Technical Library section: Automotive

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NVH Production Test System - Sunroof Application

An automotive OEM supplier of vehicle roof systems chose Sound Answers to provide engineering support for integrating their B&K Pulse NVH production test systems, to develop/set product acceptance targets, and troubleshoot issues that arise within their production environment. Operating vibration measurements were made on a number of end-of-line systems both locally and internationally. Depending on failure mode, different analysis techniques were utilized that included spectral, envelope, octave, and time domain along with applying source-path-receiver approach when troubleshooting NVH related issues. Product acceptance targets correlated to subjective preferences, which have greatly improved the customer’s ability to prevent noise and vibration related issues from reaching end-user. In addition, the production test systems have also provided NVH quality process improvements.

Reference: 2009-150 Inalfa; Offerings: target setting, troubleshooting

Pass-by-Noise Synthesis Tool

An automotive OEM requested Sound Answers to develop a pass-by-noise simulation tool that provides the functionality to predict vehicle pass-by sound pressure levels. Operating noise measurements were made at all sources that significantly contribute to pass-by-noise like tire, engine, intake, and exhaust. Measured source data were combined with measured acoustic transfer functions to estimate contributions and overall vehicle pass-by sound pressure levels. This synthesis tool provided the customer with a valued process improvement by reducing the amount of physical test time and aiding in the development of intake and exhaust systems for pass-by performance. For further discussion on this topic please see SAE 2011-01-1608.

Reference: 2009-390 Honda PNS (SAE 2011-01-1608); Offerings:

Vehicle Cooling Fan Benchmarking

An automotive OEM selected Sound Answers to assist in vehicle level sound and vibration benchmarking for cooling fan noise and vehicle sensitivity thereto. Operating noise and vibration measurements were conducted within a hemi-anechoic chamber with measurements made at customer interface locations and at key cooling fan system locations. FFT, order analysis, balancing techniques, and sound quality metrics were utilized to characterize the cooling fan systems to set vehicle level targets. The developed targets were used to gauge the current NVH performance of existing cooling fan systems, and used to set design guidelines for future platforms. In addition to developing targets Sound Answers also optimized the OEM’s current cooling fan NVH test and processing procedure.

Reference: 2010-290, 640 Ford Cooling Fan Benchmark; Offerings: standard testing

Electric Vehicle NVH Program Support

An electric vehicle automaker requested Sound Answers to provide NVH program support for a program throughout the development process and through the launch of the vehicle. Static and operating acoustic and vibration data were made within a hemi-anechoic chambers and on-road with measurements made at customer’s US facilities. Multiple techniques were utilized throughout the development process that consisted of source path contribution (SPC), arrays, multi-coherence, and troubleshooting.

Reference: 2010-430, 2011-330 Fisker

Vehicle Body Modal Testing

A subsidiary of an automotive manufacturer of commercial vehicles & light trucks chose Sound Answers to provide support and training for powertrain, full and trim body modal testing. Stationary vibration measurements were performed at the customer’s facility in China. Modal testing of components and multiple vehicle configurations were performed along with vehicle acoustic and tactile sensitivity measurements to assist in the customer’s CAE correlations. Training of experimental modal testing was provided so that the customer could move past just taking FRF data. Additionally, this training allowed the customer to continue to support their CAE correlation activities after this project was completed.

Reference: 2010-660 NVH Experts

Impact Harshness Metric Development

An automotive OEM requested Sound Answers to provide research for developing better objective metrics by gaining a more detailed understanding of the mechanisms affecting the perception of impact harshness. Operating acoustic and vibration measurements were accomplished on-road during the (jury study) subjective assessment. Operating defection shapes (ODS), wavelet spectrograms, time domain (envelope), frequency domain (energy spectral density), sound quality, and vibration quality metrics were all measured/calculated to identifying the relative importance (contribution) to overall perceived impact harshness of the different vehicle interfaces. A roadmap was developed that offered a model of impact harshness perception with more resolution compared to the current one in use by the customer, which will be used to establish targets for driver-vehicle interfaces and utilized to propagate objective targets to sub-system and component levels.

Reference: 2010-710 Honda; Offerings:

NVH Engineering Services

In recent years automotive OEM’s have taken advantage of on-site engineering services, in recognizing this trend Sound Answers has and is currently providing a range of NVH engineers from entry level to program management at vehicle OEM’s. Sound Answer’s on-site engineers provide a wide range of tests and activities from component level to vehicle level benchmarking, to electric/hybrid vehicle development. Typical tests include both static and operating acoustic and vibration measurements. These engineering services are advantageous for both parties because vehicle OEM’s get resource that is typically focused on program specific tasks without the need of large investment and Sound Answer’s receives engineers who learn vehicle OEM test process/procedure.

Reference: 2010-840, 2011-390, 2011-450 Toyota, 20XX-XXX Ford Sterling

NVH Production Test System - Driveline Application

An automotive OEM supplier that manufactures driveline parts chose Sound Answers to provide NVH production test system support, which included development of fault identification (pass/fail criteria) and integration of B&K Pulse system with the customer’s production end of line test system. Operating noise and vibration measurements were conducted on the end of line test stand at the customer’s facility in Germany. Types of analysis used included (and were not limited to) spectral, order, envelope, octave, and time domain. This NVH production test system has increased the customer’s ability to prevent noise and vibration related faults. In addition, the objective data obtained from faulty units has provided the customer with valuable information to assist in achieving true quality improvements.

Reference: 2010-890 M&R PTA; Offerings: target setting

Experimental Testing for FEA Correlation of Acoustic Cavity & Trim

A software and services company in conjunction with an automotive OEM has requested Sound Answers to assess (experimentally) all of the vehicle cabin acoustic cavity modes up to 150 Hz so that better correlation between test and CAE analysis can be achieved. Stationary acoustic and vibration measurements were conducted within a hemi-anechoic chamber with measurements made at customer defined locations. Microphone array translated throughout the cabin along with both force and acoustic excitation were used to measure acoustic and structural FRF’s (A/F, P/F, P/Q, & V/Q) for understanding the critical factors that affect frequency, damping, and mode shapes of vehicle cabin. Results & customer benefit needed…wait until project is completed?

Reference: 2011-100 Chrysler/ESI

Vehicle Interior Acoustic Package Optimization

An automotive OEM chose Sound Answers to assess the opportunity for cost reduction in relation to the interior treatments for road noise. Operating noise measurements were conducted both on-road and within hemi-anechoic chassis dynamometer with rough shells. Objective 1/3 octave data and sound quality metrics were calculated for all cost-reduced interior package iterations to ensure road noise performance was not degraded. An optimized configuration was identified that maintained NVH performance and resulted in savings of $1 million/year and 7 lb/vehicle.

Reference: 2011-410 Chrysler JS testing; Offerings:

Exhaust Acoustic and Vibration Testing

A subsidiary of an international automotive OEM selected Sound Answers to provide a test service of acoustic and vibration testing on multiple exhaust systems. Operating acoustic and vibration measurements were made within a hemi-anechoic chassis dynamometer. Multiple microphone locations (interior/exterior), binaural head, and multiple accelerometers along the exhaust systems were utilized to capture the NVH performance of the exhaust system while following the customer’s standard specifications. Data was provided to the customer for analysis while alleviating the backlog of tests the at customer’s facility.

Reference: 2011-510 Magneti Marelli; Offerings: standard testing

Technical Library section: Consumer Products

Do we want to add another summary section by separating the medical projects from other consumer products?

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Reference: Check Sorter Noise Troubleshooting

A global provider of information technology services and equipment selected Sound Answers to address the sources of noise and identify countermeasures for overall noise reduction of their paycheck sorter unit. Both operating and stationary measurements were made in a fully anechoic chamber. Near field acoustic holography measurements were made in conjunction with narrowband, 1/3 octave band, and FRF analysis to troubleshoot all relevant noise sources. Countermeasures to address resonance issues, and lower overall levels were accepted by customer. Additionally, sound quality design recommendations were also made which the customer decided to take into consideration during future design processes.

Reference: 2009-120 Unisys; Offerings: troubleshooting

Vacuum Cleaner Noise Troubleshooting

A vacuum cleaner and floor care product manufacturer chose Sound Answers to understand the main sources of noise that contribute most significantly to the overall sound pressure level and annoyance to the operator. Operating noise measurements were taken in a hemi-anechoic chamber and a quiet room to better simulate a typical operating environment. Multiple microphones, a binaural head, and sound intensity mapping were analyzed in both narrowband and 1/3 octave bands to determine key noise sources. A number of design recommendations were made which the customer has decided to incorporate into this product line and to use as design guidelines in all future platforms.

Reference: 2009-400 Bissell; Offerings: troubleshooting

DC Motor Noise Troubleshooting

A leader in the development, manufacture, and world-wide distribution of electronic and electro- mechanical components and systems requested Sound Answers to understand/root cause a noise issue experienced which delayed the release of one of their product lines. Operating acoustic and vibration, static FRF testing, and sound quality measurements were made to determine objective parameters to discriminate between good and bad. The source-path-receiver model was applied focusing on frequency domain analysis to identify the key noise characteristics of the objectionable noise. Countermeasures to reduce the noise of concern were conducted from both the source side (DC motor – brush and commutator interaction), and also the path side (housing forces, acoustic cavity modes, modal alignment, and transmission loss). The recommendations made by Sound Answers were accepted by the customer, which helped direct their efforts at launching this product line with an improved motor design and a resolution to their noise concern. Reference: 2009-550 Linear; Offerings: troubleshooting

Air Handler Unit Alternative Sound Power Testing

A global air conditioning, heating, and refrigeration systems manufacturer selected Sound Answers to conduct sound power measurements to qualify their units for delivery to the final customer. Sound power measurements were made on the air handler unit at the customer’s facility in Canada as an alternative to measuring sound power within a reverberant room located at another facility. Sound intensity based ISO specification 9614-2 was used for all measurements to quantify the sound power. Sound Answers developed a process derived from standard procedures for measurements of noise from vehicle exhaust and intake orifices which was utilized to handle the challenge associated with making sound intensity measurements in the presence of direct flow greater than 4 m/s (which is not allowed by ISO spec). This alternative method for qualifying AHU’s for sound power has saved the customer an excessive amount of time and shipping costs associated with placing and setting up the air handler units within the reverberant room which is located off-site internationally of some manufacturing facilities.

Reference: 2010-180 Racan Carrier; Offerings: standard testing

Wind Turbine Vibration Study

A maker of custom wind turbine blades and ventilation equipment requested Sound Answers to identify an imbalance related issue at the request of their customer. Operating vibration measurements were conducted on the wind turbine located in Mexico. FFT, order analysis, and balancing techniques were utilized to characterize the imbalance associated with the blades of the system. Additionally, efforts were provided on the wind turbine to troubleshoot a vibration alarm system fault. Measurements for this showed a resonance issue not related to imbalance, which was the significant contributor to the vibration faults the customer was experiencing.

Reference: 2010-420 Tecsis; Offerings: troubleshooting

Vibration Validation of Blower Motor

A global provider of HVAC systems chose Sound Answers to provide test service support and perform vibration validation tests on their blower motors. Both operating and stationary vibration measurements were made at the customer’s US facility. Vibration levels at various customer identified locations were made to identify resonant conditions and compared to acceptance criteria. Imbalance, steady state, and torsional vibration validation was performed along with identifying resonances of the system. This test service support allowed the customer to relieve their overburdened staff from excessive work hours during the validation cycles while maintaining quality validation testing. Reference: 2010-540 Trane; Offerings: standard testing

Sound Quality Testing of Dialysis System

A medical corporation that provides research and development for major corporate clients selected Sound Answers to both measure sound quality performance and define a sound quality test procedure on a home dialysis system. Operating acoustic measurements were collected within a hemi-anechoic chamber. Binaural measurements were utilized in the analysis of time domain, narrow band spectra, and sound quality metrics. A preference equation was derived based on key attributes of the sounds from the analysis techniques discussed and a formal jury study. This testing allowed the customer to improve its customer’s perception of quality for their dialysis system by moving forward from subjectively capturing customer preferences to using objective measures and to also drive development work with objective data for future products.

Reference: 2010-610 DEKA; Offerings: target setting, standard testing

Wound Therapy Device Sound and Vibration Testing

A medical devices company requested Sound Answers to evaluate NVH performance of a wound therapy device focusing on understanding the NVH mechanism of the device and identifying best guidelines for reducing noise and vibration. Operating noise and vibration measurements were conducted within a full-anechoic chamber. The source-path-receiver approach was utilized concentrating on FFT and order analysis to root cause noise and vibration mechanism of the device. Countermeasures to reduce noise and vibration were made from both the source and path side that were effective. However, only path side countermeasures were used due to the wound therapy device being so far along in the development process.

Reference: 2010-670 Smith & Nephew; Offerings: troubleshooting

Technical Library section: Off-Highway

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Tub Grinder Sound Power Troubleshooting A manufacturer of agricultural, environmental, and construction equipment selected Sound Answers to perform sound power measurements and to teach troubleshooting tasks to identify key components driving sound power results of their tub grinder. Standardized sound power measurements were conducted to quantify source and an assessment of which bands contributed the most to the overall level were focused on. Once focus was narrowed, both acoustical and structural resonances were calculated/measured to determine whether root cause was a forced response or modal. A root cause was identified and recommendations were accepted which reduced the sound power results of the tub grinder. The techniques used for this project among others were taught so that the customer can later solve similar issues in the future.

Reference: 2010-220 Vermeer (SAE 2011-01-1676); Offerings: troubleshooting

Tractor Acoustic Boom Troubleshooting

An agricultural equipment manufacturer chose Sound Answers to troubleshoot an acoustic boom and identify possible countermeasures. Static and operating noise and vibration measurements were made applying the source-path-receiver model at the customer’s US facility. Spectral, order, and modal analysis were utilized to understand key components of the acoustic boom. This boom consisted of high source levels coupled with a modal alignment issue that surfaced after a design change was made during the development process of the project. The customer accepted the countermeasures recommended by Sound Answers which consisted of reducing the source level and also shifted the coupled resonances. In addition to recommended changes, Sound Answers has also helped the customer develop a mode alignment chart to use as a reference during future tractor development processes.

Reference: 2010-560 AGCO (SAE 11NVC-0125); Offerings: troubleshooting

Vibration Validation of Subsea Equipment

An oil and gas equipment company requested Sound Answers to perform validation tests on subsea equipment. Operating vibration measurements were made on a dynamometer at customer’s supplier US facility. Vibration levels at 33 locations underwater without the use of adhesives along the 100+ ft long strings were made and compared to acceptance criteria curves. Along with steady state validation testing, 72 hour endurance testing with data acquisition done every hour was also performed on strings to confirm functionality of equipment prior to being placed in the field.

Reference: 2010-570, 2010-750,760,770 FMC Technologies; Offerings: standard testing

Gear Rattle Investigation A manufacturer of heavy duty axles and axle components for military vehicles and off-highway machines selected Sound Answers to assist in identifying the source of an objectionable rattle noise and provide countermeasure/recommendations to help customer reduce/eliminate noise. Operating noise and vibration measurements were made at an independent off-road vehicle testing facility. Time domain, frequency domain, order analysis, envelope analysis, and modal FRF measurements were utilized to understand where the rattle noise (source) originated. Design recommendations were made focusing on lowering forcing functions, understanding/moving resonances. Countermeasures were also provided which increased isolation to help reduce rattle noise further.

Reference: 2010-880 AxleTech; Offerings: troubleshooting

Fire Suppression System Acoustic Troubleshooting

A manufacturer of access equipment and specialty trucks for defense, fire and emergency, and commercial has chosen Sound Answers to identify key noise sources and paths and provide design recommendations for reducing acoustic levels of a fire suppression system. Impulsive acoustic and vibration measurements were conducted according to customer specifications at the customer’s facility within the US. Both time domain and frequency domain analysis were utilized to quantify source and to assess if there were reduction opportunities through the path of the system. Design recommendations were made to reduce the impulsive noise and additionally, countermeasures were made to further reduce noise levels in discrete frequency ranges.

Reference: 2011-530, 600 Oshkosh; Offerings: troubleshooting

Technical Library section: SBIR

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Binaural Capture and Synthesis of Ambient Soundscapes (Phase 1)

Sound Answers has developed a technique that captures the soundscape, i.e. the typical sound of an environment, along with the topographical information of that environment so that a database of sounds and topographies is created to represent different possible environments. Single microphone, binaural head and spherical beamformer recordings were conducted. Pros and cons of single microphone vs. binaural/spherical beamformer recordings were assessed and recommendations for the best soundscape recording technique were established. The recommended technique was also demonstrated at the end of Phase I.

Reference: 2008-??? Air Force phase I

Improved Analysis Techniques for Characterizing Jitter in Beam Control Systems (Phase 1)

The decomposition of the residual laser beam jitter into its contributions was achieved with a hybrid approach which made use of both parametric and model-based approaches. The best method to separate the component of the residual laser beam jitter due to external disturbances from the effect due to internal noise caused, directly or indirectly, by the control elements themselves were identified from validation testing of the most popular and innovative techniques used in the field of acoustics and vibration. Sound Answers has investigated both statistical (black/gray box) and physical signal decomposition techniques. The statistical techniques that were investigated included, and were not limited to: Independent Component Analysis (Blind Source Separation), Principal Component Analysis, Partial Singular Value Decomposition, Conditioned Input Analysis (Partial Coherence). Pattern recognition techniques such as Wavelets and Empirical Mode Decomposition were also evaluated. Finally, Sound Answers has combined these techniques with physical characterization of the system in terms of sources (or loads, such as the input jitter) and paths (or system sensitivities, such as the transfer functions of the individual sensors, or sensor mounting systems or control actuator modules). BENEFIT: The set of signal processing algorithms utilized for the decomposition of the contributions to the residual jitter will be integrated in a Residual Jitter Decomposition toolbox which can be sold to HEL manufacturers and/or Beam Stabilization and Control System providers.

Reference: 2009-060 Air Force SBIR phase I (CM recommended to remove section that is red)

Improved Analysis Techniques for Characterizing Jitter in Beam Control Systems (Phase 2)

The US Air Force needs a system to help identifying root-causes of jitter in HEL beam alignment systems. This is of particular interest to the USAF as jitter smears the HEL beam on target, reducing its integrated intensity and therefore its target damage capability. Jitter is caused by several disturbances introduced in the beam alignment system with multiple sources and complex interactions between the multitude of sub-systems and components. With the current state-of-the art it is not possible to unequivocally identify sources of jitter from the analysis of the jitter signal alone. Rather, a comprehensive, yet streamlined and efficient, test plan to map the relevant sub-systems/components is required. A process has been established using strategic measurement techniques and advanced signal processing algorithms to quantify the jitter sources and paths in a consistent and accurate manner. This process was further developed by testing on a variety of different HEL beam control installations to ensure the algorithms were optimized to effectively address jitter in all applications. The algorithms and test process will then be developed into a "Jitter Vibration Decomposition Toolbox" software program to allow increased efficiency for testing personnel to perform jitter analysis. BENEFIT: The primary objective of this Phase II project was to deliver to the USAF test and signal analysis tools to decompose beam jitter into its most important contributions. The immediate benefit was for time and cost savings during the integration phase of an HEL system when much of the jitter root-cause investigation should take place. The improvement in testing efficiency and more applicable output will lead to the supplier base implementing updated test procedures to impact their design process with updated models and more informed design decisions. This need for better and more efficient testing methods is not unique and the automated signal processing toolbox developed in this Phase II project will be the core for developing similar toolboxes geared towards other industries such as automotive, consumer products and off-highway.

Reference: 2010-040 Air Force SBIR phase II

Urban Time-to-Detect Simulator for Vehicle-Developers (Phase 1)

The proposed approach started from an investigation of psychophysical stimuli relevant to the detection of a vehicle in an urban environment. Existing simulators were then evaluated from the standpoint of their capability of high fidelity reproduction of real stimuli and on their ability to handle virtual stimuli (i.e. from virtual vehicles). Sound Answers has followed an iterative approach to the development of a multi-modal detectability metric, by first conducting experiments of vehicle detection based on one type of high quality cue (as an example, just visual or audio or vibration). Bi-modal detection experiments would then be conducted by using the (one or more) simulators that offer best signal quality for at least two stimuli. The results of both experiments would be analyzed to derive a detectability model based on one stimulus only, then a detectability model which accounts for the cross-coupling among two stimuli at a time. Finally, a hypothesis of a multi-modal metric model was formulated along with a specification document for the simulator to be built in Phase 2.

Reference: 2010-680 Army SBIR phase I