LMS Engineering Services develops a hydraulic exciter to break down HVAC noise on a vehicle
5/24/2012
May 23, 2012 - Leuven, Belgium -World leader in test and mechatronic system simulation, LMS International develops a hydraulic exciter to break down HVAC noise on a vehicle. The dedicated dynamic exciter enables engineers to measure fluid borne noise transfer paths that can be integrated in a Transfer-Path-Analysis model.
As powertrain noise is reduced by the implementation of advanced NVH refinement and downsizing, existing noise sources become perceptible to customers. Noise targets are to be set on auxiliary noise, like the HVAC system.
Determining the sound source strength of the HVAC system is one thing. Managing the total HVAC noise is something else. Noise needs to be decomposed into distinctive sub-sources and subsequently multiplied by its transfer function in order to estimate its contribution to the total noise. To generate a dynamic pressure inside the HVAC system, LMS engineers have developed a dedicated exciter for hydraulic-noise transfer function measurement.
As measurements have to be carried out in full vehicle condition, a balance needed to be found between packaging constraints and sufficient dynamic pressure generation. LMS engineers used a local pressure sensor as a reference for the transfer function measurement (FRF). This new method results in high quality data that perfectly suits the Transfer-Path-Analysis method, allowing engineers to quantify the individual source generators inside the HVAC system.
LMS Qsources - advanced excitation hardware
Benefitting from more than 30 years of experience in noise and vibration technology, LMS Engineering Services has developed innovative excitation hardware over the last two decades under the brand LMS Qsources.
Covering a wide range of advanced excitation hardware, LMS Qsources seamlessly matches hardware with LMS software. This unique combination highly exceeds current market standards with regard to productivity and data accuracy, and hence customer's expectations.
Shakers
LMS shakers introduce dynamic excitation. LMS shakers are highly efficient exciters for modal analysis and structural analysis. They benefit from their exceptionally small design without compromising on accuracy, functionality and reliability.
The portfolio ranges from miniature shakers; that are so compact that they can be mounted where conventional shakers have no access, over integral shakers; significantly improving the efficiency of testing by eliminating all of the support and alignment work associated with conventional shaker testing, to an inertia shaker, designed for the very low frequency range.
Volume sources
LMS volume sources are sophisticated acoustic excitation devices have been developed to acquire acoustic FRFs at low, mid and high frequencies without disturbing the acoustic sound field bwith its presence. The integrated volume acceleration sensors give a real-time feedback of the emitted source strength and can directly be used as a reference for FRF measurements without any post-processing.
LMS Qsources excitation hardware is used worldwide by OEM and suppliers, aeronautics, chemical industry and on large structures such as ships, windmills, etc. to improve the acoustic performance on complete system level.
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