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error analysis of FLC Experimental Data at Warm/Hot Stamping Conditions

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Chinese Journal of Mechanical Engineering 2014年第4期27卷 730-737页

作者： ZHUANG Weimin ZHANG Mengxi CHEN Yanhong State Key Laboratory of Automotive Dynamic Simulation Jilin University Department of Aeronautics Imperial College

Forming limit curves（FLCs） are commonly used for evaluating the formability of sheet metals. However, it is difficult to obtain the FLCs with desirable accuracy by experiments due to that the friction effects are non-negligible under warm/hot stamping conditions. To investigate the experimental errors, experiments for obtaining the FLCs of the AA5754 are conducted at 250℃. Then, FE models are created and validated on the basis of experimental results. A number of FE simulations are carried out for FLC test-pieces and punches with different geometry configurations and varying friction coefficients between the test-piece and the punch. The errors for all the test conditions are predicted and analyzed. Particular attention of error analysis is paid to two special cases, namely, the biaxial FLC test and the uniaxial FLC test. The failure location and the variation of the error with respect to the friction coefficient are studied as well. The results obtained from the FLC tests and the above analyses show that, for the biaxial tension state, the friction coefficient should be controlled within 0.15 to avoid significant shifting of the necking location away from the center of the punch; for the uniaxial tension state, the friction coefficient should be controlled within 0.1 to guarantee the validity of the data collected from FLC tests. The conclusions summarized are beneficial for obtaining accurate FLCs under warm/hot stamping conditions.

关键词： forming limit curve(FLC) error analysis warm/hot stamping finite element analysis

error analysis of A New Higher Order Boundary Element Method for A Uniform Flow Passing Cylinders

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China Ocean Engineering 2023年第3期37卷 369-377页

作者： SUN Shi-yan CUI Jie BAO Chao-ming School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

A higher order boundary element method(HOBEM)is presented for inviscid flow passing cylinders in bounded or unbounded *** traditional boundary integral equation is established with respect to the velocity potential and its normal *** present work,a new integral equation is derived for the tangential *** boundary is discretized into higher order elements to ensure the continuity of slope at the element *** velocity potential is also expanded with higher order shape functions,in which the unknown coefficients involve the tangential *** expansion then ensures the continuities of the velocity and the slope of the boundary at element *** extensive comparison of the results for the analytical solution of cylinders,it is shown that the present HOBEM is much more accurate than the conventional BEM.

关键词： higher order boundary element method(HOBEM) error analysis integral equations for potential and velocity cylinders

error analysis in Frequency Domain for Linear Multipass Algorithms

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Journal of Systems Engineering and Electronics 2001年第4期12卷 77-84页

作者：费景高 Beijing Institute of Computer Application and Technology 100854 P. R. China

error analysis methods in frequency domain are developed in this paper for determining the characteristic root and transfer function errors when the linear multipass algorithms are used to solve linear differential equations. The relation between the local truncation error in time domain and the error in frequency domain is established, which is the basis for developing the error estimation methods. The error estimation methods for the digital simulation model constructed by using the Runge-Kutta algorithms and the linear multistep predictor-corrector algorithms are also given.

关键词： Algorithms Computer simulation Differential equations error analysis Frequency domain analysis Runge Kutta methods

error analysis of Robotic Assembly System Based on Screw Theory

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Journal of Donghua University(English Edition) 2003年第3期20卷 72-77页

作者：韩卫军费燕琼赵锡芳 Research Institute of Robotics Shanghai Jiaotong UniversityShanghai200030

Assembly errors have great influence on assembly quality in robotic assembly systems. error analysis is directed to the propagations and accumula-tions of various errors and their effect on assembly *** the screw coordinates, assembly errors are represented as 'error twist', the extremely compact expression. According to the law of screw composition, relative position and orientation errors of mating parts are computed and the necessary condition of assembly success is concluded. A new simple method for measuring assembly errors is also proposed based on the transformation law of a *** of the compact representation of error, the model presented for error analysis can be applied to various part- mating types and especially useful for error analysis of complexity assembly.

关键词： robotic assembly system screw theory error twist error analysis

error analysis and Distribution of 6-SPS and 6-PSS Reconfigurable Parallel Manipulators

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Tsinghua Science and Technology 2010年第5期15卷 547-554页

作者：姚蕊唐晓强李铁民林春深 Department of Precision Instruments and Mechanology Tsinghua University

The purpose of this paper is to analyze an accuracy design method for reconfigurable parallel manipulators including a 6-SPS and a 6-PSS parallel *** error analysis method,based on the module error model,was used to express the relationship between the module error and the terminal error in the error transmission equation of the reconfigurable parallel *** addition,an error distribution method using a manufacturing and assembly difficulty coefficient was used to analyze each error module to determine a maximum terminal *** error distribution result was then used to set up a reconfigurable parallel *** experiments with a reconfigurable parallel manipulator show that the error analysis and distribution method for reconfigurable parallel manipulators are effective and the maximum terminal errors of the reconfigurable parallel manipulators are less than 50 μm.

关键词： reconfigurable parallel manipulator error distributing error analysis

error analysis of Three Degree-of-Freedom Changeable Parallel Measuring Mechanism

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Journal of China University of Mining and Technology 2007年第1期17卷 101-104页

作者： CHENG Gang GE Shi-rong WANG Yong Institute of Reliability and Rescue Robotics China University of Mining ＆Technology Xuzhou Jiangsu 221008 China

A three degree-of-freedom (DOF) planar changeable parallel mechanism is designed by means of control of different drive parameters. This mechanism possesses the characteristics of two kinds of parallel mechanism. Based on its topologic structure, a coordinate system for position analysis is set-up and the forward kinematic solutions are analyzed. It was found that the parallel mechanism is partially decoupled. The relationship between original errors and position-stance error of moving platform is built according to the complete differential-coefficient theory. Then we present a special example with theory values and errors to evaluate the error model, and numerical error solutions are gained. The investigations concentrating on mechanism errors and actuator errors show that the mechanism errors have more influences on the position-stance of the moving platform. It is demonstrated that improving manufacturing and assembly techniques can greatly reduce the moving platform error. The small change in position-stance error in different kinematic positions proves that the error-compensation of software can improve considerably the precision of parallel mechanism.

关键词： parallel mechanism changeable measuring mechanism kinematics forward analysis error model error analysis

“Stop-and-go” error analysis of geosynchronous SAR

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Science China(Information Sciences) 2016年第6期59卷 177-188页

作者： Yurun TIAN Shenglong GUO Weidong YU Institute of Electronics Chinese Academy of Sciences University of Chinese Academy of Sciences

In this paper, the slant range error introduced by the "stop-and-go" assumption is analyzed in detail. Owing to the high orbit and long synthetic aperture time of geosynchronous SAR(Geo-SAR), the slant range error introduced by the "stop-and-go" assumption should be considered. In addition, an accurate signal propagation delay time equation of Geo-SAR based on circle orbit is presented, and the error of the "stop-andgo" assumption is demonstrated by simulation. An "equivalent position" model is proposed and validated by simulation. The error of various powers of "stop-and-go" slant range is analyzed using Legendre orthogonal series expansion. The limitation of the stop-and-so assumption is proved by point target simulation.

关键词： geosynchronous SAR stop-and-go assumption equivalent position model Legendre orthogonal series error analysis

Development of an oscillating grinding machine tool based on error analysis

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Science China(Technological Sciences) 2020年第6期63卷 912-922页

作者： WANG LiPing WANG Dong WANG Bo LI WeiHua Institute of Manufacturing Engineering Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beier Machine Tool Works Co. LTDBeijing 102444China

Oscillating grinding machine tool is the core equipment when machining crankshaft pin journal,which directly determines the final *** paper describes the development of an oscillating grinding machine tool based on error ***,the error analysis of oscillating grinding for crankshaft pin journal is carried out,including the effect on machining accuracy caused by each error and corresponding error *** results show that the tracking error of X-axis has the greatest influence on the grinding accuracy of pin journal,thus,the grinding carriage feed system is the critical component of an oscillating grinding machine tool,which should be given priority during the development ***,the development of an oscillating grinding machine tool is *** whole structure is given,and the grinding carriage feed system is emphatically presented involving drive mode and assembly *** components of the oscillating grinding machine tool are also ***,some grinding experiments are performed on the prototype,and the results show that all workpieces are qualified under different conditions,which verify the performance of the developed oscillating grinding machine tool.

关键词： oscillating grinding machine tool error analysis crankshaft pin journal grinding carriage feed system

Simultaneous Strain and Temperature Measurement with Optical Fiber Gratings: error analysis

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Chinese Journal of Lasers 2000年第3期9卷 52-57页

作者： JIA Hongzhi LI Yulin (Xi’an Institute of Optics & Precision Mechanics, The Chinese Academy of Sciences, Xi’an 710068, China) 中科院西安光学精密机械所陕西西安

Many schemes designed to simultaneously measure strain and t emperature with optical fiber grating sensors have been reported in recent years. In this paper, the influence of systematic errors associated with the measurement process is analyzed and the error formulas are derived. The results are applied to a range of techniques that are of current interest in the literature. The performance of these schemes is contrasted with respect to the influence of wavelength measurement error and sensitivity matrix error.

关键词： fiber grating sensors strain measurement temperature measurement error analysis