The formation mechanism of an EFP(explosively formed projectile) using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this paper. Based on the detonation wave propagation theory, the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were calculated. Three-dimensional numerical simulations of the formation process of the EFP with tail as well as the ability to penetrate 45# steel were performed using LS-DYNA software, and the EFP velocity, the penetration ability, and the forming were assessed via experiments and x-ray photographs. The experimental results coincides with those of the simulations. Results indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the dimensions of the unit charge and maintaining the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the critical angle. The distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the CJ detonation pressure was greater than 2.5, 2, and 1.5was approximately 0.66 mm, 1.32 mm, and 3.3 mm, respectively. It is noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μs. The penetration depth of the EFP into a 45# steel target exceeded 30 mm, and there was radial expansion between the head and tail of the EFP, increasing the penetration resistance of the EFP. Therefore, the structural size of the unit charge and the liner can be further optimized to reduce resistance to increase the penetration ability of the EFP.

本文研究了在正斜反射产生的超压作用下，使用双曲率衬里的EFP（explosively forms projectile）的形成机制。基于爆震波传播理论，计算了不同位置的爆震波碰撞入射角变化及衬管表面超压分布区域。采用LS-DYNA软件对带尾EFP的形成过程和穿透45#钢的能力进行三维数值模拟，并通过实验和x ——射线照片。实验结果与模拟结果一致。结果表明，通过设置单位装药的尺寸，使碰撞点区域的压力保持在入射角时CJ爆轰的2.4倍以上，可以将爆轰波的碰撞控制为作用于衬管上的规则斜反射。接近临界角。衬管中线到正斜反射压力与CJ爆震压力的压力比大于2.5、2和1.5的区域边界的距离分别约为0.66 mm、1.32 mm和3.3 mm . 需要注意的是，压力梯度导致衬管在中间翻转形成 EFP 的头部并在大约 120μs 时关闭 EFP 的两个尾部。EFP对45#钢靶材的穿透深度超过30mm，EFP头尾之间有径向膨胀，增加了EFP的穿透阻力。因此，可以进一步优化单位装药和衬里的结构尺寸，以降低阻力，提高EFP的穿透能力。