柔体系统局部非线性基函数法

通过考虑动力刚化效应,建立了大范围、高速运动的柔体系统局部非线性基函数法．实例说明了该方法的正确性     

柔体系充局部非线性基函数法

通过考虑动力刚化效应,建立了大范围、高速运动的柔体系统局部非线性基函数法,实例说明了该方法的正确性。     

“地下水运动方程”课程设计

＂地下水运动方程＂是为地下水科学与工程专业本科生开设的一门新课程,以取代过去地下水专业的＂数学物理方程＂课程。开设这门课的目标是通过有针对性的讲解和讨论,在数学物理方程与地下水动力学之间架起一座桥梁,帮助学生更深入地利用数学知识来理解地下水的运动规律。＂地下水运动方程＂主要讲授地下水流偏微分方程的解析方法,具有很强的实用性,突出方程解法的灵活性。     

ON THE DYNAMICS OF MULTIARM ROBOTS

研究多臂机器人和多机器人构造的动力学．两个或两个以上机械臂夹持物体时可形成一个或更多闭环，故可视为约束多体系统进行研究．可用基于凯恩方程和休斯敦方法的最新程式进行约束多体系统的动力学分析，此程式给出方程的数值解和系统的运动仿真．用上法分析了ＰＵＭＡ７６０和５６２机器人组成的双机器人系统，理论分析和实验结果吻合良好     

定点转动刚体角速度在固定系中的推证

刚体的定点转动是刚体的一种复杂运动类型。作定点转动刚体的角速度是较难掌握的一个概念。众所周知,刚体作定点转动时,刚体相对于固定系的空间位置用欧拉角来确定。而在一般教科书中,其转动角速度只给出相对活动系(随刚体一起运动的坐标系)的欧拉方程,即为     

重构硕士生＂科学社会主义理论与实践＂教材的宏观思考

现行硕士生＂科学社会主义理论与实践＂课程教材必须重构。现行教材比较重视＂理论＂本身的分析,忽视科学社会主义产生必然性的深厚背景分析,缺乏历史说服力。现行教材比较重视孤立的＂板块＂理论和国别的＂小实践＂的分析,忽视整个科学社会主义大运动＂大实践＂的分析,缺乏对科学社会主义运动的一般规律性的分析总结。现行教材忽视科学社会主义实践与时代主题关系的分析,缺乏整体上的时代把握,没有从整体上、从发展趋势上探讨和论述社会主义革命的道路与时代主题的密切关系。     

几类非线性偏微分方程的两次变换法和准确解

本文给出了一类守恒方程的两次变换法，通过这种变换表明几类非线性偏微分方程是可准确求解的，这几类非线性偏微分方程可分别化为线性方程、Ｂｕｒｇｅｒｓ方程和ｋｄｖ方程。     

从Newton定律到广义Hamiltonian系统(Ⅲ)——关于Korteweg-de Vries(KdV)类型的非线性发展方程的一个估计

Newton定律是描述物体运动的基本定律,Hamiltonian方程则为运动的基本规律提供了另外一种表达。由Hamiltonian方程发展而来的Hamiltonian可积系统是现代孤立子理论的重要组成部分。文中证明了一个关于Korteweg-de Vries(KdV)类型的非线性发展方程的在加权Sobolev空间中的估计式。这一估计式对证明一类一般的非线性扩散型发展方程的不变性质是非常有用的。     

儒家义利观下的＂兴奋剂使用＂

＂兴奋剂使用＂在带给个人或群体＂私利＂的同时,也在侵蚀着竞技体育的精神根基,是一种不＂义＂之举.本文从儒家义利观来审视竞技体育运动中的＂兴奋剂使用＂,为保障公平、公正的竞技体育提供一种伦理道德上的思考.     

浅谈初中英语实施＂素质教育＂的几点措施

九年义务教育的核心问题是素质教育,是教育的重心必须由＂应试教育＂过渡到＂素质教育＂,使受教育者在德、智、体、美、劳各方面得到发展。而实施素质教育的关键在于教师。教师要不断改进教育观念,从以＂教＂为中心转变到以学生的＂学＂为中心,才能适应不断变化的时代发展要求。当前,创造适合学生的教育以及生本教育理念在我县教育界得到普遍的认可,教师的＂教＂要服务于学生的＂学＂正成为大家教育教学的共识。＂学导用＂分层次教学课题研究也在我县大部分学校中全面展开。结合英语实施＂素质教育＂的要求以及自身多年的教学实践,我想就如何发挥学生潜能,激发学生学习动力,开发学生英语学习潜力等在初中英语教育中的实施谈几点措施和看法。     

多体回路系统的正则运动方程

采用绝对坐标定义系统中各刚体的位置，刚体间的运动副及作用在刚体上或刚体间的力，给出了求速度变换矩阵的一般方法．经过约束方程的雅可比矩阵的零空间，用相对坐标建立了多体回路系统的运动微分方程，并进而表示成正则运动方程的形式．     

振动筛砂机执行机构仿真与分析

基于ADAMS仿真软件平台,对矿用振动筛砂机执行机构进行了建模及仿真,得到连杆刚性、柔性下的运动规律。在考虑连杆柔性时,摇杆的角速度曲线变化不大,而角加速度波动非常大,出现冲击,砂箱在此过程中速度不稳定,受力变化明显,这与实际过程非常符合。即连杆在实际工作中受力情况较差,在一定情况下会引起机械的振动。     

Bifurcation of periodic motion of rigid rotor system supported by angular contact ball bearings

Rotor systems supported by angular contact ball bearings are complicated due to nonlinear Hertzian contact force. In this paper, nonlinear bearing forces of ball bearing under five-dimensional loads are given, and 5-DOF dynamic equations of a rigid rotor ball bearing system are established. Continuation-shooting algorithm for periodic solutions of the nonlinear non-autonomous dynamic system and Floquet multipliers of the system are used. Furthermore, the bifurcation and stability of the periodic motion of the system in different parametric domains are also studied. Results show that the bifurcation and stability of period-1 motion vary with structural parameters and operating parameters of the rigid rotor ball bearing system. Avoidance of unbalanced force and bending moment, appropriate initial contact angle, axial load and damping factor help enhance the unstable rotating speed of period-1 motion.     

准轴对称陀螺体自激运动的平均化分析

The averaging analysis was carried out to study the motion of a quasi-axisymmetrical gyrostat under a small-magnitude self-excited control troque.The common approach to investigating the problem of rigid body rotatyion under the action of a small torque known in the body frame was described.Using this approach,the problem(Grammel‘s problem for the case of small torque) that is maintaining the angular velocity of a quasi-axisymmetrical gyrostat using a control torque quadratic in the angular velocity was solved.Maintaining the angular velocity of a quasi-axisymmetrical gryostat using a control torque quadratic in the angular velocity was solved.     

Transient Responses of Flexible Non—uniform Spinning Shaft with Nonlinear and Asymmetric Supports

In this paper ,a hybrid approach was developed to investigate the transient responses of a multi-span non-uniform flexble spinning shaft with nonlinear and asymmetric supports.The non-uniform spinning shaft with variable parmeters was modeled as a Bernoulli-Euler beam column with sectional constant cross-section properties by the finite element method.The supporting stiffness behavior of the nonlinear supports was described as a piecewise-linear and asymmetric model.The equations of motion in the matrix form of a multi-span non-uniform spinning shaft with nonlinear and asymmetric supports were formulated using Hamilton‘s principle and the assumed mode method.As an example,a spinning rocket with many variable stiffness supports was numerically simulated by the direct integration method.The transient response and dynamic behavior of this rotate-dynamic system are analyzed.     

非理想约束系统的Boltzmann-Hamel型方程及其正则式

本文在文献[1]、[2]的基础上,提出带有非理想约束的分析力学的普遍中心方程,建立非理想非线性非完整非保守系统准坐标形式的广义BoltZmann—Hamel方程,并建立与其对应的正则方程,最后讨论线性系、保守系、完转系和理想系情形。     

Inverse Dynamics of Delta Robot Based on the Principle of Virtual Work

While the kinematics of the parallel manipulatorhas been studied extensively during the past two dec-ades, more and more papers can be found on the dy-namics of the parallel manipulators now[1—7]. The dy-namics of robotcan be used forthe simulation, controland optimization. It plays an important role inachieving high-speed performance. There are twotypes of dynamical problems for the parallel robot: di-rect dynamics and inverse dynamics. The direct dy-namical problem is to find the response v…     

刚体平面运动的研究

从角动量的定义出发,计论了刚体平面运动时对任一定轴的角动量,推出了刚体平面运动时对质心轴、瞬心轴的转动定理.     

关于一类受非线性非完整约束航天器的运动

应用动能定理建立了常速率运动航天器的数学模型并求出两组稳态解.首先将动能定理推广到受非线性非完整约束系统.对于受速率为常数约束的运动质点,可以应用动能定理建立其运动微分方程.最后得到该方程的两组特解.     

An efficient numerical shape analysis for light weight membrane structures

The determination of initial equilibrium shapes is a common problem in research work and engineering applications related to membrane structures. Using a general structural analysis framework of the finite particle method （FPM）, this paper presents the first application of the FPM and a recently-developed membrane model to the shape analysis of light weight mem- branes. The FPM is rooted in vector mechanics and physical viewpoints. It discretizes the analyzed domain into a group of parti- cles linked by elements, and the motion of the free particles is directly described by Newton＇s second law while the constrained ones follow the prescribed paths. An efficient physical modeling procedure of handling geometric nonlinearity has been developed to evaluate the particle interaction forces. To achieve the equilibrium shape as fast as possible, an integral-form, explicit time integration scheme has been proposed for solving the equation of motion. The equilibrium shape can be obtained naturally without nonlinear iterative correction and global stiffness matrix integration. Two classical curved surfaces of tension membranes pro- duced under the uniform-stress condition are presented to verify the accuracy and efficiency of the proposed method.