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1.
Seung Man Eom Bum Suk Kim Hong Hee Yoo 《Journal of Mechanical Science and Technology》2008,22(11):2163-2170
A general multi-body formulation to analyze the tolerance effects on the statistical property variations of natural frequencies
of multi-body systems undergoing constant rotational motion is proposed in this paper. To obtain the tolerance effects, Monte-Carlo
simulation method is conventionally employed. However, the Monte-Carlo simulation has serious drawbacks; spending too much
computation time for the simulation and achieving very slow convergence around some dynamically unstable regions. To resolve
such problems, a method employing analytical sensitivity information is suggested in this paper. To obtain the sensitivities
of natural frequencies the eigenvalue problem should be differentiated with respect to a design variable. The sensitivities
of mass and stiffness matrices should be calculated at the dynamic equilibrium. By employing the sensitivities of natural
frequencies along with the tolerance of the design variable, the statistical property variations of the natural frequencies
can be calculated.
This paper was recommended for publication in revised form by Associate Editor Seockhyun Kim
Seung Man Eom graduated from the Department of Mechanical Engineering at Incheon University in 2005 and received his master degree from
the Department of Mechanical Engineering at Hanyang University in 2007. He is currently working as a Researcher of Aircraft
Development Team in KIAT(Korea Institute of Aerospace Technology, Koreanair), DaejeonDeajeon, Korea.
Bum Suk Kim graduated from the School of Mechanical Engineering at Hanyang University in 2006 and received his master degree from the
same department in 2008. He is currently working as a Ph.D. student in the School of Mechanical Engineering in Hanyang University,
Seoul, Korea.
Hong Hee Yoo graduated from the Department of Mechanical Design and Production Engineering at Seoul National University in 1980 and received
his master degree from the same department in 1982. He received his Ph.D. degree in 1989 from the Department of Mechanical
Engineering and Applied Mechanics in the University of Michigan at Ann Arbor, U.S.A. He is currently working as a professor
in the School of Mechanical Engineering in Hanyang University, Seoul, Korea. 相似文献
2.
The modal characteristics of constrained multibody systems undergoing constant accelerated motions are investigated in this
paper. Relative coordinates are employed to derive the equations of motion, which are generally nonlinear in terms of the
coordinates. The dynamic equilibrium position of a constrained multibody system needs to be obtained from the nonlinear equations
of motion, which are then linearized at the dynamic equilibrium position. The mass and the stiffness matrices for the modal
analysis can be obtained from the linearized equations of motion. To verify the effectiveness and the accuracy of the proposed
method, two numerical examples are solved and the results obtained by using the proposed method are compared with those obtained
by analytical and other numerical methods. The proposed method is found to be accurate as well as effective in predicting
the modal characteristics of constrained multibody systems undergoing constant accelerated motions. 相似文献
3.
本文以Kane方程为基础,建立了具有力约束的多体系统动力学方程,以能量最小为优化目标,实现了动力学解算。以工业机器人为例,进行了动力学分析和解算。 相似文献
4.
Virtual work in multibody systems is frequently expressed as the inner product of the virtual displacement and the resultant
force at the centroid. But provided that the resultant force is converted into the equipollent forces there is no restriction
on where the analysis reference point is placed. There are basically three candidate points : the centroid, joint point and
the instant global origin. The traditional fully recursive formulation uses the centroid, but the present work verifies that
the instant global origin always shows better efficiency (e.g. 86% CPU time of the centroid for quarter car model) and joint
point shows the efficiency between that of the centroid and the instant global origin. A discussion on how important it is
to define the analysis reference point properly in a fully recursive formulation is also presented. 相似文献
5.
A study on numerical solution method for efficient dynamic analysis of constrained multibody systems
Jae-Hwan Lim Hong Jae Yim Si-Hyung Lim Taewon Park 《Journal of Mechanical Science and Technology》2008,22(4):714-721
A new and efficient computational method for constrained multibody systems is proposed. In the proposed method, local parametrization
method is employed to apply the same solution method for position, velocity, and acceleration analyses since the coefficient
matrices for each analysis have an identical matrix pattern. The skyline solution method is used to overcome numerical inefficiency
when solving large scaled equations. Also, subsystem mpartitioning method is derived systematically to perform parallel processing
for real time simulation. To show the numerical accuracy and efficiency of the proposed method, three numerical problems are
solved. 相似文献
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Influence of manufacturing errors on the dynamic characteristics of planetary gear systems 总被引:1,自引:0,他引:1
A dynamic analysis using a hybrid finite element method was performed to characterize the effects of a number of manufacturing
errors on bearing forces and critical tooth stress in the elements of a planetary gear system. Some tolerance control guidelines
for managing bearing forces and critical stress are deduced from the results. The carrier indexing error for the planet assembly
and planet runout error are the most critical factors in reducing the planet bearing force and maximizing load sharing, as
well as in reducing the critical stress. 相似文献
9.
Dr. C. R. Nagarajah W. Thompson 《The International Journal of Advanced Manufacturing Technology》1994,9(5):333-342
There are two aspects to cell formation in flexible manufacturing systems, cell sizing or deciding on the optimum number of machines to be allocated to each cell, and then allocation of specific machines to each cell. Although the latter problem has been investigated extensively there is a paucity of published work on the former. This paper discusses the effects of cell sizing on operational flexibility.Operational flexibility is that aspect of flexibility that enables manufacturing systems to respond with speed and efficiency to changes in the manufacturing environment while maintaining an effective level of control. 相似文献
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11.
纳米尺度下的气体流动具有不同于常规尺度的规律,其中重要的特征是纳米间隙中气体分子自由输运行程将减小,进而影响气体的输运规律。利用直接模拟蒙特卡罗方法,考察了依赖于努森数Kn的气体分子壁面碰撞率,计算了分子平均自由程并给出了结果对比,最后验证了依赖于Kn数的纳米尺度效应函数。结果表明:过渡区分子与壁面碰撞率之间满足一定的关系,以此为基础得到的纳米尺度效应函数反映了纳米间隙对平均自由程的影响。 相似文献