钽爆炸成型弹丸成型及断裂特性

In order to predict the fracture behavior of rod-shaped tantalum explosively formed projectile(EFP), the forming characteristics of tantalum EFP are simulated by LS-DYNA hydrocode. The forming laws of EFP with typical charge structure are obtained by analyzing the numerically calculated results. The curvature range of the liner required for forming a solid rod-shaped EFP with large aspect ratio is determined, and the axial fracture characteristics of Ta EFP within smaller curvature range are predicted. The influence of liner's structure parameters on EFP forming and fracture characteristics are analyzed. The research results show that for tantalum, the shape of EFP is sensitive to the change of the outer curvature radius R_o of liner. When the length-to-diameter ratio of charge is 1, R_o/D_c∈[1.00, 1.13], and the formed EFP has a relatively high compactness and its aspect ratio is 3.00-4.57. For R_o/D_c>1.13, the aspect ratio of EFP is significantly reduced, and the interior of EFP gradually becomes empty. For R_o/D_c≤1.00, fracture occurs due to the excessive aspect ratio, the fracture behavior of tantalum EFP can be predicted by using 2D r-adaptive method. For R_o/D_c<0.95, the tantalum EFP will fracture axially and break into two or more parts. In order to avoid axial fracture, the minimum value of R_o/D_c is taken to be 0.95, which can ensure that the forming state of tantalum EFP is both compact and rod-shaped, and the aspect ratio is up to 4.8.