界面条件下线型超声相控阵声场特性研究

开展了界面条件下线型超声相控阵声场特性的研究.将带有楔块的超声相控阵问题合理简化为液固界面的情况进行讨论.根据射线声学理论,计算了单阵元在液固界面存在时的辐射声场,进而推导了聚焦法则,得到了超声线型阵在液固界面存在时的声场、位移场表达式.对安装在楔块上的相控阵换能器的辐射声场进行了仿真,并讨论了聚焦对换能器轴向和横向声场的影响,结果表明利用聚焦能提高分辨率和灵敏度,但聚焦区域之外声束性能更差,在实际检测中要合理利用聚焦.关键词：超声相控阵界面声场聚焦

Acoustic field characteristics of ultrasonic linear phased array for an interface condition

Acoustic field characteristics of an ultrasonic linear phased array are studied under the condition of an interface. The issue about a phased array transducer with a wedge is reasonably simplified into a liquid-solid interface problem. According to ray acoustics theory, the acoustic field produced by a single element on the liquid-solid interface is computed. Then focus laws are derived and the expressions of the sound field and the displacement of the ultrasonic linear array with a liquid-solid interface are obtained. Simulations are carried out for a phased array transducer mounted on a wedge. The focusing-generated effects on axial and horizontal acoustic field of transducer are discussed. It is shown that the focusing can enhance sensitivity and resolution, but degrades the performance of beams beyond the focal region. So focusing should be reasonably used in actual testing.