Modeling and Validation of Rotational Vibration Responses for Accessory Drive System—Part II: Simulations and Analyses

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Wen-Bin Shangguan ◽  
Xiang-Kun Zeng
Keyword(s):  
Excitation Frequency ◽  
General Purpose ◽  
Drive System ◽  
Dynamic Tension ◽  
Serpentine Belt ◽  
Rotational Vibration ◽  
Vibration Responses ◽  
System Part ◽  
Stiffness And Damping ◽  
General Purpose Software

This is the second part of the paper for modeling and validation of the rotational vibration responses for an accessory drive system. The unified formulas for modeling the rotational vibration of an accessory drive system are presented. In the modeling of an accessory drive system, the damping and stiffness of a belt are regarded as the function of the excitation frequency of an engine and the amplitude of belt stretching. Additionally, the creeping effect of a belt on the pulley wrap arc is included in the model. A general purpose software for calculating the rotational vibration of an accessory drive system is developed, based on the presented unified formulas. One accessory drive system with seven pulleys, a tensioner, and a serpentine belt is used as a studying example to demonstrate the unified formulas and the procedure for obtaining the rotational vibration. In the simulation of the accessory drive system, the stiffness and damping of the belt, the friction coefficient between the belt and pulley, and the excitation torques with multifrequency components from the crankshaft torsional vibration are obtained from the experiment in the first part of this paper. The static tension and steady-state tension of each belt span, along with the natural frequency of the accessory drive system, rotational vibrations of the driven pulley and tensioner arm, and the dynamic tension of the belt span are calculated and compared well with the experimental data, which validate the presented unified formulas and the developed general purpose software. The modeling method and the procedure described in this paper are instructive for designing an accessory drive system.

Modelling of the rotational vibrations of the engine front-end accessory drive system: a generic method

2017 ◽  
Vol 231 (13) ◽  
pp. 1780-1795 ◽  
Author(s):  
Xiao Feng ◽  
Wen-Bin Shangguan ◽  
Jianxiang Deng ◽  
Xingjian Jing ◽  
Waizuddin Ahmed
Keyword(s):  
High Efficiency ◽  
Equations Of Motion ◽  
Drive System ◽  
Slip Ratio ◽  
System A ◽  
Runge Kutta Method ◽  
Front End ◽  
Rotational Vibration ◽  
Vibration Responses ◽  
Drive Systems

To investigate the rotation vibration dynamics of the pulleys and the tension arms, and to estimate the vibrations of the belts and the slip ratio between the belt and the pulleys in the engine front-end accessory drive systems, a systematic modelling and analytical method is proposed for engine front-end accessory drive systems; this can be used for modelling engine front-end accessory drive systems with different layouts and different numbers of tensioners, including automatic and fixed tensioners. In the modelling, the rotational pulleys are classified as fixed-axis pulleys and moveable-axis pulleys (such as the pulley in the tensioner). Moreover, the belt spans are classified as the belt spans between the two fixed pulleys, and the belt spans adjacent to the pulley of a tensioner. The equations of motion for each type of pulley and the tension calculation equations for each type of belt span are developed. In this way, the equations of motion for all the pulleys and the tensioner arms can be obtained easily, irrespective of the layout of the tensioners. To obtain the dynamic rotational vibration responses of an engine front-end accessory drive system by the conventional Runge–Kutta method, high-efficiency algorithms or methods are also proposed for calculating the tangent-point coordinates between a belt and the adjacent pulleys and the belt length of the contact arc on one pulley. The proposed modelling and analysis methods are validated by modelling different layouts of the engine front-end accessory drive systems with different types and numbers of tensioners, and also by comparisons between the calculated dynamic vibration responses of the pulleys and the belts and the real experimental data.

Experimental Study of Dynamic Characteristics and Model Parameter Identification of Tensioner

2014 ◽  
Vol 988 ◽  
pp. 332-337
Author(s):  
Hong Yun Wang ◽  
Xiang Kun Zeng ◽  
Ji Yong Zhao
Keyword(s):  
Parameter Identification ◽  
Nonlinear Model ◽  
Dynamic Characteristics ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Identification Method ◽  
Serpentine Belt ◽  
Drive Systems ◽  
Set Up ◽  
Stiffness And Damping

Tensioners play a predominant role in the dynamic behavior of serpentine belt drive systems. The experimental set-up was carried out to study the dynamic characteristics of tensioner. Experimental results illustrate that tensioner shows hysteresis nonlinear dynamic characteristics, and dynamic stiffness and damping of slip motion of up stroke of tensioner are related to excitation frequency and amplitude. The first differential nonlinear model of tensioner was determined, and the parameter identification method of the model was introduced. The accurate of the nonlinear model and effectiveness of the parameter identification method was validated.

Nonstick and Stick-Slip Motion of a Coulomb-Damped Belt Drive System Subjected to Multifrequency Excitations

2003 ◽  
Vol 70 (6) ◽  
pp. 871-884 ◽  
Author(s):  
G. Cheng ◽  
J. W. Zu
Keyword(s):  
Dry Friction ◽  
Excitation Frequency ◽  
Solution Procedure ◽  
Friction Torque ◽  
Drive System ◽  
Belt Drive ◽  
Stick Slip ◽  
Harmonic Excitations ◽  
Rotational Vibration ◽  
The Impact

In this paper, the rotational vibration of a belt drive system with a dry friction tensioner subjected to multiple harmonic excitations is studied. The work is focused on the impact of the dry friction torque combined with the multiexcitation frequencies on dynamic characteristics of the system. An analytical solution procedure is developed for the first time to predict two kinds of periodic responses of the system, i.e., nonstop and one-stop motion characterized by the nonstick and stick-slip vibration of the tensioner arm in the system, respectively. Utilizing this method, parametric studies are carried out to obtain the frequency response of a prototypical belt drive system subjected to harmonic excitations from both the driving and driven pulleys. It is found that the tensioner Coulomb friction torque has a significant impact on the amplitude response of the system—it reduces the vibration amplitude of the tensioner arm, but for other components in the belt system it can either decrease or increase the amplitudes under different situations. Furthermore, if the excitation frequency from the driving pulley is larger than or equal to that from the driven pulley, the system vibration amplitudes are much larger than those under the opposite condition.

Design and structural performance measurements of a novel multi-cantilever foil bearing

2014 ◽  
Vol 229 (10) ◽  
pp. 1830-1838 ◽  
Author(s):  
Kai Feng ◽  
Xueyuan Zhao ◽  
Zhiyang Guo
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Load ◽  
Dynamic Stiffness ◽  
Excitation Frequency ◽  
Viscous Damping ◽  
Equivalent Viscous Damping ◽  
Foil Bearing ◽  
Load Tests ◽  
Stiffness And Damping ◽  
Motion Amplitude

With increasing need for high-speed, high-temperature, and oil-free turbomachinery, gas foil bearings (GFBs) have been considered to be the best substitutes for traditional oil-lubricated bearings. A multi-cantilever foil bearing (MCFB), a novel GFB with multi-cantilever foil strips serving as the compliant underlying structure, was designed, fabricated, and tested. A series of static and dynamic load tests were conducted to measure the structural stiffness and equivalent viscous damping of the prototype MCFB. Experiments of static load versus deflection showed that the proposed bearing has a large mechanical energy dissipation capability and a pronounced nonlinear static stiffness that can prevents overly large motion amplitude of journal. Dynamic load tests evaluated the influence of motion amplitude, loading orientation and misalignment on the dynamic stiffness and equivalent viscous damping with respect to excitation frequency. The test results demonstrated that the dynamic stiffness and damping are strongly dependent on the excitation frequency. Three motion amplitudes were applied to the bearing housing to investigate the effects of motion amplitude on the dynamic characteristics. It is noted that the bearing dynamic stiffness and damping decreases with incrementally increasing motion amplitudes. A high level of misalignment can lead to larger static and dynamic bearing stiffness as well as to larger equivalent viscous damping. With dynamic loads applied to two orientations in the bearing midplane separately, the dynamic stiffness increases rapidly and the equivalent viscous damping declines slightly. These results indicate that the loading orientation is a non-negligible factor on the dynamic characteristics of MCFBs.

Tilting Pad Journal Bearings: A Discussion on Stability Calculation, Frequency Dependence, and Pad and Pivot Flexibility

2012 ◽  
Author(s):  
Jason C. Wilkes ◽  
Dara W. Childs
Keyword(s):  
Degrees Of Freedom ◽  
Journal Bearing ◽  
Operating Temperature ◽  
Excitation Frequency ◽  
Full Model ◽  
Stability Calculation ◽  
Damping Coefficients ◽  
Tilting Pad ◽  
Stiffness And Damping ◽  
Tilting Pad Journal Bearing

For several years, researchers have presented predictions showing that using a full tilting-pad journal bearing (TPJB) model (retaining all of the pad degrees of freedom) is necessary to accurately perform stability calculations for a shaft operating on TPJBs. This paper will discuss this issue, discuss the importance of pad and pivot flexibility in predicting impedance coefficients for the tilting-pad journal bearing, present measured changes in bearing clearance with operating temperature, and summarize the differences between measured and predicted frequency dependence of dynamic impedance coefficients. The current work presents recent test data for a 100 mm (4 in) five-pad TPJB tested in load on pad (LOP) configuration. Measured results include bearing clearance as a function of operating temperature, pad clearance and radial displacement of the loaded pad (the pad having the static load vector directed through its pivot), and frequency dependent stiffness and damping. Measured hot bearing clearances are approximately 30% smaller than measured cold bearing clearances and are inversely proportional to pad surface temperature; predicting bearing impedances with a rigid pad and pivot model using these reduced clearances results in overpredicted stiffness and damping coefficients that are several times larger than previous comparisons. The effect of employing a full bearing model versus a reduced bearing model (where only journal degrees of freedom are retained) in a stability calculation for a realistic rotor-bearing system is assessed. For the bearing tested, the bearing coefficients reduced at the frequency of the unstable eigenvalue (subsynchronously reduced) predicted a destabilizing cross-coupled stiffness coefficient at the onset of instability within 1% of the full model, while synchronously reduced coefficients for the lightly loaded bearing required 25% more destabilizing cross-coupled stiffness than the full model to cause system instability. The same stability calculation was performed using measured stiffness and damping coefficients at synchronous and subsynchronous frequencies. These predictions showed that both the synchronously measured stiffness and damping and predictions using the full bearing model were more conservative than the model using subsynchronously measured stiffness and damping, an outcome that is completely opposite from conclusions reached by comparing different prediction models. This contrasting outcome results from a predicted increase in damping with increasing excitation frequency at all speeds and loads; however, this increase in damping with increasing excitation frequency was only measured at the most heavily loaded conditions.

A General-Purpose Software for Menu Design of CAD Projects

1993 ◽  
Author(s):  
Y. C. Pao
Keyword(s):  
Software Package ◽  
Computer Programs ◽  
General Purpose ◽  
Final Report ◽  
Sample Design ◽  
Main Menu ◽  
Sample Application ◽  
User Friendly ◽  
Four Bar Linkage ◽  
General Purpose Software

Abstract A software package MenuCAD has been developed for the general need of designing menu-driven, user-friendly CAD computer programs. The main menu is formatted similar to the major contents in the final report of the design project including Contents, Analysis, Sample Design Cases, Illustrations and Tables, References, and Program Listings. Sub-menus are further divided into items delineating the steps involved in the design. Screen help messages are provided for design of the main menu and sub-menus interactively and for applying the arrow keys on the keyboard to select a sub-menus and a particular item in the sub-menu in order to execute a desired design step. MenuCAD builds the framework, its user has to supplement with a subroutine ExecItem for describing the special features and for directing how each design step should be executed in the project. A CAD design of four-bar linkage project is presented as a sample application of this package.

General purpose software for probability computations?A virtual machine approach

1986 ◽  
Vol 1 (3) ◽  
pp. 161-173
Author(s):  
Maria Adelaide Parisi ◽  
Daniel R. Rehak
Keyword(s):  
Virtual Machine ◽  
General Purpose ◽  
General Purpose Software

Vibration analysis of a multifunctional hybrid composite honeycomb sandwich plate

2018 ◽  
Vol 22 (8) ◽  
pp. 2818-2860 ◽  
Author(s):  
Paul Praveen A ◽  
Vasudevan Rajamohan ◽  
Ananda Babu Arumugam ◽  
Arun Tom Mathew
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Hybrid Composite ◽  
Sandwich Plate ◽  
Core Material ◽  
Sandwich Plates ◽  
Composite Sandwich ◽  
Honeycomb Sandwich ◽  
Vibration Responses ◽  
Stiffness And Damping

In the present study, the free and forced vibration responses of the composite sandwich plate with carbon nanotube reinforced honeycomb as the core material and laminated composite plates as the top and bottom face sheets are investigated. The governing equations of motion of hybrid composite honeycomb sandwich plates are derived using higher order shear deformation theory and solved numerically using a four-noded rectangular finite element with nine degrees of freedom at each node. Further, various elastic properties of honeycomb core materials with and without reinforcement of carbon nanotube and face materials are evaluated experimentally using the alternative dynamic approach. The effectiveness of the finite element formulation is demonstrated by performing the results evaluated experimentally on a prototype composite sandwich plate with and without carbon nanotube reinforcement in core material. Various parametric studies are performed numerically to study the effects of carbon nanotube wt% in core material, core thickness, ply orientations, and various boundary conditions on the dynamic properties of composite honeycomb sandwich plate. Further, the transverse vibration responses of hybrid composite sandwich plates under harmonic force excitation are analyzed at various wt% of carbon nanotubes and the results are compared with those obtained without addition of carbon nanotubes to demonstrate the effectiveness of carbon nanotube reinforcement in enhancing the stiffness and damping characteristics of the structures. The study provides the guidelines for the designer on enhancing both the stiffness and damping properties of sandwich structures through carbon nanotube reinforcement in core materials.

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