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Viewing 1 to 30 of 19552
2017-06-05
Technical Paper
2017-01-1820
Martin Sopouch, Josip Hozmec, Alessandro Cadario
This paper presents a simulation environment and methodology for noise and vibration analyses of a driven rear axle in a bus application, with particular focus on medium to high frequency range (400 Hz to 3 kHz). The workflow demonstrates structure borne noise and sound radiation analyses. The fully flexible Multi–Body Dynamics (MBD) model - serving to cover the actual mechanical excitation mechanisms and the structural domain – includes geometrical contacts of hypoid gear in the central gear and planetary gear integrated at hubs, considering non-linear meshing stiffness. Contribution of aforementioned gear stages, as well as the propeller shaft universal joint at the pinion axle, on overall axle noise levels is investigated by means of sensitivity analysis. Based on the surface velocities computed at the vibrating axle-housing structure the Wave Based Technique (WBT) is employed to solve the airborne noise problem and predict the radiated sound.
2017-06-05
Technical Paper
2017-01-1808
Francis Nardella
In a previous report, it was shown that power transmission through the camshaft reduced the first mode natural frequency of the powertrain and translated its convergence with dominant engine excitatory harmonics to a lower engine speed resulting in a marked reduction in torsional vibration for geared 6 cylinder compression ignition engines for aviation. This report describes a sweep though 2 and 4 stroke engines with differing numbers of cylinders configured as standard gear reduction (SGRE) and with power transmission through the camshaft (CDSE). Four and 6 cylinder engines were modeled as opposed boxer engines and 8, 10 and 12 cylinder engines were modeled as 180-degree V-engines. Mass-elastic models of the different engine power train configurations were modeled using the torsional vibration module in Shaft Designer obtained from SKF (Svenska Kullagerfabriken). Crankshaft, camshaft, gearing, pistons, piston pins and connecting rods with bolts were modeled in Solidworks.
2017-06-05
Technical Paper
2017-01-1863
Bhaskar Avutapalli, Mayuresh Pathak, Shalini Solipuram, Ken Buczek, Aaron Lock
Road noise and speech intelligibility are becoming ever more important, irrespective of the vehicle size, due to vehicle refinement as well as connectivity with mobile phones. With better aerodynamic designs, development of refined powertrains, and a tectonic shift from I.C. engine to electric motors, road noise will play an influential role for the customer. This paper describes the efforts undertaken to identify the road noise paths and develop countermeasures for a compact SUV vehicle. A hybrid test / CAE approach was followed to improve road noise performance of this vehicle. This effort involved creating tire models from physical hardware, creating synthesized road-load input from data taken on roads. Significant efforts were made to ensure model quality; focus on performing component level tests like bushing / damper characterization at high frequencies, modal correlation, IPI, NTF, and measurement of noise levels due to road input all ensured a high fidelity model.
2017-06-05
Technical Paper
2017-01-1892
Yosuke Tanabe, Masanori Watanabe, Takafumi Hara, Katsuhiro Hoshino, Akira Inoue, Masaru Yamasaki
Predicting vibration of motor gearbox assembly driven by a PWM inverter in an early development stage is demanding, because the assembly is one of the dominant noise sources of electric vehicle (EV). In this paper, we propose a simulation model that can predict the transient vibration excited by gear meshing, reaction force from mount and electromagnetic forces including carrier frequency component of inverter up to 10 kHz. By employing the techniques of structural model reduction and state space modeling, the proposed model enables to predict the vibration of assembly in operating condition to simulate with a system level EV simulator. A verification test was conducted to compare the simulation result with running test result of EV. Although the absolute value of simulation is 10 dB different from test at most, we conclude that the model can well predict the trend of the dominant order vibration caused by the electromagnetic force of motor including the carrier frequency of inverter.
2017-06-05
Technical Paper
2017-01-1780
Yong Xu
Research Objective: For MT vehicles, gearbox rattle is a common NVH problem which influences the comfort level of vehicle. In order to prevent rattle in the design phase of vehicle, this work aimed to study the excitation mechanism and influence factors of gearbox rattle, and then to propose effective measures. Methodology: First, the root cause of gearbox rattle problem was studied with the aid of classical dynamical theories. And then the simulation model of vehicle powertrain system was built via Matlab-Simulink. Then some critical parameters of the model and some experiential optimum proposals were selected to perform a sensitivity analysis on the torsional vibration, which is the root cause of rattle. Referring the simulation results, the dual-mass flywheel was selected as the most effective solution to gearbox rattle. Results: The simulation results indicated the critical parameters for optimization to prevent gearbox rattle problem in the design phase of the vehicle.
2017-06-05
Technical Paper
2017-01-1802
Dong chul Lee, Insoo Jung, Jaemin Jin, Stephan Brandl, Mehdi Mehrgou
Classical approaches to development require a lot of time and cost to make samples involved the major design factors, which is why there have been recent researches to improve the efficiency of the development through a variety of simulation techniques. NVH simulation is of importance in this advanced phase, the design of all the parts should be satisfactory from the NVH point of view during the first phase of the project. This paper presents such an approach of simulation for the prediction radiated noise from a diesel engine with integrated powertrain model with changing combustion excitation. For changing combustion excitation, the cylinder pressure is measured and used as an input for simulation. The simulation model is validated with comparing the result of experiment in specified frequency ranges that the level of the noise is made louder than the development target.
2017-06-05
Technical Paper
2017-01-1831
Longchen Li, Wei Huang, Hailin Ruan, Xiujie Tian, Keda Zhu, Melvyn Care, Richard Wentzel, Xiaojun Chen, Changwei Zheng
The control strategy design of vehicle active noise control (ANC) relies too much on experiment experience, it costs a lot to gather mass data and the experimental results lack representation. To solve the problems, a new control strategy optimization method based on the Genetic Algorithm is proposed. First, a vehicle cabin sound field simulation model is built by sound transfer function. Based on the filtered-X Least Mean Squares (FX-LMS) algorithm and the vehicle cabin sound field simulation model, a vehicle ANC simulation model is proposed and verified by a vehicle field test. Furthermore, the Genetic Algorithm is used as a strategy optimization tool to optimize an ANC control strategy parameter set based on the vehicle ANC simulation model. The optimized results provide a reference for the ANC control strategy design of the vehicle.
2017-06-05
Technical Paper
2017-01-1904
Tan Li, Ricardo Burdisso, Corina Sandu
Tire-pavement interaction noise (TPIN) is a dominant source for passenger cars and trucks above 40 km/h and 70 km/h, respectively. TPIN is mainly generated from the interaction between the tire and the pavement. In this paper, twenty-two tires of the same size (16 in. radius) but with different tread patterns were tested on a non-porous asphalt pavement. For each tire, the noise data were collected using an on-board sound intensity (OBSI) system at five speeds in the range from 45 to 65 mph. The OBSI system used an optical sensor to record a once-per-revolution signal to monitor the vehicle speed. This signal was also used to perform order tracking analysis to break down the total tire noise into two components: tread pattern-related noise and non-tread pattern-related noise.
2017-06-05
Technical Paper
2017-01-1766
Dirk von Werne, Stefano Orlando, Anneleen Van Gils, Thierry Olbrechts, Ivan Bosmans
Methodology to secure cabin noise and vibration targets is presented. Early in the design process, typically in the Joint Definition Phase, Targets are cascaded from system to component level to comply to the overall cabin noise target in various load cases. During the Detailed Design Phase, 3D simulation models are build up to further secure and refine the vibro-acoustic performance of the cabin noise related subsystems. Noise sources are estimated for the target setting based on analytical and empirical expressions from literature. This includes various types of engine noise – fan, jet, and propeller noise – as well as turbulent boundary layer noise. For other noise sources, ECS and various auxiliaries, targets are set such as to ensure the overall cabin noise level. To synthesize the cabin noise, these noise sources are combined with estimates of the noise transfer through panels and the cavity effect of the cabin. This part is again based on analytical and empirical formulations.
2017-06-05
Technical Paper
2017-01-1878
Kevin Verdiere, Raymond Panneton, Noureddine Atalla, Saïd Elkoun
A poroelastic characterization of open-cell porous materials using an impedance tube is proposed in this paper. Commonly, porous materials are modeled using Biot’s theory. However, this theory requires several parameters which can be difficult to obtain by different methods (direct, indirect or inverse measurements). The proposed method retrieves all the Biot’s parameters with one absorption measurement in an impedance tube for isotropic poroelastic materials following the Johnson-Champoux-Allard’s model (for the fluid phase). The sample is a cylinder bonded to the rigid termination of the tube with a diameter smaller than the tube’s one. In that case, a lateral air gap is voluntary induced to prevent lateral clamping. Using this setup, the absorption curve exhibits a characteristic elastic resonance (quarter wavelength resonance) and the repeatability is ensured by controlling boundary and mounting conditions.
2017-06-05
Technical Paper
2017-01-1882
Pravin P. Hujare, Anil D. Sahasrabudhe
The reduction of vibration and noise is a major requirement for performance of any vibratory system. Due to legislative pressures in terms of external pass by noise limit of vehicles and customer requirements for better noise and ride comfort in vehicle, NVH attribute has become an important parameter. Major sources for vehicle pass-by noise consist of powertrain, tire and wind. Damping treatment is important to reduce vibration and noise radiation. The passive constrained layer dampening (CLD) treatment can be used to reduce structure-borne noise of vibrating structure using viscoelastic damping material. The performance of the passive constrained layer damping (CLD) treatment can further be enhanced by new segmentation technique. The concept of segmented CLD is based on edge effect. The efficiency of segmenting a constrained layer damping treatment relies on the fact that a high shear region is created in the viscoelastic layer.
2017-06-05
Technical Paper
2017-01-1782
Jobin Puthuparampil, Henry Pong, Pierre Sullivan
Large-scale emergency or off-grid power generation is typically achieved through diesel or natural gas generators. To meet governmental emission requirements, emission control systems (ECS) are required. In operation, effective control over the generator’s acoustic emission is also necessary, and can be accomplished within the ECS system. Plug flow mufflers are commonly used, as they provide a sufficient level of noise attenuation in a compact structure. The key design parameter is the transmission loss of the muffler, as this dictates the level of attenuation at a given frequency. This work implements an analytically decoupled solution, using multiple perforate impedance models, through the transfer matrix method (TMM) to predict the transmission loss based on the muffler geometry. An equivalent finite element model is implemented for numerical simulation. The analytical results and numerical results are then evaluated against experimental data from literature.
2017-06-05
Technical Paper
2017-01-1827
Michael J. Santora, Cyril Gbenga Ige, Jeff Otto, David Egolf
A muffler attached to an engine attenuates sound over a dedicated frequency range. This research involves the development of an active muffler that is keyed to the revolutions per minute (rpm) of the engine and suppresses the fundamental frequency being exhausted through the tailpipe. The active muffler consists of a tracking side-branch resonator terminated with a composite piezoelectric transducer. The use of an exponential horn as a resonating cavity and terminated with a composite piezoelectric transducer is presented. This would create Electromechanical Active Helmholtz Resonator (EMAHR) with a notch that can be moved between 100-1000 Hz. The use of acoustical-to-mechanical, mechanical-to-electrical, and analog-to-digital transformations to develop a system model for the active muffler are presented. These transforms will be presented as two-port network parameters. The use of two-port networks to model the electroacoustic system are a defining factor in the analysis.
2017-06-05
Technical Paper
2017-01-1764
Himanshu Amol Dande, Tongan Wang, John Maxon, Joffrey Bouriez
The demand for quieter interior cabin spaces among business jet customers has created an increased need for more accurate prediction tools. In this paper the authors will discuss a collaborative effort between Jet Aviation and Gulfstream Aerospace Corporation to develop a Statistical Energy Analysis (SEA) model of a large commercial business jet. To have an accurate prediction, it is critical to accurately model the structural and acoustic subsystems, critical noise transmission paths and dominant noise sources on the aircraft. The geometry in the SEA model was developed using 3D CAD models of major airframe and interior cabin components. The noise transmission path was characterized through extensive testing of various aircraft components in the Gulfstream Acoustic Test Facility. Material definitions developed from these tests became input parameters in the SEA model.
2017-06-05
Technical Paper
2017-01-1751
Nicolas Schaefer, Bart Bergen, Tomas Keppens, Wim Desmet
The continuous pursuit for lighter, more affordable and more silent cars, has pushed OEMs into optimizing the design of car components. The different panels surrounding the car interior cavity such as firewall, door or floor panels are of key importance to the NV performance. The design of the sound packages for high-frequency airborne input is well established. However, the design for the mid-frequency range is more difficult, because of the complex inputs involved, the lack of representative performance metrics and its high computational cost. In order to make early decisions for package design, performance maps based on the different design parameters are desired for mid-frequencies. This paper presents a framework to retrieve the response surface, from a numerical design space of finite-element frequency sweeps. This response surface describes the performance of a sound package against the different design variables.
2017-06-05
Technical Paper
2017-01-1788
Kishore Chand Ulli, Upender Rao Gade
Automotive window buffeting is a source of vehicle occupant's discomfort and annoyance. Original equipment manufacturers (OEM) are using both experimental and numerical methods to address this issue. With major advances in computational power and numerical modelling, it is now possible to model complex aero acoustic problems using numerical tools like CFD. Although the direct turbulence model LES is preferred to simulate aero-acoustic problems, it is computationally expensive for many industrial applications. Hybrid turbulence models can be used to model aero acoustic problems for industrial applications. In this paper, the numerical modelling of side window buffeting in a generic passenger car is presented. The numerical modelling is performed with the hybrid turbulence model Scale Adaptive Simulation (SAS) using a commercial CFD code.
2017-06-05
Technical Paper
2017-01-1807
Richard DeJong, Gordon Ebbitt
The SEA model of wind noise requires the quantification of both the acoustic as well as the turbulent flow contributions to the exterior pressure. The acoustic pressure is difficult to measure because it is usually much lower in amplitude than the turbulent pressure. However, the coupling of the acoustic pressure to the surface vibration is usually much stronger than the turbulent pressure, especially in the acoustic coincidence frequency range. The coupling is determined by the spatial matching between the pressure and the vibration which can be described by the wavenumber spectra. This paper uses measured vibration modes of a vehicle window to determine the coupling to both acoustic and turbulent pressure fields and compares these to the results from an SEA model. The interior acoustic intensity radiating from the window during road tests is also used to validate the results.
2017-06-05
Technical Paper
2017-01-1834
Dirk von Werne, Prasanna Chaduvula, Patrick Stahl, Michael Jordan, Jamison Huber, Korcan Kucukcoskun, Mircea Niculescu
Fan noise can form a significant part of the vehicle noise signature and needs hence to be optimized in view of exterior noise and operator exposure. Putting together unsteady CFD simulation with acoustic FEM modeling, tonal and broadband fan noise can be accurately predicted, accounting for the sound propagation through engine compartment and vehicle frame structure. This paper focuses on method development and validation in view of the practical vehicle design process. In a step by-step approach, the model has been validated against a dedicated test-set-up, so that good accuracy of operational fan noise prediction could be achieved. Main focus was on the acoustic transfer through the engine compartment. The equivalent acoustic transfer through radiators/heat exchangers is modeled based on separate detailed acoustic models. The updating process revealed the sensitivity of various components in the engine compartment.
2017-06-05
Technical Paper
2017-01-1833
Bonan Qin, Jue Yang, Xinxin Zhao
Articulated engineering vehicle travels on complex road, its working condition is bad and because of the non-rigid connection between the front and rear body, additional degrees of freedom is brought in and the transverse stiffness is relatively weak. When the articulated vehicle run in a high speed along a straight line, it is easy to cause the transverse swing and the poor manipulation stability. If it is serious enough, it will lead to "snake shape" instability phenomena. This kind of instability will increase driving resistance and tire wear, the lateral dynamic load and aggravate the damage of the parts. When steering, the center of gravity will offset laterally which will lead a higher probability of rollover accident. A mathematical model for a 35t articulated dump truck with four motor-driven wheels is established in this paper, to study the condition for its stable driving and the effects of the vehicle structural parameters.
2017-06-05
Technical Paper
2017-01-1871
Nobutaka Tsujiuchi, Masahiro Akei, Akihito Ito, Daisuke Kubota, Koichi Osamura
This paper describes new method for selecting optimal field points in Inverse-Numerical Acoustic analysis (INA), and an application to construction of sound source model for diesel engine. INA is a method that identifies surface vibration of the sound source by using acoustic transfer functions and actual sound pressures which are measured at field points located near the sound source. In the INA, for measuring sound pressures, it is necessary to determine the arrangement of field points. The increase of field points leads to longer test and analysis time. Therefore, guidelines for deciding field point arrangement are needed to conduct INA efficiently. The authors focused on the standard deviations of distance between sound source elements and field points, and proposed new guideline for optimal selection of the field points, in a past study. In the past study, the effectiveness of this guideline was verified using a simple plate model.
2017-06-05
Technical Paper
2017-01-1862
Rajesh Babu Channamaneni, P. Kannan, Karal Marx R
New legislation's, competition from global players and change in customer perception related to comfort parameters are key factors demanding manufactures to design and manufacture vehicles with very low saloon noise levels. The main causes for higher noise levels at passenger saloon compartment can be attributed to source noises (Powertrain, Driveline, Intake and Exhaust etc.), acoustic isolation and structural sensitivity of the body. Out of all above parameters, powertrain noise and acoustic isolation are two critical parameters effecting interior noise performance. This paper constitutes an attempt to explain acoustic source contribution analysis through transfer function measurement in a passenger vehicle. Acoustic transfer function between engine bay and passenger ear level was measured using reciprocity technique (reciprocal method) with reference source placed at various locations inside the vehicle.
2017-06-05
Technical Paper
2017-01-1779
Xianwu Yang, Jian Pang, Lanjun Wang, Xiong Tian, Yu Tang
With the development of automobile industry, the higher NVH performance is required for customers, and with drastically reduction of engine noise, the gear rattle noise generated by the impact between neutral gears inside transmission can be much easily perceived. It is well known that the torsional mode of powertrain system has a direct relationship with transmission gear rattle noise, the higher torsional vibration leads to more serious gear rattle noise. This paper establishes a torsional model of a front wheel drive automotive drivetrain, including clutch system, transmission box and equivalent load of a full vehicle in AMESim software. The experimental engine speed fluctuations at different gears are used to excite the torsional model.
2017-06-05
Technical Paper
2017-01-1819
Cyril Nerubenko, George Nerubenko
The results of dynamical study of new patented Torsional Vibration Dampers mounted on a crankshaft in V8 engines are presented. Design and structure of Torsional Vibration Damper is based on author’s US Patent 7,438,165 having the control system with instantaneous frequencies tuner for all frequencies of running engine. Analysis and disadvantages of conventional rubber and viscous Crank Dampers are shown. The focus of the study is on Torsional Vibration Damper having the mechanical self-tuning structure applicable for V8 engines. Mathematical model based on the system of ordinary differential equations describing the rotation and vibration of mechanical components has been used for the analysis of the dynamic behavior of V8 engine crankshaft system having proposed Torsional Vibration Damper. Attention is paid to composition and selection of optimal parameters of a proposed device for solving the problems of effective mitigation of crankshaft torsional vibrations in V6 engines.
2017-06-05
Technical Paper
2017-01-1855
Ramakanta Routaray
The basic function of a motorcycle frame is somewhat similar to that of the skeleton in the human body, i.e. to hold together the different parts in one rigid structure. One of the major benefits (for a motorcycle enthusiast) of using an advanced frame design lies in the sporty handling characteristics of the bike. A well designed frame can add to the joy of riding a motorcycle as the bike would feel more stable, effortless, and confident around corners, in straight lines and while braking. A well approved modeling techniques or adequate guide line principles have to be followed while designing the body and chassis in order to achieve the vibration within control. This paper depicts a methodological right approach to model the body and chassis of a two wheeler in order to control noise and vibration of the body and chassis.
2017-06-05
Technical Paper
2017-01-1861
Ismail Benhayoun, Frédéric Bonin, Antoine Milliet de Faverges, Julien Masson
NVH (Noise Vibration & Harshness) is one of the main focus areas during the development of products such as passenger cars or trucks. Physical test methods have traditionally been used to assess NVH, but the necessity for reducing cost and creating a robust solution early on in the design process has driven the increased usage of simulation tools. Development of well-defined methods and tools for NVH analysis allows today's OEMs to have a Virtual Engineering based Development Cycle from Concept to Test. However, not all NVH problems have been focused on, including the issue of Squeak and Rattle (S&R). In a vehicle, S&R is a recurring problem for interior plastic parts such as an Instrument Panel or Door Trim. Since 2012, Altair has been developing S&R Director (SnRD), which is a solution that identifies and combats S&R issues by embedding E-Line methodology [1] [2]. This methodology is based on Industry Best Practices, as described in the paper SAE 2012-01-1553.
2017-06-05
Technical Paper
2017-01-1884
Ruimeng Wu, David W. Herrin
Sound absorbing materials are commonly compressed when installed in passenger compartments or underhood applications altering the sound absorption performance of the material. However, most prior work has focused on uncompressed materials and only a few models based on poroelastic properties are available for compressed materials. Empirical models based on flow resistivity are commonly used to characterize the complex wavenumber and characteristic impedance of uncompressed sound absorbing materials from which the sound absorption can be determined. In this work, the sound absorption is measured for both uncompressed and compressed samples of fiber and foam, and the flow resistivity is curve fit using an appropriate empirical model. Following this, the flow resistivity of the material is determined as a function of the compression ratio. The procedure outlined in the paper is a simple approach for characterizing compressed materials that only.
2017-06-05
Technical Paper
2017-01-1903
Masami Matsubara, Nobutaka Tsujiuchi, Tomohiko Ise, Shozo Kawamura
The tire is one of the most important parts, which influence the noise, vibration, and harshness of the passenger cars. It is well known that effect of rotation influences tire vibration characteristics, and earlier studies presented formulas of tire vibration behavior. However, there is no studies of tire vibration including lateral vibration on effect of rotation. In this paper, we present new formulas of tire vibration on effect of rotation using a three-dimensional flexible ring model. The model consists of the cylindrical ring represents the tread and the springs represent the sidewall stiffness. The equation of motion of lateral, longitudinal, and radial vibration on the tread are derived based on the assumption of inextensional deformation. Many of the associated numerical parameters are identified from experimental tests.
2017-06-05
Journal Article
2017-01-1765
Albert Allen, Noah Schiller, Jerry Rouse
Corrugated-core sandwich structures with integrated acoustic resonator arrays have been of recent interest for launch vehicle noise control applications. Previous tests and analyses have demonstrated the ability of this concept to increase sound absorption and reduce sound transmission at low frequencies. However, commercial aircraft manufacturers often require fibrous or foam blanket treatments for broadband noise control and thermal insulation. Consequently, it is of interest to further explore the noise control benefit and trade-offs of structurally integrated resonators when combined with various degrees of blanket noise treatment in an aircraft-representative cylindrical fuselage system. In this study, numerical models were developed to predict the effect of broadband and multi-tone structurally integrated resonator arrays on the interior noise level of cylindrical vibroacoustic systems.
2017-06-05
Journal Article
2017-01-1770
Wallace Hill, Dennis Kinchen, Mark A. Gehringer
This paper describes a method used to assess and optimize half shaft joint angles to avoid excessive 3rd order vibrations during WOT and light drive away events. The objective was to develop a test based analytical model used to assess and optimize driveline-working angles during the early planning phases of a new program when packaging tradeoffs are decided. The 12 degree of freedom system model comprehends half shaft dynamic angle change, axle torque, P/T mount rate progression and axial forces in the tripot joints. The analytical model results enable fact-based decisions during architectural planning phases for driveline working angles, powertrain mount designs and locations relative to P/T center of gravity. There were several challenges encountered and addressed during the correlation process including half shaft dynamic angle, P/T lateral rigid body mode frequency and subjective rating predictions.
2017-06-05
Journal Article
2017-01-1774
Fabio Luis Marques dos Santos, Tristan Enault, Jan Deleener, Tom Van Houcke
The increasing pressure on fuel economy has brought car manufacturers to implement solutions that improve vehicle efficiency, such as downsized engines, cylinder deactivation and advanced torque lock-up strategies. However, these solutions have a major drawback in terms of noise and vibration comfort. Downsized engines and lock-up strategies lead to the use of the engine at lower RPMs, and the reduced number of cylinders generates higher torque irregularities. Since the torque generated by the engine is transferred through flexible elements (clutch, torsional damper, gearbox, transmission, tire), these also impact the energy that is transferred to the vehicle body and perceived by the driver. This phenomenon leads to low frequency behavior, for instance booming noise and vibration. This paper presents a combined test and CAE modelling approach (1D/3D) to reverse engineer a vehicle equipped with a CPVA (centrifugal pendulum vibration absorber).
Viewing 1 to 30 of 19552