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Efficient Modeling and Simulation of the Transverse Isotropic Stiffness and Damping Properties of Laminate Structures using the Finite Element Method

BMW Group-Vlad Somesan, Endre Barti
Fraunhofer Lbf-Thilo Bein
  • Technical Paper
  • 2020-01-1573
To be published on 2020-06-03 by SAE International in United States
The Noise Vibration and Harshness (NVH) characteristics and requirements of vehicles are changing as the automotive manufacturers turn their focus from developing and producing cars propelled by internal combustion engines (ICE) to electrified vehicles. This new strategic orientation enables them to offer products that are more efficient and environmentally friendly. Although electric powertrains have many advantages compared to their established predecessors they also produce new challenges that make it more difficult to match the new requirements especially regarding NVH. Electric motors are one of the most important sources of vibrations in electric vehicles. In order to address the new challenges in developing powertrains that match the acoustic comfort requirements of the customers and also shape the development process as efficiently as possible, car manufacturers use numerical simulation methods to identify NVH problems as early in the design process as possible. Numerically describing the dynamic properties of electric motor components such as the stator or rotor is proving to be especially difficult as they contain heterogeneous parts that have viscoelastic orthotropic or transverse isotropic stiffness and…
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Driveline Torque Profiling Based on Speed Estimation for xEVs

Hyundai Motor Group-Jiwon Oh, Jeong Soo Eo, Sung Jae Kim, Dohee Kim
  • Technical Paper
  • 2020-01-0964
To be published on 2020-04-14 by SAE International in United States
This paper suggests a method to formulate the driveline torque command for vehicles that use electric motor as part of their sources for providing driving power. The shape of the driveline torque profile notably influences the drivability criteria of the vehicle, and among them, driveline NVH and responsiveness are often tradeoffs for each other. Hence the real-time computed driveline torque profiling (DTP) enables formulation of the effective torque command at any given time to simultaneously satisfy both NVH and responsiveness criteria. Such task is fulfilled by using a shaft distortion prediction model based on a motor speed observer. A compensation torque command based on the amount of shaft distortion is formulated to prevent the shaft distortion with minimum effort. The effectiveness of the suggested driveline torque profiling method is verified using an actual vehicle, and the vehicle NVH and responsiveness are numerically assessed for comparison.
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Two-Scale Command Shaping for Reducing NVH during Engine Shutdown

Georgia Institute of Technology-Mohid Muneeb Khattak, Michael Leamy
Georgia Institute of Technology/ South Ural State University-Alexander Alyukov
  • Technical Paper
  • 2020-01-0411
To be published on 2020-04-14 by SAE International in United States
Two-scale command shaping is a recently proposed feedforward control method aimed at mitigating undesirable vibrations in nonlinear systems. The TSCS strategy uses a scale separation to cancel oscillations arising from nonlinear behavior of the system, and command shaping of the remaining linear problem. One promising application of TSCS is in reducing engine restart and shutdown vibrations found in conventional and in hybrid electric vehicle powertrains equipped with start-stop features. The efficacy of the TSCS during internal combustion engine restart has been demonstrated theoretically and experimentally in the authors’ prior works. The present article presents simulation results and describes the verified experimental apparatus used to study TSCS as applied to the ICE shutdown case. The apparatus represents a typical HEV powertrain and consists of a 1.03 L three-cylinder diesel ICE coupled to a permanent magnet alternating current electric machine through a spur gear coupling. The EM is mounted on a plate and welded frame and is used to implement a given TSCS-designed torque profile to the ICE through Controlled Area Network messaging during its shutdown. Data…
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Noise, Vibration, and Harshness Considerations for Autonomous Vehicle Perception Equipment

Kettering University-Charlie Gates, Jennifer Bastiaan, Prashant Jadhav, Javad Baqersad, Diane Peters
  • Technical Paper
  • 2020-01-0482
To be published on 2020-04-14 by SAE International in United States
Automakers looking to remake their traditional vehicle line-up into autonomous vehicles, Noise, Vibration, and Harshness (NVH) considerations for autonomous vehicles are soon to follow. While traditional NVH considerations still must be applied to carry-over systems, additional components are required for an autonomous vehicle to operate. These additional components needed for autonomy also require NVH analysis and optimization. Autonomous vehicles rely on a suite of sensors, including Light Detection and Ranging (LiDAR) and cameras placed at optimal points on the vehicle for maximum coverage and utilization. In this study, the NVH considerations of autonomous vehicles are examined, focusing on the additional perception equipment installed in autonomous vehicles. In particular, the nature of modifications to existing vehicles to increase the level of autonomy, and the associated NVH characteristics of these alterations, are reviewed with suggestions for future application to autonomous vehicles. A case study in the design of an original autonomous vehicle based on a production all-electric car, a 2017 Chevrolet Bolt, is outlined. A detailed description of the NVH design and verification process for this vehicle…
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CAE Cooling Module Noise and Vibration Prediction Methodology and Challenges

FCA US LLC-Ahmad ABBAS, Wael Elwali, Syed Haider, Suneel Dsouza, Michael Sanderson, Yoginder Segan
  • Technical Paper
  • 2020-01-1262
To be published on 2020-04-14 by SAE International in United States
In the NVH domain, the cooling module is an important subsystem in ground vehicles. Recently, with the development of small high output turbocharged internal combustion (IC) engines, cooling module noise and vibration has become more challenging. Furthermore, with plug-in hybrid electric vehicle (PHEV), in some cases the cooling fan could be operational while the IC engine is not running. This poses a significant challenge for cabin noise enhancement. Small turbocharged IC engines typically require higher cooling capacity resulting in larger fan size designs with higher speed. Accurate prediction of the unbalance loads generated by cooling fan and loads transferred to the body are critical for the Noise Vibration and Harshness (NVH) performance of the vehicle. If the NVH risk of cooling module operation is not well quantified and addressed early in the program, attempts to find solutions in post launch stage could be very expensive and not as effective. In this paper the static unbalance of the fan and motor assembly was studied and the influence of the coupled unbalance was investigated. The results of…
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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 a part of the 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). This paper explains systematic -…
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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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Acoustic Fundamentals for Solving Noise and Vibration Problems Web Seminar RePlay

  • Webinar Recordings
  • PD331309ON
Published 2019-11-24
This course will provide an introduction to the characteristics of sound waves, human perception of sound, sound and vibration measurements, measurement facilities, and various noise sources and noise control principles. It will include an overview of sound pressure, power, intensity, decibels, and frequencies. Practical examples will be used to familiarize participants with the acoustic fundamentals for solving noise and vibration problems and the associated solution principles.By participating in this course, you will be able to: Discuss the differences of various acoustic terminologies that are important to solve noise and vibration problemsDefine a relationship between sound pressure, sound power, and sound intensityAssociate decibel to both sound and vibrationPrepare effective acoustic specifications encompassing all variables that affect noise and vibrationSelect correct instrumentation for noise and vibration measurements recognizing the challenges of measurementsDefine the source-path-receiver relationshipDetermine the steps of noise and vibration source identification process for a given applicationEmploy different noise control options to address specific noise and vibration issues
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Friction Material Elastic Constants Determination through FRF Measurements and Optimization

Brake NVH Standards Committee
  • Ground Vehicle Standard
  • J3013_201911
  • Current
Published 2019-11-20 by SAE International in United States
This SAE Standard specifies necessary procedures and control parameters in estimating anisotropic elastic constants of friction material based on pad assembly FRF measurements and optimization. It is intended to provide a set of elastic constants as inputs to brake NVH simulation, with the objective of ensuring pad assembly vibration correlation between simulation and measurements.
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Effective Powertrain Isolation of Off-Highway Vehicles

John Deere Technology Center-Devendra Mandke, Balavardhan Reddy Dasabai, Sandeep Burli
Vellore Institute of Technology-Pushpak Sakhala, Sharan Chandran
Published 2019-10-11 by SAE International in United States
A Powertrain is one of the major sources of excitation of a vehicle vibration and noise in off highway vehicles. It typically has a significant contribution in whole vehicle NVH characteristics. The structure borne energy of the powertrain is transmitted to the chassis and rest of the vehicle through powertrain mounts. Hence, it is of prime importance to design an effective powertrain mounting system in such a way that it will reduce vehicle vibrations to improve vehicle NVH as well as ride comfort, resulting in an effective vibration isolation system and ensuring long service life. In this paper, a newly developed an analytical tool for effective design of isolation system is discussed. For this model, powertrain is considered as a six degree-of-freedom system. Analytical calculations are implemented to find optimum mount design parameters i.e. stiffness, orientation and position of isolators to meet desired NVH targets. To achieve a good isolation characteristic, there is a necessity of decoupling of rigid body modes using optimization of various decoupling methods, which further helps in reducing the forces transmitted…
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