<sans-serif xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsd="JATS-journalpublishing1.xsd">The Applications of Acoustic Black Holes to Attenuation of Coach/Bus Frame Structure Vibrations</sans-serif>

<div class="section abstract"><div class="htmlview paragraph">Basic structures of vehicle frames、aircraft fuselages and ship hulls are made of beams、columns and trusses. If Acoustic Black Holes(ABH) are carefully arranged alongside with the wave propagation paths in those structures, the wave propagation paths could be changed at NVH engineers’ will and the structure vibrations can be reduced. Two kinds of ABHs are used in this paper: one is ABH made of Polyurethane(PU), other one is ABH composed of several steel plate 1D ABH stacked up in parallel. Three structures are used to test the effectiveness of ABHs for vibration reductions: a squared hollow sectional steel commonly used in motorcoach/bus chassis and frame structures, a simple frame for motorcoach airbag suspension and a 12m chassis structure. The attached ABHs show a great vibration attenuation in terms of transfer functions on the basic structure element for a motorcoach. The lateral, vertical and longitudinal transfer functions for steel ABHs were greatly reduced from 13.2~14.7 dB. Then test was extended to a simple frame that is common structure for motorcoach airbag suspension. The results show that ABHs have3.6~6.3 dB vibration attenuations. Based on those tests, the ABHs were also added to a 12-meter motorcoach chassis frame. The ABHs were attached at rear left upper disk for airbag suspension and at the seat fixing bolt area, the transfer function from the airbag suspension upper disk to seat fixing bolt area was reduced about 3dB. These effective vibration reductions show the great capabilities of ABHs to attenuate the structure vibrations for motorcoach and bus and ABHs could play a crucial role in attenuating structural vibration, structural noise radiation and structure-borne noise in motorcoach and bus.</div></div>