scholarly journals Research on Dynamic Modeling and Application of Kinetic Contact Interface in Machine Tool

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Dan Xu ◽  
Zhixin Feng
Keyword(s):  
Dynamic Modeling ◽  
Equivalent Stiffness ◽  
Theoretic Analysis ◽  
Dynamic Experiment ◽  
Machining Center ◽  
Fitting Method ◽  
Vibration Model ◽  
Stiffness And Damping ◽  
Elastic Mechanics ◽  
In Virtue Of

A method is presented which is a kind of combining theoretic analysis and experiment to obtain the equivalent dynamic parameters of linear guideway through four steps in detail. From statics analysis, vibration model analysis, dynamic experiment, and parameter identification, the dynamic modeling of linear guideway is synthetically studied. Based on contact mechanics and elastic mechanics, the mathematic vibration model and the expressions of basic mode frequency are deduced. Then, equivalent stiffness and damping of guideway are obtained in virtue of single-freedom-degree mode fitting method. Moreover, the investigation above is applied in a certain gantry-type machining center; and through comparing with simulation model and experiment results, both availability and correctness are validated.

Stiffness and Damping Analysis of a Single EHL Contact Between the Rolling Element and Raceways Under Wider Load and Speed Ranges

2012 ◽  
Author(s):  
Yuyan Zhang ◽  
Xiaoli Wang
Keyword(s):  
Viscosity Coefficient ◽  
Equivalent Stiffness ◽  
Solution Convergence ◽  
Vibration Model ◽  
Rolling Element ◽  
Inlet Length ◽  
Motion Characteristics ◽  
Stiffness And Damping ◽  
Increasing Load ◽  
Ehl Contact

The numerical analysis for the equivalent stiffness and damping of a single EHL contact between the rolling element and raceways under wider load and speed ranges is presented. The unsteady EHL model and free vibration model are applied to describe the motion characteristics of the rolling element. The inlet length and dimensionless natural frequency are determined according to the corresponding working load and speed. The DC-FFT method is implemented in order to increase the computational efficiency associated with elastic deformations and the semi-system approach is applied to ensure solution convergence under severe conditions which makes the analysis of stiffness and damping in the larger ranges of load and speed possible. The numerical results demonstrate that the stiffness increases with the increasing load and decreases with speed. However, the changes of the damping are complex, which are different in various load and speed ranges, especially under heavier load and higher speed. It is also indicated that the stiffness and damping increases with the increase in ambient viscosity and the decrease in pressure-viscosity coefficient.

Reducing Vibration Analysis on Travel Stabilizing System of Wheel Loader Based on ProE and ADAMS

2011 ◽  
Vol 199-200 ◽  
pp. 839-844 ◽  
Author(s):  
Ge Ning Xu ◽  
Bing Wu
Keyword(s):  
Vibration Analysis ◽  
Influence Factor ◽  
Characteristic Parameter ◽  
Simulation Method ◽  
Equivalent Stiffness ◽  
Wheel Loader ◽  
Vibration Model ◽  
Stiffness And Damping

The mathematical vibration model of travel stabilizing system of wheel loader which was added to reduce spillage of material was built firstly. The equivalent stiffness and damping of travel stabilizing system were deduced, and influence factor was analyzed. In order to solver the characteristic parameter of the mathematical vibration model, the simulation method based on Pro/E and ADAMS was adopted. The result indicates selecting the appropriate parameter of accumulator is the important factor of the effect of travel stabilizing system. This paper is basic of further research on travel stabilizing system.

Research on Stiffness and Damping Characteristics of Fixed Oily Porous Materials Joint Interface

2011 ◽  
Vol 422 ◽  
pp. 575-579
Author(s):  
Chong Nian Qu ◽  
Liang Sheng Wu ◽  
Jian Feng Ma ◽  
Yi Chuan Xiao
Keyword(s):  
Porous Material ◽  
Porous Materials ◽  
Parallel Plate ◽  
Joint Interface ◽  
Force Model ◽  
Equivalent Stiffness ◽  
Contact State ◽  
Damping Characteristics ◽  
Stiffness And Damping ◽  
Damping Model

In this document, using the anti-squeezed force model in the narrow parallel plate when fluid is squeezed, the equivalent stiffness and damping model is derived. It is further verified that it can increase the stiffness and damping while there are oil between the joint interfaces theoretically. Because the contact state of oily porous material can divide into liquid and solid parts, the document supposes that it is correct and effective to think the stiffness and damping of the two parts as shunt connection.

Study on mechanical properties of high damping viscoelastic dampers

2019 ◽  
Vol 22 (14) ◽  
pp. 2925-2936 ◽  
Author(s):  
Yun Chen ◽  
Chao Chen ◽  
Qianqian Ma ◽  
Huanjun Jiang ◽  
Zhiwei Wan
Keyword(s):  
Mechanical Properties ◽  
Shear Strain ◽  
Strain Amplitude ◽  
Hysteretic Behavior ◽  
Loading Frequency ◽  
Equivalent Stiffness ◽  
Viscoelastic Dampers ◽  
Wide Range ◽  
High Damping Rubber ◽  
Stiffness And Damping

The mechanical properties of the viscoelastic damper made of high damping rubber produced in China are investigated in order to provide the basis for its application. At first, the test on material properties of high damping rubber is conducted. The Mooney–Rivlin model, the Yeoh model and the Prony series are applied for simulating the nonlinear behavior of the high damping rubber with the aid of software ABAQUS. Then, three viscoelastic dampers with different sizes are tested under cyclic loading. The effects of strain amplitude and loading frequency on hysteretic behavior of dampers are analyzed. Viscoelastic dampers possess large deformation capability, stable energy-dissipation capacity and good fatigue-resisting property. The effect of strain amplitude is much more significant than loading frequency. The hysteretic behavior of the dampers is simulated by the Bouc–Wen model and the model of the equivalent stiffness and damping, respectively. The prediction results by using the Bouc–Wen model are in good agreement with the experimental results, which indicates that the Bouc–Wen model is applicable to simulate the mechanical properties of high damping viscoelastic dampers with a wide range of shear strain. As to the model of equivalent stiffness and damping, it has the advantages of clear concept and simple calculation. However, the good accuracy of prediction can be obtained only when the shear strain is not greater than 60%.

Research on Vibration Model of Special Vehicle Based on Dual-Mass System

2013 ◽  
Vol 385-386 ◽  
pp. 89-92 ◽  
Author(s):  
Ya Jun Shao ◽  
Qin He Gao ◽  
Hong Jie Cheng
Keyword(s):  
Characteristic Curve ◽  
Suspension System ◽  
Mass System ◽  
Nonlinear Characteristics ◽  
Actual Structure ◽  
Vibration Model ◽  
Special Vehicle ◽  
Set Up ◽  
Stiffness And Damping ◽  
The Mathematical Model

Taking a special vehicle vibration system as the research object, according to the actual structure of the chassis, the spring damping and stiffness of the nonlinear characteristics and the tire vertical elastic accounted, a nonlinear vibration model of special vehicle based on dual-mass-system is set up. The tire radial stiffness value is analyzed in Ansys, a simulation is performed by leading the mathematical model of suspension system into Adams, a characteristic curve of stiffness and damping of suspension system is obtained.

Dynamic Analysis for Motor-Powered Periotomes in Dentistry

2018 ◽  
Author(s):  
Jianping Lin ◽  
Om A. Sharma ◽  
Wooram Park
Keyword(s):  
Dynamic Modeling ◽  
Tooth Extraction ◽  
Alveolar Bone ◽  
Extraction Procedure ◽  
Procedure Time ◽  
Detailed Consideration ◽  
Hand Motion ◽  
Long Time ◽  
Design Options ◽  
Stiffness And Damping

A periotome is a hand-held manual instrument that dentists use during tooth extraction. Using the sharp blade at the tool tip, dentists cut the periodontal ligaments that bonds the alveolar bone and the cementum surrounding the roots of teeth. Since this procedure usually requires dentists to repeatedly apply a certain level of force on the hand-held tool during the long-time procedure, it leads to dentists’ fatigue on their hands, inaccurate hand motion, and patients’ discomfort. Motorized periotomes can significantly improve the tooth extraction procedure by decreasing the force required from a dentist and reducing the procedure time. In this paper, we consider simple designs for motor-powered periotomes focusing on dynamic behaviors. Since the motor inside the tool creates motion and the hand-held tool moves as a result of dynamic response, the analysis requires detailed consideration of many factors such as tool mass, hand stiffness and damping. The motion of the tool tip should be monitored in this analysis to maximize the cutting performance. The analysis results will be used for choosing design options and parameters. This approach will be demonstrated using dynamic modeling and computer simulations.

Nonlinear Grey-box Identification of a Landing Gear based on Drop Test Data

2020 ◽  
Author(s):  
Elias Dias Rossi Lopes ◽  
Helon Vicente Hultmann Ayala
Keyword(s):  
Control Design ◽  
Simulated Data ◽  
Federal Aviation Administration ◽  
Landing Gear ◽  
Drop Test ◽  
Equivalent Stiffness ◽  
Gear Design ◽  
Drop Tests ◽  
Adequate Evaluation ◽  
Stiffness And Damping

In many aircraft applications, especially on an antiskid control design, it is important to understand and consider the gear walk phenomenon, which is characterized by the deflection on the landing gear structure due the high braking force acting at the tire contact with the ground. This phenomenon is observed on drop tests, and its prediction on landing gear design depends on an adequate evaluation of the equivalent stiffness and damping of the structure, which is difficult, since they depend on the mechanism configuration. In this paper, it is presented a grey-box identification methodology for estimating these parameters of the landing gear, based on simulated data of a drop test. As the drop tests are mandatory obligatory for certificating modern aircraft according to e.g. Federal Aviation Regulations (FARs) by the Federal Aviation Administration (FAA), we hope to introduce a method based on measurements that are available at the design phase. The method will be useful to decrease men/hour costs and increase reliability by enabling better and more accurate anti-skid design.

Theoretic Analysis on the Influence of the Press-Brake Manufacturing Precision on the Bending Precision of Sheet-Metal

2014 ◽  
Vol 633-634 ◽  
pp. 883-886
Author(s):  
Qian Li ◽  
Ying Sun ◽  
Ying Ya Huang ◽  
Gang He ◽  
Deng Lin Zhu
Keyword(s):  
Sheet Metal ◽  
High Strength ◽  
Theoretic Analysis ◽  
Spring Back ◽  
Angle Error ◽  
Development Cycle ◽  
The Press ◽  
Linearity Error ◽  
Processing Errors ◽  
Elastic Mechanics

The bending sheet metal inevitably exist bending errors including angle error, linearity error and length error of sideline for reasons that the structure of press brake, the manufacturing precision of press brake and mould and the inhomogeneous characteristics of processed sheet metal. The processing errors of sheet metal can affect the assemblage, increasing subsequent repair to the mold and forming calibration, extending the product development cycle, restricting the further promotion and application of bending forming, especially on the forming high strength and high spring-back sheet metal. The PBH110-3100 CNC press brake in Jiangsu Yawei Co.Ltd. is studied to increase the bending precision of press brake in this study. The bending errors in press break are analyzed in depth according to the elastic mechanics theory, and the rule that the manufacturing precision of press brake affect the press precision is educed. The analysis results have real significance on improving the press precision and reliability of press brakes.

A Test Rig for Air Bearings Dynamic Characterization

2005 ◽  
Author(s):  
E. Bellabarba ◽  
R. Ruiz ◽  
S. Di´az ◽  
V. Rastelli
Keyword(s):  
Dynamic Properties ◽  
Excitation Frequency ◽  
External Diameter ◽  
Air Bearings ◽  
Equivalent Stiffness ◽  
Dynamic Characterization ◽  
Dynamic Forces ◽  
Present Design ◽  
Rotation Plane ◽  
Stiffness And Damping

This paper describes the design and operation of an experimental facility for measurement of equivalent stiffness and damping of air bearings. The rig uses two magnetic bearings to impose any given orbit to the journal, including displacement in two perpendicular directions on the rotation plane and tilting on the conical mode. Dynamic forces are measured directly on the test bearing housing. Data is gathered and processed using PC based data acquisition boards and software. Only the stiffness and damping coefficients of the fluid film are calculated as a function of the excitation frequency, being it synchronous or not. The present design allows testing air bearings up to 44 mm in external diameter and at frequencies up to 1 KHz. Preliminary testing was performed on this research that demonstrates the capability of the apparatus to measure the dynamic properties with ease and accuracy.

Prediction of Resonant Response of Shrouded Blades With 3D Shroud Constraint

1998 ◽  
Author(s):  
B. D. Yang ◽  
J. J. Chen ◽  
C. H. Menq
Keyword(s):  
Relative Motion ◽  
Normal Load ◽  
Three Dimensional ◽  
Force Model ◽  
Resonant Response ◽  
Equivalent Stiffness ◽  
Stick Slip ◽  
Contact Plane ◽  
Blade System ◽  
Stiffness And Damping

In this paper, the 3D shroud contact kinematics of a shrouded blade system is studied. The assumed blade motion has three components, namely axial, tangential, and radial components, which result in a three dimensional relative motion across the shroud interface. The resulting relative motion can be decomposed into two components. The first one is on the contact plane and can induce stick-slip friction. The other component is perpendicular to the contact plane and can cause variation of the contact normal load and, in extreme circumstances, separation of the two contacting surfaces. In order to estimate the equivalent stiffness and damping of the shroud contact an approach is proposed. In this approach, the in-plane slip motion is assumed to be elliptical and is decomposed into two linear motions along the principal major and minor axes of the ellipse. A variable normal load friction force model (Yang and Menq, 1996) is then applied separately to each individual linear motion, and the equivalent stiffness and damping of the shroud contact can be approximately estimated. With the estimated stiffness and damping, the developed shroud contact model is applied to the prediction of the resonant response of a shrouded blade system. The effects of two different shroud constraint conditions, namely 2D constraint and 3D constraint, on the resonant response of a shrouded blade system are compared and the results are discussed.

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