Browse Topic: Vibration

Items (340)

Dependency of Gear Honing Machine Processing Accuracy on Machine Vibration and the Vibration Reduction Considering Contribution

2024-32-002004/18/2025

In recent years, accurate gear processing is required for various products to improve efficient power transmission and small noise and vibration. On the other hand, the accuracy tends to be worse by high speed processing for increasing production efficiency. Therefore, we investigated relationship between gear honing machine vibration and the accuracy. The vibration acceleration of the honing machine was measured at various conditions, and the gear accuracy was measured after processing. As results, the accuracy was observed to be affected by both the original gear accuracy before honing processing and the gear secondary rotational vibration of the machine in operation. Subsequently, we applied transfer path analysis (TPA) to investigate which directional force in operation increased the vibration. As the results, the contribution from the input force at gear processing point along normal direction was the main contributor. Then, vibration transmission characteristics of the machine

Hanioka, Hiroaki, Ogawa, Yunosuke, Yoshida, Junji, Onishi, Yoichi, Kurokawa, Yasuhiro

Identification of Input Force and Contribution for Electric Power UnitUtilizing Virtual Point

2024-32-001504/18/2025

In this study, vibration characteristics inside an electric power unit at gravity center where direct measurement is impossible were estimated by using virtual point transformation to consider guideline for effective countermeasures to the structure or generated force characteristics inside the power source. Vibration acceleration, transfer function and the generated force in operation at the gravity center of the electrical power source were obtained by vibration characteristics at around the power source which can be measured directly. In addition, the transfer functions from the gravity center to the power source attachment points on the product were also estimated. And then, the contribution from the gravity center to the power unit attachment point was obtained by multiplying generated force with the transfer function. As results, the obtained total contribution was almost same with the actual measured vibration at the attachment point. Furthermore, the rotational contribution

Kubo, Ryoma, Hara, Kenta, Yoshida, Junji

Computational Investigation of a Flexible Airframe Taxiing Over an Uneven Runway for Aircraft Vibration Testing

01-17-02-0011

12/15/2023

Ground vibration testing (GVT) is an important phase of the development, or the structural modification of an aircraft program. The modes of vibration and their associated parameters extracted from the GVT are used to modify the structural model of the aircraft to make more reliable dynamics predictions to satisfy certification authorities. Due to the high cost and the extensive preparations for such tests, a new method of vibration testing called taxi vibration testing (TVT) rooted in operational modal analysis (OMA) was recently proposed and investigated by the German Institute for Aerospace Research (DLR) as alternative to conventional GVT. In this investigation, a computational framework based on fully coupled flexible multibody dynamics for TVT is presented to further investigate the applicability of the TVT to flexible airframes. The time domain decomposition (TDD) method for OMA was used to postprocess the response of the airframe during a TVT. The framework was then used to

Al-bess, Lohay, Khouli, Fidel

A novel framework for accelerating EDU NVH simulation using scalable transfer functions and evaluating manufacturing defects through space order excitation

2025-01-004405/05/2023

In the ultra-luxury vehicle segment, achieving optimal NVH (Noise, Vibration, and Harshness) performance across a growing range of load cases in drive and regeneration conditions presents significant engineering challenges. As the complexity of load cases escalates with varying torque ripple and transmission errors, traditional time and frequency-domain simulations become computationally inefficient. To address these challenges, an in-house software framework that employs Noise Transfer Functions (NTFs) and Vibration Transfer Functions (VTFs) is developed. The system’s dynamic response is computed once and scaled to various excitation sources, which includes radial and tangential forces derived from EMAG simulations, and gear forces derived from MBS simulation. Speed sweep simulation is performed to systematically characterize the RPM range, allowing for precise scaling of the transfer function against the original forces to obtain the responses in mounts or microphones. The resulting

Sureshkumar, Sanjai, Shaw, Stephen, Qureshi, Manucher, Duclaux de L'Estoille, Nicolas

Metamaterial application to automotive glass for vibration reduction and reduced noise transmission

2025-01-011905/05/2023

A metamaterial which, attached to the edge of a panel, reduces vibration results in reduced noise transmission into a vehicle. In this particular case, the metamaterial is designed to be attached to the edge of a glass panel and can reduce panel vibration and noise transmission due to wind or other sources into the vehicle interior. Acoustic transmission loss and panel vibration assessments show the benefit of this approach.

Sorenson, Steve, Moore, Jaime, Robison, Scott, Li, Xiaopeng

Characterize the Sound Field Generated from a Vehicle Horn by Pellicular Analysis

2025-01-005805/05/2023

To predict the sound field produced by a vehicle horn requires a good source representation of it in the full vehicle model. This paper investigates the characterization of a physical vehicle horn by an inverse method called pellicular analysis. To implement this method, firstly an acoustic testing is performed to measure the sound pressure radiated from the horn at a certain number of microphone locations in a free field environment. Based on the geometry of a virtual horn, the locations of each microphone and measured sound pressure data, pellicular analysis is adopted to recover a set of vibration pattern of the virtual horn. The virtual horn and the recovered vibration information are then incorporated in a full vehicle numerical model to simulate its exterior sound field. The validity of this approach is confirmed by comparing the prediction for a horn in a production vehicle to the corresponding physical test which is required to meet the Brazilian regulation CONTRAN 764/2018.

Yang, Wenlong, MELO, ANDRE

Application of Hybrid SEA in Vehicle NV Package Optimization

2025-01-005005/05/2023

As India’s economy expands and road infrastructure improves, the number of car owners are expected to grow substantially in the coming years. This market potential has intensified competition among original equipment manufacturers (OEMs) to position their products with a focus on cost efficiency while delivering a premium user experience. Noise and Vibration (NV) performance is a critical differentiator in conveying a vehicle's premiumness, and as such, NV engineers must strategically balance the achievement of optimal acoustic performance with constraints on cost, mass, and development timelines. Traditionally, NV package optimization occurs at the prototype or advanced prototype stage, relying heavily on physical testing, which increases both cost and time to market. Furthermore, late-stage design changes amplify these challenges. To address these issues, this paper proposes the integration of Hybrid Statistical Energy Analysis (HSEA) into the early stages of vehicle development

Rai, Nitesh, Mehta, Makrand, Ravindran, Mugundaram

A review on Electric Vehicle NVH challenges and recent trends

2025-01-004205/05/2023

Electric vehicles (EVs) present a distinct set of challenges in noise, vibration, and harshness (NVH) compared to traditional internal combustion engine (ICE) vehicles. As EVs operate with significantly reduced engine noise, other sources of noise, such as motor whine, power electronics, and road and wind noise, become more noticeable. This review paper explores the key NVH issues faced by EVs, including high-frequency tonal noise from electric motors, gear meshing, and vibrations. Additionally, it examines recent advancements and trends in NVH mitigation techniques, such as active noise control, improved material insulation, and advanced vibration isolation systems. Furthermore, this paper discusses the role of computational tools, simulation technologies, and testing methodologies in predicting and addressing NVH concerns in EVs. By providing an in-depth analysis of the challenges and the latest innovations, this review aims to contribute to the ongoing development of quieter and

Hazra, Sandip, Khan, Arkadip Amitava

Global Vehicle Vibration Enhancement Using Circular Force Technology

2025-01-001505/05/2023

In addition to safety advantages, sound and vibration are being utilized to enhance the driver experience in Electric Vehicles (EVs). Significant interest and investment continue to grow in utilizing interior and exterior sound for pedestrian safety and driver awareness of vehicle state, as well as enabling a unique personal EV audio experience for brand recognition both inside and external to the vehicle. Several automakers are also using audio to simulate virtual gear shifting and as well as manual transmissions in EVs. According to several automotive industry articles and market research, the audio enhancements alone, without the vibration that drivers are accustomed to in combustion engine vehicles, are not sufficient to meet the engagement, excitement, and emotion that driving enthusiasts expect. In this paper, we introduce the use of new automotive high-force compact light-weight circular force generators for globally shaking vehicles. The technology was developed originally for

Norris, Mark A., Orzechowski, JEFFREY, Sanderson, Brad, Swanson, Douglas, vantimmeren, Andrew

Characterization and Prediction of Interior Noise Quality in Electric Vehicles through Drive Unit End-of-Line Testing (EOLT)

2025-01-003905/05/2023

This paper addresses the critical aspect of interior noise quality in electric vehicles (EVs), focusing on the characterization and prediction methodologies employed during drive unit end-of-line testing. The electric drive unit plays a pivotal role in determining the overall Noise, Vibration, and Harshness (NVH) quality of the final product. This study explores the impact of drive unit assembly process variation and individual component tolerance on the NVH characteristics of electric drive units, emphasizing their direct effect on overall vehicle acoustic quality and customer comfort. The research delves into the intricate relationship between drive unit vibrational response, vehicle interior noise, and customer subjective perception, providing valuable insights into their correlation and how they collectively influence user experience and satisfaction. It aims to enhance the understanding of how electric drive unit characteristics contribute significantly to the interior noise

Arvanitis, Anastasios, Parbat, Aniket, Jadhav, Prashant, Raphael, Andrew

Road noise analysis using Component TPA and FBS with vehicle component modifications

2025-01-005505/05/2023

Road noise caused by road excitation is a critical factor for vehicle NVH (Noise, Vibration, and Harshness) performance. However, assessing the individual contribution of components, particularly bushings, to NVH performance is generally challenging, as automobiles are composed of numerous interconnected parts. This study describes the application of Component Transfer Path Analysis (CTPA) on a full vehicle to provide insights into improving NVH performance. With the aid of Virtual Point Transformation (VPT), blocked forces are determined at the wheel hubs; afterward, a TPA is carried out. As blocked forces at the wheel hub are independent of the vehicle dynamics, these forces can be used in simulations of modified vehicle components. These results allow for the estimation of vehicle road noise. To simulate changes in vehicle components, including wheel/tire and mount bushings, Frequency-Based Substructuring (FBS) is used to modify the vehicle setup in a simulation model. In this

Kim, Jungu, Reichart, Ron, de Klerk, Dennis, Schütler, Willem, Malic, Mario, Kim, Hyeongjun, Kim, Uije

Indirect blocked force measurement of a hydraulic power pack for structural vibration transmission into an airframe

2025-01-005205/05/2023

Centralization of electrically driven hydraulic power packs into the body of aircraft have increased the attention on the noise and vibration characteristics of the system. A hydraulic power pack consists of a pump coupled to an electrical motor, accumulator, reservoir, and associated filter manifolds. In previous studies, the characteristics of the radiated acoustic noise and fluid borne noise were studied. In this paper, we focus on the structure borne forces generated by the hydraulic pump characterized through blocked force measurements. The blocked force of the pump was determined experimentally using an indirect measurement method. The indirect method required operation with part under test fixed to an instrumented receiver structure. Measured operational accelerations on the receiver plate were used in conjunction with transfer function measurements to predict the blocked forces. Blocked forces were validated by comparing directly measured accelerations to predicted

Smither, Matthew, Tuyls, Zachary, Patel, Pratik, Yan, Xin, Herrin, David

The applications of Acoustic Black Holes to attenuation of Coach/Bus Frame Structure Vibrations

2025-01-006505/05/2023

Abstract An acoustic black hole (ABH) is a structure whose cross-sectional thickness decreases exponentially to zero, and the phase velocity and group velocity of wave propagation in those structure acoustic black holes decrease as the thickness decreases until they are zero. ABH produce some very magical physical phenomena. For example, because the wave velocity decreases to zero, the wave can never reach the center of the ABH, so the wave propagation in the acoustic black hole has neither refraction nor reflection; that is to say the vibration wave will not go through the acoustic black hole. As a result, the wave energy is concentrated in the center of the ABH. The arrangements of those acoustic black holes in the structures could change the directions of the vibrational wave propagation in the structures at NVH engineers’ wills. These amazing phenomena could play a magical role in reducing structural vibration, structural noise radiation and structure-borne noise. Basic structures

Huang, Xianli

A Theoretical and Experimental Investigation of NVH of In-Wheel Reduced Motor System

2025-01-000605/05/2023

To enhance the power density of the system and reduce production costs, the in-wheel reduced motor system (IWRMS), characterized by its integrated design and control, is poised to become the future development trend. However, the high speeds of motors and gear reducers can lead to challenges such as system stability and issues related to NVH (Noise, Vibration, and Harshness). This paper specifically addresses the NVH concerns associated with the IWRMS. Firstly, a bench test scheme was established, and vibration and noise tests were conducted under a range of conventional operating conditions. The results indicated that at the torque of 200 Nm and the speed of 5500 rpm, the noise sound pressure level reached 86.2 dB, highlighting significant vibration and noise issues within the system. Subsequently, operating deflection shapes (ODS) testing and analysis were performed on the IWRMS. Vibration responses of 48th order show that breathing mode of the motor housing bring resonance

Huang, Chao, Xiong, Lu, Meng, Dejian, gong, Yu, Guo, Han, Zhang, Mengyuan

100+ Years of Noise and Vibration in the Auto Industry

2025-01-007105/05/2023

There have been advances in the area of noise and vibration for over 100 years in the auto industry. This presentation will highlight some of the driving forces and advances over that period.

Kach, Raymond, Thompson, James

Leveraging Vision Language Models for Automated NVH Analysis

2025-01-012705/05/2023

Optimizing Noise, Vibration, and Harshness (NVH) is crucial in the automotive industry. Traditional analysis methods, including time series analytics and frequency spectrum analysis, as well as advanced techniques like time-frequency spectrogram analysis, are often time-consuming and rely heavily on expert interpretation. This research explores the potential of Vision Language Models (VLMs) specifically LLaMA 3.2 Vision, GPT-4o, and Microsoft Phi-3 vision for automating noise spectrogram analysis. By employing techniques such as few-shot learning and fine-tuning these models on a curated dataset of spectrograms paired with expert interpretations, we aim to facilitate rapid and accurate NVH assessments and report generation. The proposed approach includes assembling a dataset derived from vibration sensors and expert analyses to inform model training. Furthermore, we will evaluate the accuracy and reliability of the trained models to ensure robust performance. The techniques discussed

CHANDRASEKARAN, BALAJI, Cury, Rudoniel

Virtual Gear Noise Analysis and Case Design Investigation for Concept Parallel Axis Drive Unit

2025-01-010205/05/2023

For electric vehicles, it is critical to develop drive units that produce a minimal amount of noise while meeting efficiency needs for a given application. Modern computational resources and accumulated experience allow for engineers to evaluate gear noise early in the development process and influence the design of the drive unit. This paper documents a high-fidelity virtual engineering approach to evaluate gear noise in a concept parallel axis drive unit and provide learnings to influence design of the external structure to improve NVH performance. By using the latest simulation tools to calculate and visualize the noise and vibration characteristics of the drive unit, designers and developers can implement design changes in optimization iterations to reduce noise and vibration. Gear harmonic response is firstly analyzed through a system model which considers structural deflection and misalignment, then a FE housing model is incorporated which is used for noise radiation evaluation

Lima, Luiz, Shi, Zhenghong, Xu, Hai, REYNOLDS, CRAIG, Miller, John

Sound quality centered measurement technique over 40+ years: experiences and perspectives

2025-01-007305/05/2023

The author’s life work in acoustics and sound quality, though continuous over more than 40 years, has followed a number of parallel and nonparallel paths all involving measurement technologies and their evolution. The illustrated discussion begins at 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 excited by various notes and damper pedal positions. 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. Involvement with binaural

Bray, Wade

The quality of vehicle horn sounds research and control

2025-01-008805/05/2023

Chinese consumers are very concerned about the quality of vehicle horn sounds, and the quality of vehicle horn sounds is very important in the overall NVH development process. This paper studies the sound quality of vehicle horns based on their working principles and characteristics, combined with the principles of vehicle vibration and noise control. It conducts research on the sound quality of vehicle horns from multiple dimensions, including vibration and noise excitation sources, transmission paths, and evaluation conditions. By analyzing the horn sound quality problems encountered in the development process of a certain domestic new energy vehicle, it proposes corresponding solutions. The results show that in addition to the common NVH phenomena of vehicle horns, the vibration and noise of vehicle horns can cause nonlinear phenomena in adjacent components, thereby producing abnormal noise. This study provides technical reference for nonlinear research and control of vehicle horn

li, 李. 治齐, zhou, changshui, Xie, Kai

Vibration refinement of two wheeler sub chassis and aesthetic parts due to engine unbalanced excitation forces

2025-01-011305/05/2023

Two wheelers are important and essential transportation mode in India. Designing a motorcycle with better riding comfort and minimal vibration are thus a major challenge for engineers now a day. Engine and road excitations are two sources of vibration acting on motor bike or scooter. These vibrations are transmitted to chassis, sub chassis, aesthetic parts and then to the rider and pillion. Unwanted vibrations will create discomfort to the rider/pillion as well as produces noises and hence needs to be minimized. This study is focused on diagnosis and control of output vibration responses of sub chassis/aesthetic parts due to engine unbalanced excitation forces. There are numerous parameters of motor bike/ scooter that govern the vibration responses of sub chassis/ aesthetic parts. Engine unbalanced inertia force characteristics and their transmission to rider and pillion has been studied and reported here. Environmental benefits demands for a complete NVH refinement for lesser

khare, saharash

Localisation of Ultra-short Sound Emissions from Automotive Components by Using the Sound Field Scanning Method

2025-01-009205/05/2023

Design verification and quality control of automotive components require the analysis of the source location of ultra-short sound events, for instance the engaging event of an electromechanical clutch or the clicking noise of the aluminium frame of a passenger car seat under vibration. State-of-the-art acoustic cameras allow for a frame rate of about 100 acoustic images per second. Considering that most of the sound events introduced above can be far less than 10ms, an acoustic image generated at this rate resembles an hard-to-interpret overlay of multiple sources on the structure under test along with reflections from the surrounding test environment. This contribution introduces a novel method for visualizing impulse-like sound emissions from automotive components at 10x the frame rate of traditional acoustic cameras. A time resolution of less than 1ms eventually allows for the true localization of the initial and subsequent sound events as well as a clear separation of direct from

Rittenschober, Thomas

A Development of Spindle drive power trunk lid system with Optimizing Actuating noise

2022-01-091603/29/2022

The power trunk lid system is a device that automatically opens and closes the trunk lid using a motor, for the purpose to improve user’s convenience. The technology was applied only to high-priced large cars such as Equus and Genesis, but in line with increasing preference for high convenience features, the scope of application is gradually expanding to semi-large and mid-size vehicles. Accordingly, the need to secure profitability through cost reduction emerged, and we developed a power trunk lid system using a spindle drive. Spindle drives can reduce costs by optimizing the required motor specifications compared to conventional swing arm drives, and are lightweight and easy to assemble. However, since a planetary gear with a high gear ratio is used and the rotational speed of the motor is generally high, it has a relatively low characteristic in terms of actuating noise. When we first applied the spindle drive type power trunk lid system to GL3 model (the successor of YG), to reduce

lim, Kyeongjun

Medium and High-Frequency Vibration Analysis of Thin Plates by a Hybrid Distributed Transfer Function Method

2021-01-105208/31/2021

Vibrations of plates are widely seen in various applications of automobile, aerospace, mechanical and civil engineering. Vibration analysis of plates in medium and high-frequency regions plays an important role in optimal design and safe operation of machines and structures in these applications. Medium and high-frequency vibration analysis of plates is usually performed by using numerical methods. Proposed in this paper is a new analytical solution method for mid- and high-frequency analysis of thin rectangular plates modeled by the Kirchhoff-Love plate theory. In the development, analytical solutions for a class of thin plates are obtained based on a hybrid formulation that combines the Distributed Transfer Function Method (DTFM) and modal expansion. The proposed method, which is an extension of the DTFM for one-dimensional continua, is called the hybrid Distributed Transfer Function Method (hybrid DTFM). The hybrid DTFM is simple and flexible in treating general loadings and

Zhang, Yichi, Yang, Bingen

Subjective and Objective Seat Feature Acoustic and Vibration Response

2021-01-107508/31/2021

Compressors, fans, and valves in seats used for occupant height adjust, lumbar, heating, and cooling can be objectionable if felt or heard. An approach to measure subjectively and objectively both vibration and noise experienced by a seated occupant will be described along with results, ranking, statistical significance, correlation, and suggestions for noise control. The objective portion included acoustic measurements through a binaural headset worn by each occupant and vibration measurements were recorded using a seat pad accelerometer disc at the buttocks and a source accelerometer. A subjective questionnaire with Likert, Borg, Magnitude Estimation, Semantical Differences, and Ranking based questions was obtained from 9 subjects. The transfer path the vibration energy takes to reach the receiver, vibration or acoustic, will be explored with transfer function measurements and a discussion of potential mitigation techniques: source mounting, encapsulation, and other design

Haylett, Jim, Romagosa, Francesc, Nelson, Erik

Tire experimental characterization using contactless measurement methods.

2021-01-111408/31/2021

Automotive NVH (Noise, Vibration and Harshness) is one of the most critical points for customers' comfort evaluation. Noise inside the cabin has recently received special attention due to the continuous development and diffusion of E-cars. Different noise sources have been identified: the engine, suspension, tire, powertrain, brake system, etc. The biggest contributor has been recognized in the tire noise. Particularly, at mid-speed driving, when the engine and the powertrain work at minimum noise, the tire noise is the most critical factor for NVH that has to be taken into account. At the state of art, the identification and characterization of Noise and Vibration sources rely on pointwise sensors (microphones, accelerometers, strain gauges). Optical methods such as Digital Image Correlation (DIC) and Laser Doppler Vibrometer (LDV) have recently received special attention in NVH field because they can be used to obtain full-field measurements. Moreover, these same techniques could

Mastrodicasa, Davide, Minervini, Domenico, Di Lorenzo, Emilio, Manzato, Simone, Peeters, Bart, Geluk, Theo, Totaro, Miriana

Metamaterials R&D TARGETS NVH ABATEMENT

21AUTP05_0405/01/2021

Nissan readies its lightweight acoustic solution for 2022 production - will Hyundai follow? Acoustics engineers have a broad variety of materials from which to choose for reducing noise, vibration and harshness (NVH) in vehicles. But their selection often comes with a measurable downside: added mass. It's not uncommon for a new vehicle to gain 100 lb (45 kg) or more during development as various absorbers, reflective barriers and absorber-barrier combinations - typically baked-on mastics, blankets, injected foams and acoustic glazing - are brought to bear. In an era where “lightweighting rules” and engineers are rewarded on a per-gram basis for cutting vehicle weight, materials researchers are betting on new developments to win the NVH-versus-mass battle. So-called metamaterials offer significant promise here, with a potential added benefit of being less costly than the traditional NVH solutions used by OEMs.

Brooke, Lindsay

Development of the Active Sound Generation Technology using Motor Driven Power Steering System

2020-01-153606/03/2020

As original engine sound is usually not enough to satisfy the driver’s desire for the sporty and fascinating sound, active noise control (ANC) and active sound design (ASD) have been great technologies in automobiles for a long time. However, these technologies which enhance the sound of vehicle using loud speakers or electromagnetic actuators etc. lead to the increase of cost and weight due to the use of external amplifier or external actuators. This paper presents a new technology of generating a target sound by the active control of a permanent magnet synchronous motor (PMSM) which is already mounted in vehicle. Firstly, an algorithm of this technology, called an active sound generation (ASG), is introduced with those signal conversion process, and then the high frequency noise issue and its countermeasure are presented. Secondly, ASG test bench is designed using a motor driven power steering (MDPS) system and then it is checked if ASG has any influence on an original function of

Chang, Kyoung-Jin, Angerpointner, Leonhard, Schubert, Dominik, Niegl, Matthias, Orehek, Martin, Pfeffer, Peter

Inter-Laboratory Characterization of Biot Parameters of Poro-Elsastic Materials for Automotive Applications

2020-01-152306/03/2020

Automotive suppliers provide multi-layer trims mainly made of porous materials. They have a real expertise on the characterization and the modeling of poro-elastic materials. A dozen parameters are used to characterize the acoustical and elastical behavior of such materials. The recent vibro-acoustic simulation tools enable to take into account this type of material but require the Biot parameters as input. Several characterization methods exist and the question of reproducibility and confidence in the parameters arises. A Round Robin test was conducted on three poro-elastic material with four laboratories. Compared to other Round Robin test on the characterization of acoustical and elastical parameters of porous material, this one is more specific since the four laboratories are familiar with automotive applications. Methods and results are compared and discussed in this work. Finally some guidelines are drawn to improve the confidence in the characterized parameters and to compare

Chevillotte, Fabien, Ronzio, Francesca, Bertolini, Claudio, Hoang, Minh Tan, Dejaeger, Ludovic, lei, Lei, Duval, Arnaud, Mordillat, Philippe

Linking Body-In-White and Trimmed Body Dynamic Characteristics in view of Body-In-White Mode Shape Target Setting

2020-01-155306/03/2020

Target setting at Body-In-White (BIW) level is typically done for natural frequencies of global modes. Target values are commonly set based on experience or from benchmark studies with competitor vehicles. A link between these targets at BIW level and the vibro-acoustic targets at Trimmed Body (TB) level is not yet well established. Therefore, it is not always guaranteed that the TB targets will be met when the targets at BIW level are reached. Also, the other way around, not reaching a frequency target for a certain BIW mode does not necessarily imply that TB targets will not be met. Hence, there is a clear need for getting more insights in the relation between BIW dynamic properties and TB vibration behavior. In this paper techniques will be presented that establish the link between BIW and TB dynamic behavior. In addition, a large DOE campaign has been carried out to further link these dynamic properties to specific areas in the body design. Key elements in this paper are the

Brughmans, Marc, Orlando, Stefano

Measurement Location Optimization of Component TPA Method for Road Noise

2020-01-158106/03/2020

In this paper, an investigation on the application of a non-intrusive on-site component Transfer Path Analysis (TPA) method is presented together with the comparison with a previously performed direct blocked forces method. The latter is the more common method to determine interface forces between active and passive parts of an assembly. Force transducers are placed between the investigated structure and a rigid measurement rig. The presented comparison shows an investigated whether the faster and cheaper TPA method was able to produce relevant results. The TPA method used in this work calculated the force component contributions, without disassembly of the interfaces, through the local stiffness of multiple indicator positions per interface combined with operational measurement. The method is based on the application of an inverse-matrix model. This approach was applied to a vehicle road noise investigation carried out on a roller bench at three different roller speeds. A rough

de Boer, Onno, Iturbe, Javier, Gagliardini, Laurent, Bragado Pérez, Beatriz

The In-Depth PHEV Driveline Torsional Vibration Induced Vehicle NVH Response Study by Integrated CAE/Testing Methodology

2020-01-150706/03/2020

In this paper,an amesim 1-d refined driveline model, including detailed engine, damper, dual clutch, transmission, differential, motor, halfshaft, wheel, body, suspension, powertrain mounting and powertrain rigid body, was built up, off a p2.5 topology phev,to predict torsional vibration induced vehicle NVH response addressing differing driving scenarios,like WOT rampup,parking engine start/stop,ev driving to tipnin(engine start) then to tipout(engine stop).firstly,the torsional vibration modes were predicted,addressing differing transmission gear steps of hev/ev driving mode,and the critical modes could be detected,as such, caveats/measures could be applied to setup the modal alignment chart/warn other engineering section from the very start of vehicle development; secondly,secondly,the holistic operational testing,which defined plenty measurement points including rpm fluctuation at differing location of engine/transmission,spark angle,crank position,injection angle,valve timing,MAP

zhao, Qian, zhang, Li, jia, Jianning, WU, LIE, zhuang, Huimin, Yu, Hongzhi, lu, Shouwei, zhao, honghui, poduturu, Anil, jain, Swejal, carter, Steven

Reduction of the Effect of the Creep Groan Brake Excitation in a Comercial Vehicle

2020-01-153006/03/2020

One of the results generated by the stick-slip intermittent motion of a brake at the friction interface is the Creep Groan Noise which is a low frequency self-excited vibration, normally less than 220 Hz. This local vibration generated between the brake couple, is transmitted through the suspension system until the passengers of the vehicle in form of vibration and noise. This paper presents a methodology that combines testing and numerical models in order to 1) detect the source of the Creep Groan, 2) create a correlated numerical model and 3) produce countermeasures that reduce the amplitude of the noise at occupant positions. The vehicle under investigation was a commercial vehicle employing air-actuated brake drums. From testing, global vehicles modes and displacements under operational conditions were respectively investigated by means of Operational Deflection Shapes and Real Time Animation. These techniques allowed to prove the existence of a feedback loop with a positive gain

Sanchez, Angel

A Generic Testbody for Low-Frequency Aeroacoustic Buffeting Phenomena

2020-01-151506/03/2020

Raising demands towards lightweight design paired with a loss of originally predominant engine noise pose significant challenges for NVH engineers in the automotive industry. Wall thickness reductions particularly emphasize low frequency contributors due to decreasing panel stiffness. From an aeroacoustic point of view, low frequency buffeting ranks among the most frequently encountered issues. The phenomenon typically arises from rooftop or side-window buffeting, structural transmission of hydrodynamic wall pressure fluctuations or, as indicated in this work, through rear vent excitation. A convenient workflow to simulate structure-excited buffeting contains a strongly coupled vibro-acoustic model for structure and interior cavity excited by a spatial pressure distribution obtained from CFD. In the case of rear vent buffeting no validated workflow has been published yet. While approaches have been made to simulate the problem for a real-car geometry, such attempts suffer from

Engelmann, Rafael, Gabriel, Christoph, Schoder, Stefan, Kaltenbacher, Manfred

Using Statistical Energy Analysis to Optimize Sound Package for Realistic Load Cases

2020-01-152506/03/2020

The statistical energy analysis (SEA) is widely used to support the development of the sound package of cars. This paper will present a model prepared to investigate the sound package of the new Audi A3 and its correlation against measurements. Special care was given during the creation of the model on the representation of the structure to able the analysis of structure borne energy flow on top of the classical airborne analysis usually done with SEA. The sound package is also detailed in the model to allow further optimization and analysis of its performance. Two real life load cases will be presented to validate the model with measurements. First, the dominating powertrain and second, a case with dominating rolling noise. An analysis of the contribution of the different source components and a way to diagnose the weak paths of the vehicle will be presented. The focus of this investigation is the application of optimally adjusted treatment.

Venor, Joseph, Caillet, Arnaud, März, Christian, Martin, Simon, Fatmi, Oussama, Glavac, Matej

Reinforcement of Low-Frequency Sound by Using a Panel Speaker Attached to the Roof Panel of a Passenger Car

2020-01-157006/03/2020

The woofer in a car should be large to cover the low frequencies, so it is heavy and needs an ample space to be installed in a passenger car. The geometry of the woofer should conform to the limited available space and layout in general. In many cases, the passengers feel that the low-frequency contents are not satisfactory although the speaker specification covers the low frequencies. In this work, a thin panel is installed between the roof liner and the roof panel, and it is used as the woofer. The vibration field is controlled by many small actuators to create the speaker and baffle zones to avoid the sound distortion due to the modal interaction. The generation of speaker and baffle zones follows the inverse vibro-acoustic rendering technique. In the actual implementation, a thin acrylic plate of 0.53ⅹ0.2 m2 is used as the radiator panel, and the control actuator array is composed of 16 moving-coil actuators. The shape of the desired speaker zone is an ellipse, and the required

Lee, Ki-Ho, Cho, Munhwan, Ih, Jeong-Guon

A Multi-Resonant Speed Piezoelectric Beam Device for Harvesting Energy from Vehicle Wheels

2020-01-123604/14/2020

This work analyzes a cantilevered piezoelectric beam device for harvesting energy from the simultaneous rotation and translational vibration of vehicle wheels. The device attaches to the wheel rim so that it displaces tangentially during operation. A lumped-parameter analytical model for the coupled electromechanical system is derived. The device has one natural frequency that is speed-dependent because of centripetal acceleration affecting the total stiffness of the device. Even though the device has one natural frequency, it experiences three resonances as the rotation speed varies. One resonance occurs when the rotation speed coincides with the speed-dependent natural frequency of the device. The other two resonances are associated with excitations from the vibration of the vehicle wheel. The device’s parameters are chosen so that these three resonances occur when the wheel travels near 30 mph, 55 mph, and 70 mph. There are two excitation frequencies that give these resonant speeds

Cooley, Christopher

Analysis of CVT Element Vibration by In-Situ Measurement

2020-01-090604/14/2020

When the belt of a metal pushing-belt CVT is wrapped around the pulleys, vibration is said to be generated from the friction force caused by the elements that make up the belt rubbing against each other. In order to verify this, a small data logger with a triaxial accelerometer (G Sensor) was developed in house, then fixed on a side surface of a movable pulley and measurements were conducted at engine speeds characteristic of actual driving (1500-2500 rpm). The measurement results showed that there is a difference between the average radius of the belt when it is wrapped around the pulley and when it is not wrapped around the pulley, demonstrating that vibration is occurring.

Matsumoto, Kenji, Koga, Hideharu, Saito, Toshihiro, Mihara, Yuji

Multifunctional Structure Stabilizes and Rotates Satellites

TBMG-3636204/01/2020

Many satellites are in space to take photos. But a vibrating satellite, like a camera in shaky hands, can’t get a sharp image. Pointing it at a precise location to take a photo or perform another task is an important function that requires accuracy. Researchers have developed a way to cancel out the vibrations of a satellite by vibrating the solar panels in the opposite direction — called active noise cancellation.

Web-Based Technology Assesses Structural Health

TBMG-3544511/01/2019

Understanding how cars, planes, bridges, and other structures handle vibrations and dynamic loads can be critical to their design and performance. Researchers have developed a new way to measure the response of civil, mechanical, and aerospace structures to dynamic loads and analyze their structural health.

Ride Index Structure and Development Methodology

J2834_201910 (Current)

10/09/2019

This recommended practice defines methods for the measurement of periodic, random and transient whole-body vibration. It indicates the principal factors that combine to determine the degree to which a vibration exposure will cause discomfort. Informative appendices indicate the current state of knowledge and provide guidance on the possible effects of motion and vibration on discomfort. The frequency range considered is 0.5 Hz to 80 Hz. This recommended practice also defines the principles of preferred methods of mounting transducers for determining human exposure. This recommended practice is applicable to light passenger vehicles (e.g., passenger cars and light trucks). This recommended practice is applicable to motions transmitted to the human body as a whole through the buttocks, back and feet of a seated occupant, as well as through the hands of a driver. This recommended practice offers a method for developing a ride performance index but does not specifically describe how to

Vehicle Dynamics Standards Committee