Browse Topic: Acoustics

Items (147)

Implementation Of Machine Learning In Acoustics Source Detection by Leveraging Synthetic Sound Data Generation Approach

2024-26-021301/16/2024

E-Mobility and Low Noise IC Engines has pushed product development teams to focus more on sound quality rather than just focus on reduced noise levels and legislative needs. Further more qualification of products from a sound quality perspective from an end of line testing requirement is also a major challenge. End of line (EOL) NVH testing is key evaluation criteria for product quality with respect to NVH and warranty. Currently for subsystem or component level evaluation, subjective assessment of the components is done by a person to segregate OK and NOK components. As human factor is included, the process becomes very subjective and time consuming. Components with different acceptance criteria will be present and it’s difficult to point out the root cause for NOK components. In this paper, implementation of machine learning is done for acoustic source detection at end of line testing. To improve the fault detection an automated intelligent tool has been developed for subjective to

Shukle, Srinidhi, Iyer, Ganesh, Faizan, Mohammed

Sound Design for Electric Vehicles: Enhancing Safety and User Experience Through Acoustic Vehicle Alerting System (AVAS)

2025-01-006805/05/2023

Silent engines are an excellent strategy to combat noise pollution. Still, they can pose risks for pedestrians who rely on auditory cues for safety and reduce driver awareness due to the absence of the familiar sounds of combustion engines. Sound design for silent engines not only tackles the above issues but goes beyond safety standards towards a user-centered approach by considering how users perceive and interpret sounds. This paper examines the evolving field of sound design for electric vehicles (EVs), focusing on Acoustic Vehicle Alerting Systems (AVAS). The study analyzes existing AVAS, classifying them into different groups according to their design characteristics, from technical concerns and approaches to aesthetic properties. Based on the proposed classification, an (adaptive) sound design methodology, and concept for AVAS are proposed based on state-of-the-art technologies and tools (APIs), like Wwise Automotive, and integration through a functional prototype within a

Esteves, Raquel, Campos Magalhães, Eduardo Miguel, Bernardes, Gilberto

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

Evaluation of invariant structural and acoustic loads estimation methods to be used in vehicle platform development independent to the boundary conditions of load generation.

2025-01-005305/05/2023

Platform based vehicle development is standardized at Deere. The challenges of frontloading the integration effects of individual components within different platforms using predictive methods is key to shorten the development cycle. Components are generally characterized on test benches and can not directly be used to evaluate system performance. Invariant characterization is needed which is possible through techniques such as blocked loads estimation. To evaluate the applicability of such methods, the test stand based, and vehicle in-situ operational loads needs to be compared. The confident use of these methods for structural and acoustic loads enables the use of combination of test and simulation models of common components and system modules in a variety of products, enhancing early NVH response predictions. In this work, we compare a powertrain characterization in a vehicle and a test stand to assess the invariance of the operating mount structural loads as well as operating

Vesikar, Prasad Balkrishna, Edgington, Jason, Drabison II, John, Chaduvula, Prasanna

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

Subjective development of EV propulsion noise to drive product differentiation

2025-01-006705/05/2023

The frequency and amplitude content of powertrain noise is motor torque and speed dependent and tends to influence the driver’s subjective perception of the vehicle. This provides manufacturers with an opportunity to drive product differentiation through consideration of powertrain noise in early stages of the development cycles for electric vehicles (EVs). This paper focuses on evaluation of customer perception to acoustic feedback of motor design options based on targeted motor orders and expected wind and road masking during high acceleration maneuvers. A jury study is used to explore the customer feedback response to a two-stage gearbox design with AC permanent magnet motor order combinations. The subjective influence of order spacing, dominant frequency content and the number of audible tones is studied to understand aural perspective product differentiation opportunities.

Joodi, Benjamin, Jayakumar, Vignesh, Conklin, Chris, Pilz, Fernando, Iyengar, Shashank, Weilnau, Kelby, Hodgkins, Jeffrey

Excavator exterior noise contribution analysis using angle-based operational acoustic load synthesis.

2025-01-006205/05/2023

Since earth moving machines (EMM) are subject to exterior noise (EN) regulations, OEMs need to develop mitigation solutions from an early design stage. It is challenging to predict solution effectiveness at early design stage. Excavators are distinct compared to other EMM as their upper frame rotate while keeping lower frame fixed. ISO 6395(2) or EC/2000/14(1) require EMMs to follow specific operating maneuvers where noise sources change their position, directivity, and speed along the operating cycle. These conditions pose challenges in performing noise contribution analysis as a function of angular position and operating condition. Authors successfully demonstrated Acoustic source quantification and contribution analysis for linearly moving EMMs. However, excavator pose data processing challenges due to angular motion. This work demonstrates the use of frequency domain ASQ for operational acoustic source quantification and use of frequency domain virtual prototype sub structuring

Vesikar, Prasad Balkrishna, Haynes, Timothy, Aquino Arriaga, Adrian Antonio, Drabison II, John, Chaduvula, Prasanna

Comprehensive EV Sound Design project from Marketing Requirements to Series

2025-01-001805/05/2023

This paper presents the results of a project to design new comprehensive sound sets for several electric vehicle models having each specific branding expectations. This was achieved thanks to a close collaboration between one major Chinese electric vehicle manufacturer and an acoustic software provider, relying on shared experience, knowledge, and tools to meet the initial requirements set. Firstly, a scenarized journey and brand-related symbolism were defined and served as a basis for creating meaningful sketches of sound design in a cross-team effort (designers, NVH, production, audio system, etc.). Various sound functions were considered for exterior sounds, such as AVAS, and interior sounds, such as ambiance, HMI, and alarms. A special care was dedicated to the so-called Active Sound Design aiming at providing speed and acceleration feedback to the driver, in the absence of a clearly audible engine noise. A listening test was then conducted in order to assess how the proposed

LI, Yanhao, Minard, Antoine, Boussard, Patrick, Zhang, Charles

Active Control of Engine Order Noise for Heavy-duty Trucks: Using the Genetic Algorithm for the Optimization of Error Microphone Arrangement

2025-01-001305/05/2023

The arrangement of error microphones for a vehicle active noise control (ANC) system is no trivial work, especially for heavy-duty trucks due to the dilemma resulted from the large volume of the cab and the limited number of microphones accepted by most manufacturers in the auto industry. Most ANC developers resort to trial and error, which is not only a heavy workload given the amount of interested working conditions to be test, but also does not guarantee to yield the optimum noise cancellation performance. In this paper, the authors proposed an error microphone selection methodology using a genetic-algorithm (GA) -based mechanism. The target vehicle was a heavy-duty truck with a six-piston diesel engine, and two scenarios were particularly interested, i.e. driver & copilot and driver & one passenger sleeping on the berth. We first arranged eight microphones at different locations in the cab, five on the headrests, two on the B pillars and one at the head position of the sleeping

Wang PhD, Jian, Ling, Zihong, Zhang, Zhe, Cai, DeHua, lv, Xiao, Zhang, Ming, Gao, GuoRan

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

Tonal noise investigation of automotive HVAC systems : a hybrid method

2025-01-002705/05/2023

There is no need to recall how the electrification trend of transport facilities has tightened the requirements around acoustic comfort. Within the automotive industry, these targets are more challenging for Heating, Ventilation and Air Conditioning systems for which passengers are in the foreground of noise emissions. The complexity of the requirements and specifications set by car manufacturers and suppliers stems from a dual aspect. First is quantitative based on the sound pressure level, whether it's the overall level or 1/3 octave band spectra. The second is purely subjective based on the perceived noise quality by stakeholders and final customers worldwide. During development phases, low frequency tone noises are frequently encountered on these systems which might induce discomfort to the passengers. The experimental investigations usually point to an aerodynamic origin, which prompted this research activity. The purpose of this work is to analyze and understand the mechanism of

Bennouna, Saad, Alaoui, Mohamed

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.

Evaluation of Automotive Closure Design for High Frequency Acoustics Performance

2025-01-004905/05/2023

A good NVH environment in a vehicle plays an important role in attracting a large customer base in the automotive market. Hence, NVH has been given significant priority while considering automotive design. NVH performance is monitored using simulations early during the design phase and testing in later prototype stages in the automotive industry. Meeting NVH performance targets possesses a greater risk related to design modifications in addition to the cost and time associated with the development process. Hence, a more enhanced and matured design process involves Design Point Analysis (DPA), which is essentially a decision-making process in which analytical tools derived from basic sciences, mathematics, statistics, and engineering fundamentals are used to develop a product model that better fulfills the predefined requirement. This paper shows the systematic approach of conducting a Design Point Analysis-level NVH study to evaluate the acoustic performance of vehicle door systems in

Ranade, Amod A., Shirode, Satish, Miskin, Atul, Mahamuni, Ketan, Shinde, Rahul, GHAN, PRAVIN, Choudhury, Ashok

Directivity driven simulation methodology for efficient Acoustic Encapsulation

2025-01-004805/05/2023

Noise Reduction at the source level is critical to achieve the overall vehicle level interior targets. This method presents a novel approach that integrates directivity analysis with simulation techniques to optimize acoustic encapsulation design for automotive sound sources to achieve the targeted radiation levels. The foundation for this methodology is to measure the angular distribution of sound pressure levels around the noise source so called Directivity, at every frequency of interest and determine the most effective Acoustic encapsulation to achieve the targeted sound radiation. Accurate measurement of directivity in physical testing with fine angular resolutions can be complex and expensive, this study utilizes numerical simulation techniques using FEA to mitigate the challenges in mid frequency range. The scope of the study is focused on mid frequency sound pressure levels between 500-2000 Hz, which are determined to be significant contributors to overall DU noise. The first

KALUVAKOTA, SRIKANTH, Ghaisas, Nikhil, Pilz, Fernando

Effects of acoustic dissipative material in applications with acoustic leakage

2025-01-011705/05/2023

In the paper, the dissipative material and other conventional acoustic materials are studied in conditions which simulates actual vehicle application with acoustic leakage. The various acoustic materials are evaluated in the lab with acoustic leakage existing in steel panel experimentally and virtually in computer simulation with the estimated Biot’s parameters of the materials. Often, the acoustic leakages exist in actual vehicle condition in pass-through or mounting faster locations. The work includes in-vehicle test results on application and show how the dissipative material works.

Yoo, Taewook, Maeda, Hirotsugu, Sawamoto, Keisuke, Anderson, Brian, Gan, KimTong, Herdtle, Thomas

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 study on active sound design and control method for vehicle interior hybrid noise to enhance sound quality

2025-01-001105/05/2023

With the current popularity of new energy vehicles and the continuous development of intelligent cabin technology, the demand for acoustic comfort within automotive cockpit is increasing. A multi-channel feedforward active sound design and control method was proposed to improve the sound quality of the hybrid broadband and narrowband noise inside the test vehicle. The method selectively designed the target amplitudes for broadband noise and narrowband noise in the vehicle to satisfy passengers comfort, mainly including the sound design phase and the control phase. During the sound design phase, objective sound quality parameter analysis was first conducted on the noise of the prototype vehicle, followed by an evaluation of the sound quality with semantic differential method. An active acoustic design strategy focusing on comfort, motivation sense and annoyance perception were proposed, including a formula for the target amplitude of adjustment order and sound pressure level. The sound

Liu, Xuexian, Xu, Wenxuan

Acoustic characterization of AC motor using sound intensity in standard laboratory environments

2025-01-001005/05/2023

Sound power is commonly used metric to quantify acoustic sources like AC motor in electrified powertrain. This testing is often performed in an anechoic environment to create free-field conditions around the unit. To eliminate the influence of extraneous noise sources, the anechoic facilities must be further isolated from driver and absorber dynamometers. These dynamometers are needed for running the AC motors in the desired speed and load conditions. For early detection of potential issues, it is advantageous to have the capability for engineers to conduct acoustic tests in standard laboratory environments. These may include non-acoustically treated rooms, presence of extraneous noise sources (e.g., driver and absorber dynos), etc. In such environments, sound intensity-based sound power determination methods could be utilized. The sound intensity-based approach is covered in ISO 9614 standard. The norm is to sweep an intensity probe on a sound source in constant speed condition to

Kumar, Aditya, Ippili, Rajani

Cabin noise modeling for seat location variation using AI and Machine Learning

2025-01-012905/05/2023

Analyzing acoustic performance in large and complex assemblies, such as vehicle cabins, can be a time-intensive process, especially when considering the impact of seat location variations on noise levels. This paper explores the use of AI and machine learning to streamline this analysis by predicting the effects of different seat configurations on cabin noise, particularly at the driver’s ear level. The study begins by establishing a baseline simulation of cabin noise and generating training data for various seat location scenarios. This data is then used to train an AI model capable of predicting the noise impact of further seat adjustments. These predictions are validated through detailed simulations. The paper discusses the accuracy of these predictions, the challenges encountered, and provides insights into the effective use of AI and machine learning in acoustic analysis for cabin noise, with a specific emphasis on seat location as a key variable. Keywords: Acoustic analysis, AI

Kottalgi, Santosh, Banerjee, Bhaskar

Fast noise prediction of an electric powertrain integrated in various vehicles

2025-01-007605/05/2023

The automotive industry's transition to electrification raises new challenges to maintain a comfortable acoustics environment both inside and outside the car. This paper presents an innovative way to make an early prediction of the overall sound of a vehicle at driver’s ear by mixing noise sources that can be simulated and noise sources that can be measured at component level. This hybrid approach combining Test and Simulation data helps make decisions in the early design phase by predicting the noise of one component integrated in the whole vehicle. For instance, Valeo, with the help of sound synthesis techniques, is able to predict the sound of an e-drive when it is combined with Rolling noise that varies depending on the vehicle speed and the car segments - more or less refined, from a dataset of multiple vehicles. Realistic signals could be generated and compared with actual acoustic measurement to validate the method.

Redon, Milan, Dendievel, Clement, Pluton, Matthias

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

Feasibility of In situ vehicle level transmission loss measurement to guide dash pass through grommet selections

2025-01-012205/05/2023

Noise transmission through the vehicle dash panel plays a critical role in isolating passengers from noise sources within the motor bay of the vehicle. Grommets containing electrical harness routing as well as HVAC lines are examples of dash panel pass throughs that should be selected with care. Acoustic performance of these components is generally characterized in terms of measured quantities such as noise reduction (NR), sound transmission loss (STL), and Insertion Loss (IL). These measurements need to be carried out as per SAE or ASTM standards in appropriate anechoic or reverberant chambers as this is important for consistency. This work explores an in-situ vehicle measurement setup utilizing a repurposed vehicle cabin designed to serve as an anechoic chamber with its frunk acting as a reverberant chamber. This in-situ setup method is then compared to results following standards to discuss the differences in results. The data is studied to understand if there are any advantages to

Joodi, Benjamin, Jayakumar, Vignesh, Chang, Michael, Geissler, Christian, Pilz, Fernando, Conklin, Chris

Acoustic Evaluation of Fiber Based Materials for Engine Bay Applications

2025-01-011505/05/2023

A newly formulated fiber-based material was developed to offer a cleaner, recyclable alternative to foam-based vehicle acoustic products. The fiber-based material was designed to be used in multiple vehicle acoustic applications, with different blends of the material available depending on the application. It performs well as an engine bay sound absorber due to its high heat tolerance and good absorption performance. A study was conducted to evaluate the sound absorption performance of this fiber-based material, specifically the engine bay blends, in comparison to that of current foam-based products. The results from this study show that the sound absorption performance of this new fiber-based material can match that of current foam-based materials while providing a recyclable product unlike the foam.

Krugh, Jack

Identification and Evaluation of Passthroughs That Affect the Acoustic Performance of a Dash System

2025-01-012105/05/2023

This paper discusses a systematic process that was developed to evaluate the acoustic performance of a production electric vehicle dash system. The production dash panel was tested under different configurations to understand the importance of passthroughs in the acoustics of the dash system. Results show that often the performance of the passthroughs strongly affects the overall performance of the dash system and this may become the limiting factor to increase the system STL. The dash with passthroughs was then extensively tested to understand the acoustic strength of different passthroughs and to understand how these passthroughs affect the overall performance of the dash system. Subsequently a test procedure based on flat panel tests was developed so the OEM can develop target values and the suppliers can provide test results of their passthroughs that are meaningful and useful to the OEM to help build an acoustically competitive vehicle.

Saha, Pranab, Baack, Gregory, Geissler, Christian, Kaluvakota, Srikanth, Pilz, Fernando

Cairene Car-Culture: How are Automobility and Social Behavior Linked to The Development of The Soundscape and Urban Fabric of Cairo.

2025-01-006905/05/2023

Cairo’s soundscape has witnessed changes due to the ongoing urban structure developments that accommodate the number of vehicles passing through the city. The soundscape produced by this growing automobility is affected not only by vehicles but also by their owners' behavior. Cairenes use their cars as a communication tool and an extension of private space. By viewing the vehicle as a component of the soundscape as well as a space that filters it, this study examines the synergy between social behavior, automobility, urban structure, and their interdependent relationship on the soundscape of Cairo. The study responds to literature elaborating on acoustic ecology, car culture, urban structure, and social behavior. The methodology applied in this study follows practice-based phenomenological research while documenting and reflecting on car cultural practices in Cairo from an aural perspective. Grounded theory contextualizes the analysis of archived audio and video material, semi

Abd El Naby, Abla Mohamed

Do EVs Snore?

2025-01-007405/05/2023

As EV and PHEV adoption continues to increase more people will have direct experiences with these quieter vehicles in their daily lives. Topics such as 'propulsion sound' via Active Sound Design (ASD) and bystander safety through Acoustic Vehicle Alerting Systems (AVAS) have been discussed widely for many, many years...but who is talking about Charging Noise? Charging noise is a less spoken about topic because most EV / PHEV owners will charge their vehicles at their home, in their garage or their driveway, overnight when they are sleeping. Because of that people do not think much about charging noise. But anyone who has plugged in their car overnight will tell you a strange cacophony of sounds come from the car...and some can be downright concerning. In this paper data from several production EVs were measured during their normal charging cycle. Binaural recordings made inside and outside the vehicle are analyzed using psychoacoustics metrics to see what sounds would cause the most

Marroquin, Marc, Bray, Wade

Hybrid 3D Sound Intensity and Simulation for Optimizing Acoustic Output of Truck Rear Axles

2025-01-010505/05/2023

This study presents a novel methodology for optimizing the acoustic performance of rotating machinery by combining scattered 3D sound intensity data with numerical simulations, focusing on the rear axle of a truck. Using Scan&Paint 3D, sound intensity data is rapidly acquired over a large spatial area with the assistance of a 3D sound intensity probe and infrared stereo camera. The experimental data is then integrated into far-field radiation simulations, enabling detailed analysis of the acoustic behavior and accurate predictions of far-field sound radiation. This hybrid approach offers a significant advantage for assessing complex acoustic sources, allowing for quick and reliable evaluation of noise mitigation solutions. While the current application focuses on the truck's rear axle far-field radiation, the same method can be extended to predict in-cabin sound pressure, providing a versatile solution for many industrial problems.

Fernandez Comesana, Daniel, Vael, Georges, Robin, Xavier, Orselli, Joseph, Schmal, Jared

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

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

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

Study of the Noise Contributors on the Interior Acoustic of a Car and Their Countermeasures

2020-01-158506/03/2020

This paper shows that the collaboration between a glass manufacturer and a passive acoustic treatment manufacturer can bring different benefits and considerably improve the interior acoustics of a vehicle. In terms of passenger safety and well-being, glazing have always played a key role by offering solutions to interior comfort, particularly when it comes to heat and acoustics. Today, cars are becoming a living space which from an acoustic point of view brings a challenge for the interior comfort. Indeed, glazing has no absorption and classically it has an acoustic insulation weakness around its coincident frequency. In most of the cases, these different aspects make glazing one of the main contributors to the sound pressure level in the passenger compartment, and the trend is not one of change. However, there are possible countermeasures. One of which is the use of laminated glazing with acoustic PVB. This solution allows to reduce the loss of insulation performance at the

Lafont, Thibault, Dalzin, Fabien, Bouillet, Fabien, Bertolini, Claudio

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

Innovative Acoustic Material Concept Integration Into Vehicle Design Process

2020-01-152706/03/2020

Integration of acoustic material concepts into vehicle design process is an important part of full vehicle design. The ability to assess the acoustic performance of a particular sound package component early in the design process allows designers to test various designs concepts before selecting a final products. This paper describes an innovative acoustic material concept which is easily integrated in a design process through the use of a database of Biot parameters. Biot parameters are widely used in the automotive industry to describe the physical interactions between the acoustics waves travelling through foams, fibers or metamaterials and the solid and fluid phase of these poro-elastic materials. This new acoustic material concept provides a combination of absorption, transmission loss and added damping on the panel it is attached to. It has shown unique vibro-acoustics performance when tested on a German car manufacturer flagship vehicle and provides the ability to reduce the

Blanchet, Denis, Feist-Muench, Michael

Development, System Integration and Experimental Investigation of an Active HVAC Noise Control System for a Passenger Car

2020-01-153806/03/2020

Current developments in the automotive industry such as electrification and consistent lightweight construction increasingly enable the application of active control systems for the further reduction of noise in vehicles. As different stochastic noise sources such as rolling and wind noise as well as noise radiated by the ventilation system are becoming more noticeable and as passive measures for NVH optimization tend to be heavy and construction space intensive, current research activities focus on the active reduction of noise caused by the latter mentioned sources. This paper illustrates the development, implementation and experimental investigation of an active noise control system integrated into the ventilation duct system of a passenger car. Making use of a model-based design process, the development is based upon a holistic numerical simulation model integrating a reduced order acoustic model derived from finite element simulations as well as simplified loudspeaker and

Millitzer, Jonathan, Kim, Joong-Kwan, Mees, Valentin, Lee, Jinmo, Oh, ChiSung, Ranisch, Christopher, Ih, Kang-Duck

Design and Optimization of a Resonant Type Acoustic Meta-Material for Sound Attenuation

2020-01-155906/03/2020

Considering the fact that most conventional acoustic materials have reached their limit in terms of performance, it is important to find new ways to attenuate sound. This study describes the design and optimization of the sound absorption and sound insulation of an Acoustic Meta-Material (AMM) based on embedding acoustic resonators in a porous material. Previous works have already addressed this kind of AMM, mostly using simulations and tests in impedance tubes. This work develops and tests the studied AMM at medium-scale (60 x 60 cm², tested in acoustic cabin). The proposed solutions are specifically used to attenuate low frequency noise are easily manufacturable. Theoretical and experimental investigations are conducted to optimize and validate the concepts under realistic density and volume constraints. Starting with analytical solutions, using transfer matrix method, and numerical simulations, using FEM/BEM module of NOVA software, various concepts are optimized in terms of sound

Bouche, Patrick, Atalla, Noureddine, panneton, raymond, Bouche, Patrick, Atalla, Noureddine, panneton, raymond

Sound Field Synthesis by Synthetic Array (SFS-SA) for Diffuse Field or TBL Structural Excitation

2020-01-152206/03/2020

Diffuse field or TBL excitation of vehicles are of huge interest in automotive industry, for such excitation reveberent rooms of wind tunnels are necessary, this means high cost experiments. The idea of sound field synthesis to create the acoustic effect corresponding to diffuse field or TBL excitation is of major interest to reduce drastically the cost of experiments. Originally techniques based on Loud speakers antenna [], [], were used. However, a major difficulty appeared due to driving simultaneously a huge number of Loud speakers. To avoid this difficulty a new technique based on Synthetic antenna was proposed in reference [] , instead of an array of loud speakers , just one loud speaker is used for scanning the surface where the acoustic field excite the structure. A post processing based on plane wave decomposition, is then applied to collected data in order to get the response of the structure or the sound transmission through the structure. Different post processing can be

GUYADER, Jean-Louis, guyader, Guillaume, Dalzin, Fabien

Leading Women in Engineering & Science: Dawn F. Massa Stancavish, Chief Innovation Officer & COO

TBMG-3626103/01/2020

Underwater Signal Processing System

TBMG-3605402/01/2020

DSIT Solutions Ltd. Givat Shmuel, Israel +972-3-531-3333

5 Ws of EarEcho

TBMG-3569312/01/2019

Anyone who uses a smartphone with in-ear earphones.

Aerospace & Defense Technology: December 2019

19AERP1212/01/2019

Engineered Solutions for Enclosure Sealing and Insulation Tips for Reducing Error When Using Eddy Current Measuring Techniques Reducing the High Cost of Titanium Streamlining Post-Processing in Additive Manufacturing Software-Defined Analog Filters: A Paradigm Shift in Radio Filter Performance and Capability SDR Interface for the NeXtRAD Multistatic Radar System Electrodeposition of Metal Matrix Composites and Materials Characterization for Thin-Film Solar Cells Metal matrix composites, which consist of silver-multiwalled carbon nanotube-silver, layer-by-layer stacks, can electrically bridge the cracks (>40 μm) that appear in semiconductor substrates and the composite grid lines. Sensing Applied Load and Damage Effects in Composites with Nondestructive Techniques Comparing and correlating piezoelectrically induced guided waves, acoustic emission, thermography, and X-ray imaging to determine the effects of applied load on a composite structure. Technology Impact Forecasting for Multi

A Comparison of Near-Field Acoustical Holography Methods Applied to Noise Source Identification

2019-01-153306/05/2019

Near-Field Acoustical Holography (NAH) is an inverse process in which sound pressure measurements made in the near-field of an unknown sound source are used to reconstruct the sound field so that source distributions can be clearly identified. NAH was originally based on performing spatial transforms of arrays of measured pressures and then processing the data in the wavenumber domain, a procedure that entailed the use of very large microphone arrays to avoid spatial truncation effects. Over the last twenty years, a number of different NAH methods have been proposed that can reduce or avoid spatial truncation issues: for example, Statistically Optimized Near-Field Acoustical Holography (SONAH), various Equivalent Source Methods (ESM), etc. Then, more recently, with the motivation of facilitating the measurement process, the principles of Compressive Sensing (CS) have been introduced in several studies to allow sound fields to be reconstructed based on a relatively small number of

Shi, Tongyang, Bolton, J Stuart

Metamaterial Mirror Reflects Sound Waves in Any Direction

TBMG-3438605/01/2019

Researchers have constructed a “metamirror” device capable of perfectly reflecting sound waves in any direction. The proof-of-principle demonstration is analogous to looking directly into a mirror and only seeing the person next to you instead of your own face. With a regular mirror, the light follows the Law of Reflection — it must bounce off of it at the same angle at which it entered. The same rules generally apply to sound. To break the law of reflection with sound waves, the researchers engineered a device that could precisely control amplitude (loudness) and speed throughout the entire wave.

Variable-Depth, Multilayer Liner for Aircraft Noise Reduction

TBMG-3391803/01/2019

NASA Langley Research Center has developed a new approach for designing aircraft liner cores for noise reduction. The cores are comprised of multiple honeycomb-shaped chambers, each of which may contain one or more embedded porous septa. By varying the resistance and insertion depth of the septa between adjacent honeycomb core chambers, the number of tuning frequencies is increased for the full liner. High-resistance septa can also be used to change the effective chamber depth. Together, these design features cause the acoustic liner to absorb sound over a broad frequency range.

Products of Tomorrow: March 2019

TBMG-3394003/01/2019

This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.

Printing Technology Uses Sound Waves to Control Size of Liquid Droplets

TBMG-3370202/01/2019

Liquid droplets are used in many applications, from printing ink on paper to creating microcapsules for drug delivery. Inkjet printing is the most common technique used to pattern liquid droplets, but it's only suitable for liquids that are roughly ten times more viscous than water. Many fluids of interest to researchers are far more viscous; for example, biopolymer and cell-laden solutions that are vital for biopharmaceuticals and bioprinting are at least 100 times more viscous than water. Some sugar-based biopolymers could be as viscous as honey, which is 25,000 times more viscous than water. The viscosity of these fluids also changes dramatically with temperature and composition, making it more difficult to optimize printing parameters to control droplet sizes.

System Makes Opaque Materials Totally Transparent

TBMG-3341112/01/2018

Most naturally occurring materials have a disordered atomic structure that interferes with the propagation of both sound and electromagnetic waves. When the waves come into contact with these materials, they bounce around and disperse — and their energy dissipates according to a highly complex interference pattern, diminishing in intensity. That means it's virtually impossible to transmit data or energy intact across wave-scattering media and fully leverage the potential of wave technology.

Hyperfine Interpolated Range Finding for CW Lidar, Radar, and Sonar Using Repeating Waveforms and Fourier Transform Reordering

TBMG-3251808/01/2018

NASA's Langley Research Center has developed a novel fine interpolation technique that is useful in signal processing for applications in lidar, sonar, radar, and similar modalities. The interpolation technique uses repeating waveforms, Fourier transform reordering, and Richardson-Lucy deconvolution to obtain faster and more accurate results. The prime target application is range finding, but the technique is equally suitable for differential absorption studies, such as determining CO 2 concentrations in the atmosphere.

Force Isolation by Locally Resonant Metamaterials to Reduce NVH

2018-01-154406/13/2018

The combination of lightweight design and performant Noise, Vibrations Harshness (NVH) solutions has gained a lot of importance over the past decades. Lightweight design complies with the ever more stringent environmental requirements, however conflicts with NVH performance, as low noise and vibration levels often require heavy and bulky systems, especially at low frequencies. To face this challenge, locally resonant metamaterials come to the fore as low mass, compact volume NVH solutions, beating the mass law in some tunable frequency zones, referred to as stopbands. Metamaterials are artificial materials made from assemblies of unit cells of non-homogeneous material composition and/or topology. The local interaction between unit cells leads to superior performance in terms of noise and vibration reduction with respect to the conventional NVH treatments. Previously the authors showed how wave propagation along one-dimensional structures can be reduced by metamaterial additions. In

Sangiuliano, Luca, Claeys, Claus, Deckers, Elke, Pluymers, Bert, Desmet, Wim

Tech Briefs: May 2018

18AERP0505/01/2018

New Technologies Tackle UAV Challenges Robotic Applique Kits Leverage Existing Assets Educating UGVs Implementing AI Advancements in Thermal Image Training Data Sets Protecting Critical Data on Unmanned Underwater Platforms Advancements Made to the Wingman Software-in-the-Loop (SIL) Simulation: How to Operate the SIL New features include the creation of virtual environments that match real-world gunnery test courses. Soldier-Robot Team Communication: An Investigation of Exogenous Orienting Visual Display Cues and Robot Reporting Preferences The effective use of robots to conduct dangerous missions depends on accurate man-machine communications. Soft Robotic Fish Swims Alongside Real Ones in Coral Reefs GPS Enabled Semi-Autonomous Robot Combining GPS signals with acoustic and encoder data gives a robot the ability to determine its location and orientation within a reference frame. Development of a Vision-Based Situational Awareness Capability for Unmanned Surface Vessels Computer vision

Items per page:

1 – 50 of 147