薄球壳换能器的源函数来源和特性分析

Origin of the Source Function of A Thin Spherical Shell Transducer and its Characteristics Analysis

法林张士勇等：薄球壳换能器的源函数来源和特性分析，测井技术，１９９６（３）２０，１６９～１７７。本文对球状（各向同性）压电换能器的激发特性（瞬间响应），中心频率等作了详尽的理论分析和仿真模拟，并用一种模型来描述在薄球壳换能器被电压信号激发期间质点的瞬态运动行为。这个模式被称为换能器的源函数。推导出的声波函数被用来等效在声波石油测井和地质勘探的研究中所采用的无方向的点源。

Three particle motion modes are presented for a piezoelectric thin sphericalshell transducer. They are determined by the type of the exciting voltage, the output impedance of the exciting circuit, the property of the surrounding coupling fluidmedium, and the physical and geometrical characteristics of the transducer. Thethree modes correspond to the overdamped, critically damped and underdampedtransmitting states of the transducer, Only the underdamped transmitting state iso f practical use. When the transducer is set at its underdamped transmitting state,the particle displacement velocity, at least I consists of one oscillatory term and onenon-oscillatory term' The simulation results show that with the increase of thedamping coefficient 9 of the oscillatory terml the first amplitude of particle vibration will increase relatively, and the duration of particle vibration will decrease.This paper sets up the equivalent circuit of the transducer for spherical wave andgives a model that describes the transient motion process of the particles during theexcitation of the transducer by different voltage signals.This function is called thesource function and can be used as the equivalent to the omnidirectional pointsource function.