Abstract: A system for detecting cracks in an underwater structure can include an acoustic signal transmitter configured to be disposed proximate to, but without physically contacting, the underwater structure, where the acoustic signal transmitter is configured to emit acoustic signals. The system can also include an acoustic field receiver configured to be disposed proximate to, but without physically contacting, the underwater structure, where the acoustic field receiver is configured to receive resulting acoustic fields. The system can further include a controller that is configured to receive the resulting acoustic fields from the acoustic field receiver. The controller can also be configured to analyze the resulting acoustic fields signal. The controller can further be configured to detect, based on analyzing the resulting acoustic fields, a crack in the underwater structure.

Abstract: System include an ultrasonic transducer configured to couple to a nondestructive testing (NDT) sample and configured to produce and direct an ultrasonic probe wave at a selected frequency into a subsurface region of the NDT sample, a 3D laser scanning vibrometer configured to direct a detection beam in a scan area on a surface of the NDT sample and to receive a return beam from the scan area, and to detect, based on the return beam, a 3D motion of the surface across a wideband frequency range, and a processor, and a memory configured with instructions that, when executed by the processor, cause the processor to produce sub-surface image data of the NDT sample at multiple harmonics of the selected frequency in the wideband frequency range based on the detected 3D surface motion, wherein the sub-surface image data describes a nonlinear defect response produced in the NDT sample by interaction of the ultrasonic probe wave with the subsurface region.

Abstract: Structure information for a substance within a volume may be obtained. The structure information may characterize structural non-linearity of the substance within the volume. A structure model for the substance within the volume may be generated based on the structure information and/or other information. The structure model may simulate one or more characteristics of the substance within the volume. Presentation of information on the characteristic(s) of the substance within the volume may be effectuated based on the structure model and/or other information.

Abstract: Provided is an additive manufacturing system capable of performing in-process, layer-by-layer non-destructive testing, the additive manufacturing system including: a plate for producing a part thereon; a transducer attached to the plate and configured to induce vibrations in the part; and a laser vibrometer configured to detect a vibrational response of the part to determine whether defect and/or anisotropy exists within the part.