考虑靶背自由面效应的中等厚度混凝土介质侵彻工程模型

为评估弹丸侵彻和贯穿中等厚度混凝土介质的能力,在半无限混凝土介质靶体侵彻模型的基础上,考虑混凝土靶背自由面效应,通过构造基于混凝土靶背自由面位置相关的阻力衰减函数,修正弹丸侵彻半无限混凝土靶体的侵彻阻力,建立可以快速预测弹丸侵彻混凝土介质的侵彻深度、贯穿速度和侵彻过载等物理量的工程计算模型。模型中加入混凝土冲塞判据,修正了弹丸临界贯穿情况下的弹丸侵彻阻力,可以预测混凝土靶背发生剪切冲塞现象。用模型对低速(650 m/s)和高速(1 100 m/s)两种侵彻速度弹丸侵彻不同厚度C40混凝土靶板试验工况进行计算,计算结果显示弹丸剩余速度计算值与试验结果绝对值误差小于22.1%,弹丸过载与仿真过载峰值误差小于4.4%; 模型对不同侵彻速度下的有限厚度混凝土靶的临界贯穿厚度进行预测,与NDRC经验公式计算结果对比发现本文模型具有更好的计算精度和速度适应范围。

Engineering Penetration Model of Medium Thickness Concrete Targets Based on the Effect of Target Rear Free Surface

To evaluate the capability of projectile penetration and perforation of medium thickness concrete targets,an engineering model,which was based on the semi-infinite penetration model,was proposed in this paper. The free surface effect of the target was considered in the model. The resistance of projectile penetration semi-infinite concrete target was revised by structuring a free surface location-based attenuation function of penetration resistance. It can be adopted to obtain projectile physical parameters such as penetration depth,residual velocity,and the acceleration of projectile. A plugging model of concrete,which can predict the shear plugging of the concrete target,was added in the model to correct the penetration resistance under critical penetration. The calculation results of projectile penetrating C40 concrete targets with different thicknesses at two penetration velocities of 650 m/s and 1 100 m/s show that the residual velocity absolute value error is less than 22.1% and acceleration absolute value error is less than 4.4%. Compared with NDRC empirical formula on calculating the critical perforation thickness under different penetration velocities,the results show that the model proposed in this paper has better precision and a larger adaptation range of impact velocity.