共查询到18条相似文献,搜索用时 42 毫秒
2.
用两个实例说明,运动学中加速度分析的几何法与投影法相比,不仅更加直观,而且可直接求出未知量的大小,判定它们的方向.此方法可作为投影法的一个对照和补充. 相似文献
3.
4.
5.
6.
7.
8.
本文研究欧美理论力学教材对运动学的处理。通过简述10部法国、英国、德国、俄国和美国著名教材,反映运动学教学内容的历史变化,选择具有一定代表性的7部美国教材、两部德国教材和一部俄国教材,分析这些教材中点的运动、刚体运动和复合运动的内容。在此基础上讨论这些教材值得参考和借鉴之处。 相似文献
9.
10.
11.
12.
13.
随着21世纪折纸工程学的发展,折纸不再仅仅是一项民间艺术,一方面数学家前期的大量工作随之浮出水面,另一方面工程应用对折纸结构折叠过程的描述与分析都提出了新的挑战.同时,折纸的对象也不再局限于简单的纸张,工程中存在大量的厚度不可忽略的平板结构,他们的折叠展开问题一直困扰着相关的工程应用.近几年超材料的发展给模块化折纸带来了一次从玩具到高科技的飞跃,然而如何协调地安排这些折纸模块使得整体结构展现出超常且可变化调控的性能是折纸领域的新热点.由此可见,折纸运动学在诸多应用与探索方面都起到了决定性的基础作用.本文重点介绍了已有的机构学理论与方法及其在各种折纸结构分析设计中的应用,旨在为折纸工程学的发展提供坚实的理论技术基础. 相似文献
14.
Jean Lerbet 《Mechanics Research Communications》2000,27(6):621-630
Using Lie group theory, we propose to give some explicit relations in kinematics of mechanisms without introducing coordinates. After a presentation of the mathematical tools, the kinematics of closed mechanisms is presented using Lie group language. We give first a family of relations between dependent and independent variables and their derivatives which may be useful for linearisation or for numerical integration. Two examples are then proposed to illustrate these relations. 相似文献
15.
《International Journal of Solids and Structures》2007,44(17):5742-5751
Single crystal FeFP kinematics are widely used as the basis for many crystal plasticity models. Within this kinematic framework, geometrically necessary dislocations (GNDs) initially do not exist and then they evolve as needed in the material. A shortcoming of this kinematic model is that there is no rigorous way to define the initial and evolving GND state in the same manner. By augmenting the single crystal FeFP kinematics with a geometric argument, a consistent methodology for determining the initial and evolving GND state has been derived. The augmented kinematics describe GND related microstructural features in the undeformed material like low angle sub-grain boundaries and high angle grain boundaries. Therefore these kinematics are particularly applicable to polycrystalline materials. 相似文献
16.
Abstract Linear dynamic analysis of lattice structures using transfer matrices and joint coupling matrices is presented. A lattice structure is defined as a network of one-dimensional members that are connected by joints. Two examples are considered to illustrate how transfer matrices and joint coupling matrices may be used to compute natural frequencies of vibration. These two examples indicate that the transfer matrix and joint coupling matrix analysis is numerically accurate over a wide range of frequencies and becomes increasingly efficient, compared to the finite element method, as the frequency increases. Some suggestions for further improvements in computational efficiency and some comments about applicability to numerical analysis of wave propagation problems are given. 相似文献
17.
18.