Paper number 1363
|MODE II AND MIXED MODE I/II DELAMINATION OF GRAPHITE/EPOXY COMPOSITE UNDER DYNAMIC LOADING CONDITIONS|
Sylvanus N. Nwosu1, David Hui2, and Gregory Czarnecki3
1Department of Physics/Engineering, Dillard University, New Orleans LA 70122
2Department of Mechanical Engineering, University of New Orleans, LA 70122
3Wright Laboratory, Wright Patterson AF, Ohio 45433
|Summary||This paper examines the split Hopkinson pressure application to mode II and mixed mode I/II delamination of unidirectional graphite/epoxy composites and the effects of dynamic loading on the energy release rate and absorption mechanism. The relationship between energy absorption and delamination follows a mode dependent power law behavior. Delamination increases linearly with mode ratio and impact energy up to a certain maximum that depends on the mode of fracture. Maximum delamination is reached when the reflected wave is more than 15% higher than the incident wave. The results show regions of damage mechanisms. The dynamic energy released rate in the present model differs slightly from quasi-static model. The differences are attributed to scaling effect or strain rate sensitivity in dynamic mode fracture failure. However, the characteristics of modes I and II contributions to the fracture toughness are the same as those observed in quasi-static test reported in the literature.
||Keywords|| delamination, dynamic interlaminar fracture, pure mode, mixed mode, energy absorbed, split Hopkinson pressure bar.
Theme : Mechanical and Physical Properties ; Fracture Mechanics and Failure
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