共查询到19条相似文献,搜索用时 109 毫秒
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实现动基座上动调陀螺仪启停锁定 总被引:1,自引:0,他引:1
本文在对动基座上DTG启停运动进行分析的基础上,介绍了实现动基座锁定的思想与方法,并具体实现了由单片机完成的动基座上动调陀螺仪的启停锁定。 相似文献
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本文研究平台惯性导航系统初始自对准技术,实际上是采用任意双位置平台方位锁定。文中首先介绍自对准原理,然后进行详细的理论分析,最后以某型号平台惯性导航系统为应用,介绍数字精调平回路、平台方位锁定回路的设计及初始自对准调试情况。对应于系统随机漂移为0.05°/hr的指标,平台方位自对准精度达到17.42角分(1σ),且重复性较好,自对准调试结果得到了光学传递对准的检验。随后进行了车载导航实验,导航精度达到4.55nm/hr(1σ)。 相似文献
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本文论述了陀螺监控中的旋转锁定回路技术的必要性、旋转锁定回路的组成及分析与设计方法,并提出了一种利用多极同步器实现锁定控制的方法。工程试验表明设计的旋转锁定回路其锁定精度的重复性优于1"。 相似文献
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基于锁相循环投影的物体形貌检测 总被引:2,自引:1,他引:1
本文提出将相位锁定循环技术应用于栅线投影方法,将规则栅线投影到物体表面得到变形栅线,用相位锁定循环法解调含有物体表面高度信息的位相。用该法不需传统的相位去包裹,即可完成对二维栅线图扫描,从而确定其相位。通过对典型试件的检测,得到了比较满意的结果。 相似文献
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管材滚切机滚切力的研究 总被引:1,自引:0,他引:1
本文用剪切理论及平面应变问题的滑移线场理论,对管材在滚切中的变形进行了分析,得出了滚切力的解析式,并将理论结果与实测值进行了比较,两者基本一致 相似文献
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线圈炮电枢(圆柱壳)的屈曲分析 总被引:1,自引:0,他引:1
对线圈炮的电枢在径、轴向复合非均布电磁荷载作用下的弹性屈曲问题进行了有限元分析。采用八节点等参元,建立了圆柱坐标下的计算模型,给出了电磁力的计算,处理了剪切锁定与荷载移置等问题,编写了完善圆柱薄壳的屈曲分析程序SBT。并对某五级炮的电枢进行了计算,获得了三个典型时刻的临界荷载。 相似文献
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用多尺度方法对冰、桩土与海洋平台系统的偏微分非线性动力学模型(见第1部分)进行了摄动分析,发现此系统存在多种组合共振现象,其固有振动频率与模型平台实测结果相符。在主参数内共振条件下,文章讨论了在不同振在型(自激、锁定、强迫)下它的非线性动力学特性,计算结果说明在某冰速范围内模型平台将产生跳跃性的剧烈振动,这与现场观察到的冰激平台共振的现象一致,本文解释了冰激振动的机理,因此为海洋平台结构系统的非线 相似文献
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用模态法识别结构弹性碰撞载荷的可行性 总被引:16,自引:5,他引:16
本文在探讨杆的纵向和横向碰撞问题基础上,论证了用模态叠加法求解结构弹性撞击载荷的可行性。发展了识别撞击载荷的数值方法。用波传播理论、弹性接触理论和模态理论等有关知识对载荷历程进行了分析和解释,并验证了所给方法的精度和实用性。 相似文献
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基于独立于单元的共旋列式(EICR),将一种几何线性的无剪切锁死的Timoshenko梁单元扩展用于空间梁结构的几何非线性分析。考虑到三维分析中发生大转动时转动顺序的不可交换性,也即转动自由度不能作为向量采用加法规则更新,采用了四元变量来存储和更新转动自由度,使得共旋列式适用于位移任意大和转动任意大但应变很小的几何非线性分析。同时改进了Riks弧长法使之适用于带有大转动的三维几何非线性分析。给出了几个数值算例,结果表明本文方法具有较高的计算精度和效率。 相似文献
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两柔性梁碰撞振动类型的实验研究 总被引:10,自引:0,他引:10
基于对两弹性部件碰撞振动的理论及数值研究,设计了两柔性梁碰撞实验来研究碰撞振动类型.在实验中观察到亚谐、超谐、概周期、混沌等多种碰撞振动类型.此外,发现系统存在类似“频率锁定”性质的碰撞振动,以及同时存在性质相异的碰撞行为,如谐碰撞与混沌振动共存现象 相似文献
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《International Journal of Solids and Structures》2004,41(5-6):1491-1518
In this paper, a new composite thin wall beam element of arbitrary cross-section with open or closed contour is developed. The formulation incorporates the effect of elastic coupling, restrained warping, transverse shear deformation associated with thin walled composite structures. A first order shear deformation theory is considered with the beam deformation expressed in terms of axial, spanwise and chordwise bending, corresponding shears and twist. The formulated locking free element uses higher order interpolating polynomial obtained by solving static part of the coupled governing differential equations. The formulated element has super convergent properties as it gives the exact elemental stiffness matrix. Static and free vibration analyses are performed for various beam configuration and compared with experimental and numerical results available in current literature. Good correlation is observed in all cases with extremely small system size. The formulated element is used to study the wave propagation behavior in box beams subjected to high frequency loading such as impact. Simultaneous existence of various propagating modes are graphically captured. Here the effect of transverse shear on wave propagation characteristics in axial and transverse directions are investigated for different ply layup sequences. 相似文献
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This paper presents a novel geometric non-linear finite element formulation for the analysis of shear deformable two-layer beams with interlayer slips. We adopt the co-rotational approach where the motion of the element is decomposed into two parts: a rigid body motion which defines a local coordinate system and a small deformational motion of the element relative to this local coordinate system. The main advantage of this approach is that the transformation matrices relating local and global quantities are independent to the choice of the geometrical linear local element. The effect of transverse shear deformation of the layers is taken into account by assuming that each layer behaves as a Timoshenko beam element. The layers are assumed to be continuously connected and partial interaction is considered by considering a continuous relationship between the interface shear flow and the corresponding slip. In order to avoid curvature and shear locking phenomena, the local linear element is formulated using “exact” displacement shape functions derived from the closed-form solution of the governing equations of a two-layer beam element. Finally, three numerical applications are presented in order to assess the performance of the proposed formulation. 相似文献
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The influence of peak-locking errors on turbulence statistics computed from ensembles of PIV data is considered. PIV measurements are made in the streamwise–wall-normal plane of turbulent channel flow. The PIV images are interrogated in three distinct ways, generating ensembles of velocity fields with absolute, moderate, and minimal peak locking. Turbulence statistics computed for all three ensembles of data indicate a general sensitivity to peak locking in the single-point statistics, except for the mean velocity profile. Peak-locking errors propagate into the fluctuations of velocity, rendering single-point statistics inaccurate when severe peak locking is present. Multi-point correlations of both streamwise and wall-normal velocity are also found to be influenced by severe levels of peak locking. The displacement range of the measurement, defined by the PIV time delay, appears to affect the influence of peak-locking errors on turbulence statistics. Smaller displacement ranges, particularly those that produce displacement fluctuations that are less than one pixel in magnitude, yield inaccurate turbulence statistics in the presence of peak locking. 相似文献