Materials Design Principles for the Dynamic Fracture of Laminar Composite Structures

摘要

The main thrust of our work was theoretical. Use was planned to be made of new data anticipated from a separately funded dynamic fracture study to be conducted at Purdue University. Unfortunately, substantial delays in specimen preparation have resulted in these data still being unavailable, which prevented us from completing a quantitative study of engineering design principles for pinned laminates, our original goal. Nevertheless, while such work cannot be included in this report, the experiments are still proceeding and the principal investigators of this project (Dr. Brian Cox with consultative support from Dr. Roberta Massabo) are personally committed to analyzing the data when they are available (see below). Our objectives were to: Conduct basic research into the development of distributed dynamic delamination cracks in laminated structures with non-trivial geometry and general loading conditions and in the presence of friction and bridging due to through- thickness reinforcement such as stitches or rods. Develop engineering principles for dynamic, multiple cracking in laminated structures, including large scale crack bridging and friction. Create a systematic method for simplified design of laminated engineering structures containing through- thickness reinforcement, which will shorten the design cycle for lightweight military vehicles and structures. Indicate means for achieving significant improvements in impact and ballistic resistance via materials and structural design, especially via manipulation of friction or the bridging effects of through-thickness reinforcement.