Browse Topic: Noise, vibration, and harshness standards and regulations

Items (186)

Design, Manufacturability, Optimization, and Validation of a Reactive-Style Muffler for a Formula SAE Race Car

2025-01-002405/05/2023

The noise generated by internal combustion engines, particularly in high-performance vehicles like Formula SAE race cars, presents a significant challenge in adhering to strict competition noise regulations. To address this issue, mufflers are essential for reducing acoustic emissions. This study focuses on the design, manufacturability, optimization, and validation of a reactive-style muffler specifically for a Formula SAE combustion competition car. The proposed muffler utilizes two chambers to generate destructive interference, targeting the two dominant exhaust frequencies of the Honda CBR600RR engine to maximize transmission loss and reduce noise levels below the SAE-mandated range of 103–110 dB(C). A 3D model of the muffler was developed using SolidWorks, capturing the precise geometries required for acoustic optimization. The exhaust noise and muffler performance were simulated using GT-Suite, allowing for an evaluation of noise attenuation across engine speeds. Experimental

Labao, Kai, Middleton, Nicholas, Nuszkowski, John

Modeling and Validation of Acoustic Emissions in Bent-Axis Pumps

2025-01-005605/05/2023

This work presents a comprehensive NVH workflow for modeling the acoustic emissions of mechanical systems, using a bent-axis pump as a case study. The workflow integrates multibody dynamics (MBD), harmonic structural analysis, and acoustic solvers. By employing these simulation tools, we capture the dynamic response of the pump and the vibration response of the enclosure's surface, enabling the estimation of equivalent radiated power (ERP) and the prediction of sound pressure level (SPL). To validate the simulation outcomes, experimental investigations were conducted in a semi-anechoic chamber, where data was collected with a microphone placed at a specific distance from the pump. At the time of this abstract, preliminary correlations between the simulation model and real-world measurements demonstrate promising accuracy and reliability. These findings are significant, offering advantages for pump manufacturers, including improved product quality, adherence to noise regulations, and

Kwarta, Michael, Banerjee, Bhaskar, Abdel Mallak, Zuher, Vallebrant, Per-Ola, Wiklund Lång, Marcus, Kayani, Omer

Prediction and Optimization of Noise radiation from a Heavy-Duty Commercial Vehicle Transmission using Statistical Energy Analysis

2025-01-005105/05/2023

Heavy Duty (HD) linehaul vehicles are majorly used in transportation of goods and heavy loads between different cities or long distances. Considering the current trend, payload capacity of these heavy-duty trucks are increasing due to constant increase in the load demand. Due to which engine torques of these HD vehicles are increasing which in turn increases the transmission input torque. At higher torque levels, gear excitation also increases and transmission becomes more susceptible towards higher noise radiation. Global vehicle pass-by noise regulations for HD commercial vehicles are becoming more stringent. Historically transmissions have been considered a secondary noise source but with overall HD vehicle noise becoming quieter, the transmission can be more of a significant noise contributor. Hence, noise radiation from the transmission is also an important factor to be considered in the design phase. Gear whine is the major concern for sound radiation from the transmission. The

Rastogi, Sarthak, Milind, T. R.

Reduction of Aeroacoustics Tonal Noise for a Tractor Cooling Fan

2021-26-029909/22/2021

Currently, noise pollution has become one of the major environmental concerns. To address this, new noise standards and regulations are being introduced and mandate the tractor OEM's to meet the defined noise levels. Fan noise from the cooling fan is one of the key contributors to the overall vehicle noise. Hence, the reduction of fan noise at the source is a very important and critical task. Even though fan noise is broadband in nature its aerodynamic noise sources are most dominant at the higher harmonics of the blade pass frequency (BPF). Aerodynamic noise of a fan can be varied by changing the fan geometry viz. blade profile, fan width & diameter, no. of blades, and ring on its periphery. Cooling fan is an important component of the cooling system which ensures adequate airflow for radiator cooling and avoids engine overheating with uniform heat dissipation. The important parameters that need to be considered while designing a cooling fan are noise level, airflow, and power

Avinash, D., Shankar, M, Maller, Rathish, V, Ravindran

Sound Measurement - Construction Site

J1075_202107 (Current)

07/15/2021

This SAE Standard sets forth measurement procedures and instrumentation to be used for determining a “representative” sound level during a representative time period at selected measurement locations on a construction site boundary. The document is not intended for use in determining occupational hearing damage risk. Determination of a representative time period is left to the judgment of the user.

OPTC3, Lighting and Sound Committee

Enhanced Windshield NVH Modeling for Interior Cabin Noise

2020-01-110004/14/2020

The windshield is an important component in vehicle NVH performance. It plays an integral role in affecting the interior cabin noise. The windshield acts as a large panel typically oriented near vertical at the front of vehicle’s acoustic cavity, hence modeling it appropriately is key to have a reliable prediction of cabin interior noise. The challenge of modeling the windshield accurately rises from the structural composition of different types of windshields. For automotive applications, windshield come in several structural compositions today. In this paper, we will discuss two types of windshield glass. First is a typical laminated glass with polyvinyl butyral (PVB) layer and second is a typical acoustic glass with PVB and vinyl layers. Acoustic glass improves acoustics characteristics of the glass in frequencies of ~ 1200 Hz to ~4000 Hz range. Low frequency interior cabin noise studied with FEA is typically below 500 Hz. The acoustic glass doesn’t provide any benefits in this

Abbas, Ahmad, Elwali, Wael, Thirukonda, Aravindhan, Haider, Syed, Sturla, Francisco

Human Response to Vibrations and Its Contribution to The Overall Ride Comfort in Automotive Vehicles – A Literature Review

2020-01-108504/14/2020

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

Wang, Xiaojuan, Osvalder, Anna-Lisa, Höstmad, Patrik, Johansson, Ingemar

Road Noise Prediction Assessment Using CAE Instead Of Costly And Time Consuming Physical Tests

2020-01-049204/14/2020

Virtual Product Development (VPD) with a vision to eliminate prototype testing is the trend in automotive industry. Reducing the total vehicle development period with optimized output has been the major requirement of this new trend, fueled by increasing competition and shorter product life cycle. In this regard, Computer Aided Engineering (CAE) has taken more significant role than ever in the vehicle development programs. Prediction of road noise in passenger car is one of the important attribute to NVH Simulations. In the present work, CAE - NVH simulation of road noise is carried out on the Finite element model of the vehicle, eliminating the costly and laborious test procedures. An alternative to the existing MBD/Test input method is explored in this work. Generating the load inputs for the structure-borne road noise in a cost and time saving method with accuracy is one of the challenges in these simulations. Enforced displacements in the frequency domain are generated using ISO

S, Vishnu, J, Prajith, Holla, Muralidhara, Suhas, Patil, Bhattacharyya, Indranil

Independent Aftermarket (IAM) and the Three Dimensions of Friction Material Evaluation

2019-36-000601/13/2020

It is well known the difference between development levels and engineering investment applied to passenger car brake pads when compared to Original Equipment Manufacturer (OEM) and items sold in the Independent Aftermarket (IAM). Based on these differences, the objective of this paper is to propose a simple evaluation for the IAM that can provide at least some level of the understanding of frictional material behavior. Based on a tripod of variables, or three Dimensions Development, described in this work as Performance, Comfort (NVH) and Durability; and using internationally and established testing procedures to measure these dimensions in order to meet the IAM demands for the cost-benefit engineering investment. An important part of the proposed tool is to position friction material against competition for market known issues, and, more importantly, to ensure end product safety and reliability.

Oliveira, Pedro, Rodrigues, Henrique, Ferro, Eduardo

GKN spreads premium propshaft tech to quiet pickup cabins

19AUTP10_1110/01/2019

It may seem a long way in engineering and NVH terms from premium European cars such as Audi's A5 and A7 to light duty trucks, but GKN Automotive has bridged that gap with its latest lightweight all-wheel drive (AWD) modular propshaft. Many pickups suffer a significant amount of unwanted NVH emanating from the front propshaft, with its two universal or CV joints and an interconnecting shaft positioned below and close to the passenger cabin. But now GKN Automotive has “re-characterized” its premium car driveline system to an entirely different vehicle category. “With a traditional truck front propshaft, the level of noise entering the cabin is perceived as a drone,” explained Michael Miller, GKN's propshaft product technology manager. “We've worked on applications of our new technology where the cabin NVH levels have been dramatically reduced. Positive results stem from the combination of joints used in our lightweight modular front propshaft.”

Frequency Inspection of Brake System Components

2019-01-211709/15/2019

Frequency inspection has long been a tool utilized by manufacturers of brake system components as a means of quality control. This is important to combat perceived defectiveness of a system that experiences issues, such as brake squeal, as well as to identify actual defects in the parts going out to customers. Every component has its own resonance frequencies based on the dynamics of that component. Knowledge of the resonance frequencies of each component provides insight that can prevent manufacturers from sending out defective units, whether they be perceived defects or actual defects. NVH engineers who understand these phenomena perform theoretical analysis and acquire experimental data in the lab to gain insight into their parts that will eventually be produced on the assembly line. Unfortunately, the frequency requirements, and the consequences thereof, defined by the NVH engineers can still remain somewhat of a mystery to the manufacturing engineers who are tasked with applying

The Influence of Differential Pad Wear on Low-Frequency and High-Frequency Brake Squeal

2019-01-213009/15/2019

The NVH behavior of disc brakes in particular, is in the focus of research since a long time. Measurements at a chassis dynamometer show that brake pad wear has a significant influence on the occurrence of low- and high-frequency squealing [1]. It is suspected that high-frequency squealing is more likely to occur when the wear difference between the inner and outer brake pad is small. In the other case, if the differential wear rate between the inner and outer pads becomes higher, the prevalence of low-frequency squealing increases. In order to examine this hypothesis, this work focuses on a simplified model of a commercial brake system [2]. In a first step, the inner pad’s wear is iteratively increased, while the wear on the outer pad remains unaffected. In a second step, the coefficient of friction at the worn pad is iteratively increased to investigate the influence on the low and high-frequency squealing. With the aid of the Complex Eigenvalue Analysis (CEA), the real part of the

Otto, Johannes, Ostermeyer, Georg-Peter, Rhee, Seong K.

Role of Dynamic Stiffness in Effective Isolation

2019-01-149506/05/2019

In any machinery, avoiding noise and vibration completely is a difficult task due to the structural dynamic behaviors of components. To safeguard the operator, it is important to best isolate the operator station from NVH environment. Cabin isolation is an important aspect to minimize structure borne noise and tactile vibrations to be transferred into the cabin. Isolators are selected based on the isolation system inertial properties at mounting locations in the operating frequency range interested. The most important assumption to select isolators are that the active side and passive side of the isolators are nearly rigid so impedance mismatch is created for effective isolation. This paper describes the importance of dynamic stiffness of the structures on both the active and passive side for better NVH performance. NVH performance of passive side is evaluated analytically and computationally in terms of tactile vibrations and structure borne noise for various ratios of the dynamic

Dasabai, Balavardhan Reddy, Yang, Yuzhen

Design Optimization of Differential Bevel Gear for NVH Improvement

2019-01-155206/05/2019

With fast pacing development of automobile industry and growing needs for better driving experience, NVH performance has become an important aspect of analysis in new driveline product development especially in hybrid and electric powered vehicles. Differential bevel gear has significant role in the final drive. Unlike parallel axis gears such as spur or helical gear, bevel gear mesh shows more complicated characteristics and its mesh parameters are mostly time-varying which calls for more extensive design and analysis. The purpose of this paper is to conduct design study on a differential bevel gear unit under light torque condition and evaluate its NVH characteristics. Unloaded tooth contact analysis (UTCA) of those designs are conducted and compared for several design cases with different micro geometry to investigate their pattern position and size variation effects on NVH response. Loaded tooth contact analysis (LTCA) that is based on semi-analytical and semi-FE method is used to

Shi, Zhenghong, Chen, Jui, Kolivand, Mohsen, Sun, Zhaohui, Kopp, Gregory, Peng, Ying

Interior Floor Engineering: The Dynamic-vs-Static-Stiffness Compromise

2019-01-149306/05/2019

When it comes to the design of multi-functional automotive interior floors, engineers face the challenging conflict between a dynamically-soft, NVH performing treatment, and a statically-stiff construction, which increases the perception of solidity. Nowadays, the former requirement is well-specified and advanced CAE tools exist to support performance prediction and engineering of the construction. On the contrary, neither well-established requirements specify the compressional performance, nor defined CAE processes are available to support the engineer in its prediction. In this context, the aim of this paper is twofold. Firstly, insightful conclusions about the compression behavior of typical interior floor materials are drawn by means of tests carried out both at sample- and part-level. Such an analysis allows highlighting a clear direction towards meaningful assessment of the mechanical characteristics of the floor. Secondly, the paper focuses on how CAE tools can support part

Pezzani, Flavio, Godano, Philippe, Ronzio, Francesca, D'Amico, Roberto

Application of Model Order Reduction to Nonlinear Finite Element Tire Models for NVH Design

2019-01-150706/05/2019

In current practice, tire development and testing are typically experimentally driven. However, as the need to simultaneously optimize multiple noise vibration and harshness (NVH) performance criteria increases and development cycles become shorter, predictive numerical simulation techniques are becoming necessary. In addition, many tire performance areas are coupled and therefore the experimental approach often lacks detailed insights which numerical simulations can provide. Currently, no industrially applicable fully predictive high-fidelity numerical approach that incorporates the use of nonlinear Finite Element (FE) tire models for NVH design is available in literature. Therefore, a fully predictive numerical simulation approach that predicts the rolling of a tire over a coarse road surface is described in this work. The proposed approach allows to predict the dynamic contact- and hub forces that arise during rolling without the need for experimental data. Based on these results

De Gregoriis, Daniel, Naets, Frank, Kindt, Peter, Desmet, Wim

Optimization of Hypoid Gear Tooth Profile Modifications on Vehicle Axle System Dynamics

2019-01-152706/05/2019

The vehicle axle gear whine noise and vibration are key issues for the automotive industry to design a quiet, reliable driveline system. The main source of excitation for this vibration energy comes from hypoid gear transmission error (TE). The vibration transmits through the flexible axle components, then radiates off from the surface of the housing structure. Thus, the design of hypoid gear pair with minimization of TE is one way to control the dynamic behavior of the vehicle axle system. In this paper, an approach to obtain minimum TE and improved dynamic response with optimal tooth profile modification parameters is discussed. A neural network algorithm, named Back Propagation (BP) algorithm, with improved Particle Swarm Optimization (PSO) is used to predict the TE if some tooth profile modification parameters are given to train the model. With the optimal hypoid gear tooth profile modification, a system level analysis of vehicle axle system is performed to verify the improvement

Lin, Chia-Ching, Wang, Yawen, Wang, Kan, Zhang, Weiqing, Sun, Shouli, Lim, Teik C.

Determining Vibro-Acoustic Characteristics and Structural Damping of an Elastic Monolithic Panel

2019-01-153806/05/2019

Evaluations of the dynamic and acoustic responses of panels, partitions, and walls are of concern across many industries, from building home appliances, planning meeting rooms, to designing airplanes and passenger cars. Over the past few decades, search efforts for developing new methodologies and technologies to enable NVH engineers to acquire and correlate dynamically the relationship between input excitations and vibro-acoustic responses of arbitrary-shaped panels has grown exponentially. The application of a particular methodology or technology to the evaluation of a specific structure depends intimately on the goals and objectives of the NVH engineers and industries. In this work, we present the comparisons between the traditional modal analyses for structural vibrations together with sound intensity measurements of sound radiation and a laser-assisted Helmholtz equation least squares (HELS) method [1, 2, 3, 4] to characterize the dynamic and acoustic responses of an arbitrarily

Figueroa, Antonio, Wu, Sean, Chen, Lingguang

Reducing Vehicle Interior NVH by Means of Locally Resonant Metamaterial Patches on Rear Shock Towers

2019-01-150206/05/2019

Stringent regulations for CO2 emissions and noise pollution reduction demand lighter and improved Noise, Vibration Harshness (NVH) solutions in automotive industries. Designing light, compact and, at the same time, improved NVH solutions is often a challenge, as low noise and vibration levels often require heavy and bulky additions, especially to be effective in the low frequency regime. Recently, locally resonant metamaterials have emerged among the novel NVH solutions because of their performant NVH properties combined with lightweight and compact design. Due to the characteristic of stop band behavior, frequency ranges where free wave propagation is inhibited, metamaterials can beat the mass law, be it at least in some tunable frequency ranges. Previously the authors demonstrated how metamaterials can reduce the vibrations in a simplified shock tower upon shaker excitation. In this work, the authors apply the metamaterial concept on the real rear shock towers of a vehicle. In order

Sangiuliano, Luca, Claeys, Claus, Deckers, Elke, De Smet, Jasper, Pluymers, Bert, Desmet, Wim

Paradigm shift in NVH

19AUTP06_0206/01/2019

A new wave of vehicle technologies is changing the way Brüel & Kjaer attacks noise, vibration and harshness. When you're in the business of NVH solutions, you get to know noise and vibration up close and personal. And for these experts, it can be difficult to sequester the ‘N and V’ throughout their own day. Ask Dr. Gabriella Cerrato, manager of global sound and vibration engineering services at Brüel & Kjaer. “I can't be in a hotel room and not be aware of things like the refrigerator compressor, the ice maker, or the air conditioning,” she noted. “Although I'm not a geek about it-I don't immediately ponder the sources and potential noise paths of the hotel HVAC, for example-it sometimes drives me nuts.”

Brooke, Lindsay

Foam for NVH solutions

19AUTP06_0506/01/2019

New innovations for a wide variety of sound-deadening applications.

Everything brake science and technology

1243705/16/2019

Over 800 braking professionals from all corners of the industry will gather at Orlando's JW Marriott Grande Lakes Resort for the 37th annual installment of the Brake Colloquium and Exhibition this coming September. Join engineers, executives, management and marketing professionals for four full days of networking and immersive discussion and learning about brake design, emissions, materials, NVH, testing and more. Plus, discover the new technology and solutions driving the next generation of brakes on a bustling show floor of over 85 exhibitors. Register today at sae.org/brake.

Parameters Analyses and Identification for Rubber Bush Based on Theoretical Dynamic Model with Effects of Temperature and Preload

2019-01-127204/02/2019

A series connection of the KVBC (Kelvin-Voigt and Bouc-wen) theoretical model of rubber bush in automobile suspension is established. The numerical calculation model is also developed through Matlab/simulation and 9 parameters are identified. Experiments are conducted on the rubber bush on a bench for dynamic and static characteristics and to supply appropriate and reliable data for parameter identification. Based on this, preload and temperature are taken into consideration in an ordinary KVBC model as two important additional factors. As a result, it leads to developing a novel model with new parameter identification, which is validated under different conditions. This new modeling method of rubber bush has three advantages. First, it shows improved accuracy for solving non-linear problems in a multi-body calculation, which is useful for researchers and vehicle engineers. In addition, this new method leads to a very important step for choosing appropriate bush model type before

He, Rong, Zhou, Hong

Automotive Engineering: March 2019

19AUTP0303/01/2019

Rethinking the HUD Advanced tech solutions move toward augmented reality to bring greater capability to head-up displays. Motor matters New designs and materials are key to the next generation of electric machines for EV propulsion. Harnessing the power of Sim Serious cost savings could come from eliminating vehicle- and systems-level tests. Powerful simulation tools may be the only way to tackle the increasing complexity in mobility development. An OBE for the SAE Meet Paul Mascarenas-SAE International's 2019 president. He's a staunch advocate for professional development for engineers amid the mobility industry's transformation. Solving the propulsion puzzle Must-attend expert panels at SAE's WCX '19 will cover the propulsion-tech future like no other. Editorial Kill the EV tax credit by 2025 SAE Standards News SAE and Synopsys collaborate on cyber study Supplier Eye New Co. vs. Old Co. What We're Driving Supra's revival is Toyota's spin on German engineering 2020 Explorer is the

BIOT’s Parameters Evaluation and Prediction of Flat and Molded Dash Panel Acoustic Performance and It’s Validation

2019-26-019501/09/2019

In today’s automotive industry sound package material design and optimization is important considering the need for weight reduction and achieving targeted sound absorption and sound transmission loss values. As per traditional approach vehicle level noise reduction targets are defined considering flat samples, but in actual vehicle condition molded trimmed parts are used. This paper discusses about the systematic methodology developed for molded sample characterization in terms of BIOT’s properties. Effects of different parameters like area wise thickness variation, density variation on BIOT properties is studied. Comparison of BIOT’s properties of flat and molded dash sample is done to study the effect of molded structure. Using these BIOT’s properties prediction of sound absorption and sound transmission loss results carried out using FTMM approach for flat sample and SEA approach for molded sample. These predicted results validated with experimental sound absorption and sound

Joshi, Manasi P., Jain, Sachinkumar, Kamble, Jr., Prashant Prakash, Karanth, Nagesh Voderahobli

Closures weatherstrips with variable cross sections

2018-36-015209/03/2018

Closures systems performance is a trade-off between NVH (Noise, Vibration and Harshness) and DCE (Door Closing Efforts) requirements. Dynamic sealing performance and sheet metal rigidity are the key contributors for a stable system. The seals actuate like a spring on the system. Higher seal load is good for NVH performance, adding more dumping to the system, but it will negatively affect DCE, as it will demand additional energy to close the system. Nominal seal load must be defined to achieve a balance between these attributes. This study is about dynamic sealing profiles with variable seal load, which provides tunable solutions to address the trade-off between NVH and DCE on the side doors or rear closures. Dynamic sealing weatherstrips are made of sponge EPDM extruded profiles with a specified load, defined by its CLD (Compression Load Deflection), which is given by the cross section design. While standard extrusion process produces a single cross section profile, a new extrusion

Filho, Rineu Santamaria, Fromel, Ingo, Osti, Reinaldo

The Use of “Big Data” for the Analysis and Design of Vehicle Sound Packages

2018-01-157006/13/2018

With the ever-decreasing timescales and increased performance requirements afforded to OEM’s, it has become essential that NVH suppliers provide optimum palliative solutions that comply with a vehicles acoustic targets. The acoustic effect of any palliative treatment attached to a vehicle body system depends on its ability to attenuate noise energy passing through or radiating from the system or its interaction with reflected sound from other areas. Acoustic performance uses targets relating to sound insertion loss (SIL) and / or sound absorption and these are identified to the component supplier by the OEM at the “request for quotation” (RFQ) stage. For many potential suppliers, especially those with a limited portfolio of material options, success or failure is quite straightforward. However, the problem occurs when the material and processing opportunities cover wide parameters and the available combinations and permutations are extensive. It is no longer a simple choice to get the

Morris-Kirby, Rod

Stationary Sound Level Measurement Procedure for Recreational Motorboats

J2005_201806 (Current)06/12/2018

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

Stress Analysis on the Single-Lap SPR- Adhesive Hybrid Joint

2018-01-144504/03/2018

Self-pierced rivet (SPR) and adhesive are two important joining technologies widely used in automobile industry, and they are often used together to form a hybrid joint. SPR and adhesives can often be used in close proximity in a component, leading to an interaction of the two joints. This interaction can influence the corrosion and noise, vibration and harshness (NVH) characteristics of the structure, as well as its strength and durability. In this paper, the stress distribution in an SPR-adhesive hybrid joint is evaluated by using the finite element method, and then compared with that in an adhesive joint. Results indicate that the stress concentrates at the edge of adhesive layer in hybrid joint and adhesive joint and around the rivet in an SPR joint. The effect of rivet is numerically investigated by either removing the rivet from the hybrid joint or changing the position of the rivet on the overlapping area.

Wu, Guanghan, Li, Dayong, Shi, Yandong, Avery, Katherine, Huang, Li, Huang, Shiyao, Su, Xuming, Peng, Yinghong

In-Plane and Out-of-Plane Vibrations of Brake Linings on the Rotor

2017-01-253009/17/2017

The dynamics and, in particular, the NVH phenomena in brakes are still in the focus of research. Recent investigations of for example Rhee et al. show two principal vibrational forms of the linings on the rotor [1]. The first form is characterized by vibrations where both linings are in-phase (minimal differential torque between the inner pad and the outer pad). This produces in-plane vibrations of the rotor and results in high-frequency squealing events in the brake. The second form is an antiphase vibration of the brake linings with respect to each other (increased differential torque between the inner pad and the outer pad). This produce directly out-of-plane vibrational modes of the disc, which results in lower-frequency caliper and rotor oscillations. One hypothesis is that different wear densities of the linings essentially characterize the two vibrational modes. The wear behavior is not taken into consideration of this paper as it will be discussed in further publications. This

Ostermeyer, Georg Peter, Otto, Johannes, Rhee, Seong Kwan

Enhancement of Damping Performance of CLD Treatment Using Segmentation Method

2017-01-188206/05/2017

The reduction of vibration and noise is a major requirement for performance of any vibratory system. Due to legislative pressures in terms of external pass by noise limit of vehicles and customer requirements for better noise and ride comfort in vehicle, NVH attribute has become an important parameter. Major sources for vehicle pass-by noise consist of powertrain, tire and wind. Damping treatment is important to reduce vibration and noise radiation. The passive constrained layer dampening (CLD) treatment can be used to reduce structure-borne noise of vibrating structure using viscoelastic damping material. The performance of the passive constrained layer damping treatment can further be enhanced by new segmentation technique. The concept of segmented CLD is based on edge effect. The efficiency of segmenting a constrained layer damping treatment relies on the fact that a high shear region is created in the viscoelastic layer. The shear deformation in the viscoelastic material is not

Hujare, Pravin P., Sahasrabudhe, Anil D.

Simulation and Optimization Driven Design Process for S&R Problematic - PSA Peugeot Citroën Application for Interior Assembly

2017-01-186106/05/2017

NVH (Noise Vibration & Harshness) is one of the main focus areas during the development of products such as passenger cars or trucks. Physical test methods have traditionally been used to assess NVH, but the necessity for reducing cost and creating a robust solution early in the design process has driven the increased usage of simulation tools. Development of well-defined methods and tools for NVH analysis allows today’s OEMs to have a virtual engineering based development cycle from concept to test. However, a subset of NVH problems including squeak and rattle (S&R) have not been generally focused upon. In a vehicle, S&R is a recurring problem for interior plastic parts such as an instrument panel or door trim. Since 2012, Altair has been developing S&R Director (SnRD), which is a solution that identifies and combats S&R issues by embedding the Evaluation-Line (E-Line) methodology [1] [2]. This methodology is based on industry best practices, as described in the paper SAE 2012-01-1553

Benhayoun, Ismail, Bonin, Frédéric, Milliet de Faverges, Antoine, Masson, Julien

A Modal Study of Damping Treatments to Improve Low Frequency Sound Transmission Loss of a Structure

2017-01-185206/05/2017

Most of NVH related issues start from the vibration of structures where often the vibration near resonance frequencies radiates the energy in terms of sound. This phenomenon is more problematic at lower frequencies by structureborne excitation from powertrain or related components. This paper discusses a laboratory based case study where different visco-elastic materials were evaluated on a bench study and then carried on to a system level evaluation. A body panel with a glazing system was used to study both airborne and structureborne noise radiation. System level studies were carried out using experimental modal analysis to shift and tune the mode shapes of the structure using visco-elastic materials with appropriate damping properties to increase the sound transmission loss. This paper discusses the findings of the study where the mode shapes of the panel were shifted and resulted in an increase in sound transmission loss. This eventually resulted in reduced sound level inside the

Deshpande, Satyajeet P., Saha, Pranab, Cone, Kerry

SAE Eye on Engineering: Honda's Quiet New Odyssey

1228106/02/2017

One of the hardest-fought battles in developing a new vehicle is the battle against noise, vibration and harshness, or NVH. Honda attacked NVH on all fronts. In this episode of SAE Eye on Engineering, Editor-In-Chief Lindsay Brooke looks at Honda's 2018 Odyssey minivan. SAE Eye on Engineering also airs Monday mornings on WJR 760 AM Detroit's Paul W. Smith Show. Access archived episodes of SAE Eye on Engineering.

Automotive Engineering: June 2017

17AUTP0606/01/2017

Tackling NVH one dB per day New tools and technologies are helping engineers reduce vehicle Noise, Vibration and Harshness. Artificial intelligence becomes a reality Automakers could be among the leaders in deploying AI in free-standing, high-reliability environments. But developers must determine how to mitigate undesirable side-effects. Lidar: autonomy's mission-critical component Automated-driving capability likely won't happen without Lidar. But what technology-and at what price? Formula One goes longer, lower, wider for 2017 New rules make the cars faster and more aggressive-looking, with a wider track, wider tires and bigger wings. Editorial: Core Ford, New Ford...OneFord? SAE Standards News Seeking a common language for vehicle automation Supplier Eye Are you innovating for NVH? Exa simulation aims to keep ADAS sensors clean CO2 buildup in vehicle cabins becoming a safety issue DSD's low-cost 12V hybrid aims for small cars VW finally fills its SUV gap with 2018 Atlas Loss leader

Ting Noise Generation in Automotive Applications

2017-01-112103/28/2017

Automobile customers are looking for higher performance and quieter comfortable rides. The driveline of a vehicle can be a substantial source of NVH issues. This paper provides an understanding of a driveline noise issue which can affect any variant of driveline architecture (FWD, AWD, RWD and 4X4). This metallic noise is mostly present during the take-off and appropriately termed as ting noise. This noise was not prevalent in the past. For higher fuel economy, OEMs started integrating several components for lighter subsystems. This in effect made the system more sensitive to the excitation. At present the issue is addressed by adding a ting washer in the interface of the wheel hub bearings and the halfshafts. This paper explains the physics behind the excitation and defines the parameters that influence the excitation. The halfshaft and the wheel hub are assembled with a specified hub nut torque. Based on powertrain torque input to the wheel and road resistance, the halfshaft

Bonnerjee, Deb, Bouzit, Djamel, Iqbal, Javed

Mitigating the Brake Squeal Noise Occurrence of Car Disc Brake through Modification of Caliper-Bracket

2017-26-021801/10/2017

As an automobile brake manufacturer, brake noise always been a prime concern as it define the degree of customer satisfaction and warranty claim. Brake squeal is a concern in the automotive industry that has challenged many researchers and engineers for years. In case of disc brake, brake-squeal (1 to 16 kHz) occurrence is predominant than the any other types of brake-noise (i.e. moan, grown, judder etc.), since squeal is a friction induced, self-excited, and self-sustained phenomenon from a nonlinear dynamics viewpoint. Due to the complexities involve squeal mechanism is not well understood yet, hence makes it one of the unresolved brake Noise, Vibration, and Harshness (NVH) problem till this date. Since squeal is a high-pitched and tonal noise, therefore it is very annoying and getting more attention by occupants. Brake squeal can occur at any temperature and with or without the presence of humid condition and therefore highly unpredictable. However, it is state-of-the-art to provide

Chilbule, Chaitanya, Phadke, S B, Kulkarni, R N, Raajha, M P

SAE International Journal of Vehicle Dynamics, Stability, and NVH

E-JOURNAL-1001/01/2017

Associate Editor Dr. Pranab Saha Awarded Medal of Honor Call for Papers: Special Issue on Vehicle Motion Controls: From Chassis Controls to Autonomous Vehicle Control -- Present Technologies and Future Vision Editor-in-Chief: Peijun Xu, Ph.D., Ebco, Inc., USA Indexed in CNKI ESCI (Emerging Sources Citation Index, Web of Science) Engineering Village (Ei Compendex) IET Inspec Scopus 2.1 2020CiteScore 55th percentile Powered by Author Resources Call for Papers Library Recommendation Form Published Volumes Subscription Options Aims and Scope The SAE International Journal of Vehicle Dynamics, Stability, and NVH is a scholarly publication of original research and review papers focusing on vehicle dynamics, stability, noise, vibration, and harshness (NVH). The Journal provides a peer-reviewed platform for researchers, engineers, and academicians to present their advanced theoretical and experimental work for developing quieter, more comfortable, and dynamically superior vehicles. Therefore

Rotorcraft Noise Model (RNM)

TBMG-2455605/01/2016

The Rotorcraft Noise Model (RNM) is a suite of computer models that predicts far-field noise for single or multiple flight vehicle operations. RNM calculates the effects of sound propagation over varying ground terrain for acoustic sources using geometrical theory of diffraction algorithms, and through a horizontally stratified atmosphere over uniform terrain with winds. RNM calculates the noise levels in the time domain and with a variety of integrated metrics at receiver positions on or above the ground at specific points of interest and over a uniform grid.

Development Of A Practical Multi-disciplinary Design Optimization (MDO) Algorithm For Vehicle Body Design

2016-01-153704/05/2016

The present work is concerned with the objective of developing a process for practical multi-disciplinary design optimization (MDO). The main goal adopted here is to minimize the weight of a vehicle body structure meeting NVH (Noise, Vibration and Harshness), durability, and crash safety targets. Initially, for simplicity a square tube is taken for the study. The design variables considered in the study are width, thickness and yield strength of the tube. Using the Response Surface Method (RSM) and the Design Of Experiments (DOE) technique, second order polynomial response surfaces are generated for prediction of the structural performance parameters such as lowest modal frequency, fatigue life, and peak deceleration value. The optimum solution is then obtained by using traditional gradient-based search algorithm functionality “fmincon” in commercial Matlab package. The stated goal of optimization can also be achieved using a practical MDO methodology in which a substantially reduced

Deb, Anindya, Srinivas, Gunti R., Chou, Clifford C.

Hyundai enhances NVH with 2016 Tucson's re-engineered suspension-including ‘world first’ dual-member damper housing

15MEIP12_1612/01/2015

No area of the third-generation Tucson crossover utility vehicle was left untouched by Hyundai engineers, but particular attention was placed on re-engineering the chassis for improved ride and handling, and importantly, better NVH (noise, vibration, and harshness) characteristics. Not surprisingly, the 2016 Tucson platform is larger than the previous generation's; however, engineers focused on improving width and wheelbase for greater ride comfort and linear stability, according to Mike O'Brien, Vice President, Corporate and Product Planning, Hyundai Motor America (HMA).

Vibro-Acoustic Properties of a Very Long Flax Fibers Reinforced Thermoset “Flaxpreg” Light Sandwich

2015-01-234506/15/2015

The Flaxpreg is a green and light very long flax fibers thermoset reinforced sandwich, which can be effectively used as multi-position trunk loadfloor or structural floor in the passenger compartment of a vehicle. The prepreg FlaxTapes of about 120 g/m2 constituting the skins of the sandwich, are unidirectionally aligned flax fibers tapes, with acrylic resin here, easily manipulable without requiring any spinning or weaving step and thus without any negative out of plane crimping of the almost continuous flax fibers. Thanks to their very low 1.45 kg/dm3 density combined with an adaptive 0°/90°/0° orientation of the FlaxTapes (for each skin) depending on the loading boundary conditions, the resulting excellent mechanical properties allow a - 35% weight reduction compared to petro-sourced Glass mat/PUR sandwich solutions (like the Baypreg). The vibro-acoustic damping properties of these FlaxTape skins are remarkable with an almost 2 % Damping Loss Factor, whereas glass/resin or carbon

Duval, Arnaud, Marcel, Valérie, Dejaeger, Ludovic, Lhuillier, Francis, Khalfallah, Moussa

Interior Noise Design of a Light Rail Vehicle Using Statistical Energy Analysis

2015-01-230006/15/2015

This paper addresses the NVH design of a light rail vehicle whose maximum allowable interior SPL levels at certain speeds are regulated and may vary between countries, states, and cities. The objective of this study was to predict sound pressure levels (SPL) at several interior locations across a wide range of frequencies and estimate if the current design configuration will meet the noise level limits. Statistical Energy Analysis (SEA) was used to predict interior SPL and to understand and rank the various noise contribution paths and give a better understanding of the physics of transmission and what types of design changes are most effective to reduce the overall interior SPL to meet targets. A typical light rail vehicle is composed of a frame-like structure covered by lightweight panels and with interior panels that are increasingly made from composites, sandwich, laminated, or honeycomb materials or extruded panels. These lightweight structures made from materials that have

Fiedler, Robert, Musser, Chadwyck, Cuchý, Petr

Internal Pressure Characteristics when Evaluating Dynamic Door Blow Out Deflection

2015-01-232706/15/2015

Wind noise is one of the most influential NVH attributes that impact customer sensation of vehicle interior quietness. Among many factors that influence wind noise performance, the amount of dynamic door deflection under the pressure load due to fast movement of a vehicle plays a key roll. Excessive deflection could potentially lead to loss of sealing contact, causing aspiration leakage, which creates an effectual path through which the exterior aerodynamically induced noise propagates into the vehicle cabin. The dynamic door deflection can be predicted using CFD and CAE approaches which, in addition to modeling the structure correctly, require a correct pressure loading composed of external and internal pressure distributions. The determination of external pressure distributions can be fulfilled fairly straightforward by using commercial CFD codes such as Fluent, Star CCM+, Powerflow and others. However, the capability of predicting the internal pressure due to high wind speed outside

Hou, Hangsheng, Zhao, Wei, Hou, Jian

Impact of Sunroof Deflector on Interior Sound Quality

2015-01-232406/15/2015

When a sunroof opens to let in fresh air while driving, there might be several noise issues associated with it. The most common and painful one is the wind throb issue, which is nevertheless largely resolved by implementing a sufficiently high wind deflector along the front edge of the sunroof. However, with the wind throb suppressed, other sound quality issues might emerge. The most notable one is the hissing noise issue, which becomes increasingly objectionable with the increase of vehicle speed. This work looks into the impact of sunroof deflector on interior sound quality with the consideration of wind throb, hissing noise and booming noise in terms of psychoacoustic attributes that could be felt subjectively. The goal is to achieve a better understanding of the sound quality associated with the sunroof deflector design, and inspire a balanced design, potentially targeting the most NVH demanding customers in the premium vehicle segment.

Hou, Hangsheng, Yue, Guiping

Study on the Influence of Material Parameters to Acoustic Performance

2015-01-220006/15/2015

Acoustic performance of auto interiors is definitely important to control the NVH (noise, vibration, and harshness) performance inside a vehicle, and it is determined by the material parameters, such as density (ρ), thickness (d), open porosity (OP), airflow resistivity (σ), tortuosity (T), viscous characteristic length (VCL), thermal characteristic length (TCL), young's modulus, poisson's ratio, and damping coefficient. Firstly, by making different felt samples (of different surface density and thickness), the sound absorption performance and related parameters were obtained. Then the correlation between the parameters and the sound absorption coefficient (SAC) was summarized. Through this method, database of acoustic parameters and the corresponding SAC for porous materials can be established and sound package design and adjustment can be easily conducted based on the database.

Zhou, Guojian, Tian, Xiujie, Zhu, Keda, Huang, Wei, Wentzel, Richard E., Care, Melvyn J.

Natural Frequency Analysis of Tire Vibration Using a Thin Cylindrical Shell Model

2015-01-219806/15/2015

Early studies on the tire vibration characteristics of road noise focused on radial modes of vibration because these modes are dominant in vertical spindle force. However, recent studies of Noise, Vibration and Harshness (NVH) prediction have suggested that tire modeling not only of radial modes, but also of lateral vibration, including lateral translational and lateral bending modes, affect interior noise. Thus, it is important to construct tire dynamic models with few degrees of freedom for whole-vehicle analysis of NVH performance. Existing tire dynamics model can't express tire lateral vibrations. This paper presents a new approach for tire vibration analysis below 200Hz, and a formula for tire natural frequencies. First, a tire dynamic model is developed based on the thin cylindrical shell theory. Kinetic and potential energies are derived. Mode shape function is also derived by the assumption of inextensility in the neutral of the tread ring. The formulas of natural frequencies

Matsubara, Masami, Tsujiuchi, Nobutaka, Koizumi, Takayuki, Ito, Akihito, Bito, Kensuke

Advancements in Liquid Damping Materials

2015-01-220206/15/2015

Over the past decade damping materials have contributed major improvements to passenger comfort. Noise Vibration and Harshness (NVH) engineers have further shaped material specifications to reflect key targeted properties that improve vehicle design. The specified damping material is then applied to the formed surfaces of the vehicle body to provide optimal performance and achieve the required results. This paper describes how liquid dampers have advanced to meet increased performance requirements through improved loss modulus of the final coating. Data generated by dynamic mechanical analysis shows that this viscoelastic behavior is what drives the performance in damping materials. Through the correlation of loss moduli to damping performance of Oberst bars, the mechanism can be further quantified and explained. In addition to the increase in damping efficiency, liquid dampers continue to offer increased application flexibility to NVH engineers with improved resistance to blister

Jackson, Catheryn, Gimbal, Justin E., Metla, Dhara

Study of Stick-Slip Friction between Plunging Driveline

2015-01-217106/15/2015

Driveline plunge mechanism dynamics has a significant contribution to the driver's perceivable transient NVH error states and to the transmission shift quality. As it accounts for the pitch or roll movements of the front powerplant and rear drive unit, the plunging joints exhibit resisting force in the fore-aft direction under various driveline torque levels. This paper tackles the difficult task of quantifying the coefficient of static friction and the coefficient of dynamic friction in a simple to use metric as it performs in the vehicle. The comparison of the dynamic friction to the static friction allows for the detection of the occurrence of stick-slip in the slip mechanism; which enables for immediate determination of the performance of the design parameters such as spline geometry, mating parts fit and finish, and lubrication. It also provides a simple format to compare a variety of designs available to the automotive design engineer.

Spencer, Winston, Bouzit, Djamel, Pace, Joseph, Dhillon, Sudeep

Light-weight Liquid-Applied Sound Damping Material for Automotive Industry

2015-01-234406/15/2015

In today's world, automotive manufacturers are required to decrease CO2 emissions and increase the fuel economy while assuring driver comfort and safety. To achieve desired acoustic performance targets, automotive manufacturers use various Noise-Vibration-Harshness (NVH) materials which they apply to the vehicle Body-In-White structures either in the body or paint shop. Beside the sound deadening coatings applied onto the underbody of vehicles, they have historically used either constrained or free-layer sheets. The majority of these damping pads/sheets, so called asphalt sheets, are applied onto the floor pan inside the vehicle. These pre-manufactured and vehicle specific die-cut sheets are typically highly metal-carbonate, sulfate or silicate filled asphalt systems with a high specific gravity. Depending on the size of vehicle, the amount of these sheets can reach application weights of 10∼20 kg/vehicle. This paper will document the technical path that Dr. H. Oberst1 laid with his

Erman, Murteza T.

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