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D.N. Nikolaev M.I. Kulish S.V. Dudin V.B. Mintsev I.V. Lomonosov V.E. Fortov 《等离子体物理论文集》2021,61(10):e202100113
Measurements of the brightness temperature and compressibility of a dense silicon plasma formed by powerful shock waves (SWs) passing through a single-crystal sample have been carried out. Plane SWs were created using an explosive technique: the traditional plane acceleration of a steel driver plate made it possible to obtain pressures in silicon up to 133 GPa, and the use of “Mach” cumulative generators realized the pressures up to 510 GPa. The shock Hugoniot of silicon was determined by the impedance matching with α-quartz as the reference. The intensity of emitted thermal radiation was measured in the infrared range λ ∼ 1.5 μm, where silicon is optically transparent, and in the visible range of the spectrum. A significant (up to five times) understatement of the measured values of the brightness temperature in comparison with the values calculated by the equation of state was found. Taking into account the reflective properties of the SW in silicon does not lead to an agreement with the experiment. The estimates of relaxation processes behind the shock front suggest the presence of a zone of the establishment of ionization equilibrium with a width of ∼10 μm. 相似文献
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设计了一种双锥药型罩与双向装药结构相结合的聚能射孔弹模型,通过数值模拟方法研究其射流成型机理,并计算其射流参数。结果显示:双锥药型罩的小锥角部分形成聚能射流,大锥角部分形成翻转弹丸,射流头部和弹丸的速度分别为6 250 m/s和1 620.9 m/s,弹丸长度和平均直径分别为26.1 mm和8.6 mm。结合数值模拟结果,对射流侵彻公式进行了修正,并利用修正公式预测该射孔弹侵彻钢靶的深度,计算结果为69.6 mm。最后,按照该模型进行侵彻实验,实验回收弹丸的长度和平均直径分别为28.1 mm和8.8 mm,侵彻钢靶的深度和孔径分别为70 mm和17 mm。实验表明:数值模拟与理论计算方法相结合是可行的,能够有效地计算射孔弹的射流参数并预测其侵彻深度;该射孔弹侵彻性能优越。 相似文献
15.
抛射体运动方程的非近似解的一种求法 总被引:1,自引:1,他引:0
给出一种在考虑地球自转情况下求解抛射体运动方程的非近似解的较简便方法。 相似文献
16.
Based on the equations which describe the dynamic behavior of material under high-velocity and high-pressure shock, corresponding equations at shock front whose surface is general space curve surface were established. For concrete material, a normal expansion theory was proposed by which some deceleration about time history of the projectile can be analytically given. This normal expansion theory is not only suitable for spherical and cylindrical-nose projectile, but also suitable for other general nose projectile, for example conical nose or ogive-nose. And it is not only suitable for perpendicular shock but also for oblique shock. 相似文献
17.
A STUDY ON THE COUNTER-INTUITIVE BEHAVIORS OF PIN-ENDED BEAMS UNDER PROJECTILE IMPACT 总被引:1,自引:0,他引:1
Li Haiwang Qin Dongqi 《Acta Mechanica Solida Sinica》2006,19(2):135-140
The counter-intuitive behaviors of pin-ended beams under the projectile impact are investigated with ANSYS/LS-DYNA in this paper. It studies in detail their displacement-time history curves, final deformed shapes, energy relationships and projectile impact velocity ranges related to their counter-intuitive behaviors. The influences of the impact positions on their counterintuitive behaviors are also discussed. The results show that no matter where the impact position on the beam is, the counter-intuitive behaviors of pinned beams will occur as long as the impacting velocity lies within a proper range. Corresponding to the occurring of the counter-intuitive behaviors, the rebounding number in the displacement history curves of the beams decreases from a few times to zero with an increase of the impact velocity. The final deformation modes of the beam corresponding to the counter-intuitive behaviors will appear in symmetrical and unsym-metrical forms no matter where the impact position is; the impact velocity of the first-occurring of the counter-intuitive behaviors of the beam increases slowly with the deviation of the impact position away from the mid-span. 相似文献
18.
Transient and steady state dynamic response of a class of slider-crank mechanisms is investigated. Specifically, the class
of mechanisms examined involves rigid members but compliant supporting bearings. Moreover, the mechanisms are subjected to
non-ideal forcing. Namely, both the driving and the resisting loads are expressed as a function of the angular coordinate
describing the crank rotation. First, an appropriate set of equations of motion is derived by applying Lagrange's equations.
These equations are strongly nonlinear due to the large rigid body rotation of the crank and the connecting rod, as well as
due to the nonlinearities associated with the bearing action and the form of the driving and the resisting loads. Consequently,
the dynamics of the resulting dynamical system is examined by solving the equations of motion numerically. More specifically,
transient response is captured by direct integration, while determination of complete branches of steady state response is
achieved by applying appropriate numerical methodologies. Initially, mechanisms whose crankshaft is supported by bearings
with rolling elements and linear stiffness characteristics are examined. Then, numerical results are presented for rolling
element bearings with nonlinear stiffness characteristics. Finally, the study is focused on mechanisms supported by hydrodynamic
bearings. In all cases, the attention is focused on investigating the influence of the system parameters on its dynamics.
Moreover, models with constant crank angular velocity are first analysed, since they provide valuable insight into some aspects
of the system dynamics. Eventually, the emphasis is shifted to the general case of non-ideal forcing, originating from the
dependence of the driving and the resisting moments on the crankshaft motion. 相似文献
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射弹倾斜撞击带盖板炸药引发爆轰的条件 总被引:10,自引:0,他引:10
用二级轻气炮发射圆柱形、球形钢射弹以不同的角度撞击带不同厚度钢盖板的 TNT/RDX(40/60)炸药,得到了不同条件下引发炸药爆轰的阈值射弹速度。可以用vd~ (1/2)=(1 +k)[A+Bh/(dcos)]描述临界引爆条件。对于带钢盖板的TNT/RDX(40/60)炸药,A= 3.33.B=5.34;圆柱形平头射弹撞击,k/75,球形射弹撞击,k0.5+0.2(1/cos-1)。由 此,本研究将Jacobs 引爆判据推广到了斜碰撞条件。 相似文献