accomplished and used in conjunction with Dr. Sih's theoretical analysis to define potential EDC configurations and charge sizes. Subsequently, small size panels made from stretched acrylic material will be fabricated by Swedlow, Inc. and tested by ET, Inc. Correlations of test data with design predictions will allow for the creation of a design methodology which can be applied and demonstrated on full size canopies during the Phase II effort. At the end of Phase I research, the feasibility of using EDC as the basis for an improved fracturing system for thick canopies will have been demonstrated. Most notably, this new fracturing system will not obscure pilot vision and both noise and debris will be minimized by virtue of developing systems which use the minimum amount of EDC charge.
