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Extended Solution of a Trimmed Vehicle Finite Element Model in the Mid-Frequency Range

Audi Hungaria Zrt.-Antoine Guellec, Daniel Feszty
Hexagon | Free Field Technologies-Markus Brandstetter, Jonathan Jacqmot
  • Technical Paper
  • 2020-01-1549
To be published on 2020-06-03 by SAE International in United States
The acoustic trim components play an essential role in Noise, Vibration and Harshness (NVH) behavior by reducing both the structure borne and airborne noise transmission while participating to the absorption inside the car and the damping of the structure. Over the past years, the interest for numerical solutions to predict the noise including trim effects in mid frequency range has grown, leading to the development of dedicated CAE tools. Finite Element (FE) models are an established method to analyze NVH problems. FE analysis is a robust and versatile approach that can be used for a large number of applications, like noise prediction inside and outside the vehicle due to different sources or pass-by noise simulation. Typically, results feature high quality correlations. However, future challenges, such as electric motorized vehicles, with changes of the motor noise spectrum, will require an extension of the existing approaches. In this paper, the vibro-acoustic frequency response of an existing MSC Nastran FE model is extended using the Actran Statistical Energy Analysis (SEA) approach, Virtual SEA. In Virtual SEA, the necessary…
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Tire NVH Optimization for Future Mobility

CEAT Ltd-Rahul R. Sanghani, Thomas Cherian, Subramaniam Loganathan, Kamal Suhalka, Juban Thomas
  • Technical Paper
  • 2020-01-1520
To be published on 2020-06-03 by SAE International in United States
Vehicle NVH (Noise, Vibration and Harshness) is one of the most critical customer touchpoints which may lead to buying decisions. The importance of Noise inside the cabin is increasing day by day because of the new era of E-mobility and autonomous driving. Noise source could be the engine, powertrain, tyre, suspension components, brake system, etc. depending on driving conditions. Among these, tire noise is being identified as biggest contributor at constant mid-speed driving where engine and powertrain operate at minimum noise and wind noise is also at a moderate level. This driving condition becomes very significant for electric vehicles where engine noise is replaced by motor noise which is a tonal noise at very high frequency. This makes the improvement of tire noise levels quintessential for good cabin acoustic feel. This demands a proactive approach to develop low noise tire platforms for future mobility by leveraging research tools and best practices in the industry. With a greater emphasis on ride and comfort in passenger car vehicles, tyre manufacturers will be challenged to meet stringent harshness…
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A Holistic Approach to Develop a Modern High Power Density Diesel Engine to Meet Best-in-class NVH levels.

Mahindra & Mahindra, Ltd.-Vikraman Vellandi, Prasad Namani, Rajkumar Bhagate, Madhu Chalumuru
  • Technical Paper
  • 2020-01-0406
To be published on 2020-04-14 by SAE International in United States
The ever-increasing customer expectations put a lot of pressure on car manufacturers to constantly reduce the noise, vibration and harshness (NVH) levels. This papers presents the holistic approach used to achieve best-in-class NVH levels in a modern high-power density 1.5 lit 4 cylinder diesel engine. The base engine architecture was designed with NVH reduction features such as crank-offset, cast iron crankcase, stiffened ladder frame, structural oil pan and front cover. Piston skirt profile was optimized to reduce the slapping noise by carefully studying the secondary motion and skirt contact pressure. The plastic parts such as cylinder head cover and intake manifold were designed with closely spaced ribs and high wall thickness. Natural frequency targets for different parts were set for the entire engine at component level and system level and confirmed through simulations. High frequency acoustic simulation was carried out to identify and improve the areas of high surface velocity. "Acoustic holography" technology was extensively used to identify the areas of high noise radiation in the running engine. Based on the measurements, it was identified…
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Engine Mount Stopper Design Techniques to Balance Vehicle Level Buzz, Squeak, Rattle and Durability

Tata Motors, Ltd.-Sandip Hazra, Sagar Deshmukh
  • Technical Paper
  • 2020-01-0401
To be published on 2020-04-14 by SAE International in United States
In the highly competitive global automotive market and with the taste of customer becoming more refined, the need to develop high quality products and achieve product excellence in all areas to obtain market leadership is critical. Buzz, squeak and rattle (BSR) is the automotive industry term for the audible engineering challenges faced by all vehicle and component engineers. Minimizing BSR is of paramount importance when designing vehicle components and whole vehicle assemblies. Focus on BSR issues for an automobile interior component design have rapidly increased due to customer’s expectation for high quality vehicles. Also, due to advances in the reduction of vehicle interior and exterior noise, engine mounts have recently been brought to the forefront to meet the vehicle interior sound level targets. Engine mounts serve two principal functions in a vehicle, vibration isolation and engine support. The objective of this paper to experimentally analyze the impact of conventional engine mount design on the rattle and whistling noise audible from the engine mounts when the vehicle is subjected to rough road conditions and pot holes…
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Human Response to Vibrations and Its Contribution to The Overall Ride Comfort in Automotive Vehicles – A Literature Review

Chalmers University of Technology-Anna-Lisa Osvalder, Patrik Höstmad
China Euro Vehicle Technology AB-Xiaojuan Wang, Ingemar Johansson
  • Technical Paper
  • 2020-01-1085
To be published on 2020-04-14 by SAE International in United States
The various factors that affect ride comfort have been in focus in many research studies due to an increasing demand in ride comfort in the automotive industry. Noise, vibration and harshness (NVH) and the human response to NVH has been highlighted as an important contribution to assess and predict overall ride comfort. The purpose of this paper is to present an approach to explain ride comfort with respect to vibration for the seated occupant based on a systematic literature review of previous fundamental research and to relate these results to the application in the contemporary automotive industry. The results from the literature study show that numerous research studies have determined how vibration frequency, magnitude, direction, duration affect human response to vibration. Also, the studies have highlighted how body posture, age, gender and anthropometry affect the human perception of comfort. An analysis was made of the consistency and inconsistency of the results obtained in the different studies. The deviations of the research results from real-world ride comfort in automotive vehicles were analyzed and divided into three…
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NVH Full Vehicle Development - Virtual Simulation Process for Low Frequency Structure-Borne Regions

Tata Technologies, Ltd.-Prajith J, Vinayak Sagade
  • Technical Paper
  • 2020-01-1266
To be published on 2020-04-14 by SAE International in United States
NVH (noise, vibration and harshness) is a key attribute in Vehicle development. Refined vehicle enhances customer’s perception and also the brand image. Most of the OEMS have well-articulated NVH Development process which is integrated in to Product development Cycle (PDC). The need for such process is essential to identify the inherent weakness or threats at earlier stage. And so the mitigation process need not warrant deviation or protection of resources, which would be a bottleneck at later stage. NVH is complex phenomena which deals with structure borne and airborne sources. So a NVH compliant vehicle is the product of resources which includes the skilled manpower, process and computational infrastructure. The stress for NVH front loading has gained traction in Global OEMS, to deliver “First Time Right “NVH products. Full Vehicle NVH (VNVH) simulation is one of the complex virtual methods, done to understand and mitigate the inherent weakness of the systems and integration. Evaluations are based on load cases which are designed to simulate RWUP (Real World Usage Profiles). A systematic - “Sub System to…
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Sound Quality Development Using Psychoacoustic Parameters with Special Focus on Powertrain Noise

Geely Powertrain Research Institute-Garanto Victor, Geng Zhirong, Hu Junfeng, Deng Xiaolong, Yang Wanli, Wang Hao
  • Technical Paper
  • 2020-01-5000
Published 2020-01-24 by SAE International in United States
This research uses vehicle interior noise at the driver position during full load acceleration to objectively define the resultant Sound Quality (SQ) of the vehicle analyzed by focusing on powertrain noise. A calculation method is developed to rank vehicles in order of customer preference (Sound Rank) and provide a subjective evaluation score for different error states a vehicle can encounter. In order to calculate these two scores, a pleasantness parameter is obtained using standard calculated psychoacoustic parameters with different weighting scores depending on their importance toward the preference ranking. Then pleasantness is correlated with jury test results and subjective evaluations.The results obtained show that the model is capable of quantifying the vehicle SQ during the vehicle development process and position a vehicle within a two-dimensional (2D) powerful-refined plot. This is achieved with the help of psychoacoustic parameter scatter bands. The model provides an objective tool to quantify and verify the resultant SQ to help meet and optimize Noise, Vibration, and Harshness (NVH) targets.
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Applications of Strain Measurements to Improve Results on Transfer Path Analysis

Centro Federal de Educação Tecnológica de Minas Gerais-C. A. P. Melo
Escola de Engenharia de São Carlos, Universidade de São Paul-A. C. R. Ramos, L.P.R de Oliveira
  • Technical Paper
  • 2019-36-0323
Published 2020-01-13 by SAE International in United States
Vehicles with lower noise levels and better levels of vibratory comfort for passengers made the area of noise, vibration and harshness (NVH) one of the main areas related to the perception of vehicle quality. Several approaches on the contribution of transfer paths have been studied to define the propagation energy in vehicular structures. Transfer Path Analysis (TPA) is a tool to improve NVH performance with the primary goal of reducing and improving perceived vibrations and noise in the cabin vehicle by occupants. Indirect methods are especially important in cases where the force signals are immeasurable in practice in terms of cost and space for sensor couplings, in the measurement configuration, and particularly in the case of distributed forces. The matrix inversion method, perhaps the most popular classic TPA, identifies operational forces using passive body acceleration. However, removal of the source can change the dynamic characteristics of the assembled structure and increase the time of the experiment, which results in misleading information in the measurements. For this reason, the inversion operation of the acceleration matrix can…
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Optimizing NVH for EVs

Automotive Engineering: October 2019

Lindsay Brooke
  • Magazine Article
  • 19AUTP10_03
Published 2019-10-01 by SAE International in United States

Unique acoustic and harmonic challenges require an integrated approach to simulation and analysis. An expert at Adaptive Corp. explains.

Despite global sales market share stuck at single-digit levels, electric vehicles (EVs) are steadily filling the development pipelines at major OEMs. And as engineers are acutely aware, EVs bring a paradigm shift in the noise, vibration and harshness (NVH) arena. Their harmonic spectra are dramatically different than those of even the smoothest, most refined combustion-engine vehicles and hybrids.

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Open-Access Testbench Data for NVH Benchmarking of E-Machines under Electromagnetic Excitations

EOMYS Engineering-Karine Degrendele, Jean Le Besnerais
L2EP-Emile Devillers, Michel Hecquet
Published 2019-06-05 by SAE International in United States
This paper presents an experimental setup dedicated to the analysis of noise and vibration due to Maxwell magnetic forces in electrical machines, a significant NVH source in hybrid and electric vehicles traction motors. Both electromagnetic excitations and structural response of the electrical machine are simplified to provide the first public benchmark of e-NVH phenomenon (electromagnetic Noise, Vibration, Harshness).The paper first describes how the testbench is designed and tested in order to reduce as much as possible modelling and experimental uncertainties. A Permanent Magnet Synchronous Machine topology used in EV/HEV applications is used to illustrate tooth modulation effect and interaction between radial and tangential force-induced vibrations, and designed to generate the resonance of several stator structural modes with simplified electromagnetic loading (open-circuit case). A larger air gap allows the insertion of a fine search-coil network to measure time and space distribution of the air-gap flux density and resulting Maxwell stress harmonics. Accelerometers are placed on stator tooth tips to capture tooth bending motion, as well as on the outer yoke of the stator. Besides vibration measurements,…
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