Durability and Stiffness Estimation for the Composite Overwrap Electromagnetic Rail Launcher Barrel

Abstract

One of the ways to decrease electromagnetic rail launcher (EMRL) barrel mass is to utilize composite material overwrap. Design of novel light, stiff, and durable EMRLs requires accurate computational prediction of barrel strength. This paper presents numerical model and corresponding computer code for the calculation of stresses in composite overwrap EMRL barrel. The computer code named, NDSPDE, based on the finite-element method for stresses analysis in complex geometric shapes designs in a plane strain. The code allows carrying out numerical structural studies of EMRL barrels under various electromechanical loads accounting for the orthotropic properties of utilized constructive materials. Depending on the requirements for EMRL barrel stiffness and durability the results of numerical studies allow to select suitable construction materials to optimize both the barrel design and the barrel electromechanical loading conditions. The safety margin evaluation of the side insulators and the overwrap was carried out by classical criterion of maximum tensile stress. Note that in durability assessing of other launcher elements the above safety margin is not applicable, since the stress is not unixial in the most loaded parts of those elements. In case of nonuniaxial stress, evaluation of the launcher structural elements durability requires utilization of more complex criteria, which account for the type of the stress state arising in the launcher elements. This paper presents the numerical results of the EMRL barrel cross-sectional parameter estimation including the glass fiber overwrap, rails, and insulators. Estimations were carried out both for stresses and for durability of the EMRL barrel structural elements.