We investigate the mechanics and physics of localization and fragmentation in ductile materials and polymer coated multi-layer structures. The behavior of ductile metals at strain rates of about 4,000–15,000 per second is considered. Specifically, the effect of polymer coatings on Al 6061-O tubes is examined. Polyurea and polycarbonate are investigated as coating materials. It is demonstrated that there are two effects of the polymer coating on the overall deformation of the Al 6061-O tube specimens. First, the additional mass of the coating material results in an inertial effect; therefore, thicker coatings result in a slower overall expansion and hence for a limited impulse loading, and less overall straining of the metallic specimen. Second, the flow resistance of the polymer contributes to additional energy dissipation (or storage) and can prevent failure in the metallic specimen. This effect is much more pronounced in polycarbonate, the material with a larger strength. Finally, it is demonstrated that coating with a much stronger material such as Dyneema may inhibit strain localization completely; some exploratory results on this topic will be presented as well.

Dynamic strain localization and fragmentation in tubes influenced by polymer coating

2019 Spring National Meeting

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