Fragmentation Prediction of a Steel Cylinder Using an Advanced Meshless Numerical Method Coupled with a Comprehensive Fracture Model Embedding Tensile and Shear Failure Modes

Abstract Understanding the fragmentation of an artillery shell during detonation is crucial for predicting the behavior of metallic envelopes. The process begins with a dynamic radial expansion leading to structural damages characterized by two fracture mechanisms: tensile cracks (mode I) and Adiabatic Shear Bands (ASB, mode II). These fractures interact to form the typical cross-shaped natural fragment, a process that occurs in microseconds, making analysis challenging. To elucidate these mechanisms, a comprehensive approach combining experimental analysis and numerical modeling using a novel meshless discretization technique has been initiated. Firstly, the fracturing of 36NiCrMo16 steel under tensile and shear dynamic loadings is examined. Mode I damage is studied using uniaxial tensile tests on notched specimens, while ASB conditions are identified through hat-test samples in a Hopkinson-bar setup. These experiments are then modelled in ABSTRAO software with Gamma-SPH method in order to fit parameters of physical models able to address, respectively, mode I breakup mechanisms and ASB propagation. Finally, 36NiCrMo16 mock-ups filled with Comp B explosive are tested in a detonation chamber so as to provide data for fragment analysis, which is compared with ASBTRAO HPC Solver calculations. This integrated approach aims to enhance the understanding of fragmentation phenomena and improve predictive capabilities.