Abstract: Network wavefield imaging methods are able to image significantly complex discontinuities or shapes in plate-like structures for superior ultrasonic structural health monitoring (SHM)/nondestructive evaluation (NDE). The imaging provides high-resolution location, shape and/or size images of a structure, and for discontinuities with more complicated profiles. Guided wave (GW) network wavefield imaging methods combine tomography and wavefield/wavenumber imaging algorithms. Metallic plate damage detection uses guided ultrasonic waves and non-contact laser vibrometry. Guided waves are generated by piezoelectric transducers (PZT). A non-contact scanning laser Doppler vibrometer (SLDV) measures the full velocity plate guided wave wavefields. Developed network wavefield imaging algorithms account for multiple-actuator excitations from different angles enclosing the discontinuity, with algorithms using intrinsic wave characteristics such as wavefield, wavenumber, or reconstructed wave energy.

Abstract: A container comprising a threshold assembly. The threshold assembly comprises an outer end plate, a horizontal connecting member and a middle connecting member. The outer end plate comprises a horizontal portion and a vertical portion; the horizontal member connects to a floor of the container; and the middle member connects to the plate and the horizontal member, wherein one end of the middle member extends to the intersection of the horizontal portion and the vertical portion of the plate; an opening and a clamping groove at the other end of the middle member; and an inserting portion at one end of the horizontal member for inserting into the clamping groove through the opening to connect the horizontal member and the middle member. When force is applied to the threshold assembly, gaps among the horizontal and middle members and the plate are sealed, preventing liquids from causing steel corrosion.

Abstract: Network wavefield imaging methods are able to image significantly complex discontinuities or shapes in plate-like structures for superior ultrasonic structural health monitoring (SHM)/nondestructive evaluation (NDE). The imaging provides high-resolution location, shape and/or size images of a structure, and for discontinuities with more complicated profiles. Guided wave (GW) network wavefield imaging methods combine tomography and wavefield/wavenumber imaging algorithms. Metallic plate damage detection uses guided ultrasonic waves and non-contact laser vibrometry. Guided waves are generated by piezoelectric transducers (PZT). A non-contact scanning laser Doppler vibrometer (SLDV) measures the full velocity plate guided wave wavefields. Developed network wavefield imaging algorithms account for multiple-actuator excitations from different angles enclosing the discontinuity, with algorithms using intrinsic wave characteristics such as wavefield, wavenumber, or reconstructed wave energy.

Abstract: A container comprising a threshold assembly. The threshold assembly comprises an outer end plate, a horizontal connecting member and a middle connecting member. The outer end plate comprises a horizontal portion and a vertical portion; the horizontal member connects to a floor of the container; and the middle member connects to the plate and the horizontal member, wherein one end of the middle member extends to the intersection of the horizontal portion and the vertical portion of the plate; an opening and a clamping groove at the other end of the middle member; and an inserting portion at one end of the horizontal member for inserting into the clamping groove through the opening to connect the horizontal member and the middle member. When force is applied to the threshold assembly, gaps among the horizontal and middle members and the plate are sealed, preventing liquids from causing steel corrosion.