Method of Improvement in Identification Accuracy of the Dynamic Characteristics of Joints in Jointed Structure

2012 ◽  
Vol 523-524 ◽  
pp. 451-456
Author(s):  
Shinji Shimizu ◽  
Yoshiaki Kabaya ◽  
Haruhisa Sakamoto ◽  
Kenichi Yamashita
Keyword(s):  
Dynamic Characteristic ◽  
Influencing Factors ◽  
Dynamic Characteristics ◽  
Vibration Mode ◽  
Relative Displacement ◽  
Identification Accuracy ◽  
Characteristic Parameters ◽  
Characteristic Values

In this study, we examined influencing factors on the identification accuracy and improving method of the identification accuracy. As a result, the influence of the condition of the dynamic characteristic values is large and these values should correspond to the tangential and vertical directions. The influence of treating dynamic characteristic parameters of the same plural joints is also large, and then the parameters of the same plural joints should have the same value. In addition, the tangential dynamic characteristics should be identified from the vibration mode which has large tangential relative displacement between the joint interfaces. Similarly, the vertical one should be identified from the vibration mode which has large vertical relative displacement between the joint interfaces. Finally, the identification accuracy can be improved greatly by considering these influences.

Identification Method of Dynamic Characteristics of Joints in Jointed Structures

2013 ◽  
Vol 7 (2) ◽  
pp. 221-227
Author(s):  
Shinji Shimizu ◽  
◽  
Yoshiaki Kabaya ◽  
Haruhisa Sakamoto ◽  
Kenichi Yamashita ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Transfer Function ◽  
Dynamic Characteristic ◽  
Dynamic Characteristics ◽  
Vibration Mode ◽  
Joint Model ◽  
Characteristic Parameters ◽  
Element Analysis ◽  
Spring Element

In this paper, we propose a method of identifying the dynamic characteristics of joints in jointed structures. We first consider a joint model for finite element analysis. We then propose, based on the consideration, a method of identifying dynamic characteristic parameters of the joint, such as the spring stiffness and damping coefficient, with the joint model. As a result, we obtain a joint model with the spring and damping elements in vertical and tangential directions between a pair of nodes with changeable numbers and locations. The number and location of these elements can be determined so that the vibration mode and the inertance transfer function of the jointed structure obtained from finite element analysis with infinite stiffness of the spring element agree with those of the structure without joints. In addition, we identify the dynamic characteristic parameters of the joint so the experimental inertance transfer function and vibration mode agree with those obtained from the finite element analysis.

Effect of Clamped Toolholders on Dynamic Characteristics of Spindle System of Machining Center

2012 ◽  
Vol 6 (2) ◽  
pp. 168-174 ◽  
Author(s):  
Haruhisa Sakamoto ◽  
◽  
Taiga Matsuda ◽  
Shinji Shimizu ◽  
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Characteristics ◽  
Dynamic Stiffness ◽  
Physical Parameters ◽  
Characteristic Parameters ◽  
Spindle System ◽  
Press Fit ◽  
Equivalent Damping Coefficient ◽  
Response Method ◽  
Tooling System

In this study, dynamic characteristics are determined based on the impulse response method, the correction of discretization errors and the identification of equivalent physical parameters, as found in the vibration model having one degree of freedom. In the experiments, the test tool is cylindrical bar shaped and made from solid tungsten carbide, and four toolholders with chucking mechanisms, including the shrinkfit type, collet type, hydraulic type, and press-fit type, are used. Since it had been previously confirmed that one of the tool preparation jigs had dynamic characteristics similar to those of an actual machine tool’s spindle, the dynamic characteristics of the jig could be measured the way the spindle system is measured in this study. From the experimental examinations, the following were clarified. (1) Chucking of the tooling system enhances the first mode vibration of the spindle system markedly. (2) The type of tool chuck used changes the dynamic characteristics of the spindle system. The trend in the dynamic stiffness corresponds well with that in the equivalent damping coefficient but is opposite to that in the equivalent stiffness. (3) The magnitude order of the dynamic characteristic parameters of the spindle system corresponds well with the inherent values of the dynamic characteristic parameters of the toolholders themselves; that is, the inherent dynamic characteristics of the tooling system can be used as the criteria to estimate the effect on the dynamic characteristics of the spindle system.

Influence of Bolted Joint on Dynamic Characteristics of Combined Three-Section Crossbeam

2010 ◽  
Vol 37-38 ◽  
pp. 534-539
Author(s):  
Tie Neng Guo ◽  
Dong Liang Guo ◽  
Li Gang Cai ◽  
Bin Song ◽  
Jing Nan Zhao
Keyword(s):  
Machine Tool ◽  
Dynamic Analysis ◽  
Dynamic Characteristic ◽  
Dynamic Characteristics ◽  
Bolted Joints ◽  
Experimental Result ◽  
Bolted Joint ◽  
Cnc Milling ◽  
Characteristic Parameters

The combined three-section crossbeam is an important component in the heavy gantry CNC milling-lathing machine tool and the dynamic characteristics are key precision factors for the machine tool. Three sections of the combined crossbeam are bolted by large industrial bolts and the influence of bolted joints should be evaluated in the dynamic analysis of the combined crossbeam. The dynamic characteristics of the combined three-section crossbeam were extracted by the modal experiment. The FEM of the monolithic crossbeam was modeled to analyze the dynamic characteristic parameters. The comparison of the analysis result and experimental result were shown. The experimental result matched well with the FEM of the monolithic crossbeam without bolted joints. As a result, the influence of the bolted joints could be ignorable in dynamic characteristic for the combined three-section crossbeam.

Dynamic Characteristic Analysis of the Micropump Considering the Diaphragm Stiffness

2008 ◽  
Vol 575-578 ◽  
pp. 1228-1233
Author(s):  
Dan Jiang ◽  
Song Jing Li ◽  
Gang Bao
Keyword(s):  
Dynamic Characteristic ◽  
Flow Rate ◽  
Dynamic Characteristics ◽  
Vibration Mode ◽  
Functional Material ◽  
Characteristic Analysis ◽  
Element Analysis ◽  
Vibration Displacement ◽  
Simulation Results ◽  
The Mathematical Model

Being as a functional material, piezoelectric ceramics is applied to drive a micropump when it is composed to be a thin membrane on a brass film to form a diaphragm. According to the properties of the piezoelectric material, the stiffness of the diaphragm influences the vibration displacement and therefore the supply flow rate of the micropump. This paper focuses on the dynamic characteristic study of the micropump and the stiffness influence of the diaphragm on the characteristics. The mathematical model of the valve-less micropump considering the diaphragm stiffness is developed in order to predict the dynamic characteristics of the piezoelectric valve-less micropump. Using the 3-D finite element analysis (FEA) method, the static and vibration mode of the diaphragm are analyzed to obtain the diaphragm stiffness and natural frequency. The method using Matlab is to predict the pressure and flow rate characteristics of the micropump when the diaphragm stiffness is considered or not. Comparison of the simulation results shows the stiffness of the diaphragm influences the dynamic characteristics of micropumps. It also shows that the method combining FEA software with Matlab provides a possible and effective tool to take the diaphragm stiffness into account when the pressure and flow rate characteristics of micropumps are studied.

scholarly journals Simulation evaluation of dynamic characteristic identification accuracy of sliding bearing considering test error

2021 ◽  
Vol 13 (12) ◽  
pp. 168781402110668
Author(s):  
Runlin Chen ◽  
Chen Du ◽  
Xiaotuan Wang ◽  
Yanchao Zhang ◽  
Kai Liu
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Characteristics ◽  
Low Frequency ◽  
Identification Accuracy ◽  
Single Frequency ◽  
Sliding Bearing ◽  
Test Error ◽  
Simulation Evaluation ◽  
Frequency Excitation ◽  
Excitation Method

Aiming at the dynamic characteristics test bench of sliding bearings, the dynamic model is established. Based on the forward and inverse dynamic problems of the bearing, a simulation evaluation method for the identification accuracy of the sliding bearing dynamic characteristics is proposed and the algorithm is verified. The identification errors of dynamic characteristic coefficients under different excitation frequencies are analyzed, the sensitivities of single frequency excitation method and dual-frequency excitation method to test error are contrastively analyzed, and the influence laws of dynamic characteristic identification accuracy of sliding bearing are evaluated. Based on which the traditional single frequency excitation method has been improved. The dynamic characteristic test should be carried out respectively in the low frequency range and the high frequency range. The main stiffness and cross damping are the average of two tests, the main damping is the identification value in the high frequency, and the cross stiffness is the identification value in the low frequency. That will effectively reduce the impact of test error. The obtained data and laws could support the improvement of the dynamic characteristics test method of sliding bearings and the confirmation of test parameters, thereby the accuracy of dynamic characteristics identification is improved.

scholarly journals INFLUENCE OF A LIQUID ON THE NATURAL FREQUENCIES OF ALMOST CIRCULAR PLATES

2014 ◽  
Vol 06 (05) ◽  
pp. 1450052 ◽  
Author(s):  
MANUEL GASCÓN-PÉREZ ◽  
PABLO GARCÍA-FOGEDA
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Vibration Mode ◽  
Normal Modes ◽  
Virtual Mass ◽  
Circular Plates ◽  
Hankel Transformation ◽  
Fluid System ◽  
Surrounding Fluid ◽  
Good Agreement

In this work, the influence of the surrounding fluid on the dynamic characteristics of almost circular plates is investigated. First the natural frequencies and normal modes for the plates in vacuum are calculated by a perturbation procedure. The method is applied for the case of elliptical plates with a low value of eccentricity. The results are compared with other available methods for this type of plates with good agreement. Next, the effect of the fluid is considered. The normal modes of the plate in vacuum are used as a base to express the vibration mode of the coupled plate-fluid system. By applying the Hankel transformation the nondimensional added virtual mass 2 increment (NAVMI) are calculated for elliptical plates. Results of the NAVMI factors and the effect of the fluid on the natural frequencies are given and it is shown that when the eccentricity of the plate is reduced to zero (circular plate) the known results of the natural frequencies for circular plates surrounded by liquid are recovered.

Research on Dynamic Characteristics of Disc Brake

2011 ◽  
Vol 383-390 ◽  
pp. 2845-2849
Author(s):  
Fei Chen ◽  
You Fu Hou ◽  
Hong Yun Wu ◽  
He Wei Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Experimental Method ◽  
Dynamic Characteristics ◽  
Vibration Mode ◽  
Disc Brake ◽  
Experiment Method ◽  
Improvement Measures ◽  
The Time Domain ◽  
Element Method

To obtain the dynamic characteristics of the disc brake, the modal of the disc of brake is analyzed by finite element method and experimental method, the natural frequency and the vibration mode of the disc are obtained, the research shows that the result of finite element method is basically identical with the experimental method. The axial vibration of the disc and tangential vibration of the brake pad are tested by experiment method and the time domain charts are obtained, the main vibration frequencies of brake are studied, the vibration cause is analyzed and the corresponding improvement measures are put forward.

Simulation and Test Study on Dynamic Characteristic of Air Spring with Auxiliary Chamber

2013 ◽  
Vol 341-342 ◽  
pp. 391-394 ◽  
Author(s):  
Li Qing Sun ◽  
Zhong Xxing Li ◽  
Xu Feng Shen ◽  
Jia Yi Zhu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Characteristic ◽  
Dynamic Characteristics ◽  
Excitation Frequency ◽  
Initial Pressure ◽  
Element Model ◽  
Air Spring ◽  
Chamber Volume ◽  
Lower Excitation

In order to improve dynamic characteristics of air spring with auxiliary chamber, finite element model of air spring R1A390-295 with auxiliary chamber connected with pipe is established,and through analysis to the dynamic characteristics of the model, influence discipline of sitffness characteristics to air spring with different pipe, different auxiliary chamber or different initial pressure are analysed under different excitation. The result show that:minor dynamic sitffness is obtained by using larger pipe or under lower excitation frequency,and as volume of auxiliary chamber increases, the spring dynamic sitffness will decrease accordingly and its amplitude tends to gentle,and influence for decreasing the spring dynamic sitffness is not obvious by continuing to increase the auxiliary chamber volume; the spring dynamic sitffness will increases as initial pressure increases. The validity of Finite element model is verified through dynamic characteristic test .

Analysis and Application of Acoustic Emission Signals in Accurate Grinding Machining

2006 ◽  
Vol 315-316 ◽  
pp. 868-871
Author(s):  
Ya Dong Gong ◽  
H. Li ◽  
Tian Biao Yu ◽  
Wan Shan Wang
Keyword(s):  
Acoustic Emission ◽  
Influencing Factors ◽  
Characteristic Parameters ◽  
Ae Signals

This paper analyzes Acoustic Emission (AE) signals in accurate-grinding machining, and influencing factors related in the process. It is indicated that there is favorable corresponding relationship between AE signals with different characteristic parameters and accurate-grinding status, which can be used to monitor the accurate-grinding machining and grinding quality.

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