Establishment of Gun Blast Wave Model and Structural Analysis for Blast Load

Abstract

The muzzle of a gun mounted on an airplane emits repetitive gun blast waves during the firing. These blast waves expand in open space and they are reflected on the airplane surface adjacent to the gun. The vibration resulting from the reflected waves can cause adverse effects to the airplane. Therefore, it is very important to establish an accurate blast wave model for the prediction of the vibration level. In the present study, the blast wave model is established using a scaling approach and CFD calculation, and this model is then verified with experimental data. The established blast wave model is applied to two kinds of structural models. Firstly, to investigate the effect of the muzzle distance from the surface, the responses of a graphite epoxy composite panel exposed to the blast wave are analyzed for various muzzle distances. Secondly, the transient response analyses of a left wing model are carried out for several repeated fires. From the results, it can be shown that the assumption of uniform blast wave is not applicable in the near muzzle distance, and the vibration resulting from the repetitive blast waves can cause high frequency damage to the structure and equipments mounted in the aircraft. The blast wave model can be applicable not only to the prediction of the vibration but also to a blast resistant structural design.