Improvement of Sailplane Crashworthiness through Keel Beams with Silicone Cores

Abstract

Occupant safety is a major concern in the development of modern sailplanes. Particularly, the crashworthiness of cockpit structures is an important design consideration. In this paper a structural concept for a forward fuselage is presented which has been developed to improve the crash performance of sailplanes. The proposed design solution primarily addresses the issues of survival space integrity as well as occupant acceleration. It is based on the use of composite box beams filled by silicone rubber as crash elements in the lower cockpit structure. The elastomeric material was selected owing to its remarkable properties in terms of shock absorption and damping. The crash performance of this design concept was evaluated through numerical simulation using an explicit transient dynamic code. For this purpose a detailed finite element model of a generic glider fuselage was established comprising all relevant structural elements. Additionally, the model was equipped with occupant dummies which provided high fidelity acceleration data. A comprehensive parametric study was conducted which demonstrated the capability of the proposed keel beam concept to improve the crashworthiness of glider cockpit structures.