Research On The Rupture Of Cylindrical Shell Structure Under Internal Explosive Loading

The rupture of the metal cylindrical shell structure under internal explosive loading is studied in the paper against the background of Fuel-Air-Explosives (FAE) Devices. The work is focused on the FEM simulation of the actual object. Combined with the numerical work, a theoretical rupture criterion of thin cylindrical shells at high strain rates is deduced approximately; the fracture parameters of the shells are measured in the explosion chamber and the fractured surfaces of shell debris are observed by micrographs. With theoretical guidance and experimental verification, the numerical results show the substantial laws of the total dynamic process of the shells from initial expansion to eventual rupture. The main parts of the paper are as follow:1). By improving the integral route and method in the fracture criterion based on the damage variable, a new fracture criterion for determining the rupture state of thin metal cylindrical shells has been given. The relations of critical fracture parameters and model and materials parameters are obtained. In addition, to be integrable, the classical dynamic institution for high-strain-rate materials is decoupled and natural strain is introduced.2). The destructive process of cylindrical shell structure is simulated with finite element models of FAE Devices. The discrete technique for shell debris is realized using the Constrained-Tied-Nodes-Failure Method, and the primary fracture parameters of the shells are evaluated. In this part of work, the numerical precision of simulation results is greatly improved due to two achievements, which have established sound foundation for eventual optimal structural design. The first one is that a general notch affecting function is put forward using curve fitted method, so that the notch's effect can be considered in debris simulation. The second is that mesh can be fine as required for we have solved the conventional problem that the shell's mesh must be limited in notch. Moreover, the mesh size's significance to the results is displayed by calculation and compare of models with different mesh sizes. Besides, we have simulated the cloud-shaped field distribution of moving FAE Devices with a...