Studies of broadband PMN transducers based on nonlinear models

The US Navy has an immediate need for large-scale, 3D, nonlinear simulations of broadband sonar projectors. The example considered here is a volume array of high-power, electrostrictive (PMN) flextensionals. Analysis and design of these complex arrays are clearly pushing the limits of simplified models. Hence, the analytical burden should be shifted from clever but overextended designers to computers. Very large-scale models, broadband response and nonlinearity favor explicit time-domain methods over implicit time- or frequency-domain methods. We demonstrate comprehensive finite element modeling of an icosahedral array of 12 flextensionals. Behavior of the PMN driver is illustrated with a 1D electrostrictive finite element (nonlinear harmonic oscillator) and generalized to a 3D element. Full-scale, SMP simulations are shown for individual flextensionals and the icosahedral array including tow-body structure