9 results about "Flexural waves" patented technology

The invention provides an additional locally slotted acoustic black hole board, which is mounted on a main board to be damped and comprises a black hole board main body and a damping layer, the black hole board main body is fixed on the main board to be damped and comprises a uniform thickness area and one or more acoustic black hole areas, one or more weight reduction grooves are formed in the uniform thickness area, and the damping layer is arranged on the damping layer. And a damping layer is arranged on the acoustic black hole area. According to the additional type locally-slotted acoustic black hole plate, by forming the weight reducing grooves in the non-key area of an original additional acoustic black hole plate structure, redundant materials are removed, the weight reduction of an additional structure is achieved, meanwhile, the local resonance vibration reduction effect and the energy gathering capacity of the acoustic black hole effect on bending waves are kept, and the acoustic black hole plate has the advantages of being simple in structure and convenient to use. Finally, broadband vibration control of the mainboard is achieved under the low additional mass, the overall structure meets the requirement for light weight, and the structure is particularly suitable for a plate-shaped system sensitive to the additional mass.

The invention provides an acoustic black hole structure and an acoustic black hole assembly, and belongs to the technical field of vibration noise control. The acoustic black hole structure comprises a substrate; the at least one acoustic black hole plate is located on the substrate, the acoustic black hole plate is constructed to be of an integrated gradually-shrinking structure in the thickness direction and is provided with a first surface and a second surface which face each other in the thickness direction, the sectional area of the first surface is smaller than that of the second surface, the first surface abuts against the substrate, and the second surface abuts against the substrate; a plane, which is orthogonal to the thickness direction, of the substrate is taken as a projection plane, and the projection of the second surface coincides with the projection of the substrate in the projection along the thickness direction; the damping layer is arranged on the second surface, provided with the two opposite ends in the first direction, of the acoustic black hole plate; the acoustic black hole plate is made of nonmetal. Through the combination of a non-metal material and the structure, bending waves are captured, mechanical vibration is dissipated through the arranged damping layer, and effective absorption of the bending waves in a wide frequency range is achieved.

The invention discloses a topological metamaterial for sheet bending wave isolation and a design method of the topological metamaterial. The topological metamaterial is composed of basic unit cells (1) and sheets (2). Each basic unit cell (1) comprises a regular hexagon area (1-1) and a regular triangle stand column (1-2) which are arranged on a thin plate. A topological common unit cell (3) is obtained by clockwise rotating for 0-30 degrees along the plane normal of the thin plate, and a topological non-common unit cell (4) is obtained by anticlockwise rotating for 0-30 degrees along the plane normal of the thin plate; the topological common unit cells (3) and the topological non-common unit cells (4) are alternately arranged on the thin plate (2) to form a topological metamaterial structure; the topological metamaterials arranged alternately can generate total reflection on incident thin plate bending waves, so that effective isolation of the thin plate bending waves is realized. The system has the advantages of simple design, remarkable vibration isolation effect, high expandability and the like, and is suitable for the fields of vibration prevention of building structures, vibration isolation of precise instruments, interference resistance of aerospace vehicle structures and the like.

System, methods, and other embodiments described herein relate to a high-Q resonant state embedded system in a continuous body. In one embodiment, a system includes a longitudinally extending body that is subject to a flexural wave. The longitudinally extending body is attached to a fixed structure at a first end. The system also includes a mechanical resonator coupled to a surface of the longitudinally extending body along a length dimension of the longitudinally extending body. The mechanical resonator is located at a distance away from a second end of the longitudinally extending body to exhibit an infinite Q factor based on physical properties of the mechanical resonator.

The application discloses a casing well ultrasonic bending wave logging multi-mode signal separation method, which comprises the following steps: inputting original mixed casing well ultrasonic bending wave logging data and a related parameter file; simulating A0 mode waves in the instrument centering condition; adopting a variational mode decomposition algorithm to decompose the original mixed signal into a set of multiple scale intrinsic mode functions; taking the correlation coefficient of the reconstructed A0 mode wave and the simulated standard A0 mode wave as an inversion objective function; adopting a simulated annealing method to optimize the optimal decomposition layer number and the reconstruction vector in the inversion objective function; and calculating a reconstructed A0 mode wave A' based on the optimal decomposition layer number k and the reconstruction vector v obtained by optimizing the inversion objective function. o The application can realize adaptive decomposition of A0 and S0 mode waves of a single detector in a non-axisymmetric casing well measuring environment, and can provide accurate A0 mode waves for a method for calculating wave impedance of a post-casing medium based on A0 first wave attenuation information.

Disclosed are systems and devices for absorbing flexural waves. In one example, a pair of scatterers for absorbing a flexural wave acting on a structure includes a monopole scatterer and a dipole scatterer configured to be mounted to the structure at the same location.

The invention provides an additional local slotted acoustic black hole beam, which is mounted on a structure to be damped, and comprises a black hole beam main body and a damping layer, the black hole beam main body is fixedly arranged on the structure to be damped, the black hole beam main body comprises a uniform thickness area and an acoustic black hole area which are connected with each other, one or more groups of weight reduction grooves are formed in the uniform thickness area, and the damping layer is arranged in the acoustic black hole area. The damping layer is disposed on the acoustic black hole area. According to the structure, the weight reduction grooves are formed in the non-key area of an original additional acoustic black hole beam structure, redundant materials are removed, light weight of the additional structure is achieved, meanwhile, the local resonance vibration reduction effect and the energy gathering capacity of the acoustic black hole effect on bending waves are kept, and finally broadband vibration control over the main beam is achieved under the low additional mass. And the whole structure meets the requirement for light weight, and is particularly suitable for a beam-shaped system sensitive to additional mass, and particularly suitable for vibration reduction of beam-shaped structures such as beam-shaped components in an automobile body and frame beams of aerospace vehicles.

The application discloses a honeycomb-shaped local area resonance topological insulator and an optimization design method thereof, comprising a honeycomb-shaped substrate with C-shaped openings, six pairs of oscillators with the same radius arranged on both sides of nodes, and a band gap inversion realized by changing the height difference of the oscillators, so as to construct a boundary state with different shapes. The topological transmission has backscattering suppression and channel defect immunity characteristics. Based on a particle swarm algorithm, key geometric parameters of a unit cell are optimized, and a topological insulator with a target band gap is customized. The honeycomb-shaped local area resonance topological insulator provides a new idea for flexural wave regulation, and auxiliary design is conducted in combination with a particle swarm optimization algorithm, so that the regulation range of the topological metamaterial on the flexural wave can be increased, and the vibration reduction effect can be improved.

Disclosed are systems that utilize metamaterials to improve the acoustic performance of a panel, such as a glass panel used in automotive applications. In one example, the system may include a panel having an exterior edge and a metamaterial attached adjacent to the exterior edge of the panel. The metamaterial is configured to minimize the reflection coefficient of flexural waves acting upon the panel.