On vibrational behavior of pulse detonation engine tubes

This paper presents a set of analytic solutions for the transient elastodynamic response of orthotropic cylindrical tubes to sequential moving pressures with specific profiles. The general form of the presented formulations and the solution methods are applicable to a number of theoretical and practical problems. However, the final solutions are tailored for sequential gaseous detonations, with direct application in the stress analysis of pulse detonation engines (PDE). The PDE generates trust by high cycling of gaseous detonations and is regarded as a promising candidate for providing very efficient propulsion systems for aviation and electric power generation. The presented analytic solutions are validated with the available experimental data and complementary finite element simulations. Representative analyses are carried out for an experimental detonation tube subjected to different boundary conditions and loading sequences. It is shown that the proper (or improper) combinations of the relevant parameters can result in substantial attenuation (or amplification) of the tube vibration. It is also demonstrated that the realistic analysis of the overall vibrational behavior, which can be highly affected by the specifications of the loadings and boundary conditions, requires the simulation of hundreds of sequential detonations.