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SAE International Journal of Passenger Cars Mechanical Systems
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Application of Boundary Characteristic Orthogonal Polynomials on Vibration of Circular Plates with Circular Eccentric Holes

SAE International Journal of Passenger Cars - Mechanical Systems

Camfil Farr Canada Inc.-Alfin Leo
Concordia University-Khodabakhsh Saeedi, Rama Bhat, Ion Stiharu
  • Journal Article
  • 2011-01-1688
Published 2011-05-17 by SAE International in United States
A new approach is proposed to solve for the eigen-values and eigen-functions of circular plates with circular holes by using the Rayleigh Ritz Method. In this method, the spatial solution is expanded into separable functions in terms of polar coordinates. While trigonometric functions are used along the circumferential direction, the Boundary Characteristic Orthogonal Polynomials build the radial shape functions. Written in terms of the assumed functions, the potential and kinetic energies are modified in order to account for the holes. Although the proposed approach is applicable for plates with different boundary conditions and different hole shapes, the free vibration of a clamped circular plate with circular holes is considered in the present study. The edges of the holes are free. Four different case studies are carried out. The results of the Rayleigh Ritz Method are compared with those available in the literature.
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Dynamics of Coupled Nonlinear Hypoid Gear Mesh and Time-varying Bearing Stiffness Systems

SAE International Journal of Passenger Cars - Mechanical Systems

Univ of Cincinnati-Junyi Yang, Teik Lim
  • Journal Article
  • 2011-01-1548
Published 2011-05-17 by SAE International in United States
A new capability to analyze the dynamic interaction of nonlinear hypoid gear mesh characteristics and time-varying bearing stiffness is proposed. Both backlash nonlinearity and time-varying mesh parameters, such as mesh stiffness, mesh point and line-of-action, are included in the nonlinear hypoid gear mesh model. The time-varying bearing stiffness behavior due to the changing orbital position of rolling elements is also modeled. A practical application is studied to reveal the dynamic characteristics of the complex interactions. Dynamic simulation results show that dynamic mesh force is relatively insensitive to the temporal variation in the bearing stiffness. On the other hand, the dynamic bearing loads are affected significantly by the time-varying bearing stiffness, especially in the case of heavy drive torque load without the occurrence of jump response phenomenon. However, for the case of light load condition assuming time-invariant mesh parameters, the dynamic bearing loads are insensitive to time-varying bearing stiffness. The analysis also reveals that the presence of appropriate backlash nonlinearity can stabilize the parametric resonance caused by the time-varying bearing stiffness for the case of light…
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Tire and Road Input Modeling for Low-Frequency Road Noise Prediction

SAE International Journal of Passenger Cars - Mechanical Systems

Toyota Motor Corporation-Seigo Yamamoto, Minoru Tsuchiyama , Hiroo Yamaoka
Toyota Technical Development Corporation-Ichiro Kido, Sagiri Ueyama, Masato Hashioka
  • Journal Article
  • 2011-01-1690
Published 2011-05-17 by SAE International in United States
This paper presents a modeling method for prediction of low-frequency road noise in a steady-state condition where rotating tires are excited by actual road profile undulation input.The proposed finite element (FE) tire model contains not only additional geometric stiffness related to inflation pressure and axle load but also Coriolis force and centrifugal force effects caused by tire rotation for precise road noise simulation. Road inputs act on the nodes of each rib in the contact patch of the stationary tire model and move along them at the driving velocity. The nodes are enforced to displace in frequency domain based on the measured road profile.Tire model accuracy was confirmed by the spindle forces on the rotating chassis drum up to 100Hz where Coriolis force effect should be considered. Full vehicle simulation results showed good agreement with the vibration measurement of front/rear suspension at two driving velocities.
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Nonlinear Characteristics Study and Parameter Optimization of DMF-RS

SAE International Journal of Passenger Cars - Mechanical Systems

Wei Sun, Yinong Li, Jingying Huang
  • Journal Article
  • 2011-01-1550
Published 2011-05-17 by SAE International in United States
Dual Mass Flywheel (DMF) has better damping capacity than the conventional Clutch Torsional Damper (CTD), and is more suitable for diesel engine, Dual Clutch Transmission (DCT) and hybrid vehicles. Dual Mass Flywheel-Radial Spring (DMF-RS) is a DMF that has a specific structure. In the light of working principal and static analysis, the hard nonlinear torsional stiffness of DMF-RS is derived in this paper, which is very important to a driveline damper. On this basis, a simulation model is developed to analyze the dynamic response of DMF and CTD excited by idle engine; the comparison of the two dampers reveals that the DMF has better damping capacity, high-frequency filter ability and can reduce crankshaft load. Further, the nonlinear vibration transfer behavior of DMF-RS and its influencing factors are investigated using the method of harmonic balance; it not only indicates that appropriate damping ratio will avoid unstable jump and bifurcation, but also illustrates that resonance frequency of DMF-RS is lower than that of CTD. Besides, the virtual prototype is optimized by Generalized Reduced Gradient (GRG) method, and…
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Direct Aeroacoustic Simulation of Flow Impingement Noise in an Exhaust Opening

SAE International Journal of Passenger Cars - Mechanical Systems

Exa Corporation-Robert E. Powell, Dena Hendriana
General Motors LLC-Brian Gutzeit, Kevin Golsch, Gregory Fadler
  • Journal Article
  • 2011-01-1517
Published 2011-05-17 by SAE International in United States
Unusual noises during vehicle acceleration often reflect poorly on customer perception of product quality and must be removed in the product development process. Flow simulation can be a valuable tool in identifying root causes of exhaust noises created due to tailpipe openings surrounded by fascia structure. This paper describes a case study where an unsteady Computational Fluid Dynamics (CFD) simulation of the combined flow and acoustic radiation from an exhaust opening through fascia components provided valuable insight into the cause of an annoying flow noise. Simulation results from a coupled thermal/acoustic analysis of detailed tailpipe opening geometry were first validated with off-axis microphone spectra under wide open throttle acceleration. After studying the visualizations of unsteady flow velocity and pressure from the CFD, a problem that had proved difficult to solve by traditional “cut and try” methods was corrected rapidly.
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Effect of Contamination on Acoustic Performance of Microperforated Panels

SAE International Journal of Passenger Cars - Mechanical Systems

University of Kentucky-J. Liu, D. W. Herrin
  • Journal Article
  • 2011-01-1627
Published 2011-05-17 by SAE International in United States
Microperforated panel (MPP) absorbers are rugged, non-combustible, and do not deteriorate over time. That being the case, they are especially suitable for long term use in harsh environments. However, the acoustic performance is modified when contaminated by dust, dirt, or fluids (i.e. oil, water). This paper examines that effect experimentally and correlates the absorption performance with Maa's theory for micro-perforated panels. Transfer impedance and absorption coefficient are measured for different levels of aluminum oxide and carbon dust accumulation. The amount of dust contamination is quantified by measuring the luminance difference between clean and dirty panels with a light meter. The porosity and hole diameter in Maa's equation are modified to account for dust obstruction. The effect of coating the MPP with oil, water, and other appropriate viscous fluids was also measured. This effect was simulated by modifying the viscous factor in Maa's equation.
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Experimental Study of the Factors Affecting Transfer Case NVH Performance in 4-Lo Operation Mode

SAE International Journal of Passenger Cars - Mechanical Systems

American Axle & Manufacturing-Haris Ligata, Habib Rehman, James Rutter, Jason Ley
  • Journal Article
  • 2011-01-1558
Published 2011-05-17 by SAE International in United States
In this paper, the results of the experimental study are presented to describe the impact of several gear design and manufacturing related factors on NVH performance of a transfer case operating in 4-Lo mode. The investigated gear design factors include lead crowning and profile crowning of the planet gears. The influence of manufacturing and assembly is investigated by varying carrier pinhole tangential position error and carrier pinhole tangential tilt error. The experimental DOE study is performed on chassis dynamometer by using actual vehicle. The strategically placed accelerometers and microphones are used for data acquisition. The results show that, among the gear design related factors, lead modification has larger influence on the NVH performance than profile modification. The study also shows how manufacturing errors influence NVH performance of the transfer case by causing lead misalignment of gears and unequal planet load sharing.
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Active Control of Gear Mesh Dynamics

SAE International Journal of Passenger Cars - Mechanical Systems

Univ of Cincinnati-Mingfeng Li, Jie Duan, Teik Lim
  • Journal Article
  • 2011-01-1635
Published 2011-05-17 by SAE International in United States
Gears are essential parts of many precision power and torque transmitting machines. However, the radiated intensive tonal noise due to the gear meshing is highly undesirable and annoying. In very severe cases, the gear vibrations can reduce the life and performance of the power transmitting components. Typical gearbox vibration and sound spectra contain several dominant narrowband tonal signals that are mixed in with a lower level broadband response signals. Hence, the control of mesh response of gearbox housing belongs to the problem of the rejection or cancellation of periodical disturbance. The frequencies of these tonal signals are related to the number of teeth and rotation speed, and highly predictable. Thus, a feedforward control system was normally adopted. In most of existed applications, an accurate reference based on the frequency information of tachometer pulse train signal is required for this kind of control system. However, in the proposed ANC system, the feedback control with internal model control structure is used. The controller is designed using the inverse modeling technique. In this paper, numerical simulation was conducted…
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Mobility at the Development of Exhaust System

SAE International Journal of Passenger Cars - Mechanical Systems

Faurecia Emissions Control Technologies-Mauricio Monteagudo Galindo
  • Journal Article
  • 2011-01-1523
Published 2011-05-17 by SAE International in United States
This document describes the advantages of using Mobility transfer function simulations during the development of exhaust systems. The automotive industry demands increasingly stringent levels of acceptable interior noise. The exhaust system is an important contributor to the total vehicle noise and vibration and thus is a target for noise reduction. The use of good vibration isolation systems makes it possible to decrease noise in the vehicle interior compartment. In other words, the vibratory motion in automotive structures results in tactile and acoustic responses. This occurs when the energy coming from the engine (source) is transferred by the Exhaust System (path) and then is transformed into Structural Borne Noise received by the Driver (receiver) through the hanging arrangement of the Exhaust System. In this paper, a procedure to apply the Mobility transfer function to exhaust system design is first described and then an example of correlation results between experimental tests and finite element simulations are shown. These simulations are then used in an optimisation phase to define the proper design to meet the targets.The most interesting…
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Investigation of the Acoustic Performance of After Treatment Devices

SAE International Journal of Passenger Cars - Mechanical Systems

Ain Shams University-Tamer Elnady, Sara Elsaadany
University of Kentucky-D. W. Herrin
  • Journal Article
  • 2011-01-1562
Published 2011-05-17 by SAE International in United States
Diesel engines produce harmful exhaust emissions and high exhaust noise levels. One way of mitigating both exhaust emissions and noise is via the use of after treatment devices such as Catalytic Converters (CC), Selective Catalytic Reducers (SCR), Diesel Oxidation Catalysts (DOC), and Diesel Particulate Filters (DPF). The objective of this investigation is to characterize and simulate the acoustic performance of different types of filters so that maximum benefit can be achieved. A number of after treatment device configurations for trucks were selected and measured. A measurement campaign was conducted to characterize the two-port transfer matrix of these devices. The simulation was performed using the two-port theory where the two-port models are limited to the plane wave range in the filter cavity. These models are implemented in SIDLAB Software for the simulation of low frequency sound propagation in ducts, and SIDLAB was used to predict the transfer matrix of the tested configurations. This paper presents guidelines for dividing these complicated systems into a number of simple 1D elements. Specifically, strategies for modeling the side inlet and…
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