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基于ANSY/SLS-DYNA头部形状对钻地斜侵彻土壤影响的数值分析 总被引:1,自引:0,他引:1
运用ANSYS/LS-DYNA软件,分别对头部形状为30°锥角,60°锥角和抛物线形的钻地弹斜侵彻土壤的过程进行数值模拟,得到了运动轨迹图,弹丸侵彻加速度过载曲线,以及弹丸侵彻深度曲线;分析了过载曲线的特征,通过比较,总结出了钻地弹的头部形状对其斜侵彻土壤时运动规律和运动特性的影响,为钻地弹设计提供了参考依据。 相似文献
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《机械制造与自动化》2015,(6)
弹丸在水中高速运动时涉及到复杂的流固耦合及多相流流体动力学问题,对于弹丸高速侵彻水介质的研究一直以来没有获得较大的突破。通过理论分析,给出了弹丸高速侵彻水介质的理论分析模型。并应用ANSYS/LS-DYNA软件,采用ALE算法对高速弹丸侵彻水介质过程进行了流固耦合的数值仿真计算。结果表明:该仿真模型有效解决了弹丸高速侵彻水介质时,由于流固耦合计算中流体形变引起的数值计算困难;弹丸初速越高,速度衰减越快,且变形越严重;衰减系数和阻力系数都随着弹丸初速的增大而增大。为弹丸高速侵彻水介质的理论分析和数值仿真研究提供有价值的参考。 相似文献
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为了研究头部形状对穿甲弹侵彻性能的影响,首先建立了4种头部形状穿甲弹的有限元模型,然后应用LS-DYNA软件对模型进行了数值仿真和分析,获得了它们的速度衰减曲线及其变化规律。结果表明,4种头部形状的弹芯在斜侵彻时的侵彻性能差异明显,结构方案一的弹芯在斜侵彻时的极限速度最小,其最大速度方向改变角也最小,综合侵彻性能最好。 相似文献
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《机械制造与自动化》2015,(5)
为给枪榴弹机械触发引信性能优化设计提供参考,利用LS-DYNA软件仿真截锥形弹头不同端面直径的枪榴弹以不同着角侵彻不同厚度木质薄靶板过程,得到了弹丸头部在贯穿靶板过程中弹丸前冲过载系数和弹丸速度。结果表明:着角、弹头端面直径、靶板厚度不同时,弹丸侵彻过程中前冲过载系数变化和速度变化不同;弹丸最大前冲过载系数出现在弹丸垂直碰击靶板的初始时刻;弹丸速度在侵彻初始阶段衰减最快。在靶场射击试验考核引信触发作用灵敏度和钝感度时,应考虑弹丸着角、立靶姿态、靶板厚度和弹头端面直径等因素的影响。 相似文献
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试验验证超高速弹丸连续侵彻靶板时的侵彻效果代价过大,数值模拟预测提供了新的解决途径.建立了超高速弹丸与连续靶板模型,利用ABAQUS软件,结合Mie-Grüneisen状态方程、Johnson-Cook本构方程和Johnson-Cook断裂准则,对钨合金弹丸2km/s初速下连续侵彻钢质靶板进行仿真研究.超高速弹丸可连续侵彻6层厚度为30mm的靶板,相邻靶板受到了弹丸与飞溅单元的共同冲击,最后2块靶板主要受到飞溅单元的冲击.超高速弹丸每穿透一层靶板,头部及弹体表层发生着侵蚀变化、能量损失与速度变化.充塞穿甲是超高速动能弹的典型穿甲形式,穿甲威力大.数值模拟有助于认识超高速弹丸连续侵彻靶板的过程. 相似文献
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采用计算流体力学方法结合动网格技术建立了双管火炮异步发射时膛口流场的二维数值模拟模型,正确描述了双管不同步发射时炮口流场的激波系结构的形成﹑发展与相互干扰的过程。模拟结果得出双管不同步发射时对弹丸飞出膛口后的飞行姿态影响较大,从而弹丸偏移速度会影响双管火炮的射击精度。 相似文献
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聚合物齿轮质轻而耐腐蚀,可降低噪声,提高经济效益.相对地,聚合物轮齿强度低于金属轮齿,故采用非对称设计提高聚合物齿轮的强度.为探究非对称聚合物齿轮的弹流润滑特性,在水润滑条件下,采用多重网格法对非对称聚合物齿轮进行了瞬态弹流润滑分析:对比非对称齿轮与传统对称齿轮的水膜压力与厚度;改变齿轮运行工况及考虑轮齿的表面粗糙度,研究其对齿轮弹流润滑分析的影响.结果表明,非对称齿轮可有效改善弹流润滑,润滑膜的压力和膜厚受齿轮转速和载荷影响较大,表面粗糙度对于非对称聚合物齿轮的弹流润滑有着不利影响,在应用中应保证齿面加工质量. 相似文献
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G. Rajesh J. M. Lee S. C. Back Heuy Dong Kim 《Journal of Mechanical Science and Technology》2006,20(7):1019-1029
The ballistic range has long been employed in a variety of engineering fields such as high-velocity impact engineering, projectile
aerodynamics, creation of new materials, etc, since it can create an extremely high-pressure state in very short time. Of
many different types of ballistic ranges developed to date, two-stage light gas gun is being employed most extensively. In
the present study, a theoretical work has been made to develop a new type of ballistic range which can easily simulate a flying
projectile. The present ballistic range consists of high-pressure tube, piston, pump tube, shock tube and launch tube. The
effect of adding a shock tube in between the pump tube and launch tube is investigated. This improvement is identified as
the reduction in pressures in the high pressure tube and pump tube while maintaining the projectile velocity. Equations of
motions of piston and projectile are solved using Runge-Kutta methods. Dependence of projectile velocity on various design
factors such as high pressure tube pressure, piston mass, projectile mass, area ratio of pump tube to launch tube and type
of driver gas in the pump tube are also analyzed. Effect of various gas combinations is also investigated. Calculations show
that projectile velocities of the order 8 km/sec could be achieved with the present ballistic range. 相似文献
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Rajesh Gopalapillai Heuy-Dong Kim Toshiaki Setoguchi Shigeru Matsuo 《Journal of Mechanical Science and Technology》2007,21(7):1129-1138
A computational fluid dynamics method has been applied to simulate the unsteady aerodynamics of the projectile launched from
a ballistic range. A moving coordinate scheme for a multi-domain technique was employed to investigate the unsteady flow with
moving boundary. The coordinate system fixed to each moving domain was applied to the multi-domains, and the effect of virtual
mass was added in the governing equations for each domain. The unsteady, axisymmetric Euler equation systems were numerically
solved using the third order Chakravarthy-Osher total variation diminishing scheme, with MUSCL approach. The projectile mass
and configuration effects on the unsteady aerodynamics were investigated based on the computational results. The present computations
were validated with results of some other CFD works available. The computed results reasonably capture the major flow features,
such as shock waves, blast waves, shear layers, vertical flows, etc. which are generated in launching a projectile up to a
supersonic speed. The present computational method properly predicts the velocity, acceleration and drag histories of the
projectile. 相似文献
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为了探讨超高压水射流破碎轮胎过程中,冲击波和微射流的作用机理,基于FLUENT软件环境,采用VOF模型求解Navier-Stokes方程,数值模拟了近壁面的空泡溃灭过程,结果表明,射流冲击物面时,空泡溃灭产生的压力脉冲远大于微射流产生的冲击压力。结合超高压水射流破碎轮胎试验,通过对胎面胶的切槽断面形貌进行观察,研究了微射流和冲击波对橡胶材料的破坏作用,认为橡胶材料在受到空化作用破坏时,表现出明显的冲击脆化现象,微射流在材料壁面冲击出边缘齐整的针孔状形貌,冲击波引发材料产生拉伸破坏。 相似文献
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Ammar Melaibari Pal Molian Pranav Shrotriya 《The International Journal of Advanced Manufacturing Technology》2012,63(5-8):641-649
In the laser/water jet hybrid machining (LWJ), a novel process applicable to brittle materials, the laser beam creates a groove through evaporation and causes solid-state phase transition through heating and shock waves while the water jet performs quenching. Both laser and water jet induce stresses and phase changes that lead to cutting via crack formation and controlled fracture mechanism through the rest of the thickness. While LWJ is very well documented by our group for one-dimensional cutting, it remains as a challenge for two-dimensional cutting because of the changing direction of the crack in relation to the laser beam path. In this paper, a focused continuous wave CO2 laser (400?W) was combined with abrasive-free water jet at 0.4–1.4?MPa (60–200?psi) to generate and steer the controlled crack in two directions in polycrystalline cubic boron nitride tool blanks. A 42.33-mm/s (100?in./min) cutting speed was used in all the tests. The direction of the cracks generated by LWJ was changed to 60°, 108°, 120°, 135° and made to follow a curve with 1?mm radius in accordance with the standard tool shapes. The cut quality was investigated at the point of change in the crack direction using optical profilometer, Raman spectroscopy, and scanning electron microscopy. Results indicated that successful cuts were made with obtuse angles (120° and 135°) in contrast to acute angles (60°). The crack propagation in the heat affected zone, where the phase transition from c-BN to a new phase has occurred, is responsible for the inability to obtain good quality cuts in the acute angle cases. A preliminary graphical representation that explains the observed experimental results is formulated. 相似文献
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Sungcho Kim Jeong Soo Kim Jongwook Choi Jeong Park Soon Duk Kwon 《Journal of Mechanical Science and Technology》2008,22(6):1174-1180
The compressible flow field is numerically analyzed in a two-dimensional converging-diverging nozzle of which the area ratio,
exit to throat, is 1.8. The solver is FLUENT and the embedded RNG k − ε model is adopted to simulate turbulent flow. The plume characteristics such as shock-cell structure are discussed when nozzle
pressure ratio and stagnation temperature at the nozzle entrance are varied. The downstream flow field can be classified into
two types based on the shock shapes generated near the nozzle exit. First, a reiterative pattern in the plume is not formed
between the slip streams in case that a strong lambda-type shock wave exists. Second, when oblique shock waves are crossing
each other on the nozzle centerline, a shock cell structure appears in the plume field. Even when the flow field is changed
due to stagnation temperature, the upstream of the shock wave is little affected. Especially, the pressure distributions on
the nozzle centerline behind the shock wave are rarely influenced by the stagnation temperature, that is, the product of density
and temperature is nearly constant provided that the working fluid is a perfect gas. Therefore, the pressure field shows quasi-isobaric
behavior far downstream. 相似文献
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低温氮气射流对钛合金高速铣削加工性能的影响 总被引:7,自引:0,他引:7
在钛合金的高速切削过程中,切削区温度很高,加速了刀具的磨损,限制了切削速度的进一步提高。为降低切削区温度、防止刀具的氧化磨损,提出在低温氮气射流条件下进行钛合金的高速铣削加工。在干铣削、浇注切削液、常温氮气油雾、低温氮气射流和低温氮气射流结合微量润滑等冷却润滑条件下进行了钛合金的高速铣削对比试验。试验结果表明,低温氮气射流结合微量润滑能够最有效地降低铣削力,抑制刀具磨损。借助扫描电镜的检测手段,研究了不同冷却润滑条件下刀具的失效形式。指出在低温氮气射流条件下高速铣削钛合金时,只要热裂纹的形成与扩展未引起刀具的崩刃及刀面的剥落,进一步降低低温氮气的温度将提高刀具的使用寿命。 相似文献
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针对微孔抛光的问题,提出了一种新的抛光方法,该方法利用激光聚焦水中产生空泡,并利用激光等离子体冲击波、空泡溃灭冲击波和射流推送磨粒进行微孔抛光。通过高速摄影仪和高频动态压力传感器对激光诱导空泡机理进行了研究。利用不同激光脉冲能量、脉冲次数和脉冲频率对304不锈钢管进行抛光实验,发现随着激光脉冲能量(7~21.6mJ)和脉冲次数(0~7000)的增加,微孔表面粗糙度也随之改善;同时激光在低脉冲频率(1~10Hz)情况下,改变脉冲频率的大小对微孔的抛光效果影响不大。对微孔在不同位置的抛光效果进行了对比分析,发现孔入口1~1.5mm处的抛光效果较好,孔中和孔尾的抛光效果不佳。通过激光诱导空泡微孔抛光机理和实验研究,表明微孔抛光过程是激光等离子体冲击波、空泡溃灭冲击波和射流共同作用的过程,并得到了激光微孔抛光的一般规律。 相似文献
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Based on an underwater gun firing project, a mock bullet with several holes on the head was designed and experimented to observe the combustion gas injected into a cylindrical water chamber through this mock bullet. The combustion gas jets contain one vertical central jet and 4 to 8 slant lateral jets. A high speed camera system was used to record the expansion of gas jets in the experimental study. In numerical simulations, the Euler two-fluid model and volume of fluid method were adopted to describe the gas-liquid flow. The results show the backflow zone in lateral jet is the main factor influencing the gas-liquid turbulent mixing in downstream. On cross sections, the gas volume fraction increased with time but the growth rate decreased. With a change of nozzle structure, the gas fraction was more affected than the shock structure. 相似文献