Measurement of Mechanical Properties of Solid Fuels and Advanced Composite Materials Related to Short-Time High Acceleration Generated by Lorentz Rail Accelerators

The technology of electromagnetic driven Lorentz rail accelerators (LRAs) has been significantly improved in the last years. Due to the extreme acceleration in LRA systems, there are high demands regarding the mechanical stresses. It is assumed that materials can withstand stresses exceeding the nominal limits related to static conditions if they are applied for a short time. To assess the short-time material strength of a hydroxyl-terminated-polybutadiene rocket fuel grain, experiments shall be carried out using the High-Enthalpy Shock Tunnel Göttingen of the German Aerospace Center in Göttingen as a high-acceleration test facility. In the first step, different samples of the rocket fuel grain and composite materials are tested under high acceleration and analyzed by a visual check. In this paper, first of all, different samples of the rocket fuel grain and composite materials are tested under high acceleration and analyzed by a visual check. In the second step, onboard electronics mounted on the piston are developed to collect the data of the strain and the deformation of the composite/fuel grain and to directly measure the acceleration. With this electronically enhanced specimen, another test is carried out, and measurement data are acquired. The evaluated experiments shall provide useful information to design a hybrid rocket engine for a small launcher, capable to be launched from an LRA.