Browse Topic: Noise, Vibration, and Harshness (NVH)

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Use of the Sound-intensity Method to Identify Acoustic Leakages from Off Highway Machine Cab2025-28-0267To be published on 11/06/2025
The operator station or “cab” in off Highway equipment plays a critical role to provide a comfortable environment for the operator. The cab interfaces with several elements of the off-highway equipment which can create gaps and openings. These openings have the potential for acoustic energy leakage, ultimately increasing sound within the cab. During machine operation, noise generated around the cab conducts inside through these leakages resulting in increased sound levels. Acoustic leakages are among the key noise transfer paths responsible for noise inside the cab. Therefore, before considering noise control treatments it is best to first identify and minimize any leakages from joints, corners, and pass-throughs to achieve required cab noise reduction. In this effort the sound intensity technique is used to detect the acoustic leakages in cab. The commercial test system is used for measuring the sound intensity field over objects. For the cab, an acoustic source is used inside the cab
Pawar, Sachin M., Mandke, Devendra, Fapal, Anand, Cone, Kerry
Mechanical Boom Vibration Mitigation using Active Force Control2025-28-0345To be published on 11/06/2025
In off-highway vehicles, an undesirable vibration in a mechanical structure is a well-known problem. Such vibrations are discomforting in humans and can even lead to serious health issues related to orthopedics. Passive vibration attenuation approaches are popular in engineering practice but rely heavily on vehicle structural changes. Moreover, such approaches are known to be less effective on low frequency vibrations. In the last decade or so, there has been significant technological advancement in actuators as well as sensing mechanisms. This has enabled us to realize active vibration control as an important tool in managing excessive vibration levels. It is noteworthy that a typical active vibration control assumption is that the controlled structure maintains its dynamic properties throughout the control procedure. This simplifies linear-time invariant (LTI) model-based control design approaches. We note that in certain applications, such as gantry cranes, spraying mechanical booms
Patil, Bhagyesh, Bawankar, Shubham
Arcing simulation in automatic transfer switches2025-28-0284To be published on 11/06/2025
Automatic transfer switches (ATS) play an important role in the providing uninterrupted power to various applications like data centre, hospitals etc. They can be connected between two utility sources, two gensets or a combination of them. It operates when one of the sources to which load is connected to is not available or the preferred source is up. While they do their job smoothly, they internally see harsh conditions. When one of the sources is active and other ATS is disconnecting, an arc is generated. The arc exists when the air medium breaks into ions and electrons at very high temperatures, typically above 10000K. This arc needs to be quenched quickly to avoid damage to the contacts and current carrying conductors. This paper throws light on an inhouse methodology that is developed using commercial tool Ansys Fluent. The physics of arc consisting flow, thermal and electromagnetic fields are modelled. This paper includes the simulation of arc propagation along with the moving
Badhe, Vivek, Gaikwad, Nikhil Ravindra
Electric fan arrangement and performance predictions of an off-highway cooling system2025-28-0241To be published on 11/06/2025
Traditionally, off-highway vehicles like tractors and construction machinery have been using either hydraulic or viscous or fixed fan to meet the cooling demands of the diesel engine. These fans draw power from the engine, affecting fuel consumption and contributing to noise levels that impact operator comfort. Recently, the use of electric fans in off-highway applications has increased due to their energy efficiency, lower noise, and flexible design. Electric fans can be used to cool various components, such as radiators and condensers, and can be positioned for optimal performance. They are easy to select from established supplier catalogs based on application requirements like machine voltage, fan size, and type. This study examines different fan arrangements in relation to coolers and the engine, using pusher and puller types, and multiple electrical fans based on cooler zones to enhance cooling system performance without altering cooler size or specifications. A mathematical flow
Durairaj, Renganathan, Dewangan, Nitin, Anand, Ketan, BHUJBALE, SAGAR
Dynamic Stiffness Simulation Driven Design Changes for Tractor Cab to Mitigate Structure Borne Noise Levels2025-28-0291To be published on 11/06/2025
The dynamic stiffness of mount systems is a critical factor influencing the overall dynamic behavior and vibration isolation capabilities of mechanical assemblies. Effective cab isolation in product design can reduce structure borne noise and tactile vibrations experienced by operators. Detailed dynamic stiffness analysis of mounting brackets coupled with modal analysis using finite element method provide insights into the vibration response and resonant frequencies of components. By systematically varying parameters such as material properties, shape and geometry, the study elucidates the sensitivity of dynamic stiffness to design alternations. This study investigates on dynamic stiffness and their consequential impact on system dynamics on various design alternations by considering the space constraints at mount locations due to components, wiring harness and structural analysis driven solutions. In overall, this paper emphasizes the pivotal role of dynamic stiffness analysis in
Saveenkumar, Valakeerthi, Cone, Kerry, Mandke, Devendra Laxmikant, Fapal, Anand
Isolation of Engine Vibrations from 3 Cylinder Engines on Off-Highway Machines2025-28-0292To be published on 11/06/2025
The BS4 regulation for emission required several changes on engines as well as design and development of new auxiliary systems. These changes affected the engine dynamic behavior and ultimately noise and vibration in engine. These changes are validated for various operating conditions on engine test cell in a controlled environment where engine is mounted on test cell with dyno. Further, this engine is used in various equipment application and needs to be validated for noise and vibration performance. Three-cylinder engines have inherent imbalance forces, hence it is extremely critical to select the proper engine isolators to reduce the vibrations and noise. This paper covers the methods used for verification of engine isolation performance. NVH tests are conducted for integration of three-cylinder engine with roadbuilding machine. An analytical model is developed to identify rigid body modes and mount transmissibility. Results from this analytical model were verified with a physical
Pawar, Sachin M., Mandke, Devendra Laxmikant, KASABE, SANDEEP, Jadhav, Vijay
Order Dispersion Method by Crankpin Arrangement into Enhancements of Structural Reliability and Sound Quality for V8 Outboard Motor2025-32-0021To be published on 11/03/2025
This paper provides insight into the utility of the low vibration crankshaft for outboard motors, especially focuses on the enhancements of the structural reliability of the crankshaft and the sound quality of the outboard motor. In previous research, we developed the crankshaft which can balance by itself for V8 outboard motor with V bank angle of 60 degrees. We specifically showed the theoretical basis of the balancing and the measurement results of actual vibration levels on boat. Meanwhile, note that the crankshaft has a distinctive structure of crankpin offset angle of 60 degrees, so that combustion interval becomes unequal. As to the combustion, however, we just mentioned the effects on the engine output performance, not the practicality. In this paper, we clarify the following two benefits of unequal interval combustion in terms of the structural reliability and the sound quality. One is that the order dispersion resulting from unequal interval combustion can reduce the
Takanishi, Kentaro, Muramatsu, Hideta, Kondo, Takashi, Naoe, Gaku
Aero-acoustic characterization of a Commercial Vehicle configuration using CFD2025-28-0429To be published on 10/30/2025
Noise pollution from automotive vehicles is a significant concern in urban areas, emphasizing the need for improved vehicle engineering of automotive vehicles to reduce noise levels. The necessity for automotive vehicles to have a low acoustic signature may further be emphasized by local regulatory requirements, such as the EU's regulation 540/2014, which sets sound level limits for commercial vehicles at 82 dB(A). In addition to this the external noise may propagate inside the cabin affecting the overall wellbeing of the driver. To address the issue vehicles are tested to measure noise levels at various locations, including inside and outside the cabin. These tests facilitate noise source identification and categorization of noise into structure-borne noise and air-borne noise. The air-borne noise, which can be either broadband or tonal in nature, is particularly discomforting and may require mitigation. To analyse these complex aero-acoustic behaviour of the vehicle, CFD can be used
sharma, Shantanu, Pawar, Sourabh, singh, Ramanand, kalamdani, Sreenath
Numerical study to predict the Impact of Geometric Modification on Aero-Acoustic behaviour of a Commercial Vehicle2025-28-0426To be published on 10/30/2025
To address the growing concern of increasing noise levels in urban areas, modern automotive vehicles need improved engineering solutions. The need for automotive vehicles to have a low acoustic signature is further emphasized by local regulatory requirements, such as the EU's regulation 540/2014, which sets sound level limits for commercial vehicles at 82 dB(A). Moreover, external noise can propagate inside the cabin, reducing the overall comfort of the driver, which can have adverse impact on the driving behavior, making it imperative to mitigate the high noise levels. This study explores the phenomenon of change in acoustic behaviour of external tonal noise with minor geometrical changes to the A-pillar turning vane (APTV), identified as the source for the tonal noise generation. An incompressible transient approach with one way coupled Acoustics Wave solver was evaluated, for both the baseline and variant geometries. Comparison of CFD results between baseline and variant showed
Pawar, Sourabh, Sharma, Shantanu, singh, Ramanand
Noise mitigation techniques in vehicle HVAC system2025-28-0378To be published on 10/30/2025
Noise produced by Heating, Ventilation, and Air Conditioning (HVAC) systems in automobiles considerably influences passenger comfort and the overall driving experience. As automotive manufacturers strive to improve the acoustic environment within vehicles, the reduction of HVAC system noise has emerged as a significant concern. The main sources of noise in HVAC systems consist of fan operation, compressor vibrations, and airflow turbulence occurring within ducts. This paper investigates several technical strategies to diminish HVAC system noise, emphasizing advanced methods such as Campbell diagrams, waterfall charts, and techniques for system optimization One significant approach for noise mitigation is the utilization of Campbell diagrams, which serve as essential instruments for pinpointing resonant frequencies in HVAC components. By graphing frequency in relation to rotational speed, engineers are able to identify critical resonance points and devise solutions to either avoid or
Trivedi, Arpita, Kumar, Ravi, Madaan, Ashish, Shrivastava, Pawan
DESIGN AND DEVELOPMENT OF FIBER OPTIC VIBRATION SENSOR FOR AUTOMOBILE APPLICATIONS2025-28-0371To be published on 10/30/2025
Fiber optic sensors are impervious to EMI, which makes them ideal for usage in high-EMI settings like automotive and aerospace applications. These problems might result in expensive repairs and less comfortable driving if they are not fixed right away. In order to lessen this, fiber optic vibration sensors have been developed as a way to detect and analyze vibrations produced by automobile systems by detecting and observing changes in transmitted optical signals. These sensors, which are usually based on fiber optic technology, allow for real-time condition monitoring of the vehicle. Unusual vibration patterns can be identified by installing these sensors in crucial parts like the engine block, gearbox, suspension, or wheels. This allows for early diagnosis and preventative measures. In addition to preventing major malfunctions, this finite element analysis technique increases fuel economy, boosts driver comfort, and guarantees the vehicle’s general dependability. A major development
P, Geetha, Koppala, Neelima, Nagarajan, Sudarson
A Strategic TQM Approach to Enhance Passenger Cabin Comfort Using T-Matrix2025-28-0423To be published on 10/30/2025
This study demonstrates the application of the T-Matrix, a Total Quality Management (TQM) tool to improve thermal comfort in automotive climate control systems. Focusing on the commonly reported customer issue of insufficient cabin cooling, particularly relevant in hot and congested Indian driving conditions, the research systematically investigates 36 failure modes identified across the product lifecycle, from early design through production and post-sale customer usage. Root causes are first categorized using an Ishikawa diagram and then mapped using the T-Matrix across three critical stages: problem creation, expected detection, and actual detection. This integrated approach reveals process blind spots where existing validation and inspection systems fail to catch known risks, particularly in rear-seat airflow performance and component variability from suppliers. By applying this TQM methodology, the study identifies targeted improvement actions such as improved thermal targets
Jaiswara, Prashant, Kulkarni, Shridhar, Deshmukh, Ganesh, Nayakawadi, Uttam, Joshi, Gaurav, Shah, Geet, Jaybhay, Sambhaji
Understanding End-of-Line NVH Scatter Bands in Electric Drives with High-Precision Simulations2025-01-0406To be published on 10/07/2025
An important characteristics of battery electric vehicles (BEVs) is their noise signature. Besides tire and wind noise, noise from auxiliaries as pumps, the electric drive unit (EDU) is one of the major contributors. The dynamic and acoustic behavior of EDUs can be significantly affected by production tolerances. The effects that lead to these scatter bands must be understood to be able to control them better and thus guarantee a consistently high quality of the products and a silent and pleasant drive. The paper discusses a simulation driven approach to investigate production tolerances and their effect on the NVH behavior of the EDU, using high precision transient multi-body dynamic analysis. This approach considers the main effects, influences, and the interaction from elastic structures of electric motor and transmission with accurate gear contact models in a fully coupled way. It servs as virtual end of line test, applicable in all steps of a new EDU development, by increasing
Klarin, Borislav, Schweiger, Christoph, Resch, Thomas
Methodology for Replicating and Quantifying Clicking-Noise Phenomenon in Gen 3 Wheel Hub Bearings and CVJ Using NVH Analysis and Data Processing2025-01-0368To be published on 09/15/2025
This paper presents a comprehensive methodology for replicating and quantifying the clicking-noise phenomenon occurring between Generation 3-wheel hub bearings and Constant Velocity Joints (CVJ), particularly in electric vehicles (EVs) where quiet operation makes this noise more noticeable. The study focuses on characterizing the system through contact pressure and distribution measurements, alternating torque tests, and advanced NVH (Noise, Vibration, and Harshness) data processing. The methodology includes detailed descriptions of the physical phenomena, driving conditions generating the noise, and the specific test setup used to simulate real-world conditions. The NVH analysis make use of high-pass filtering techniques to isolate clicking-noise events from background noise, ensuring accurate identification and quantification. Candidate solutions are assessed based on their ability to mitigate clicking noise through the utilization of inherent system components. The results
Nardicchia, Riccardo, Mauro, Ivan
Efficient Simulation Methodology for Caliper Rattle Noise Based on a Reasonably Simplified Model and Integrated NVH CAE Approach2025-01-0348To be published on 09/15/2025
Brake caliper rattle noise is difficult to simulate due to its non-stationary, random, and broadband frequency characteristics. Many CAE engineers have adopted rattle vibration as an alternative metric to quantitative noise levels. Previous rattle noise simulations primarily presented relative displacement results derived from normal mode analysis or vibration dB levels rather than actual noise dB levels. However, rattle noise consists of continuous impact noise, which must account for reflections, diffractions, and refractions caused by transient nonlinear contacts and localized vibrations—especially during extremely short contact events. To accurately simulate impact noise, vibration and acoustic characteristics should be analyzed using a simplified structure, given the numerous mechanisms influencing impact noise generation. The rattle noise can be effectively modeled using LS-Dyna, which incorporates both explicit and BEM solvers. The correlation between test results and CAE
Park, Joosang
Evaluation of Switching Effect on Acoustic Noise of an Interior Permanent Magnet Synchronous Motor for a Traction Application14-14-03-001809/09/2025
In recent years, the automotive industry has shown growing interest in the vibroacoustic characteristics of electric propulsion motors. Investigation of such characteristics can open avenues for motor design optimization and refined control strategies to mitigate vibration and acoustic noise in an electric motor. This article presents a comprehensive vibroacoustic analysis of a propulsion interior permanent magnet synchronous motor (IPMSM) under various current excitations generated by the power converter in combination with three different modulation schemes. To evaluate the switching effect from the inverter drive on motor noise, different simulations and processes are performed in ANSYS Workbench and MATLAB/Simulink. The multi-physics noise and vibration workflow, and sampling requirements used for the study are also presented. The simulation results, presented as equivalent radiated power (ERP) waterfall diagrams, show diverse acoustic noise signatures for the different types of
Juarez-Leon, Francisco Alejandro, Sahu, Ashish Kumar, Haddad, Reemon Z., Al-Ani, Dhafar, Bilgin, Berker
Design of a High-Speed Pure Synchro-Reluctant Machine with Asymmetrical Poles for Automotive Applications2025-24-012909/07/2025
In this article, the authors present the various choices made to design a magnet free and directly recyclable pure synchro-reluctant (Pure-SynRel) machine with asymmetrical poles operating at a maximum speed of ~21,000 rpm dedicated to automotive. This project focused on identifying design levers and optimizing the magnetic circuit to address three well-known challenges of this topology that limit its application as an automotive traction machine. These challenges include: maximizing the power factor to reduce inverter rating and cost, minimizing sources of NVH (noise, vibration, and harshness) and torque ripples, and ultimately maximizing efficiency to bridge the performance gap with magnet-based technologies (PMaSynRel). The sizing of stator components—such as the choice of winding (concentric or distributed, full or fractional pitch, round or hairpin wire)—and rotor components (e.g., the number of pole pairs, shape, and number of barriers) are explained. Additionally, the
Applagnat-Tartet, Antoine, Milosavljevic, Misa, Delpit, Pierre
Fitting More Functionality Into Increasingly Smaller, Smarter Devices: Heterogeneous IntegrationTBMG-5376909/01/2025
The increased functionality of today’s medical devices is astounding. Optical devices, for example, analyze chemicals, toxins, and biologic specimens. Semiconductor devices sense, analyze, and communicate. Microelectromechanical system (MEMS) devices utilize inertial methods to detect motion, direct light, and move components over short distances. Radiofrequency (RF) devices communicate wirelessly to other devices directly and remotely over the Internet. Handheld acoustic devices scan the body and build a virtual 3D model that shows conditions in the body. The innovation currently happening in the medical device industry is staggering, limited only by imagination and finding technical methods to implement the vision.
New Technique Could Accelerate Noise-Free Superconducting Qubits for Quantum ComputingTBMG-5371909/01/2025
A research team led by scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) has developed a new fabrication technique that could improve noise robustness in superconducting qubits, a key technology for enabling large-scale quantum computers.
Validation of Wind Noise for Class-8 Truck Using Lattice Boltzmann Method02-18-03-002108/29/2025
The transportation and mobility industry trend toward electrification is rapidly evolving and in this specific scenario, wind noise aeroacoustics becomes one of the major concerns for OEMs, as new propulsion systems are notably quieter than traditional ones. There is, however, very limited references available in the literature regarding validation of computational fluid dynamics (CFD) simulations applied to the prediction of aeroacoustics contribution to the noise generated by large commercial trucks. Thus, in this work, high-fidelity CFD simulations are performed using lattice Boltzmann method (LBM), which uses very large eddy simulation (VLES) turbulence model and compared to on-road physical tests of a heavy-duty truck to validate the approach. Furthermore, the effect of realistic wind conditions is also analyzed. Two different truck configurations are considered: one with side mirror (Case A) and the other without (Case B) side mirrors. The main focus of this work is to assess the
Guleria, Abhishek, Novacek, Justin, Ihi, Rafael, Fougere, Nicolas, Dasarathan, Devaraj
Active–Passive Torsional Vibration Suppression Method for Electromechanical Coupling System of Parallel Hybrid Electric Vehicles10-09-04-003408/21/2025
The diversity of excitation sources and operating modes in hybrid electric vehicles (HEVs) exacerbates the torsional vibration issues, presenting significant challenges to the vehicle’s overall noise, vibration, and harshness performance. To address the complex torsional vibration challenges of the HEVs, this study proposed an active–passive collaborative vibration suppression approach. In terms of passive suppression, a multi-condition parameter optimization scheme for the torsional vibration dampers is designed. In terms of active suppression, a fuzzy control–based electronically controlled damper is proposed, and a hybrid feedforward–feedback motor torque compensation strategy is developed. Simulation results demonstrated that the proposed method reduces the root mean square value of the angular acceleration by over 65% under acceleration and idle conditions and the maximum transient vibration value by 55% during the engine starting condition.
Yan, Zhengfeng, Liu, Shaofei, Huang, Tianyu, Zhong, Biqing, Bai, Xianxu, Huang, Yin
Optimization of Window Glass Parameters on Vehicle Weight and Wind Noise15-18-03-001808/20/2025
In this article, a three-dimensional transient CFD simulation method is used to simulate the wind noise of a vehicle model’s external flow field. The transient noise excitation of external noise sources outside each window glass are analyzed, and the statistical energy analysis method is used to calculate the articulation index of the front and rear passenger inside the vehicle. Then, the variation range of the thickness of each window glass is set, and the side window glass is also divided into two types: single-layer glass and laminated glass. After the design parameters are defined, the design space is established. The articulation index of the front and rear passengers and the total weight of the glass are the three design objectives for multi-objective optimization simulation, based on the results of optimization simulation, the change trend of each design parameter and design objective is analyzed; the sensitivity of the design objective to each design parameter is studied; the
Xiong, Zhenfeng, Zhang, Xiao, Liu, Ping, Li, Bo, Yuan, Qingpeng, Chen, Shiwen, To, Chi Hin
Stationary Sound Level Measurement Procedure for Recreational MotorboatsJ2005_202508 (Current)08/20/2025
This SAE Recommended Practice establishes the procedure for determining if recreational motorboats have effective exhaust muffling means when operating in the stationary mode. It is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.
Marine Technical Steering Committee
Shoreline Sound Level Measurement Procedure for Recreational MotorboatsJ1970_202508 (Current)08/15/2025
This SAE Recommended Practice establishes the procedure for measuring the sound level of recreational motorboats in the vicinity of a shore bordering any recreational boating area during which time a boat is operating under conditions other than stationary mode operation. It is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.
Marine Technical Steering Committee
Brief Communication: Measurement of Boundary Layer Turbulent Transition Using an Acoustic Microphone Unit01-18-02-001107/16/2025
In this article the transition of a laminar boundary layer (BL) over a flat plate is characterized using an acoustic technique with a pitot probe linked to a microphone unit. The probe was traversed along a BL plate at a fixed wind tunnel flow velocity of 5.5 m/s. A spectral analysis of the acoustic fluctuations showed that this setup can estimate the streamwise location and length of the BL transition region, as well as the BL thickness, by using the intermittency similitude approach. Further work is required to quantify the uncertainty caused by signal attenuation within the data acquisition system.
Lawson, Nicholas John, Zachos, Pavlos K.
Shimmy Analysis of Differential Steering-by-Wire System for Electric Vehicles with In-Wheel Motors and Steering Trapezoidal Mechanism2025-01-504907/15/2025
The differential steering-by-wire (DSBW) system eliminates the need for steering gear, i.e., rack and pinion, while preserving a trapezoidal steering structure with knuckles. This design offers significant advantages for vehicles equipped with in-wheel motors, primarily due to reduced vehicle weight and the maintenance of front wheel alignment parameters. However, the noise force acting on one steering wheel will directly transmit to the other in this differential steering mechanism due to a lack of mechanical connection to the vehicle body through the steering gear, which increases the risk of steering wheel shimmy (SWS). This article qualitatively analyzes the shimmy characteristics of the steering wheel based on a three-degrees-of-freedom (3-DOF) DSBW shimmy model established using Lagrange’s equation and the Hopf bifurcation theorem. The results indicate the vehicle range that this steering system will shimmy, and the maximum steady amplitude is [4.80 m/s, 31.57 m/s] and 0.1516 rad
Zhao, Huiyong, Liang, Guocai, Wang, Baohua, Feng, Ying
Optimisation of Rotor Skewing of a Yokeless and Segmented Armature Axial Flux Machine2025-01-031107/02/2025
This paper presents an optimisation approach for rotor skewing in a Yokeless and Segmented Armature (YASA) design Axial Flux Machine (AFM) for electric vehicle applications. Torque ripple amplitudes are a critical factor influencing the noise, vibration and harshness (NVH) behaviour of electric motors. The focus of this paper is to reduce the torque ripple amplitudes of the dominant harmonics over the entire torque-speed characteristic of the AFM. The principle of the proposed approach is a segmented permanent magnet configuration of the AFM, where individual magnet segments can be circumferentially shifted to achieve optimal skewing configurations. Initial optimisations are performed using 2D finite element (FE) simulations, modelled as linear motors with multiple slices and different numbers of magnet segmentation. However, the accuracy of the 2D FE results is limited due to the lack of interaction between the individual segments and the insufficient representation of three
Müller, Karsten, Maisch, Hannes, De Gersem, Herbert, Burkhardt, Yves
Evaluation of Static and Dynamic Stiffness of Rubber Grommet by Experimental and FEA Method2025-01-027407/02/2025
Vibration control is most important in automotive applications, and generally, rubbers are used to dampen these vibrations due to their inherent nature and low-cost manufacturing methods. Now, to select a rubber material, Shore hardness is considered in engineering applications, but to additionally control the behaviour, we need to understand its static and dynamic stiffness. These values help to determine the vibration isolation obtained by these rubbers. In this paper, we will discuss methods to calculate the static and dynamic stiffness of rubber grommets using experimental methods and FEA modelling. As elastomers have non-linear material properties, various material modelling techniques in FEA are used to capture multiple phenomena like creep, fatigue, and dynamic conditions. Rubber compounding is used in order to improve the physical and chemical properties, which in turn would give desirable linear characteristics. Certain guidelines and thumb rules are used in the rubber
Khamkar, Prasad Subhash, Gaikwad, Vikrant Chandrakant
Improving Gearbox Acoustics through Elastomer-Based Bearing Damping2025-01-032307/02/2025
This study analyses the effect of external damping of roller bearings on the acoustic behaviour of gearboxes in electric powertrains. The growing use of electric vehicles has increased the importance of reducing gearbox noise, as the lack of noise masking from internal combustion engines and the higher operating speeds of electric motors exacerbate the acoustic challenges. Gearbox noise, which is primarily caused by tooth mesh excitation and its transmission through shafts and bearings, requires strategies to minimise its impact on vehicle comfort and performance. External damping is achieved through the integration of specific elements at the circumference of the outer bearing ring. These elements are utilised to modify the vibration transfer behaviour of the bearing assembly. This, in turn, can lead to a reduction in both structure-borne and airborne noise emissions at the gearbox housing. A test design was created to quantify the effects of different damping configurations. This
von Schulz, Kai, Linde, Tilmann, Jäger, Steffen
Measurement of Noise Emitted by Accelerating Road VehiclesJ2805_202507 (Current)07/01/2025
This SAE Standard is equivalent to ISO 362-1:2015 and specifies an engineering method for measuring the noise emitted by road vehicles of categories M and N under typical urban traffic conditions. It excludes vehicles of category L1, L2, L3, L4, and L5. The specifications are intended to reproduce the level of noise generated by the principal noise sources during normal driving in urban traffic. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustical environment that is obtained only in an extensive open space. Such conditions are usually provided for during: Measurements of vehicles for regulatory certification and/or type approval Measurements at the manufacturing stage Measurements at official testing stations Annex A provides background information on the use of this standard consistent with the intent.
Light Vehicle Exterior Sound Level Standards Committee
Noise, Vibration, and Harshness Countermeasures of Permanent Magnet Synchronous Motor with Viscoelastic Layer Material10-09-04-003106/30/2025
An electric motor exhibits structural dynamic excitation at high frequency, making it particularly prone to noise, vibration, and harshness (NVH) problems. To mitigate this effect, this article discusses a novel countermeasure technique to improve NVH performances of electric machines. A viscoelastic rubber layer is applied on the outer surface of a permanent magnet synchronous motor (PMSM) as vibration damping treatment. The goal is to assess the countermeasure effectiveness in reducing acoustic emissions at different temperatures, through a combination of numerical modeling and experimental validation. A finite element model of the structure is realized, considering a viscoelastic material model for the rubber material, with frequency-dependent loss factor and storage modulus. The numerical model is validated by means of experimental modal tests performed on a house-built cylindrical structure, designed to mimic the geometry of a typical cooling jacket of a PMSM for automotive
Soresini, Federico, Barri, Dario, Ballo, Federico, Manzoni, Stefano, Gobbi, Massimiliano, Mastinu, Giampiero
Exterior Sound Level Measurement Procedure for Recreational MotorboatsJ34_202506 (Current)06/30/2025
This SAE Recommended Practice establishes the procedure for measuring the maximum exterior sound level of recreational motorboats while being operated under a variety of operating conditions. It is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.
Marine Technical Steering Committee
Road Noise Improvement Method for Battery Electric Vehicles Based on Bushing Stiffness Optimization10-09-04-003206/23/2025
The chassis bushing is one of the key components affecting the vibration isolation efficiency of a vehicle, and a comprehensive optimization method combining the experimental process and transmission path analysis (TPA) is proposed to reduce the low- and medium-frequency road noise response in the passenger compartment of a battery electric vehicle (BEV). First, the noise signals were obtained in the vehicle road noise test under two working conditions of 40 and 60 km/h at uniform speeds on rough road surfaces. Then, the excitation transmission path was analyzed based on the structural noise transmission model, and the chassis bushing parts with more considerable vibration isolation contribution were screened out. By matching the stiffness values of the chassis bushings in the optimization problem through experimental methods, the optimization scheme reduces the stiffness of the front swing arm bushing and the rear longitudinal arm bushing by 30%. Additionally, a flexible connection is
Liu, Ke, Liao, Yinghua, Wang, Hongrui, Zhou, Junchao
TOC99-07-03-0TOC06/17/2025
TOC
Tobolski, Sue
Sound Granular Synthesis Method for Sci-Fi Sound Quality of Electric Vehicles2025-01-025306/16/2025
Since the powertrain systems of electric vehicles (EVs) lack the traditional engine sound, their NVH performance differs from that of conventional fuel-powered vehicles, making the use of active sound design (ASD) systems increasingly common to provide compensatory sound. With the increasing demand for ASD systems, sci-fi sounds are emerging as a design direction to enhance the acoustic feedback of powertrain systems and to elevate the futuristic and immersive driving experience of vehicles. A method for generating sci-fi soundscapes using a granular synthesis algorithm is proposed in this paper. First, based on the designed sci-fi target sound characteristics, a sound grain generation method using the adaptive principal frequency technique is proposed, and the overlap-and-add (OLA) method is employed to synthesize the sound grains. Then, to enhance the sound continuity and smoothness during the sound synthesis process, a method for optimizing a composite cosine window function using a
Liu, Dezhu, Liu, Zhien, Xie, Liping, Lu, Chihua
Noise Management in Electric Vehicle Compressors for Superior Cabin Comfort2025-01-019106/16/2025
This research addresses the issue of noise, vibration, and harshness (NVH) in electric buses, which can hinder their widespread adoption despite their environmental benefits. With the absence of traditional engines, NVH control in electric vehicles focuses on auxiliary components like the air compressor. In this study, the air compressor was identified as a major source of vibration, causing harsh contact between its oil sumps and mounting bracket. Analyzing the vibrations revealed that the sump and bracket were not moving freely, increasing noise. Modifying the bracket design to allow more movement between the components successfully reduced both noise and vibration. The paper details the experimental process, findings, and structural damping methods to mitigate NVH in electric buses.
Paroche, Sonu, Patel, Shubhanshi, Patidar, Ashok Kumar
Numerical Simulation and Parametric Optimization of Engine/Powertrain Mounts: Identifying Key Design Variables to Reduce NVH Noise2025-01-025106/16/2025
Engine and powertrain mounts are vital for isolating vibrations and reducing the transmission of Noise, Vibration, and Harshness (NVH) from the engine to the vehicle structure. Despite technological advancements, addressing NVH issues related to tribological factors continues to pose significant challenges in automotive engineering. This study aims to systematically identify and optimize design parameters of engine/powertrain mounts to minimize NVH levels using CAE tools and parametric optimization techniques in Abaqus and Isight, respectively. The purpose of this research is to investigate the correlation between various design parameters of powertrain mounts and their impact on NVH characteristics. Specific attention is focused on noises such as clunking, banging, or thumping that emerge from the engine bay under dynamic conditions like acceleration, braking, or turning. These sounds often occur as the engine moves excessively due to worn mounts, making unintended contact with other
Ganesan, Karthikeyan, Seok, Sang Ho
A Pitch Shift Synthesis Algorithm for Electric Vehicle Sound Based on Quadratic Interpolation and Continuous Sample Indexing2025-01-025406/16/2025
The electric vehicle driveline generates less vibration and noise compared to a conventional internal combustion engine vehicle, making it harder for the driver to perceive the vehicle’s operating status through driveline sounds, thereby diminishing driving engagement and experience. To compensate for the absence of engine sound in EV drivelines, Active Sound Design (ASD) technology has become a crucial method for drivetrain sound enhancement, with sound synthesis algorithms playing a key role in this process. Although pitch-shifting algorithms based on frequency shift principles can synthesize engine sounds, they suffer from spectral leakage and stuttering caused by sound splicing. To address these issues, a pitch-shifting synthesis algorithm (QCPS, Quadratic interpolation-based Continuous audio sample indexing Pitch Shifting algorithm) is proposed in this paper, which combines a quadratic interpolation method with a continuous audio sample indexing strategy. First, the frequency
Liu, Dezhu, Xie, Liping, Liu, Zhien, Lu, Chihua
NVH Improvement of Transmission Electric Oil Pump with Uneven Pitch Control2025-01-025206/16/2025
This paper proposes an uneven pitch control for electric oil pumps. For the noise reduction of vane pumps, mechanical arrangements of uneven pitch vain angle are widely used. However, the tooth angle of gear-type pumps should be even mechanically. The proposed uneven pitch control provides similar effects of the mechanical uneven pitch arrangement by instantaneous motor torque controls of the electric oil pump which cannot have uneven pitch mechanically. The magnitude of motor torque for each pump tooth is determined by an uneven pitch formula which is widely used for mechanical vane pumps in previous study and patents. A formula for the shape of motor torque is proposed by analyzing pressure fluctuations of pump as a combination of trigonometric and exponential functions. The calibration factors for the magnitude and shape are adjusted by characteristics of pumps. The experimental results showed that noise reduction and dispersion effects of the proposed method.
Choi, Chinchul, Kim, Jongbeom
Temperature Effect on the Rattle and Squeak Noise of Automotive Instrument Panel and Console2025-01-504206/10/2025
In order to improve the comfort and perceptive quality of vehicle on the climate conditions worldwide, the temperature effect on rattle and squeak of instrument panel and console is studied under temperatures of −30°C, 23°C, and 60°C. First, the modal accuracy of finite element model is certificated by real vehicle test. The first global mode shapes are reciprocating rotation and reciprocating translation for instrument panel and console, respectively, corresponding to frequencies of 36.6 Hz and 29.6 Hz, which attain about 91% and 92.5% relative to the experiment values. Second, on basis of the “3σ” threshold of 0.27%, an assembly clearance in left instrument panel has non-negligible rattle risk under all temperatures. Another three clearances have no rattle risk but get rattle increase under temperatures of −30°C and 60°C. In addition, the rattle risk is increased around console end clearances at the temperature of 60°C. In other cases, the rattle risk is 0% or can be neglected. Third
Yang, Xiaoyu, Mu, Yongtao
2025 Ford Expedition: New friendly features and a Tremor for legit off-roading25AUTP06_1506/01/2025
Ford has engineered the 2025 Expedition with an eye to putting it at the top of the large SUV class in which it has usually been a contender. With loads of tech that works well and is controlled easily, friendly features and a highly capable new Tremor off-road edition, it offers plenty of justifications for its pricing. SAE Media was hosted by Ford in Louisville, Kentucky, for a drive of various Expedition trim levels, including a first-hand view of the Tremor's off-road prowess. Among the useful features is the new Split Gate, of which the top 75% lifts like a traditional SUV liftgate. The utility comes in with the lower 25%, which drops like a truck tailgate and can support up to 500 pounds for your football tailgating or other purposes. And avoiding a potential user annoyance is available Open-on-Approach, which opens both gate portions by merely standing near the back of the Expedition. The design of the upper part of the Split Gate, by the way, evokes the apocryphal quote from
Clonts, Chris
Aircraft Noise Level Reduction Measurement of Building FaçadesARP6973A (Current)05/27/2025
This ARP provides two methods for measuring the aircraft noise level reduction of building façades. Airports and their consultants can use either of the methods presented in this ARP to determine the eligibility of structures exposed to aircraft noise to participate in an FAA-funded Airport Noise Mitigation Project, to determine the treatments required to meet project objectives, and to verify that such objectives are satisfied.
A-21 Aircraft Noise Measurement Aviation Emission Modeling
High-Resolution Option for the Sottek Hearing Model tonality enables Accurate Order Analysis2025-01-009305/05/2025
The Sottek Hearing Model provides a comprehensive framework for understanding the nuances of sound perception, including such aspects as loudness, tonality, roughness, fluctuation strength, sharpness, and impulsiveness. The principal model was first published more than three decades ago as part of a doctoral thesis. Over the past few decades, the model has been refined and recently standardized in the international standard ECMA 418-2. This standard addresses several psychoacoustic parameters, including a new approach to time-varying loudness based on a nonlinear combination of partial tonal and noise loudness (as part of the tonality). This is the preferable approach because the loudness of tonal components (i.e., tonal loudness) may have a more pronounced impact on loudness perception than the loudness caused by other components (i.e., noise loudness). Other standardized parameters include psychoacoustic modulation analyses. These are roughness, which is employed to evaluate rapidly
Sottek, Roland, Bray, Wade
Leveraging Vision Language Models and Prompt Engineering for Bearing Defect Classification from Vibration Signals2025-01-012705/05/2025
Bearings are fundamental components in automotive systems, ensuring smooth operation, efficiency, and longevity. They are widely used in various automotive systems such as wheel hubs, transmissions, engines, steering systems etc. Early detection of bearing defects during End-of-Line (EOL) testing and operational phases is crucial for preventive maintenance, thereby preventing system malfunctions. In the era of Industry 4.0, vibrational, accelerometer, and other IoT sensors are actively engaged in capturing performance data and identifying defects. These sensors generate vast amounts of data, enabling the development of advanced data-driven applications and leveraging deep learning models. While deep learning approaches have shown promising results in bearing fault diagnosis, they often require extensive data, complex model architectures, and specialized hardware. This study proposes a novel method leveraging the capabilities of Vision Language Models (VLMs) and Large Language Models
Chandrasekaran, Balaji, Cury, Rudoniel
Brake Noise CAE Enhancement with the Synergy between Design of Experiments and Machine Learning2025-01-012405/05/2025
The digitalization of industrial systems has led to increased data availability. Machine learning (ML) methodologies are now commonly used for data analysis in industrial contexts. Not all contexts have abundant data; sometimes data collection can be scarce or expensive. Design of Experiments (DOE) is a technique that provides an informative dataset for ML analysis when data are limited. It involves systematically designing experiments to collect relevant data points with regression models. Disc brake noise is a challenging problem in vehicle noise, vibration, and harshness (NVH). Different noise events occur under various operating conditions and across frequencies (1-16 kHz). To enhance computer-aided engineering (CAE) techniques for brake noise, ML is used to generate additional data. Sequential experimentation in DOE aligns well with ML’s ability to continuously learn and improve as more data become available. DOE is applied in CAE to collect data for training ML models. ML helps
Song, Gavin, Sridhar, Gurupriya, Vlademar, Michael, Venugopal, Narayana
A Comprehensive Evaluation of PU Foam Sealing for EV NVH Performance2025-01-012005/05/2025
Low density polyurethane foam was first proposed as an alternative to expandable baffles and tapes for sealing vehicle body cavities towards the end of the last century. Despite several inherent advantages for cavity sealing, the high equipment cost of dispensing amongst other reasons, this technology has not spread as widely as expected. With the advent of electric vehicles, there is an increased emphasis on controlling higher frequencies from motors, inverters and other components, and polyurethane foam can be a viable solution by providing more robust sealing. Polyurethane foam sealing is already being employed in the new breed of electric vehicles, but its NVH advantages have not been fully studied or published in literature. Using an existing electric vehicle with conventional expandable baffles & tape sealing measures, a comprehensive evaluation of NVH performance using the closed-cell polyurethane foam solution was conducted. Testing included component level bench test on body
Kavarana, Farokh, Guertin, Bill
Effects of Acoustic Dissipative Material in Applications with Acoustic Leakage2025-01-011705/05/2025
This paper investigates the performance of a dissipative material compared to conventional acoustic materials under conditions that simulate real-world vehicle applications with acoustic leakage. Various acoustic materials were evaluated through laboratory experiments, which included acoustic leakage in both the steel panel and the acoustic materials. Acoustic leakages commonly occur in actual vehicle conditions at pass-throughs or fastener mounting locations. The study also presents in-vehicle test results to demonstrate the effectiveness of the dissipative material in managing acoustic leakage.
Yoo, Taewook, Maeda, Hirotsugu, Sawamoto, Keisuke, Anderson, Brian, Gan, KimTong, Herdtle, Thomas
Reducing LiDAR Cabin Noise with Damped Elastomers a Novel Method for Predicting Performance and Durability2025-01-011405/05/2025
Mechanical light detection and ranging (LiDAR) units utilize spinning lasers to scan surrounding areas to enable limited autonomous driving. The motors within the LiDAR modules create vibration that can propagate through the vehicle frame and become unwanted noise in the cabin of a vehicle. Decoupling the module from the body of the vehicle with highly damped elastomers can reduce the acoustic noise in the cabin and improve the driving experience. Damped elastomers work by absorbing the vibrational energy and dispelling it as low-grade heat. By creating a unique test method to model the behavior of the elastomers, a predictable pattern of the damping ratio yielded insight into the performance of the elastomer throughout the operating temperature range of the LiDAR module. The test method also provides an objective analysis of elastomer durability when exposed to extreme temperatures and loading conditions for extended periods of time. Confidence in elastomer behavior and life span was
Russell, Casey, Masterson, Peter, O'Connell, Kerry
Sound Quality Centered Measurement Technique over 40+ Years: Experiences and Perspectives2025-01-007305/05/2025
The author’s life work in acoustics and sound quality, continuous over more than 40 years, has followed a number of branches all involving measurement technologies and their evolution. The illustrated discussion begins 60 years ago in 1965 at Arizona State University in its Frank Lloyd Wright-designed Gammage Auditorium, and moves to the Research and Development Division of Kimball International, Inc. (Jasper, Indiana) in 1976 with piano research using a Federal Scientific Ubiquitous analog real-time FFT analyzer and Chladni-plate-mode studies with fine sand and high-speed photography of sound board modes. It continues at Jaffe Acoustics, Inc., a concert-hall-specializing consultancy in Norwalk, CT, with early-reflection plotting using a parabolic microphone on an altazimuth angular-readout mounting and either photographing oscillograms, or running a high-speed paper chart printer, assembling “wheel plots” incremented every 10 degrees in azimuth and altitude to map reflection patterns
Bray, Wade
The Applications of Acoustic Black Holes to Attenuation of Coach/Bus Frame Structure Vibrations2025-01-006505/05/2025
Basic structures of vehicle frames、aircraft fuselages and ship hulls are made of beams、columns and trusses. If Acoustic Black Holes(ABH) are carefully arranged alongside with the wave propagation paths in those structures, the wave propagation paths could be changed at NVH engineers’ will and the structure vibrations can be reduced. Two kinds of ABHs are used in this paper: one is ABH made of Polyurethane(PU), other one is ABH composed of several steel plate 1D ABH stacked up in parallel. Three structures are used to test the effectiveness of ABHs for vibration reductions: a squared hollow sectional steel commonly used in motorcoach/bus chassis and frame structures, a simple frame for motorcoach airbag suspension and a 12m chassis structure. The attached ABHs show a great vibration attenuation in terms of transfer functions on the basic structure element for a motorcoach. The lateral, vertical and longitudinal transfer functions for steel ABHs were greatly reduced from 13.2~14.7 dB
Xu, Chuanyan, Wang, Jianjun, Xing, Qisen, Chen, Hengbin, Huang, Xianli
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