Abstract: A system for inspecting an acoustic treatment applied to the hull of a maritime vessel includes an underwater inspection system including at least one signal emitter configured to emit a signal, at least one receiver configured to receive the signal after the signal has come into contact with the acoustic treatment applied to the hull of the maritime vessel, wherein the signal provides information about the integrity of the acoustic treatment and a processor configured to perform signal processing on the received signal and generate an output comprising information about one or more parameters of the acoustic treatment. The inspection system thereby allows for in-water inspection of acoustic treatments applied to a maritime vessel thus avoiding the need for a costly and time-consuming inspection of such a vessel while in dry-dock.

Abstract: Systems and methods for computing linear and non-linear explicit, matrix-free, statics with applications to functionally graded mechanical metamaterials. In some aspects, these systems and methods use an algorithm based on a special finite element formulation called the Jacobian Free Newton Krylov (JFNK) method.

Abstract: An apparatus and method use a hybrid absorbing element defined by a implementation of matched layer and infinite element concepts to model time-domain and frequency domain wave propagation finite element calculations. The hybrid absorbing element includes three or more semi-infinite facets providing an essentially reflectionless interface for outgoing waves. Matched layer conditions are coupled to finite-element wavefield computation regions and infinite element conditions, which effectively disperse advancing waves at infinity. The disclosed apparatus and method result in the rapid attenuation of waves arriving at arbitrary angles, leading to elimination of reflection artifacts.

Abstract: A system for inspecting an acoustic treatment applied to the hull of a maritime vessel includes an underwater inspection system including at least one signal emitter configured to emit a signal, at least one receiver configured to receive the signal after the signal has come into contact with the acoustic treatment applied to the hull of the maritime vessel, wherein the signal provides information about the integrity of the acoustic treatment and a processor configured to perform signal processing on the received signal and generate an output comprising information about one or more parameters of the acoustic treatment. The inspection system thereby allows for in-water inspection of acoustic treatments applied to a maritime vessel thus avoiding the need for a costly and time-consuming inspection of such a vessel while in dry-dock.

Abstract: Disclosed an acoustically transparent material including an acoustic wave steering material, and methods for fabrication and use thereof. The materials are specially designed structures of homogenous isotropic metals. These structures are constructed to propagate waves according to Pentamode elastic theory. The metamaterial structures are two-dimensional, intended to propagate acoustic waves in the plane in a manner which closely emulates the propagation of waves in water. The acoustically transparent materials described herein have particular utility as acoustic wave steering materials and acoustic cloaks.

Abstract: Disclosed an acoustically transparent material including an acoustic wave steering material, and methods for fabrication and use thereof. The materials are specially designed structures of homogenous isotropic metals. These structures are constructed to propagate waves according to Pentamode elastic theory. The metamaterial structures are two-dimensional, intended to propagate acoustic waves in the plane in a manner which closely emulates the propagation of waves in water. The acoustically transparent materials described herein have particular utility as acoustic wave steering materials and acoustic cloaks.