122 results about "Plate wave" patented technology

A plate wave element includes a piezoelectric body, a comb-shaped electrode disposed on an upper surface of the piezoelectric body, and a medium layer disposed on the upper surface of the piezoelectric body so as to cover the comb-shaped electrode. The comb-shaped electrode excites a Lamb wave as a main wave. The medium layer has a frequency temperature characteristic opposite to that of the piezoelectric body. The plate wave element has a preferable frequency temperature characteristic.

An elastic wave device making use of an SH plate wave propagating in LiNbO₃ substrates includes a LiNbO₃ substrate, IDT electrodes located on at least one surface of the LiNbO₃ substrate, and a support which is bonded to the LiNbO₃ substrate such that the support is located outside a region provided with the IDT electrodes and supports the LiNbO₃ substrate, wherein θ of the Euler angles (0°, θ, 0°) of the LiNbO₃ substrate ranges from about 92° to about 138° and the thickness of the LiNbO₃ substrate ranges from about 0.05λ to about 0.25λ, where λ is the wavelength determined by the pitch between electrode fingers of the IDT electrodes.

A method and an apparatus for non-contact and non-invasive characterization of a moving thin sheet and in particular of a paper web on a production line. The method uses a laser for the generation of sonic and ultrasonic waves in the thin sheet and a speckle insensitive interferometric device for the detection of these waves. The generation is performed in conditions to avoid damage impeding further use of the sheet. When the generation and detection spots overlap, the method provides a measurement of the compression modulus. When the generation and detection spots are separated by a known distance and plate waves (Lamb waves) are generated and detected, the method provides a measurement of the in-plane modulus and of the tension applied to the sheet. By detecting waves propagating in various directions, either by rotating the detection sensor head or multiplexing the signals provided by several detection or generation locations, the anisotropy of the in-plane modulus is determined.

Formed Laser Sources (FLS) using pulsed laser light for generation of ultrasonic stress waves are combined with air-coupled detection of ultrasound to provide for the hybrid non-contact, dynamic and remote ultrasonic testing of structural materials, especially railroad tracks. Using this hybrid technique, multimode and controlled frequency and wavefront surface acoustic waves, plate waves, guided waves, and bulk waves are generated to propagate on and within the rail tracks. The non-contact, remote nature of this methodology enables high-speed, fill access inspections of rail tracks. The flexibility and remote nature of this methodology makes possible the detection of critical cracks that are not easy, or impossible to detect, with current inspection techniques available to the railroad industry.

The invention relates to the technical field of hydrodynamic experiment and search, and more specifically, relates to a nonlinear and multidirectional irregular wave and internal wave generating system and a control method therefor, wherein the system is used for generating high-precision nonlinear multidirectional irregular waves and internal waves in a pool. The system based on vertical multilayer and horizontal multi-plate control comprises a test pool (comprising a wave absorbing segment), a computer control drive system, a mechanical transmission system, a wave generating plate system (vertical multiple plates and horizontal multiple groups), and a wave height monitoring system. There are two fluid layers with different densities in the test pool during wave generating, or there is one fluid layer in the test pool otherwise. The system achieves the simulation of the nonlinear and multidirectional irregular waves and internal waves in the pool through the simultaneous control of a plurality of groups of horizontally arranged vertical multi-plate wave generating mechanisms and the different nonlinear vertical speed distribution of the two fluid layers or the single fluid layer, is higher in accuracy and precision, and meets the requirements of different tests.

The invention relates to the technical field of hydrodynamic experimental researches, in particular to a vertical multi-plate wave maker. The vertical multi-plate wave maker comprises a water tank, a hydraulic station, a computer control system, a support, an actuator and a wave-making plate, wherein the hydraulic station is arranged on the water tank; the computer control system is used for generating nolinear wave control signals; the actuator is connected with the support; the wave-making plate is hinged with the actuator; the computer control system is electrically connected with the hydraulic station; the hydraulic station is connected with an actuator; the actuator is used for driving the wave-making plate to perform reciprocating motion; and the wave-making plate is formed by hinging a plurality of independent wave-making plates. According to the vertical multi-plate wave maker, vertical speed distribution can be accurately input, waves which are more complex and more variable than those produced by a vertical single-plate wave maker can be produced, and the wave-making accuracy is improved; an embedded system, a programmable logic controller or an industrial personal computer can be selected as a computer control unit, and the quantity and the size of required split plates are selected according to different application requirements of control accuracy, response speed, stability and the like; and on the premise that high accuracy and high response speed are guaranteed, the flexibility and the stability of system operation are enhanced, and the repairing and maintenance costs are reduced.

The invention discloses a hydraulic driving type push plate wave making test device under a supergravity condition. A wave making unit and a wave absorbing unit are respectively arranged at the innerwalls of the left side and the right side of a model box filled with liquid; a wave making hydraulic cylinder and a wave absorbing hydraulic cylinder are respectively arranged on the outer walls of the left side and the right side of the model box; a seabed model is arranged in a groove formed between a bottom stop block of the wave making unit and a bottom stop block of the wave absorbing unit; amarine structure model is buried in the seabed model; and two sets of hydraulic driving systems outside the model box respectively provide hydraulic power for the wave making hydraulic cylinder and the wave absorbing hydraulic cylinder through a centrifugal machine rotary joint. The device is suitable for high-frequency large wave making under the supergravity condition; the push plate type wavemaking is adopted, a power conversion system from a hydraulic driving system to a wave making plate has simpler and more reliable form than a conventional wheel disc type power conversion system driven by a servo motor; and during a test process, a distance between the wave absorbing plate and the wall of the model box and an aperture ratio of the wave absorbing plate are both adjustable, the simulation of waves under different working conditions can be met, and the wave absorbing efficiency is improved.

The invention relates to a biologic detecting sensor combining surface plasma resonance with flexible plate wave that is applicable for detecting the biologic affinity reaction feature in such fields as clinic inspection, medicine screening, environment and food inspection, etc., which comprises an optic sensing component and a sound wave sensor, between which a sample pond for bearing the object to be detected is arranged. By the biologic sensor, a plurality of parameters of the object can be measured in the same test condition, and the accuracy of the physical characterization of the biologic reacting object can be greatly improved.

The invention belongs to the field of new renewable energy technologies and ocean equipment, and in particular relates to a double-swing-plate wave energy conversion device design. The double-swing-plate wave energy conversion device design comprises swing plates, generators, a truss and gear cylinders, wherein the swing plates are connected with the generators through the gear cylinders; the front and rear swing plates are connected through the truss; the entire device is fixed by connecting anchor chains to four corners of the truss. The double-swing-plate wave energy conversion device design is characterized in that the swing plates rotate back and forth under the action of waves, drive gears in the gear cylinders to rotate, and drive the generators to work to generate power through an output rotary shaft. The double-swing-plate wave energy conversion device design is applied to deep sea water areas with richer wave energy resources; the wave energy of incident waves on a vertical plane can be fully utilized by using the double swing plates, and the capturing efficiency of the wave energy is improved; the front and rear swing plates are distributed at an interval of half-wavelength, so that the stability of the device is improved; the entire device is simple in form, easy to operate, higher in reliability, and easy to install and transport.

The invention discloses a two-dimensional numerical simulation method of a tsunami wave overtopping process. The method comprises the steps that 1, the numerical water channel element form is determined according to the seawall outline; 2, initial wave height valves needed by wave pushing plate wave making are generated iteratively according to a target wave height of a tsunami wave; 3, through adirectly-discrete continuity equation and N-S equation in a lagrangian form, fluid motion is controlled, and the tsunami wave overtopping process is simulated to obtain the motion form, a flow velocity field and a pressure field of the wave; 4, the output results are calculated to obtain the maximal impact pressure value and the position of the maximal impact pressure value. By means of the method, the whole tsunami wave overtopping process and a changing process of the flow velocity field can be simulated, and the overtopping rate and the overtopping flow velocity of the top of a seawall canbe calculated to obtain the maximal impact pressure point of a seawall body and the position of the maximal impact pressure point.

An ultrasonic wave propagating method capable of propagating plate waves between a probe and a test piece despite variations in the thickness or the surface angle of a test piece, and an ultrasonic propagating device and an ultrasonic testing device using this method. Ultrasonic waves are propagated between a probe (20) for transmitting or receiving ultrasonic waves and a test piece (100) for propagating plate waves. When propagating ultrasonic waves, a probe that can set an ultrasonic wave incident angle from the probe (20) to the test piece (100) and/or an ultrasonic wave receivable angle from the test piece to the probe in a plurality of states is used. A focal point type probe may be used as the above probe (20). When this type of a probe is used, it is oriented such that an oscillating direction axis L1 in the direction of which a reference axis along the propagation route of ultrasonic waves is oscillated around the focal point of the probe crosses the propagation element surface L2 including the test piece surface of a ultrasonic wave propagation element.

The invention relates to the technical field of microwave darkrooms, in particular to a flipping cover plate for a microwave darkroom pit. The flipping cover plate comprises a cover plate body, a first telescopic mechanism and a second telescopic mechanism; a cover plate wave-absorbing material layer covers the upper side face of the cover plate body, the two telescopic mechanisms are rotationallyconnected with the cover plate main body, by means of the telescopic height difference of the two telescopic mechanisms, when the flipping cover plate is opened, the cover plate body is lifted firstand then flipped, when the flipping cover plate is closed, rotation is conducted first, then falling is conducted, interference between the cover plate wave-absorbing material layer and the nearby ground wave-absorbing material layer is avoided, the partial wave-absorbing material layer does not need to be cut off due to reserved cover plate flipping space, both the cover plate main body and the surrounding ground can be covered by the wave-absorbing material layer, and opening and closing of the cover plate main body can be controlled conveniently.

The invention discloses a composite material stiffness coefficient non-destructive recognition method based on an ultrasonic Lamb wave technology. The method comprises the four parts including direct problem theoretical modeling, sensitivity analysis, measurement of phase velocity value by experiments and stiffness coefficient inverse problem solving; for a direct problem theoretical model, the self derived novel third-order plate theory is used for solving the spread theoretical phase velocity value of Lamb waves in a composite material plate; the theory considers the plate wave stress free boundary conditions; the complicated step of shearing correction factor calculation required by the ordinary plate theory is avoided; for the sensitivity analysis, the proper spreading angle and the Lamb wave mode are selected, and are the premise for complete reconstruction of nine stiffness coefficients; the experiment uses a non-contact type laser ultrasonic system, and an advanced signal processing method is combined, so that the multi-angle waveguide phase velocity value measurement is completed; finally, an intelligent optimization algorithm is combined; the optimal solution of the composite material stiffness coefficient is obtained through the minimum experimental measurement phase velocity value and the theoretical calculation phase velocity value.