Interior noise of a conventional vehicle can be decomposed in several contributors like: powertrain, road & wind noise. Nowadays, engines are becoming more and more silent, so more, not so common, sources will get more dominant in interior noise. The test techniques used to analyse engine contribution are not dedicated enough to analyse the new generation of noise sources. Because the need for dedicated testing devices increased, LMS used its experience to develop a new tool.
This contactless shaker transmits energy via a local pressure field. With its integrated pressure sensor it can be used not only for wind noise analysis, but also to study the in-situ acoustic impedance of trim. This data can be used as input for updating CAE models on full assembly level.
The exciter can simply be held in hand during the measurement which enables the user to sample the complete vehicle trim very fast. The impedance can be investigated by using an accelerometer on the surface together with the integrated pressure sensor. The acoustic impedance can be used as input for more accurate trimmed body models for example.
Without a mechanical stinger that conventional shakers have, there is no mechanical coupling anymore between shaker and testobject. This, together with a low weight and no need of alignment of a stinger, makes the device perfect for fast modal analysis of lightweight panels and structures.
Concerning power supply, the LMS Qsources Measurement Amplifier or similar can be used. The integrated sensors do not need any type of power supply. The pressure signal can be read by the LMS SCADAS III input module or similar.
Features:
- Covers 20-2000Hz frequency range with nearly constant noise energy spectrum.
- Time/environment-stable real-time pressure reference signal.
- Integrated electronic overload protection device.
Benefits:
- Fast surface sampling for acquiring in-situ trim impedance.
- Automatic overload protection stands for very robust test device.
- Small preparation compared to conventional impedance tube.
