Abstract

The motion of a projectile oblique impacting sand bed with deep penetration was captured in experiment. Penetration depth, velocity and acceleration of the projectile were analyzed in terms of kinematic data. Horizontal and vertical penetration depths were measured under a series of impact angles, impact velocities and projectile diameters, and the collapsed curves were obtained. Specifically, an impact drag force model was assumed, which consists of an inertial term, a linear viscosity term, a linear static term, and a constant term. Then, we confirmed the terms related with velocities for both horizontal and vertical direction at the fixed depth-dependent term and obtained the linear depth-dependent static force at certain velocities. It demonstrated that viscous drag force is significant in deep penetration cases (vertical penetration depths are larger than the diameter of projectiles), but it can be neglected in shallow penetration cases. The generalized phenomenological resistance force model were proposed, which can predict the motion of projectile and resistance force exerted on the projectile by the granular medium at oblique impact cases.

Graphic abstract

中文翻译：

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弹丸对粒状介质的倾斜影响：穿透深度和动态过程

摘要

实验中捕获了深穿透的弹丸倾斜冲击砂床的运动。根据运动学数据分析了弹丸的穿透深度，速度和加速度。在一系列冲击角，冲击速度和弹丸直径下测量水平和垂直穿透深度，并获得坍塌曲线。具体地，假设冲击阻力模型，其由惯性项，线性粘度项，线性静态项和常数项组成。然后，我们在固定的深度相关项下确定了与水平和垂直方向的速度有关的项，并获得了在某些速度下线性的深度相关的静力。结果表明，在深穿透情况下（垂直穿透深度大于弹丸的直径），粘性阻力是很重要的，但在浅穿透情况下可以忽略不计。提出了广义的现象学抵抗力模型，该模型可以预测在倾斜冲击情况下颗粒介质对弹丸的运动和粒状介质施加在弹丸上的抵抗力。

图形摘要