Shock failure analysis of military equipments by using strain energy density

Mercimek, Ümit
Failure of metallic structures operating under shock loading is a common occurrence in engineering applications. It is difficult to estimate the response of complicated systems analytically, due to structure’s dynamic characteristics and varying loadings. Therefore, experimental, numerical or a combination of both methods are used for evaluations. The experimental analysis of the shocks due to firing is done for 12.7mm Gatling gun and 25mm cannon. During the tests, the Gatling gun and the cannon are located on military Stabilized Machine Gun Platform and Stabilized Cannon Platform respectively. For the firing tests, ICP (integrated circuit piezoelectric) accelerometers are attached to obtain the loading history for corresponding points. Shock Response Spectrum (SRS) analysis (nCode Glypworks) is done to define the equivalent shock profiles created on test pieces and the mount of 25mm cannon by means of the gun and the cannon firing. Transient shock analysis of the test pieces and the mount are done by applying the obtained shock profiles on the parts in a finite element model (ANSYS). Furthermore, experimental stress analysis due to shock loading is performed for two different types of material and different thicknesses of the test pieces. The input data for the analysis is obtained through measurements from strain rosette precisely located at the critical location of the test pieces. As a result of the thesis, a proposal is tried to be introduced where strain energy density theory is applied to predict the shock failure at military structures.