摘要
指向性是衡量辐射体声学性能的重要参数。同相弯曲振动方板阶梯辐射体具有辐射阻抗低、面积大等特点,可广泛应用于大功率气介质超声领域。分别从材料、几何尺寸两个方面对影响辐射体指向性的因素进行了研究。并以材料为钢,边长为50 mm,基底厚度为6 mm,阶梯厚度为10 mm的方板阶梯辐射体(Ⅱ~#)为例,利用有限元将辐射体划分为多个微元,提取各微元位移振幅,计算其指向性。计算结果表明,工作频率一定时,材料对辐射体的指向性没有影响;当辐射体边长与基底厚度的比值较小时,其指向性较尖锐。实验测试与理论计算结果相符,方板阶梯辐射体指向性图案有单一主瓣,其辐射主要集中在主轴方向,形成一个半开角宽度较小的锥形射线束。
The directivity is an important parameter for evaluating radiator. With the features of low impedance and large surface, the square plate stepped radiator in bending vibration has been widely applied in high power air ultrasonic processing. For an example of square steel plate stepped radiator, the side length and thickness of the base plate are 50 mm and 6 mm respectively, and the stepped thickness is 10 mm. By using finite element method, the directivity pattern of the radiator is calculated. It shows that the square plate stepped radiator exhibits better directivity, for its major lobe is sharper and its side lobes are small. In addition, the relationships of both material and geometrical dimension with di- rectivity pattern are studied. It shows that the directivity of the square plate stepped radiator is independent of material but dependent on radiator dimensions. The smaller of the side length to thickness ratio of the radiator, the shaper of the directivity pattern will be. Finally, the directivity of a fabricated radiator is measured, and it shows that the calculated result is in good agreement with the measured one.
出处
《声学技术》
CSCD
北大核心
2018年第1期6-10,共5页
Technical Acoustics
基金
国家自然科学基金资助项目(11774211)
关键词
方板阶梯辐射体
指向性
材料
几何尺寸
square stepped radiator
directivity
material
geometrical dimension