Modelling Approach for a High Speed Machine Tool Spindle-Bearing System

2005 ◽  
Author(s):  
Vincent Gagnol ◽  
Belhassen C. Bouzgarrou ◽  
Pascal Ray ◽  
Christian Barra
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
High Speed ◽  
Modal Identification ◽  
Coordinate Frame ◽  
Mass Unbalance ◽  
Spindle Bearing ◽  
Milling Forces ◽  
Bearing System ◽  
Modelling Approach

This paper presents a modelling approach of a high-speed spindle-bearing system based on a finite-element model analysis coupled to an experimental modal identification. Dynamic equations of the rotating entity are obtained using Lagrangian formulation associated with a numerical finite element method based on Timoshenko beam theory. Element kinematics is formulated in a co-rotational coordinate frame. A method for the experimental characterization of the dynamic behavior of a High Speed Machining (HSM) spindle is proposed. The goal of this method is to understand the influence of spindle structure elements on overall dynamic behavior. Each element is individually characterized and is integrated or not into the global model depending on the results. The choice of the finite element type for generating the numeric model is carried out on the basis of modal and harmonic experimental results. High-speed rotational effects including gyroscopic coupling and spin softening effects are investigated. The Campbell diagram indicates the potential critical speed for mass unbalance response and for synchronous excitation representative of the milling forces at tooth impact frequency. Excessive vibration levels at specific node location enable spindle component stress or failure during manufacturing processes to be predicted. The model is a useful tool for qualifying spindles in the manufacturing process and predicting their reliability. The proposed modeling approach can be transferred to other type of spindle.

Prediction of the Structural Dynamic Behavior of High Speed Turning Machine Spindles

2014 ◽  
Vol 555 ◽  
pp. 567-574
Author(s):  
Constantin Dogariu ◽  
Doru Bardac
Keyword(s):  
Finite Element ◽  
Dynamic Behavior ◽  
Dynamic Characteristics ◽  
High Speed ◽  
3D Model ◽  
Element Model ◽  
Structural Dynamic ◽  
Spindle Bearing ◽  
Machine Spindle ◽  
Bearing System

This paper presents a method to investigate the dynamic behavior of a turning high-speed spindle system. The machine tool main spindle unit is focused on direct driven spindle units for high-speed and high performance cutting. This paper analyzes the static behavior for a turning machine spindle and presents some activities to improve the CAD model for such complex systems. The proposed models take into account the spindle with the bearing detailed system. The analysis was performed during the design activity and was based on Finite Elements Method. Starting from the 3D model, using FEM done by means of ANSYS analysis, structural dynamic behavior was evaluated. The aim of this paper is to develop a finite element model of the machine spindle system and use this method for design optimization. The 3D model was designed using the Solidworks CAD software. In order to obtain accurate dynamic characteristics of the spindle-bearing system during the design stage, the finite element model is simulated using dedicated software, and a method in which springs and damping units imitate bearing support. The proposed method can predict the regular pattern in which bearing stiffness and bearing span affect natural frequency and harmonic response. The research demonstrates that this method predicts the dynamic characteristics of the spindle-bearing system therefore it can be a reference for dynamic optimization design of spindle-bearing systems in turn-milling centers. The static analysis was presented in another paper. The thermal analysis will be presented in a future paper.

scholarly journals World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages

2021 ◽  
pp. 25-42
Author(s):  
A. Y Kuzyshyn ◽  
S. A Kostritsia ◽  
Yu. H Sobolevska ◽  
А. V Batih
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Mathematical Models ◽  
Dynamic Behavior ◽  
High Speed ◽  
Vertical Direction ◽  
Rolling Stock ◽  
Air Spring ◽  
Advantages And Disadvantages ◽  
Mechanical Models

Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.

scholarly journals Modeling of Self-Vibratory Drilling Head-Spindle System for Predictions of Bearings Lifespan

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
F. Forestier ◽  
V. Gagnol ◽  
P. Ray ◽  
H. Paris
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Dynamic Behavior ◽  
Potential Risk ◽  
Feed Rate ◽  
High Speed ◽  
Element Model ◽  
Experimental Measurements ◽  
Alternative Response ◽  
Tool Breakage

The machining of deep holes is limited due to inadequate chip evacuation, which induces tool breakage. To limit this drawback, retreat cycles and lubrication are used. An alternative response to the evacuation problem is based on high-speed vibratory drilling. A specific tool holder induces axial self-maintained vibration of the drill, which enables the chips to be split. The chips are thus of a small size and can be evacuated. To anticipate the potential risk of decreased spindle lifespan associated with these vibrations, a model of the behavior of the system (spindle—self-vibrating drilling head—tool) is elaborated. In order to assess the dynamic behavior of the system, this study develops a rotor-based finite element model, integrated with the modelling of component interfaces. The current results indicate that the simulations are consistent with the experimental measurements. The influence of spindle speed and feed rate on bearing lifespan is highlighted.

scholarly journals Multi-body Dynamic Modelling and Error Analysis of Planar Flexible Multilink Mechanism Considering Clearance and Thermal-mechanical Coupling Effect of the Crankshaft-bearing Structure

2021 ◽  
Author(s):  
Hongfan Long ◽  
Zhao Han ◽  
Shuyun Jiang ◽  
Enlai Zheng ◽  
Yongnian Zhang ◽  
...  
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Coupling Effect ◽  
Dynamic Modelling ◽  
Variable Stiffness ◽  
Position Error ◽  
Mechanical Coupling ◽  
Spindle Bearing ◽  
Bearing Structure ◽  
Bearing System

Abstract In order to study the dynamic position accuracy of bottom dead point (BDP) for multilink high-speed precision presses (MHSPPs), it’s essential to develop a dynamic model of planar multilink mechanism with clearance and spindle-bearing structure. Traditional models always neglect the effect of thermal characteristics of spindle-bearing structure, which reduces the prediction accuracy of dynamic model for multilink transmission mechanisms. To overcome the shortcomings of the previous models, a thermal network model (TNM) of the crankshaft-bearing system is established firstly considering the effects of thermal contact resistance and variable stiffness of bearing concerning the temperature rise. Then, dynamic model of the crankshaft-bearing system is built through the finite element method, which includes rigid disk, Timoshenko beam and quasi-statics model of ACBB. On this basis, an improved dynamic model of planar flexible multilink mechanism with clearance considering the thermal-mechanical coupling effect of the crankshaft-bearing structure is developed and the corresponding dynamic error dimension chain between slider and crankshaft is constructed in this work. Compared to the simulation from traditional models, the simulated slider’s BPD position error from the improved model agrees better with experimental data, which verifies the correctness of the proposed model. It’s demonstrated that the punching force and thermally induced variable stiffness of bearing lead to a significant increase of slider’s BDP position error, which reduces the machining precision of MHSPP. Furthermore, the influence of crankshaft speed, contact angle of bearing and clearance size on the slider’s BDP position error is also investigated.

Approximate Explicit Calculation of First Vibration Frequencies of an Unsymmetrical High Speed Rotor

2003 ◽  
Author(s):  
J. F. Antoine ◽  
G. Abba ◽  
C. Sauvey
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Behavior ◽  
Stiffness Matrix ◽  
High Speed ◽  
Explicit Calculation ◽  
Beam Model ◽  
Element Analysis ◽  
Switched Reluctance ◽  
Reluctance Motor

In order to easily predict and optimize the dynamic behavior of a high speed switched reluctance motor, a full analytic model, that gives directly and quickly the three first eigenfrequencies of the rotor, is proposed. The rotor is modelled as a 3 DOF Timoshenko’s beam model. The stiffness matrix is calculated with the Castigliano’s second theorem in structural analysis, which allows to obtain explicitly the eigenfrequencies expression and prevents to use classical finite element analysis. The influence of design and material modifications is studied and the dynamic behavior quickly predicted. The calculation time needed for testing a geometry is strongly smaller than with a finite element analysis.

scholarly journals Nonlinear Dynamic Behavior of Double-Disk Isotropic Rotor System with Axial Rub-Impact

2011 ◽  
Vol 2-3 ◽  
pp. 678-682
Author(s):  
Y. Zhang ◽  
W.M. Wang ◽  
J.F. Yao
Keyword(s):  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
Element Model ◽  
Rotor System ◽  
Self Healing ◽  
Rotor Bearing ◽  
Nonlinear Dynamic Behavior ◽  
Operation Stability ◽  
Bearing System

In the case of considering the shear effect and gyroscopic effect, a finite element model is developed to study the nonlinear dynamic behavior of a double-disk isotropic rotor- bearing system with axial rub-impact in this paper. The influences of rotational speed and initial phase difference on the operation stability of the rotor-bearing system are discussed. It transpires that the response of the rotor system with axial rub- impact is mainly synchronous periodic motion. The vibration signals of axial rub-impact include such as the synchronous signal and the multiple frequencies, in which the synchronous signal is dominating signal. There is no weakening wave phenomenon in time wave plot. All the results are in reasonable good agreement with those observed in engineering. The results of this paper could provide certain reference for fault diagnosis and self-healing of large high-speed rotating machinery system, thus ensuring the safe operation of the system.

Nonlinear Dynamic Behavior of Rotor-Bearing Systems Involving Two Hydrodynamic Oil Films in Series: Prediction and Test Application to High-Speed Turbochargers

2006 ◽  
Author(s):  
Kostandin Gjika ◽  
Chris Groves
Keyword(s):  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
High Speed ◽  
High Performance ◽  
Maximum Speed ◽  
Inlet Temperature ◽  
Oil Viscosity ◽  
Rotor Bearing ◽  
Nonlinear Dynamic Behavior ◽  
Bearing System

In recent years, the desire for increased engine performance has led to technology that increasingly relies on robust and reliable turbocharging solutions. The rotor-bearing system (RBS) operates under extreme oil conditions of low viscosity, high temperatures, low HTHS (high temperature high shear) value and low pressure, while the demand for maximum turbocharger speed and variable geometry technology continues to increase. The rotordynamics instability is a potential issue and the development of RBS is becoming a challenge for design optimization at the development stage. It is further complicated by a lack of industrial standards to guide design practices related to the dynamics and the effort to combine high performance with low cost. This paper concerns the progress on nonlinear dynamic behavior modeling of turbocharger rotor-radial bearing system with fully floating bearing design. A developed fluid dynamics code predicts bearing rotational speed, operating inner and outer bearing clearances, effective oil viscosity taking into account the shear effect and hydrostatic load. The data are input to a rotordynamics code which predicts nonlinear lateral response (total shaft motion) of the rotor-bearing system. The model is validated with a high speed turbocharger RBS of 7.9 mm journal diameter running up to 160,000 rpm (maximum speed) with oil 0W30, 100 °C oil inlet temperature and 4 bar oil feed pressure. The test is conducted on a rotordynamics technology cell. An advanced data acquisition system is implanted and a powerful code is developed for automated data reduction. Prediction/test data show good correlation with the respect of synchronous response and total motion. The predictive model helps the development of high performance RBS with faster development cycle times and increased reliability.

Thermal-structure interaction characteristics of a high-speed spindle- bearing system

2019 ◽  
Vol 137 ◽  
pp. 42-57 ◽  
Author(s):  
Jialan Liu ◽  
Chi Ma ◽  
Shilong Wang ◽  
Sibao Wang ◽  
Bo Yang ◽  
...  
Keyword(s):  
High Speed ◽  
Thermal Structure ◽  
Structure Interaction ◽  
Spindle Bearing ◽  
Bearing System
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