【作者】 张爽；

【导师】 武海军；

【作者基本信息】 北京理工大学 ， 兵器科学与技术， 2018， 博士

【摘要】 钢筋混凝土靶的侵彻/贯穿研究可为钻地武器有效发挥毁伤作用以及钢筋混凝土结构有效承担防护功能提供必要的理论支撑。本文以素混凝土靶侵彻/贯穿的相关研究为基础,利用实验对比、理论建模、计算分析等方法,围绕弹体侵彻/贯穿钢筋混凝土靶机理与弹道轨迹开展研究。(1)开展计及钢筋效应的对比侵彻实验研究;钢筋因粘结作用实现对混凝土整体约束并带来间接侵彻阻力,钢筋因与弹体碰撞带来直接侵彻阻力,埋深较浅的首层钢筋网可减小弹体开坑深度,着靶位置和配筋方式将影响弹体侵彻受力;总结钢筋的影响,完成弹体侵彻/贯穿钢筋混凝土靶机理分析。(2)将钢筋混凝土当作复合式均匀材料,以韧度为桥梁将配筋率引入本构方程,推导修正钢筋混凝土空腔膨胀理论,反映配筋率变化对钢筋间接阻力的影响;基于实验数据回归分析,建立考虑弹体质量、初速度、首层钢筋网埋深影响的开坑深度模型;结合理论与模型共同提升钢筋混凝土靶侵彻深度与弹体过载的计算精度。(3)将钢筋混凝土当作组合式结构材料,结合钢筋动态响应、弹体着靶位置、同时与两层钢筋作用分析,建立较为完备的、可反映着靶相对位置及钢筋配置细节对侵彻深度和弹体过载(脉冲式峰值凸出)影响的刚性弹体正侵彻钢筋混凝土靶阻力模型。钢筋间接和直接侵彻阻力的比重随具体弹靶初始条件而不同,配筋率提高将降低侵彻深度,相同配筋率细直径配筋方式往往更有利于靶板防护,当弹体直径/网眼尺寸>2时,因弹体着靶位置不同造成的侵彻深度差异可忽略。(4)整理并对比分析现有经验公式,建立修正的Forrestal半经验侵彻计算公式以及修正的Chen靶板正贯穿计算公式,综合考虑钢筋对开坑深度、贯穿塞块、间接阻力、直接阻力的影响,无需迭代运算便可快速给出因着靶相对位置不同造成的弹体侵彻深度/贯穿余速上下限。相同配筋率细直径小网眼配筋时的平均侵彻深度/贯穿余速相对较低,随着弹体直径/网眼尺寸比值增大,因着靶位置不同而造成的侵彻深度/贯穿余速差异明显减小。(5)通过引入首/末层钢筋网埋深建立钢筋混凝土靶正/背表面自由面效应模型,通过钢筋离散、坐标转换以及钢筋动态响应分析建立钢筋对弹体的碰撞作用分析模型,进而结合微分面力法与钢筋混凝土空腔膨胀理论,编制刚性弹体侵彻/贯穿有限厚钢筋混凝土靶的弹道预测程序。首层钢筋网埋深越浅对自由面效应的削弱作用越明显,钢筋对弹体的直接碰撞可加剧或抑制弹体偏转,钢筋的加入使弹道轨迹和各运动参量的变化趋于复杂化。完成初速度、质心位置、倾角/攻角、着靶位置、弹体尺寸、配筋方式等主要弹道影响因素的讨论与分析,尤其是对于弹体质量和转动惯量较小且靶板配筋率较高、钢筋直径较粗、强度较大、分布较密的情况,钢筋将通过直接碰撞给弹体侵彻/贯穿弹道规律带来随机性。更多还原

【Abstract】 The research on penetration / perforation of reinforced concrete targets can provide the necessary theoretical support for effective damage effect of earth penetrating weapons and effective protection capability of reinforced concrete structures.In this paper,based on the relevant research achievements of plain concrete targets,the mechanism and trajectory of projectile penetrating / perforating reinforced concrete target were researched using the methods of experimental comparison,theoretical modeling and computational analysis.(1)The meticulous contrast experiments considering the reinforcement effects were conducted and comparatively analyzed.The reinforcements provide indirect penetration resistance by restricting the whole concrete with bonding effect,and also provide direct penetration resistance by the collision with projectile.The shallow layer of reinforcements can reduce the depth of crater,and the impact position and reinforcing method also affect the penetration resistance of projectile.The mechanism of projectile penetrating / perforating reinforced concrete target was given through summarizing the influences of reinforcements.(2)By treating reinforced concrete as a composite uniform material,the reinforcement ratio was introduced into the constitutive equation through toughness,and the cavity expansion theory of reinforced concrete was modified and deduced to reflect the influence of reinforcement ratio on indirect resistance.The crater depth model considering the mass of projectile,the initial velocity and the embedment depth of first reinforcement layer was established based on the regression analysis of experimental data.Combined the theory and model together,the calculation accuracy of penetration depth and overload were improved.(3)By treating reinforced concrete as a combined structural material,combined with the analysis of reinforcement dynamic response,projectile impact position and interaction with two reinforcement layers,the relatively complete penetration resistance model of rigid projectile penetrating reinforced concrete target was established,which can reflect the influences of relative impact position and reinforcement configuration details on penetration depth and overload(pulse-like peak raising).The proportion of indirect and direct penetration resistance is depending on the initial conditions,and the penetration depth decreases with the increasement of reinforcement ratio.The small diameter reinforcing target with the same reinforcement ratio is usually more effective in protection,and when the projectile diameter / mesh size >2,the differences of penetration depth caused by different impact positions can be ignored.(4)The existing empirical formulas were collected and comparatively analyzed.The modified Forrestal semi-empirical penetration calculation formula and the modified Chen perforation calculation formula were established,which considered the influences of reinforcements on crater depth,cone-shaped plug,indirect and direct resistance.The upper and lower limit of penetration depth / residual velocity caused by different impact positions can be quickly obtained without iteration calculation.The average penetration depth / residual velocity of the small diameter reinforcing target with the same reinforcement ratio is relatively low.As the ratio of projectile diameter to reinforcement mesh size increasing,the differences between the upper and lower limit of penetration depth / residual velocity are significantly reduced.(5)The free surface effect model of reinforced concrete targets was established by introducing the embedment depth of first / last reinforcement layer.The collision analysis model was established through the dispersion,coordinate transformation and dynamic response analysis of reinforcements.Based on the differential area force law and reinforced concrete cavity expansion theory,the trajectory prediction program of rigid projectile penetrating / perforating finite thickness reinforced concrete target was compiled.The first reinforcement layer can weaken the free surface effect,and the direct collision of reinforcements on projectile can aggravate or suppress the trajectory deflection.The trajectory and motion parameters tend to be complicated when adding reinforcements in target.The main factors affecting trajectory,such as initial velocity, position of mass center,inclination / attack angle,impact position,projectile size and reinforcing mode,were discussed and analyzed.Especially for the condition that the mass and moment of inertia are small,the reinforcement ratio is high,the reinforcement diameter and strength are big and the density of reinforcement configuration is large,the reinforcements can introduce randomness into the regularity of penetration / perforation trajectory due to the direct collision.更多还原