This study presents the initial assessment for a new approach to frequency selectivity aimed at mimicking the function of the basilar membrane within the human cochlea. The term cochlea tonotopy refers to the passive frequency selectivity and a transformation from the acoustic wave into a frequency signal assisted by the hair cells in the organ of Corti. While high-frequency sound waves vibrate near the base of the cochlea (near the oval windows), low-frequency waves vibrate near the apex (at the maximum distance from the base), which suggests the existence of continuous frequency selectivity. Over the past few decades, frequency selectivity using artificial membranes has been utilized in acoustic transducers by mimicking cochlea tonotopy using cantilever-beam arrays with defined physical parameters such as length and thickness. Unlike the conventional cantilever-beam array type, the travelling wave propagation based-mechanoluminescence (ML) membrane made of ZnS:Cu- polydimethylsiloxane (ZnS:Cu-PDMS) composite that we describe here provides new frequency selectivity more similar to that demonstrated by the human membrane. Here, we explored the potential of the ML membrane to deliver new frequency selectivity by using a non-contact image sensor to measure visualized frequencies. We report that the ML basilar membrane can provide effective visualization of the distribution of strain rate associated with the position of maximal amplitude of the travelling wave.

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The present paper introduced a computer program, called WISH, which is based on a time-domain Rankine panel method. The WISH has been developed for practical use to predict the linear and nonlinear ship motion and structural loads in waves. The WISH adopts three different levels of seakeeping analysis: linear, weakly-nonlinear and weak-scatterer approaches. Later, WISH-FLEX has been developed to consider hydroelasticity effects on hull-girder structure. This program can solve the springing and whipping problems by coupling between the hydrodynamic and structural problems. More recently this development has been continued to more diverse problems, including the motion responses of multiple adjacent bodies, the effects of seakeeping in ship maneuvering, and the floating-body motion in finite-depth domain with varying bathymetry. This paper introduces a brief theoretical and numerical background of the WISH package, and some validation results. Also several applications to real ships and offshore structures are shown.

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