【作者】 何雨；

【导师】 文鹤鸣；

【作者基本信息】 中国科学技术大学 ， 工程力学， 2013， 博士

【摘要】 本文对长杆弹撞击下金属靶板侵彻与穿透的问题作了进一步研究。对长杆弹高速侵彻下半无限金属靶中开坑问题进行了分析,结合理论分析和实验数据研究了侵彻过程中弹体头部的形状变化；建立了靶体中的开坑模型,很好地预测了开坑半径；研究了有限靶板在长杆弹高速撞击下的穿透问题；探讨了长杆弹高速侵彻第三阶段的侵彻机理,并在新的一维长杆弹侵彻模型基础上,推导了弹体消蚀碎片形成二次侵彻的临界条件,建立了二次侵彻的理论分析模型；在A-T模型的基础上,分析了材料可压缩性对长杆弹高速侵彻的影响；建立了平头弹撞击贯穿中厚靶的塑性波理论模型,着重分析了弹体变形对弹道极限、残余速度的影响。本文主要研究内容和结果如下：1.半无限金属靶在长杆弹高速侵彻下的开坑理论模型通过两种不同方法分析了半无限金属靶在长杆弹高速侵彻下的开坑过程及最终开坑半径。方法1运用弹体头部控制域内弹体材料质量、动量和能量守恒定律,考虑弹体材料因进入控制域后由刚体状态转化为近似流体状态而耗散的能量,建立了相应的理论分析模型；方法2利用流线反转模型和力平衡方法分析了弹体头部消蚀材料的运动轨迹,同时结合数值模拟和实验X光照片,得出了弹体头部的几何形状,并通过能量守恒定律给出了靶体中最终的开坑半径。模型预测与实验结果吻合得较好。2.长杆弹高速侵彻半无限金属靶第三阶段的侵彻机理分析探讨了长杆弹高速侵彻第三阶段的侵彻机理,认为弹体碎片形成的薄壁管是造成二次侵彻的主要原因,并给出了碎片二次侵彻的临界条件；在等效密度模型的基础上,建立了二次侵彻的理论模型。3.半无限金属靶在夹心弹高速侵彻下的理论模型分析了在夹心弹高速侵彻半无限金属靶过程中,弹体保持co-erosion状态的临界条件,并将均值长杆弹在靶体中的开坑模型推广至夹心弹,给出了夹心弹侵彻半无限靶的开坑半径和侵彻深度,理论预测与实验结果吻合较好。4.长杆弹高速侵彻半无限金属靶的工程模型长杆弹初始动能的耗散主要分为三部分：一部分被靶体塑性变形耗散,形成靶体开坑；一部分被弹体自身消蚀耗散；还有一部分动能残留在弹体碎片中。基于能量守恒定律,建立了长杆弹对半无限金属靶侵彻深度的工程模型,模型预测与实验结果吻合得很好。5.有限厚金属靶板在长杆弹高速撞击下的穿透模型把弹体穿透有限靶板的过程分为侵彻、塞块形成和塞块滑出及分离三个阶段,结合新的一维长杆弹侵彻理论和绝热剪切冲塞模型建立了长杆弹高速垂直侵彻穿透有限金属靶板的分析模型。与实验结果对比表明,模型能较好地预测靶体弹道极限速度、弹体残余速度和弹体残余长度。6.可压缩性对长杆弹高速侵彻的影响在A-T模型基础上采用了Murnaghan状态方程来描述材料密度与压力的关系；建立了考虑材料可压缩性的一维侵彻模型。与经典的A-T模型进行了比较,由于材料的可压缩性影响,弹靶界面处的压力、弹靶密度随着撞击速度的增加将显著地提高。7.中厚金属靶在平头弹丸撞击下穿透的塑性波理论模型采用塑性波理论分析了平头弹撞击穿透中厚金属靶板过程中的三种响应模式,即刚体弹、变形弹、消蚀弹；引入唯象热粘塑性本构模型,并结合剪切带宽度两阶段模型建立了平头弹丸撞击穿透中厚靶的理论模型。与实验结果比较表明,模型能很好地预测弹道极限速度和残余速度。更多还原

【Abstract】 Further study is conducted in this thesis on the penetration and perforation of metallic targets struck by long rod penetrators at high speeds. The crater formed in semi-infinite metallic targets is analyzed and the geometry of the rod head during the penetration process examined by combined experimental and theoretical methods. A theoretical model for the perforation of finite metallic targets by long rods is proposed; Based on the recently suggested ID theory of long rod penetration, Phase three penetration mechanism is investigated and an equivalent density model is suggested to predict the depth of secondary penetration; The effect of material compressibility on the penetration of long rods into semi-infinite targets at high velocities is considered; Plastic wave models are proposed for the plugging failure of intermediate and thick metallic plates struck by flat-ended cylindrical projectiles. The main contents and results of the thesis are as follows:Two analytical models are presented to predict the diameter of crater in semi-infinite metallic targets struck by long rod penetrators. One of models is constructed by using the laws of conservation of mass, momentum, energy, together with the u-v relationship of the newly suggested ID theory of long rod penetration; and another by using the balance of forces exerted on the eroded rod debris which flows around the mushroom head. The shape and diameter of the mushroom head in the second model was suggested based on numerical analysis and experimental investigations. It is demonstrated that the model predictions are in good agreement with available experimental data.Secondary penetration is examined in the present thesis due to the fact that the eroded rod debris forms a tube which can penetrate the target further if the density of rod is greater than that of target and the impact velocity is high enough. A critical condition for secondary penetration is obtained and an equivalent density model proposed to study the depth of secondary penetration. Models for predicting the penetration depth and crater diameter in semi-infinite metallic targets by long rods are extended to jacketed rods in co-erosion mode. It transpires that the present model predictions are in good agreement with the experimental observations for EN24steel jacketed tungsten alloy long rods penetrating semi-infinite armor steel targets in terms of crater diameter and penetration depth.An analytical equation is presented to predict the penetration depth of semi-infinite metallic targets struck normally by long rods at high velocities based on energy balance method. It is assumed that the kinetic energy loss of a long rod is related to the energy dissipated by the plastic deformations in the target, the energy consumed by the long-rod penetrator itself and the energy carried by the eroded rod debris. The present analytical equation is found to be in good agreement with the experimental data for a wide range of impact velocities.The perforation of a finite metallic target struck by a long rod at high speeds is examined based on the newly suggested1D theory of long rod penetration,the adiabatic shear plugging model and the assumption that the perforation processcan be divided into three stages:(1) initial penetration into the plate;(2) plug formation;(3) plug sliding and separation. A theoretical model is proposed to predict the ballistic limit, residual velocity and residual length of the rod. It is found that the model predictions are in good agreement with experimental observations in terms of ballistic limit, residual velocity and residual length of the rod.The effect of material compressibility on long rod penetration is investigated based on the A-T model. The Murnagham equation of state is employed in the present model, where the effect of ordinary p-v work and shock waves are considered. It transpires that the density and pressure near the interface between target and rod increases with increasing impact velocity.Plastic wave models are suggested for the plugging failure of intermediate and thick metallic plates struck by flat-ended cylindrical projectiles. Three cases are examined i.e. rigid projectiles, deformable projectiles and erosive projectiles. A two-stage model is employed to describe the width of the shear band, where the simple shear band will be transformed into adiabatic shear band. The widths of simple shear and adiabatic shear band were theoretically derived by Bai et al. The rod plastic deformation, residual velocity and residual length of the rod, the diameter and length of the plug were investigated. It transpires that the present model predictions are in good agreement with the experimental data for metallic plates struck normally by flat-ended cylindrical projectiles.更多还原