基于细观建模的电子束预控弹体破裂机理数值研究

In order to study the fracture mechanism of the projectile melted by the electron beam, a parameterized modeling method based on the micromechanical characteristics of the projectile was proposed. Scanning electron microscope and hardness tester were used to accurately obtain the characteristics of the electron beam melted zone. The typical electron beam controlled area was composed of the melting zone, the transition zone, the hollow zone and the matrix zone. Three hypotheses were proposed based on the mesoscopic characteristics of the electron beam controlled projectile. First, the structural characteristic parameters of the electron beam controlled projectile were summarized. Second, diamond-shaped finite element mesh elements were constructed through translation nodes. Third, the electron beam controlled pattern was constructed by combining diamond-shaped finite elements. Finally, the materials of melting zone and transition zone are defined, and finite elements of the hollow zone were deleted. A three-dimensional finite element model of the projectile with matrix, melting zone, transition zone and hollow zone was established. The explosion driving and fracture process of the typical projectile was simulated and analyzed by LS-DYNA software. The results show that the fracture process of the projectile can be divided into three stages: the tensile fracture in the hollow zone after the expansion of the projectile under the action of the circumferential tensile stress; the crack propagation and tensile fracture in the transition area; and the shear failure of the matrix at the bottom of the cavity area under the action of the tensile stress at both sides and the compressive stress at the bottom, which is 45° to the normal of the inner wall of the projectile. The numerical simulation results are in good agreement with the recovered fragment section shape and failure mode. The research results are of reference value to the forming control of projectile fragments by electron beam controlled.