共查询到12条相似文献,搜索用时 0 毫秒
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本文介绍了一种适用于计算机分析的多刚体系统运动学分析的自然坐标法。利用自然坐标描述多刚体系统时,只需要一些点和一些单位向量,刚体的约束方程和运动副的约束方程组成了多刚体系统的运动学约束方程。约束方程均为线性或二次方程,因此求解方便。文中利用该方法分析了Maepherson悬架的轮胎横向滑移量、主倾内倾角等与车轮上、下跳动距离的关系。 相似文献
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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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Feature-based validation techniques for dynamic system models could be unreliable for nonlinear, stochastic, and transient dynamic behavior, where the time series is usually non-stationary. This paper presents a wavelet spectral analysis approach to validate a computational model for a dynamic system. Continuous wavelet transform is performed on the time series data for both model prediction and experimental observation using a Morlet wavelet function. The wavelet cross-spectrum is calculated for the two sets of data to construct a time-frequency phase difference map. The Box-plot, an exploratory data analysis technique, is applied to interpret the phase difference for validation purposes. In addition, wavelet time-frequency coherence is calculated using the locally and globally smoothed wavelet power spectra of the two data sets. Significance tests are performed to quantitatively verify whether the wavelet time-varying coherence is significant at a specific time and frequency point, considering uncertainties in both predicted and observed time series data. The proposed wavelet spectrum analysis approach is illustrated with a dynamics validation challenge problem developed at the Sandia National Laboratories. A comparison study is conducted to demonstrate the advantages of the proposed methodologies over classical frequency-independent cross-correlation analysis and time-independent cross-coherence analysis for the validation of dynamic systems. 相似文献
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This paper mainly intends to present new stability results of a discrete-time switched system with unstable subsystems. By adopting multiple Lyapunov functions? (MLFs?) method, new and less conservative stability conditions are derived in terms of a set of numerical feasible linear matrix inequalities (LMIs) with mode-dependent average dwell time (MDADT) techniques. Different from previous literatures, unstable subsystems are considered under two situations in this paper. It is shown that the discrete-time switched system can achieve exponential stability under a slow switching scheme and even in the presence of fast switching of unstable subsystems. Finally a numerical example is given to demonstrate the effectiveness of the proposed method. 相似文献
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With power mapping (conformal mapping), stability analyses of fractional order linear time invariant (LTI) systems are carried out by consideration of the root locus of expanded degree integer order polynomials in the principal Riemann sheet. However, it is essential to show the left half plane (LHP) stability analysis of fractional order characteristic polynomials in the s plane in order to close the gap emerging in stability analyses of fractional order and integer order systems. In this study, after briefly discussing the relation between the characteristic root orientations and the system stability, the author presents a methodology to establish principal characteristic polynomials to perform the LHP stability analysis of fractional order systems. The principal characteristic polynomials are formed by factorizing principal characteristic roots. Then, the LHP stability analysis of fractional order systems can be carried out by using the root equivalency of fractional order principal characteristic polynomials. Illustrative examples are presented to explain how to find equivalent roots of fractional order principal characteristic polynomials in order to carry out the LHP stability analyses of fractional order nominal and interval systems. 相似文献
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Mohan V. Tatikonda Mary K. Stietz 《The International Journal of Advanced Manufacturing Technology》1994,9(4):245-252
This paper contributes a novel methodology for operations analysis of computer integrated manufacturing systems. The methodology employs an integrated set of personal computer-based manufacturing systems modelling software, and is conducted in three stages. The methodology is illustrated in detail for analysis of materials flow and staffing for a flexible manufacturing system (FMS) installed at a medical instruments manufacturing plant. First, a rough-cut capacity and materials flow analysis was performed using a queueing model. Second, a detailed analysis of FMS system characteristics was conducted by creating and analysing a discrete-event simulation model. Finally, a graphical animation package was used to verify previous results and provide visual feedback on FMS system performance. Analysis results were obtained rapidly and conveniently, and were used to advise manufacturing managers regarding FMS operating policy. This analysis methodology can be applied to a wide range of computer integrated manufacturing systems and manufacturing cells. 相似文献
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Q. S. Li Ke Yang Lixiang Zhang N. Zhang 《International Journal of Mechanical Sciences》2002,44(10):2067-2087
This paper is concerned with the vibration analysis of a liquid-filled pipe system, which extends the frequency domain analysis of the fluid–structure interaction from single pipe to a pipe system with multi-pipe sections using transfer matrix method. Taking into account all the three major coupling mechanisms, namely the friction coupling, Poisson coupling and junction coupling, the proposed method can be used to analyze the free vibration and the forced vibration of a pipe system with multi-pipe sections subjected to various kinds of external excitations. The transform matrix, impedance matrix and frequency equation in frequency domain are also presented and discussed. Numerical examples are presented to illustrate the application of the proposed method, which shows how the natural frequencies and mode shapes change with the radius and materials of the pipe system. 相似文献
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Optimization of multiple responses using principal component analysis and technique for order preference by similarity to ideal solution 总被引:1,自引:0,他引:1
Lee-Ing Tong Chung-Ho Wang Hung-Cheng Chen 《The International Journal of Advanced Manufacturing Technology》2005,27(3-4):407-414
Optimizing multi-response problems has become an increasingly relevant issue when more than one correlated product quality
characteristic must be assessed simultaneously in a complicated manufacturing process. This study proposes a novel optimization
procedure for multiple responses based on Taguchi’s parameter design. The signal-to-noise (SN) ratio is initially used to
assess the performance of each response. Principal component analysis (PCA) is then conducted on the SN values to obtain a
set of uncorrelated components. The optimization direction for each component is determined based on the corresponding variation
mode chart. Finally, the relative closeness to the ideal solution resulting from the technique for order preference by similarity
to ideal solution (TOPSIS) is determined as an overall performance index (OPI) for multiple responses. Engineers can easily
employ the proposed procedure to obtain the optimal factor/level combination for multiple responses. A case study involving
optimization of the chemical-mechanical polishing of copper (Cu-CMP) thin films from an integrated circuit manufacturer in
Taiwan is also presented to demonstrate the effectiveness of the proposed procedure. 相似文献