共查询到20条相似文献,搜索用时 0 毫秒
1.
根据不同层次学生在教学设计、教学方法等方面的不同需求,并兼顾"零零"后大学生特点,提出一个基于BOPPPS模型的旋转体体积的有效教学设计方案并详细阐述了教学过程中所采用的方法.该方案注重教师的引领作用和学生的自主学习及分类培养,从而为旋转体体积内容的教学提供一定的理论与实践参考. 相似文献
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旋转刚柔耦合系统在航空航天、机器人、高速机构以及车辆等领域有着广泛的应用,主要描述负载在旋转刚体上的柔性梁的运动。对旋转刚柔耦合系统施加控制使得整个闭环系统达到:1)旋转刚体以预期的旋转角速度运动;2)负载在刚体上的柔性梁镇定。本文将从控制器设计的角度出发,介绍目前在旋转刚柔耦合系统控制方面取得的主要研究成果。 相似文献
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Ming Liao 《Journal of Theoretical Probability》1997,10(1):201-211
We study the random motion of a rigid body through a stochastic differential equation on the special orthogonal group SO(d). 相似文献
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Summary. We propose a new three-dimensional dynamic theory of transforming materials intended to make realistic simulations of the
dynamic behavior of these materials accessible. The theory is appropriate for materials whose free energy function rises steeply
from its energy wells. Essentially, the theory is the multiwell analog of ordinary rigid body mechanics with three additional
features: the full stress is not treated as arbitrary (the average limiting tractions on each interface enter the theory as
unknowns), a certain component of the local balance of linear momentum is used, and kinetic laws for interfacial motion are
introduced based on ideas of Eshelby and Abeyaratne and Knowles. In an interesting special case of the resulting equations
of motion, all material constants together with all information about the shape of the body collapse to a single dimensionless
constant. We prove well-posedness up to the time of a collision between interfaces, and do a preliminary study of the problem
of annihilation and nucleation of interfaces. Conservation laws and a dissipation inequality are identified. We also give
generalizations of the theory to magnetic and thermodynamic piecewise rigid media. A probable application area for the theory
is the assessment of the use of transforming materials at small scale as ``motors' for propulsion or actuation. 相似文献
5.
为了研究不同水深下,动水效应对连续刚构桥抗震性能的影响,基于一实际工程,利用有限元软件Midas建立全桥模型,采用反应谱数值分析法,并考虑桩土的相互作用,研究了动水效应对连续刚构桥抗震性能的影响.结果表明:考虑动水效应将会减小结构的频率,且高阶频率对动水效应更加敏感;另外,动水效应将会放大结构的地震响应,随着水深的增加,地震响应的增大幅度也越大.当水深达到20m以上时,动水效应将使结构的内力增大约10%,此时在抗震设计中应重点考虑动水效应的影响. 相似文献
6.
刘鹏林 《数学的实践与认识》2005,35(5):80-84
通过运用波前干涉理论,得到了贴片云纹干涉法测圆柱壳的位移与应变公式,分析了刚体位移及曲率对测试结果的影响情况.指出了在对压力容器及管道进行测试时应注意的事项. 相似文献
7.
In this paper the dynamics of rigid bodies is recast into a Clifford algebra formalism. Specifically, the algebra Cℓ(0, 6,
2), is used and it is shown how velocities, momenta and inertias can be represented by elements of this algebra. The equations
of motion for a rigid body are simply derived by differentiating the momentum of the body. 相似文献
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刚体动力学方程的一个辛积分方法 总被引:1,自引:0,他引:1
针对四元数和对应广义动量表示的刚体定点动力学方程,利用一种位移格式的微分—代数方程积分方案,实现了非独立广义动量表示的拉格朗日方程的辛积分算法.数值实验显示该算法具有精度高和保持系统守恒量的特点.更为重要的是,广义动量表示的拉格朗日方程较之传统形式的拉格朗日方程在辛积分中表现出独特的优越性. 相似文献
10.
Elizabeth J. O'Neil 《Studies in Applied Mathematics》1969,48(3):227-256
The stability of certain steady flows in a rotating system with rigid bottom and free top surfaces is investigated. The simplest flow states having the essential spatial variations of steady responses of a rotating fluid system to differential heating in the horizontal are studied, that is, those with a constant gradient temperature distribution with both horizontal and vertical components, and the accompanying Coriolis-balanced constant velocity shear (thermal wind). Ekman boundary layers and intermediate boundary layers are encountered in a systematic asymptotic analysis in two small parameters, the Ekman number and an inverse Richardson number. The resulting neutral stability curves indicate the possibility of instabilities above the inviscid stability criterion due to Eady, for some mean flow configurations. The estimate of the critical Taylor number is numerically close to the values obtained in the most nearly applicable experiments. 相似文献
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Doklady Mathematics - The article describes results obtained for the problem of maximum rotation of a rigid body in a given time interval by moving an internal mass. The mass moves by applying a... 相似文献
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A constrained system associated with a 3×3 matrix spectral problem of the nonlinear Schrodinger(NLS) hierarchy is proposed. It is shown that the constrained system is a Hamiltonian system with the rigid body type Poisson structure on the Poisson manifold R3N. Further, the reduction of the constrained system extended to the common level set of the complex cones is proved to be the constrained AKNS system on C2N. 相似文献
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V. N. Starovoitov 《Journal of Mathematical Sciences》2005,130(4):4893-4898
This paper is devoted to the problem on motion of a rigid body in a viscous incompressible fluid. It is proved that there exist at least two weak solutions of this problem if collisions of the body with the boundary of the flow domain are allowed. These solutions have different behavior of the body after the collision. Namely, for the first solution, the body goes away from the boundary after the collision. In the second solution, the body and the boundary remain in contact. Bibliography 15 titles.To Vsevolod Alekseevich Solonnikov on the occasion of his jubilee__________Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 306, 2003, pp. 199–209. 相似文献
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梁的横向变形会导致梁纵向缩短,建模过程中考虑梁横纵变形二次耦合项则存在动力刚化现象,这说明梁的纵向变形会对模型的广义刚度造成影响.对于做旋转运动的梁结构,旋转运动时还会受到离心力的作用而产生轴向拉力,轴向拉力同样也会引起梁的轴向变形,这种影响对粗短梁更加明显.以大范围运动中心刚体-Timoshenko梁模型为研究对象:首先,运用Timoshenko梁理论以及Hamilton原理建立含离心力的动力学模型;其次,引入非约束模态概念,采用Frobenius方法求解非约束模态振型函数以及固有频率;最后,通过数值仿真探究不同恒定转速时非约束模态与约束模态广义刚度的差异和非约束模态条件下离心力对模型的影响. 相似文献
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In this paper we show that there exist wavelet frames that have nice dual wavelet frames, but for which the canonical dual frame does not consist of wavelets, i.e., cannot be generated by the translates and dilates of a single function. 相似文献
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Nyurgun Lazarev Galina Semenova 《Journal of Optimization Theory and Applications》2018,178(2):614-626
The equilibrium problem for a two-dimensional body with a crack is studied. We suppose that the body consists of two parts: an elastic part and a rigid thin stiffener on the outer edge of the body. Inequality-type boundary conditions are prescribed at the crack faces providing a non-penetration between the crack faces. For a family of variational problems, dependence of their solutions on the length of the thin rigid stiffener is investigated. It is shown that there exists a solution of an optimal control problem. For this problem, the cost functional is defined by a continuous functional on a solution space, while the length parameter serves as a control parameter. 相似文献