Composite impact dynamics research at NASA LaRC: A review

The Landing and Impact Dynamics Branch of NASA Langley Research Center has been involved in impact dynamics research since the early 1970's. For the first ten years, the emphasis of the research was on metal aircraft structures in both the General Aviation Crash Dynamics Program and the Controlled Impact Demonstration (CID) Program, a transport aircraft program culminating in the controlled crash test of a Boeing 720 aircraft in 1984. Subsequent to the transport work, the emphasis has been on composite structures with efforts directed at understanding the behavior, responses, failure mechanisms, and general loads associated with the composite material systems under crash type loadings. Considerable work has been conducted to address the energy absorption characteristics and it indicates that composites can absorb as much if not considerably more energy than comparable aluminum structures. However, due to their brittle nature, attention must be given to proper geometry and designs to take advantage of the good energy absorbing properties while providing desired structural integrity. Achieving the desired new designs often requires an understanding of how more conventional designs behave under crash type loadings. The purpose is to present a review of the composite impact dynamics research being conducted at NASA Langley Research Center. Examples are presented of experimental and analytical data to illustrate the activities in the four program elements of the composite research.