Transient sound radiation from an impulsively excited piezoelectric composite hollow sphere in a wedge shaped acoustic domain
Abstract The exact 3D linear piezoelasticity theory, the linear acoustic wave equation, and the classical method of images are employed for the coupled acousto elastodynamic time response analysis of an arbitrarily thick two layered elasto piezoelectric composite hollow sphere that is freely suspended in a perfect acoustic wedge with impenetrable (rigid/compliant) boundaries, while subjected to arbitrary (non axisymmetric) non stationary electro mechanical excitations. Problem solution is attained by application of the method of eigen function expansion, a revised form of translational addition theorems for modified spherical Bessel functions in Laplace transform domain, and Durbin's numerical inversion algorithm with an advanced (modified Cesaro) convergence improvement scheme. Numerical simulations include selected radiated pressure time signatures of a water submerged air filled PZT4/aluminum spherical shell driven by a pair of external diametrical short duration mechanical pulses. The effects of sphere wall thickness, wedge opening (apex) angle g p 6 p 4 p 2 and surface condition (hard or pressure release) are examined. Also, some noteworthy features of the transient fluid/structure interaction are recognized through proper 2D visualizations of the internal and external sound fields. Lastly, accuracy of the proposed acousto elastic model is confirmed with the help of a commercial FEA software in addition to comparison with the available data.