矩形平板和矩形阶梯板的辐射声场指向性

The directivity patterns of the sound radiated from a rectangular plate and stepped radiators

利用有限元方法,提取板中各微元振幅,迭代计算了平板和阶梯板所产生的辐射声场,并测试了所加工的平板和阶梯板的声场指向性。结果表明:在平板中沿x轴与平板垂直的平面,声场指向性在轴线方向存在主瓣,但是在其他方向同时存在副瓣,副瓣声能分布较多,声能分散。在阶梯板中沿x轴与阶梯板垂直的平面,声场指向性在轴线方向存在开角较小的主瓣,声能分布主要集中在轴线方向;在沿y轴与阶梯板垂直的平面,声场指向性在轴线方向也存在开角较小的主瓣,同时在轴线方向之外存在副瓣,但副瓣声能分布较少,故声能主要集中分布在轴线方向。因此,阶梯板的声场指向性优于平板指向性,实验测试与理论计算结果相吻合。

Using finite element method,the displacement of each segment in a rectangular plate is extracted, and the radiated pressure is calculated by the directive theory of built-up point sources. The directivity patterns of a fabricated fiat plate and a stepped plate are measured. It shows that the directivity of the stepped plate radiator is better than that of the flat one. In rectangular plate radiators,directivity pattern along the x-axis of perpendicular to the fiat plate exist major lobe, but at the same time in the other direction exist side lobes. Energy distribution is decentralized. In stepped radiator, along the x-axis perpendicular to the stepped plate exist sharper lobe~ along the y-axis perpendicular to the stepped plate exist sharper major lobe, although there are side lobes in the other direction, the side lobes are very small,sound energy distribution is concentrated. It shows that the direetivity pattern of the stepped rectangular plate radiator is better than that of the rectangular plate radiator. The calculated results are in good agreement with the tested ones.