颗粒阻尼影响封闭空腔目标场点声压的试验研究

Experimental Study on Acoustics of Target Point in Enclosed Cavity Affected by Particle Damping

针对某封闭空腔,研究了颗粒阻尼对其目标场点声压的影响。推导了声压与模态振型函数的关系式,揭示了声压随模态变化的规律。对某封闭空腔进行模态试验,研究了其主要模态振型的构成。通过在封闭空腔模态振型中相对位移较大的面上布置颗粒阻尼,降低了封闭空腔内目标场点的声压。结果显示,相比无颗粒阻尼,当颗粒阻尼布置于封闭空腔的第1阶模态振型中相对位移较大的面上时,封闭空腔内目标场点的声压总有效值降低程度最大,由107.99 dB降至104.08 dB,下降值达到了3.91 dB。

Acoustic pressure in the enclosed cavity affected by particle damping was studied. By inducing the formula of acoustic pressure, the law of acoustic pressure changing with modal shape function was unveiled. The modal shapes of the enclosure cavity were analyzed by the modal test. By equipping the board of which relative displacement is the maximum in lower-order modal shapes of the enclosure cavity with particle damper, the vibration of the lower-order modal is reduced. Then the acoustic pressure of the target point in the enclosure cavity is reduced. The results show that compared with none particle damper, the decrease of the acoustic pressure root mean square（RMS） at the target point in the enclosure cavity is the most, from 107.99 dB to 104.08 dB, decreased by 3.91 dB when particle damper was equipped on the board of which relative displacement is the maximum in first modal shape of the enclosure cavity.