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991.
面向载体自转的无陀螺捷联惯导系统 总被引:1,自引:1,他引:1
鉴于大多数无陀螺捷联惯导系统忽略载体质心位置和加速度计组件中心位置之间的距离,从理论上推导出了面向载体自转的无陀螺捷联惯导系统的基本方程,分析了载体自转对无陀螺捷联惯导系统性能的影响,为无陀螺捷联惯导系统进一步提高导航精度奠定基础。 相似文献
992.
参数激励的刚体混沌运动 总被引:7,自引:0,他引:7
讨论定点运动或圆轨道上运动的自由刚体,由于其内部或外部附件转动或振动引起转动惯量的周期变化,使系统受到周期的激励,而成为一受周期扰动的近Euler情形的运动刚体。通过计算动力学方程宿轨道的Melnikov函数,以及Poincare截面的数值计算,证明系统具有Smale马蹄意义下的混沌。 相似文献
993.
Electro-hydrodynamic (EHD) flows are investigated theoretically and numerically in this paper and results are presented for
the flow field in model electrostatic precipitators (EPs). The resulting flow fields are shown in various representations
and explained qualitatively. Numerical calculations with different flow models (non-turbulent and RANS) were conducted to
investigate the influence of the flow model on the resulting secondary flows. Furthermore, a perturbation analysis is presented,
leading to a simple differential equation of the Helmholtz type. This allows a more detailed view of the important mechanisms
forming the secondary flows as well as being able to obtain a very fast estimation of the resulting flow field. The calculations
reveal a strong influence of a vortex formation at the beginning of the precipitation zone on the whole flow field. Furthermore,
a strong effect of the boundary conditions of the electric field and the operating parameters is shown.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
994.
软岩流变过程与强度研究 总被引:2,自引:0,他引:2
文中通过分析软岩流变特征找出流变速度与作用载荷之间的关系。利用U-σ相关曲线确定能够反映流变过程的4个特征点(流变起始点、等速流变起始点、加速流变起始点、流变破坏点).根据4个特征点的变化规律确定临界等速流变应力的方法和流变强度取值原则。 相似文献
995.
Using the boundary integral equation method, the problem of stationary heat conduction and thermoelasticity for a semi-infinite
body with a crack parallel to its boundary is solved. Temperature or heat flow on the crack is prescribed. The body boundary
is heat-insulated or is at zero temperature. The dependence of the stress intensity factor on the depth of occurrence of a
circular crack at a constant temperature or under a constant heat flow is studied. In contrast to mechanical loading, thermal
loading shows less SIF values than in an infinite body
__________
Translated from Prikladnaya Mekhanika, Vol. 43, No. 4, pp. 46–54, April 2007. 相似文献
996.
V. K. Kalpakides K. G. Balassas C. V. Massalas 《Archive of Applied Mechanics (Ingenieur Archiv)》2007,77(2-3):135-146
A computational scheme for the determination of the interface in a strain-induced phase-transition problem for an elastic
bar is proposed. The algorithm is based on the material force notion and more specifically on the simultaneous solution of
equilibrium equations for the physical and material forces. The weak form of both equations is derived with the aid of a variational
principle that accounts for the variations of the dependent and the independent variables. The whole scheme concludes in a
nonlinear algebraic system which is numerically solved by the Newton method. The numerical results thus derived seem to be
quite encouraging for further application of the concept of material forces in computations related to phase transition problems.
The austenite–martensite transformation could be a possible application of the proposed model. 相似文献
997.
V. D. Kubenko 《International Applied Mechanics》2004,40(1):51-60
An approach is proposed to study a collision of a long cylinder with the inside surface of a circular cylindrical cavity in an elastic medium. The problem is solved in plane formulation. A nonstationary mixed initial–boundary-value problem with unknown boundaries moving with a variable velocity is formulated and then reduced to an infinite system of Volterra integral equations of the second kind or, in a simplified formulation, to a sequence of Volterra integral equations. The penetration velocity is determined as a function of the cylinder mass and initial conditions. It is established that the reaction force peaks instantaneously and then dies out 相似文献
998.
V. D. Kubenko 《International Applied Mechanics》2006,42(11):1231-1245
The shock-interaction problem for a rigid spherical body and a spherical cavity in a compressible liquid is formulated and
solved. Three typical cases of typical dimensions of the body and cavity are examined. An asymptotic solution valid at the
earliest stage of interaction is obtained. In the general case, the problem is reduced to an infinite system of integral equations
of the second kind. It is numerically solved for the case of a nonsmall air gap
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 11, pp. 40–56, November 2006. 相似文献
999.
利用Somigliana公式及有限部积分的概念,导出含两平行平片裂纹三维有限体裂纹干扰问题的超奇异积分方程组,联合使用有限部积分与边界元法,建立了数值求解方法,为提高数值计算结果的精度,在裂纹前疝附近单元,采用平方根位移模型,并在此基础雌出直接计算应力强度因子的公式,最后计算若干典型例子裂纹前沿的应力强度因子。 相似文献
1000.
介绍了一种卫星用高可靠性惯性敏感器,它的六个陀螺的输入轴按正十二面体安装,任意三个陀螺工作均能给出卫星的三轴姿态信息,这样在单个陀螺平均寿命一定的条件下,惯性敏感器的可靠性大大提高。文中还介绍了该方案的其它优点和结构设计巧妙之处,目前已应用该方案设计、加工、调试出实用的惯性敏感器,并通过了各项地面试验,适用于高精度、长寿命的三轴稳定卫星。 相似文献