This paper describes an acoustical study performed on a medium-duty truck, with aim of acoustic optimization of face-lifted cabin. Complete acoustic characterization of current vehicle was done, including subjective evaluation and jury test. The main problem was located in low frequency range, where engine harmonics excite structural-acoustic resonances of the cabin. For the complete noise prediction in the low frequencies (0 - 200 Hz) a hybrid numerical-experimental method has been used, combining results of FEM simulation with measured acoustical transfer functions. Several structural modifications were tested, resulting in a noise prediction driving the choices for feasible countermeasures. Also medium-high frequency range (250 - 10000 Hz) was considered for complete optimization: computer aided design tool was used for proper revamping of interior trim. This tool makes use of measurement database for sound power contribution calculation of cabin panels and is able to predict the treatment efficiency. Using results of structural-acoustic simulation and prediction of acoustic treatment effect, the new cabin was updated and tested on road: improvements of 3 dB(A) on overall levels and about 10 points in articulation index were obtained: also subjective impression was highly improved, obtaining for new truck an acoustic result well in line with best-in-class vehicles for this range.
Acoustic optimization of medium-duty truck cabin using numerical and experimental procedures
Akustische Optimierung des Führerhauses von mittelschweren Lastkraftwagen mit Hilfe numerischer und experimenteller Verfahren
International Congress on Sound and Vibration, 7 ; 2735-2742
2000
8 Seiten, 11 Bilder, 7 Quellen
Aufsatz (Konferenz)
Englisch