共查询到19条相似文献,搜索用时 156 毫秒
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讨论超高速碰撞数值模拟方法,用ANSYS/AUTODYN程序的SPH方法对球形弹丸超高速撞击时弹丸破碎、碎片云形成过程进行数值模拟并与实验结果比较,验证计算方法及模型参数的正确性。在此基础上研究钨合金、轧制均质装甲(Rolled Homogeneous Armor,RHA)两种材料球形弹丸破碎的临界速度随比值(ts/dp,ts为靶板厚,dp为弹丸直径)的变化规律,给出两种材料超高速碰撞时应变率及平均碎片尺寸随撞击速度的变化曲线以及碎片质量分布规律。 相似文献
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Alekseevskii-Tate(A-T)模型广泛应用于长杆弹超高速冲击的终点效应分析中。A-T模型对于金属弹靶强度有明确的表达式,而对于陶瓷靶体强度尤其是弹体初始冲击速度大于1 500 m/s时还没有统一的结论。基于长杆钨弹超高速(1 500~5 000 m/s)侵彻三种陶瓷(Al N,B4C,Si C)/铝复合靶体的缩比逆弹道实验数据;基于A-T模型,给出了上述陶瓷材料在不同侵彻速度范围内的靶体强度表达式。进一步通过与47发长杆钨弹超高速(1 250~2 500 m/s)侵彻陶瓷(Al N,B4C,Si C,AD85)/RHA钢复合靶体DOP实验数据对比,验证了提出的陶瓷靶体强度表达式的适用性。 相似文献
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椭球弹丸超高速撞击防护屏碎片云数值模拟 总被引:6,自引:0,他引:6
低地球轨道的各类航天器易受到微流星体及空间碎片的超高速撞击.本文采用AUTODYN软件进行了椭球弹丸超高速正撞击及斜撞击防护屏碎片云的数值模拟.给出了三维模拟的结果.研究了在相同质量的条件下,不同长径比椭球弹丸以不同速度和入射角撞击防护屏所产生碎片云的特性,并与球形弹丸撞击所应产生的碎片云特性进行了比较.结果表明:在相同的速度下,不同长径比椭球弹丸撞击的碎片云形状、质量分布和破碎程度是不同的,随撞击入射角的增加弹丸的破碎程度增大,滑弹碎片云的数量增加;随撞击速度的增加,弹丸的破碎程度也增加. 相似文献
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动能弹侵彻多层陶瓷靶板数值模拟研究 总被引:3,自引:1,他引:2
结合试验对钨合金长杆弹垂直侵彻多层陶瓷靶板进行了三维数值模拟,得出了侵彻的物理图像及各种参量的变化规律。模拟结果中,后置钢靶剩余穿深和陶瓷破碎锥形状与试验基本一致。对于多层陶瓷靶板,每一层都会有漏斗形的破碎锥出现,且这些破碎锥的形状基本一致。随着陶瓷层数的增多,弹体的速度和动能下降速率逐渐变小。比较了相同厚度的多层和单层陶瓷靶板的抗弹性能,结果表明两者的陶瓷破坏形式不同,多层靶板的抗弹性能要优于相同厚度的单层陶瓷靶板,且仅在一定厚度范围内这种优势才较为明显。 相似文献
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本文提出了一种新型电磁发射拦截弹,以拦截弹与钨合金长杆弹碰撞过程为例,使用LS-DYNA程序建立了拦截弹和钨合金长杆弹的三维有限元模型。在拦截弹对钨合金长杆弹的拦截效果问题上进行了数值模拟分析,并得出了不同着角和钨合金长杆弹运动速度对拦截效果影响的关系曲线,给出了拦截弹与钨合金长杆弹碰撞后的速度变化及状态改变情况,结果表明,拦截弹对钨合金长杆弹起到了较好的拦截作用,两者碰撞后,钨合金长杆弹对装甲车辆的穿甲效果明显降低。 相似文献
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使用某小口径弹道炮,发射次口径脱壳尾翼稳定钨合金穿甲弹,分别侵彻45钢及30CrMnMo钢靶板,发现残余弹体微观结构有明显不同.说明钨合金残余弹体的破坏特征与靶板性能有关.运用固体与分子经验电子理论(EET)对两种靶板的价电子结构进行了分析.发现对于45钢靶板,由于C-Fe原子结合较弱,受冲击后对弹体产生的反作用力小,使残余弹体不产生剪切变形,头部的破坏特征为晶粒破碎及沿垂直侵彻方向的变形,宏观上表现为典型的"蘑菇头"状;对于30CrMnMo钢靶板,由于C-Mo原子间的强烈结合,受冲击后对残余弹体产生很强的反作用力,使钨合金残余弹体头部产生剪切破坏,具有一定程度的"自锐化效应". 相似文献
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Debris clouds generated by hypervelocity impact of cylindrical projectiles with thin aluminum plates 总被引:2,自引:0,他引:2
Andrew J. Piekutowski 《International Journal of Impact Engineering》1987,5(1-4):509-518
Orthogonal, flash x rays were used to observe the debris clouds produced by the hypervelocity impact of cylindrical aluminum projectiles with thin aluminum sheets or bumpers. Three major structural features were observed in the debris clouds--a front cone, a bulbous main debris cloud, and an inner cone. Inclination of the projectile at impact changed the orientation of these features and the severity of damage to the rear wall of a double-sheet structure; projectiles with the greatest inclination produced the most damage. Two experiments, using aluminum and copper as projectile and target or target and projectile, respectively, were performed to determine the source of material in each of the three structural features of the debris clouds. The front cone and main cloud were shown to consist of bumper debris while the inner cone was composed of projectile fragments. 相似文献
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Chantal G. Lamontagne Gerald N. Manuelpillai Justin H. Kerr Emma A. Taylor Roderick C. Tennyson Mark J. Burchell 《International Journal of Impact Engineering》2001,26(1-10):381-398
This paper explores the effects of projectile density, impact angle and energy on the damage produced by hypervelocity impacts on carbon fibre/PEEK composites. Tests were performed using the light gas gun facilities at the University of Kent at Canterbury, UK, and the NASA Johnson Space Center two-stage light gas gun facilities at Rice University in Houston, Texas. Various density spherical projectiles impacted AS4/PEEK composite laminates at velocities ranging from 2.71 to 7.14 km/s. In addition, a series of tests with constant size aluminum projectiles (1.5 mm in diameter) impacting composite targets at velocities of 3, 4, 5 and 6 km/s was undertaken at incident angles of 0, 30 and 45 degrees. Similar tests were also performed with 2 mm aluminum projectiles impacting at a velocity of approximately 6 km/s. The damage to the composite was shown to be independent of projectile density; however, debris cloud damage patterns varied with particle density. It was also found that the entry crater diameters were more dependent upon the impact velocity and the projectile diameter than the impact angle. The extent of the primary damage on the witness plates for the normal incidence impacts was shown to increase with impact velocity, hence energy. A series of tests exploring the shielding effect on the witness plate showed that a stand-off layer of Nextel fabric was very effective at breaking up the impacting debris cloud, with the level of protection increasing with a non-zero stand-off distance. 相似文献
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Hypervelocity impacts on thin brittle targets: Experimental data and SPH simulations 总被引:4,自引:0,他引:4
Y. Michel J.-M. Chevalier C. Durin C. Espinosa F. Malaise J.-J. Barrau 《International Journal of Impact Engineering》2006,33(1-12):441-451
The meteoroids and debris environment play an important role in the reduction of spacecraft lifetime. Ejecta or secondary debris, are produced when a debris or a meteoroid impact a spacecraft surface. Brittle materials are particularly sensitive to HVI in term of damages and amount of ejected matter: the ejected fragments total mass is in the order of 100 times bigger than the impacting mass. The French atomic energy commission (CEA) faces the same problem in the Laser MégaJoule project. The lasers optics will be bombarded by hypervelocity debris and shrapnel resulting from target disassembly. Two millimeter thick fused silica disposable debris shields (DDS) located in front of the main debris shields might be used to reduce very small shrapnel cratering on the main debris shields. The aim of this paper is to study the damaging and ejection processes that occur during HVI on thin brittle targets. A two-stage light-gas gun has been used to impact 2 mm DDS with 500 μm steel projectiles. Experimental characterization of ejected matter has also been performed: lightweight paperboards coated with adhesive have been used to collect ejected fragments including spalls. Numerical simulation using the smooth particle hydrodynamics (SPH) method of LS-DYNA and the Johnson Holmquist material model were performed. The results of these calculations are compared to experimental data which include the damage features in the targets (spalled zones and perforation hole) and the ejection clouds. Satisfying agreement between numerical and experimental simulations was obtained for damage characteristics and ejection phenomena. 相似文献
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利用小波包分析技术对碎片云撞击载荷作用下铝合金板声发射信号的能量分布特征进行了研究。首先,介绍了碎片云撞击信号的获取方案及撞击引起的损伤情况;其次,对获取的声发射信号进行小波包分析,得到了信号在频率带上能量分布特征图。最后,讨论了碎片云撞击损伤特征与声发射信号能量分布的关系。分析结果发现,对于相同质量的弹丸,随着其破碎程度的提高,形成的碎片云对后板的损伤程度减少;弹丸具有的初始速度越大,弹丸破碎越完全,碎片云撞击声发射信号中的能量越小;当弹丸破碎程度低时,碎片云撞击引起的声发射信号能量集中在约488kHz以下;弹丸破碎程度越高,信号中488kHz以上的能量所占总能量的比例越大。 相似文献
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U. Weishaupt 《International Journal of Impact Engineering》1987,5(1-4):663-670
The hypervelocity impact of small masses on large surface piezoceramics was investigated to study the impact behavior of hypervelocity projectiles. From a linear elastic model obtained at lower velocities, solutions were found for the hypervelocity case which determine both the size and the momentum of impacting projectiles from the rising slope of the charge signal generated by the impact. The results lead to the development of a new generation of impact detectors for small masses at hypervelocities which consists only of a plate of piezoceramic material. 相似文献
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Kathleen S. Holian 《International Journal of Impact Engineering》1990,10(1-4):231-239
When a metal projectile hits a thin metal plate at a high enough velocity to penetrate it, a cloud of debris is produced, whose structure for normal impacts provides a unique test for hydrodynamic computer simulation. Since the equations of state (EOS) of the materials involved are a vital ingredient for hydrocode calculations, we would like to determine how important it is to use an accurate EOS. This paper reports results of benchmark calculations of hypervelocity impacts of a lead sphere on a lead plate where significant vaporization occurs. The results are somewhat sensitive to the EOS used, particularly in the regime where the material is expanded. The results are greatly affected when an attempt is made to include nonequilibrium effects by allowing negative pressures in the EOS. 相似文献
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A case history in debris characterization is presented for oblique impacts of chunky tungsten projectiles against thin plates. The integrated approach of scaled experiments and hydrocode simulations led to a semi-analytic model of behind the plate debris fragment distributions. This debris distribution model agreed quite well with the experimental fragment distributions derived from witness plate measurements. The 1/4 scale test program included three projectile masses, two target geometries (single and dual plates), a velocity range of 4–7 km/s and a strike angle range of 15–55 degrees. Close correlation of measured and predicted fragment distributions encouraged the extension of the model to higher velocities not currently obtainable in the laboratory.
The paper also includes discussions of critical features of debris in oblique hypervelocity impact, the scalability of fragment data, and the utilization of the derived fragment models in semi-analytic damage assessment codes. 相似文献