337 results about "Vibration velocity" patented technology

Disclosed are a method and system for blade tip timing measurement of full-frequency-domain vibration of a rotor blade. The method includes: identifying low-frequency, medium-frequency, high-frequency, and super-high-frequency mode parameters of the rotor blade to determine the number and mounting angles of sensors; identifying low-frequency vibration parameters based on blade tip timing according to blade tip vibration displacement; identifying medium-frequency vibration parameters based on blade tip timing according to blade tip vibration velocity; and identifying high-frequency vibration parameters based on blade tip timing according to blade tip acceleration and identifying super-high-frequency vibration parameters based on blade tip timing according to blade tip jerk. The present disclosure also provides a system for implementing the method for full-frequency-domain vibration measurement based on blade tip timing. The method for blade tip timing measurement of full-frequency-domain vibration extends the range of blade vibration frequency effectively measured by the blade tip timing technology.

The invention relates to an underground cavern surrounding rock three-dimensional vibration measurement method and device, and the method comprises the steps: generating a light spot meeting a preset clear condition through beam splitting laser; acquiring the vibration condition of the laser source and the vibration condition of the photographic lens; cutting the tracking record image of the light spot, and respectively calculating the relative displacement time history of the feature points and the boundary of the light spot; based on curvature, length and area changes of the circular light spot in different directions, a vertical relative displacement time travel curve of the light spot perpendicular to the surface of the surrounding rock of the target underground cavern is calculated; and differentiating the obtained plane and vertical displacement time histories to obtain corresponding vibration velocity time histories, and combining to construct the actual three-dimensional vibration velocity of each light spot. According to the embodiment of the invention, the monitoring cost is reduced, the field monitoring efficiency and the monitoring data volume are improved, the applicability in the construction environment with poor light of the underground cavern is higher, the defects of a high-speed photographing single lens in three-dimensional data representation are overcome, and effective monitoring and evaluation of three-dimensional vibration of the underground cavern are realized.

The invention discloses a double-row medium-length hole blasting method for a filling stope. According to the method, a theoretical value range of each blasting parameter is deduced according to field engineering practice, an ore rock blasting crushing mechanism and a blasting parameter theoretical formula. The method comprises the following steps of: constructing a stope blasting model with different hole bottom distances, explosive unit consumption and resistance line combinations by using ANSYS numerical simulation software in combination with physical and mechanical properties of ore rocks and field explosive performance parameters, and preferably selecting double-row medium-length hole blasting parameters according to a chamber effective stress distribution rule and a roof area vibration velocity peak value of the ANSYS blasting model. According to the method, by selecting the double-row optimal medium-length hole blasting parameters, it is guaranteed that ore rocks in the chamber are fully crushed, the effective stress invading the roof and the blasting vibration velocity peak value are reduced, and the roof is prevented from being damaged. And meanwhile, the explosive loading amount is reduced, the economic cost is reduced, and the production efficiency of a mine is improved.

The invention provides a grouting curtain parameter design method for structure protection under the blasting vibration effect, and relates to the technical field of underground engineering and blasting engineering, and the grouting curtain parameter design method comprises the following steps: S1, determining main factors influencing the vibration velocity of a protection structure, and constructing a vibration velocity prediction model containing an undetermined coefficient by adopting a dimension analysis white golden-han theorem; s2, establishing a finite element blasting numerical model, and obtaining structural vibration velocity data under different parameter combinations; s3, fitting the structural vibration velocity data by using the vibration velocity prediction model, and determining an undetermined coefficient in the vibration velocity prediction model; and S4, a relational expression between the structural vibration velocity and stress is established, and grouting curtain design parameters meeting structural safety requirements are determined in combination with engineering conditions. By means of the method, the problem that the grouting curtain damping effect and grouting curtain parameters are difficult to determine in actual engineering is solved, the blasting vibration peak value of the protection structure under the blasting vibration effect is effectively reduced, and a guarantee is provided for underground and ground structure protection and blasting engineering safety construction.

The invention discloses an aircraft noise source positioning method comprising the following steps: sound field signals are collected, and the sound field signals comprise sound pressure signals and three-dimensional particle vibration velocity signals; preprocessing the sound pressure signal and the three-dimensional particle vibration velocity signal to obtain frequency spectrum data; inputting the frequency spectrum data into a trained noise recognition model, and judging a noise event; when the noise event is judged to be aircraft noise, noise source positioning is carried out according to corresponding spectrum data; according to the invention, noise event identification can be carried out firstly, so that the influence of the sound source arrival direction and other noise sources is eliminated, and errors are avoided; and the sound pressure and the three-dimensional particle vibration velocity are collected for preprocessing, effective sound intensity signals are obtained for positioning, and the positioning precision is improved.

The invention relates to the technical field of data processing, in particular to an elevator operation fault detection and alarm system based on artificial intelligence. Obtaining a suspected abnormal moment according to the vibration speed curve; obtaining a mutation coefficient according to the change speed difference characteristics of the vibration speed at the suspected abnormal moment and other moments; obtaining a discrete coefficient according to discrete degree difference characteristics of three axial vibration speeds at the suspected abnormal moment and other moments; obtaining a stability coefficient according to the distribution characteristics of the three axial vibration speeds at the suspected abnormal moment and the adjacent moment; and obtaining an abnormal index of the suspected abnormal moment according to the mutation coefficient, the discrete coefficient and the stability coefficient, and determining a final abnormal moment. According to the method, the anomaly detection model is trained and constructed according to the vibration speeds of the three axial directions at the final anomaly moment, detection and early warning are conducted on the elevator anomaly according to the anomaly detection model, and the accuracy of elevator anomaly detection is improved.

The invention provides a method for measuring acoustic impedance of a material surface in situ by using an embedded microphone array. The method comprises the following steps: arranging a rectangular microphone array on the surface of a material to be measured; the microphones are divided into two groups; setting a sound wave incidence angle, arranging a sound source in a half space on one side of the surface of the material based on the sound wave incidence angle, and collecting sound pressure through two groups of microphones; respectively describing a sound source radiation sound field and a boundary reflection sound field by using two groups of spherical wave primary functions; on the basis of the two groups of spherical wave primary functions, a mass point vibration velocity component in a unit normal vector direction is obtained, and the mass point normal vibration velocity at the first group of microphones is reconstructed by using sound pressure distribution collected by the two groups of microphones; and based on the material surface sound pressure and the mass point normal vibration velocity collected by the first group of microphones, calculating the acoustic impedance rate at the first group of microphones, and averaging to obtain the surface acoustic impedance rate of the to-be-measured material. Influence of sound scattering of components on a sound field is avoided, and sound pressure measurement precision is improved.

The utility model relates to the technical field of sensors, and discloses a vibration velocity sensor for a blasting vibration meter, which comprises an auxiliary mechanism, a protection mechanism and a testing mechanism, the protection mechanism is arranged at the top end of the auxiliary mechanism, and the testing mechanism is arranged on the surface of the protection mechanism; the auxiliary mechanism comprises a mounting plate, a mounting hole is formed in the middle of the mounting plate, a connecting plate is arranged at the bottom end of the mounting plate, and a connecting screw rod is fixedly connected to the middle of the connecting plate. According to the utility model, the adjusting screw sleeve is arranged, the connecting screw rod passes through the mounting hole of the mounting plate, after the X-axis direction of the indication coordinate points to an explosion source, the sensor is fixed on the ground by using the positioning column, and the adjusting screw sleeve is rotated to adjust the distance between the connecting screw rod and the positioning column so as to adjust the inclination angle of the sensor; after it is observed that a horizontal bubble in the leveling device is located in the center, the connecting plate and the mounting plate are fixed through the fixing nuts, leveling can be completed, and convenience during leveling is improved.

The invention provides a wave finite element and boundary element mixed composite board structure sound insulation performance prediction method, and the method belongs to the acoustics field, and comprises the steps: carrying out the post-processing of a wave finite element model based on the wave finite element model of a composite board structure and a corresponding equivalent nodal force, and obtaining the wave finite element equation of the whole composite board structure; based on a sound-structure coupling equation, through a boundary element method, a discrete boundary element equation related to the surface vibration speed of the composite board and the radiation sound wave pressure is constructed; coupling the wave finite element equation and the discrete boundary element equation of the whole composite board structure, and determining the sound pressure of radiation sound waves of the composite board structure and the surface vibration speed of the composite board; and based on the sound pressure of the radiation sound wave of the composite board structure and the surface vibration speed of the composite board, obtaining a sound insulation performance prediction result by calculating the sound power of the incident sound wave and the radiation sound wave, and completing prediction of the sound insulation performance of the composite board structure. The problems that the sound transmission loss of large plates and medium-high frequency plates is difficult to predict and the calculation cost is high are solved.

The invention belongs to the technical field of acoustics, and particularly relates to an index type open-pore rigid plate internal vector sound field calculation method, program and equipment and a storage medium. According to a Webster equation satisfied by a simple harmonic plane sound source excitation sound pressure field, circular piston radiation acoustic impedance on an infinite baffle plate is adopted to represent radiation impedance at an opening of an exponential open pore, a sound field analytical solution of any depth in the open pore of the exponential open pore rigid plate is constructed, system calculation is carried out in combination with sound source conditions, and a sound field of any depth in the open pore of the exponential open pore rigid plate is obtained. Therefore, sound field quantities such as internal accurate sound pressure and vibration velocity of the exponential type open-pore rigid plate under the vertical incidence condition can be quickly solved, and sound field distribution conditions under different section change rules and different open-pore rigid plate sizes can be calculated. According to the method, the calculation complexity is low, the influence problem caused by sound field changes under the non-free field condition can be solved, and the calculation stability and reliability under the complex boundary condition are ensured.

The invention provides a big data-based material detection method and system, relates to the field of material quality detection, and solves the technical problems of insufficient detection precision and poor supply chain quality control linkage in an existing material detection method. The method comprises the following steps: transmitting sweep-frequency sound waves to warehouse-in materials of a peripheral warehouse by using a sound wave transmitting device; collecting vibration velocity spectrum data and sound pressure gradient data of the warehouse-in material after the warehouse-in material receives the frequency sweep sound wave; according to the vibration velocity spectrum data and the sound pressure gradient data, calculating a defect index of the warehouse-in material; and when the defect index is greater than a preset threshold value, marking the warehousing material as a defective material, sending a traceability detection instruction to a previous node warehouse, and starting a grading detection process of the previous node warehouse. The method and the device are used for warehousing detection, quality traceability and full-chain management and control processes of the materials in the supply chain.

The invention relates to the technical field of tunnel engineering, in particular to a method and a system for optimizing design parameters based on unsymmetrical pressure tunnel blasting excavation dynamic response. The method comprises the following steps of obtaining geological parameters and construction parameters of surrounding rock of the bias tunnel, constructing a discontinuous structure equivalent damage model, and obtaining initial stress field distribution of a rock mass in combination with the discontinuous structure equivalent damage model, the geological parameters and the construction parameters; analyzing the time-varying modified dynamic mechanical parameters, and calculating through a stress wave propagation path and an energy dissipation rule to obtain a time travel curve of dynamic stress and vibration speed of each point of the surrounding rock in the blasting process; correcting a dynamic response index by using a self-adaptive artificial boundary condition to obtain a dynamic response state characteristic; and on the basis of the initial stress field distribution of the rock mass, the time history curve and the dynamic response state characteristics, optimal design parameters are obtained according to optimal design indexes. According to the method, the balance between the blasting vibration strength and the construction efficiency is realized by optimizing and adjusting the design parameters.

The invention discloses a tunnel blasting vibration prediction method suitable for a sand shale interbed area, and mainly relates to the technical field of tunnel blasting. Comprising the following steps: S1, determining key factors influencing the vibration velocity; s2, building a blasting vibration prediction model in the sand shale interbed area; s3, carrying out data normalization processing; s4, introducing a BP neural network to train the prediction model; s5, introducing a particle swarm optimization algorithm and initializing related parameters of a particle swarm; s6, improving a particle swarm optimization algorithm; s7, a sand shale interbed tunnel blasting vibration prediction model of the improved particle swarm optimization BP neural network is obtained, the model is combined with blasting characteristic parameters of specific sand shale interbed area tunnel engineering for prediction, and a blasting effect prediction result is obtained; according to the method, important theoretical guidance can be provided for blasting vibration prediction of the stratified structure with changeable rock strata, and a practical safety evaluation tool is provided for ground surface vibration velocity control of similar projects.

The invention discloses a method for judging the safety state and interference construction of a buried gas pipeline based on vibration waveforms. The method specifically comprises the following steps: S1, establishing a vibration waveform database of the buried gas pipeline at the cross construction section through a large amount of monitoring data; s2, vibration monitoring is carried out on the buried gas transmission pipeline in the cross construction section, and a vibration speed measured value and a vibration speed threshold value of the buried gas transmission pipeline in the cross construction section are compared to judge the safety state and the interference construction type of the buried gas transmission pipeline in the cross construction section; and S3, the judgment result is transmitted to an early warning platform for early warning. According to the method, the effectiveness, accuracy and reliability of safety state judgment of the buried gas pipeline can be improved, early warning can be performed in time, main factors possibly influencing safety operation of the pipeline can be clearly determined, a reliable basis is provided for later control, and the situation of one-step construction beside the pipeline is avoided.

The invention discloses a non-linear static analysis method for influence of blasting vibration on surrounding buildings based on field measurement vibration velocity, and belongs to the technical field of engineering blasting. The safety evaluation method comprises the following steps: step 1, field detection and data acquisition; the vibration velocity condition of the target structure and a blasting seismic wave velocity vibration curve of the blasting at the target structure are obtained; 2, calculating a structure inelastic quasi-absolute acceleration-relative displacement SA, e-SD, e curve, namely a demand curve of a target structure; 3, establishing a multi-degree-of-freedom structure model, performing static pushing analysis on the multi-degree-of-freedom structure model to obtain a load and displacement response relation V-D curve of the structure, and performing deformation to obtain a capacity curve of the equivalent SDOF structure; and 4, moving the demand curve and the capability curve of the target structure into the same coordinate system, wherein the intersection point of the demand curve and the capability curve reflects the local damage condition of the structure. By adopting the method, whether the structure is integrally damaged or not can be judged, and the local damage condition and position can be analyzed.

The invention provides a non-free field sound source localization method, a storage medium and computer equipment. The method comprises the following steps: setting a measurement surface; constructing a virtual sound source; performing spectral analysis on the sound pressure data; establishing a mathematical model; calculating a sparse base; establishing a sparse base model; calculating the boundary vibration velocity of the target sound source; and forming an acoustic image. The technical scheme of the invention is easy to implement and low in cost, and can be widely applied to the technical field of sound field separation and noise positioning.

The invention discloses an ultrasonic viscoelasticity measurement method, device and equipment and a medium, and relates to the field of shear wave elasticity imaging. The method comprises the following steps: establishing a non-uniform viscoelastic wave equation; encoding the non-uniform viscoelastic wave equation into a loss function, and constructing a physical information neural network; the physical information neural network comprises a space-time neural network and a space neural network; the space-time neural network is used for predicting a stream function; the non-uniform viscoelastic wave equation obtains the vibration speed of the mass point in the vertical direction according to the output flow function; the spatial neural network is used for predicting shear modulus and viscosity; the loss function calculates the total loss according to the vibration speed, the shear modulus and the viscosity of the mass point in the vertical direction; and inputting a physical information neural network to obtain shear modulus spatial distribution and viscosity spatial distribution of the to-be-measured object by taking the multi-frame particle vertical vibration velocity of the to-be-measured object as data supervision. According to the method, the shear modulus spatial distribution and the viscosity spatial distribution can be accurately estimated, and the elasticity prediction precision is improved.

The invention discloses a laser piston sounder normal vector microphone low-frequency calibration device and method, and solves the technical problems that the calibration frequency range is limited, the model dependence is strong and the environmental noise interference is obvious in a low-frequency band in the existing vector microphone calibration method. The device comprises a piston sounder, a laser interferometer, a vector microphone and a data acquisition system, the piston sounder comprises a piston, an excitation source and a piston cavity, an end cover of the piston cavity is provided with an optical window, and the laser interferometer measures the movement speed and displacement of the piston through the optical window; the vector microphone is hermetically coupled to the piston sounder from the side wall of the piston cavity through the adapter; and electric signal outputs of the laser interferometer and the vector microphone are connected to an input channel of the data acquisition system. The calculation model of the sound pressure and the particle vibration velocity in the piston sounder is clear, does not depend on the type of a piston excitation source, and is high in universality.

The invention discloses a flow-induced vibration velocity effect similarity method based on an equivalent mode, and belongs to the field of aircraft structure dynamic strength optimization. According to the method, the scaling model is established, the flow velocity difference caused by different sound velocities of the scaling model and the full-size model is considered at the same time, a new thickness scaling factor is established in combination with the velocity ratio on the basis of a length scaling factor, and the structural vibration parameters of the full-size model are predicted through the scaling model. The influence caused by flow velocity difference can be made up, the characteristic frequency and the structural response of the full-size model can be accurately predicted through the scaling model, and the flow-induced vibration velocity effect similarity prediction precision based on the equivalent mode is improved. According to the method, a complex structure characteristic frequency is changed into a similar form only containing the combination of a thickness scaling factor and a length scaling factor through an equivalent modal method, and a curved plate flow-induced vibration structure response similar expression is deduced, so that the defects of a current flow-induced vibration similarity theory are overcome; and the prediction reliability of the aircraft structure dynamic response similarity method is improved.

The invention discloses a high-speed dragging device and method applied to a permanent magnet synchronous servo motor vibration test, and relates to the technical field of motor vibration tests. The motor testing device comprises a testing platform arranged on a testing box and a motor to be tested, a driving roller is arranged at the driving end of the motor to be tested, and the motor testing device further comprises a positioning testing unit which comprises a positioning assembly and a testing assembly; and the dragging load unit comprises a loading assembly, a damping assembly and an accelerating assembly. The device has the advantages that the vibration speed test and the overall displacement vibration test of the driving end of the to-be-tested motor can be synchronously carried out, the flexible adjustment of the load capacity can be realized in a non-stop dragging state, the test efficiency can be improved, the test sample data can be increased, the precision of the test result is improved, and the test cost is reduced. And meanwhile, effective damping can be carried out when the load is adjusted, vibration is prevented from being transmitted to the motor to be tested to influence the accuracy of a test result, and the test precision is higher.

The invention discloses a woodworking machine tool noise sound power level measurement method based on a sound intensity method, and belongs to the technical field of machine tool noise measurement, and the method specifically comprises the steps: determining a housing surface covered by a tool rotation plane projection as a main sound radiation region, and determining a main bearing pedestal installation surface as an infrasound radiation region; sound pressure, vibration acceleration signals and dynamic air pressure signals of a main sound radiation area are collected; resampling a dynamic air pressure signal rotation angle domain, extracting a reference pneumatic pulsating waveform synchronous with tool tooth sweeping, and establishing an airflow induced sound pressure model according to the reference pneumatic pulsating waveform and a phase relation; calculating a surface normal vibration speed according to the vibration acceleration, and establishing a structure radiation sound pressure model in combination with a sound wave equation; decomposing the sound pressure signal to obtain two types of component estimation values, and performing parameter optimization to obtain net sound intensity of a main sound radiation area; extracting vibration frequency band energy of an infrasound radiation area, calculating equivalent sound intensity by combining a sound radiation efficiency model, and outputting a total sound power level by space integration; the invention provides an effective method for accurately measuring and controlling the noise of the woodworking machine tool.

The invention discloses a method for identifying blade surge characteristics based on blade tip vibration velocity, and relates to the technical field of non-contact measurement of rotating machinery rotor blades. According to the method, the vibration speed and the vibration displacement of the blade tip are monitored according to the two blade tip timing sensors installed in a small angle difference mode, the theoretical arrival time of the blade does not need to be considered when the vibration speed and the vibration displacement of the blade tip are calculated, and the calculation efficiency and the calculation accuracy are greatly improved; in combination with the time-frequency enhancement characteristic of a synchronous compression wavelet transform method, the dominant subsynchronous frequency of the blade is tracked and identified through the blade tip vibration speed, and meanwhile, a frequency ridge line is extracted for surge frequency identification and a surge interval is positioned; and finally, the vibration intensity during blade surge is judged according to a proposed intensity quantized value calculation method based on the blade tip vibration speed. The method for efficiently calculating the blade tip vibration parameters is provided, the surge frequency can be quickly recognized, the surge interval can be positioned, and the surge intensity can be quantitatively evaluated.

The invention discloses a method for rapidly and accurately judging a blasting vibration safety allowable distance, and belongs to the technical field of geotechnical engineering blasting. The method specifically comprises the steps of establishing a simplified mathematical model of explosive wave propagation and an explosive wave propagation control equation; basic mechanical parameters of rocks of the blasting engineering are obtained; obtaining a blast hole wall stress wave action time history curve; solving the explosion wave propagation control equation to obtain a radial stress complex variable function and a mass point displacement complex variable function at any moment around an explosion source; obtaining a radial stress time domain variable function and a mass point vibration velocity function; constructing a characteristic function relationship between a radial stress peak value and a mass point vibration velocity peak value, introducing a peak value stress wave propagation attenuation function, finally obtaining a mass point peak value vibration velocity, and drawing a mass point peak value vibration velocity distribution curve; and the blasting vibration safety allowable distance is obtained. According to the method, the blasting vibration safety allowable distance conforming to the specification can be rapidly and accurately calculated, the calculation efficiency is high, and the prediction result is accurate.

The invention relates to a blasting vibration prediction method and system based on an integration algorithm, and belongs to the technical field of blasting engineering. The method comprises the following steps: obtaining a blasting vibration case database; correlation analysis is conducted on the blasting design parameters, the geological parameters and the blasting particle peak vibration speed, and prediction model input variables are determined; by calculating prediction results of a single gradient enhanced regression device, a single random forest regression device and a single decision tree regression device, integrating three base regression devices by adopting a voting algorithm, and generating a prediction model; optimizing hyper-parameters of the prediction model by using a genetic algorithm and nested 5-fold cross validation to obtain optimized hyper-parameters; a trained GA-VR model is obtained; according to the prediction model input variable, obtaining prediction sample data; and inputting the prediction sample data into the GA-VR model to obtain a prediction value. According to the method, high-precision blasting particle peak vibration velocity prediction can be realized, and the technical problem of errors caused by low precision of a traditional prediction model is solved.

The invention discloses a high-precision identification method and system for a noise source of an asynchronous motor, and relates to the technical field of asynchronous motor detection, and the method comprises the following steps: constructing a finite element model of a to-be-analyzed asynchronous motor, dividing the surface into a plurality of detection sub-regions, and carrying out the operation simulation of the finite element motor, analyzing vibration speed and sound pressure signal data of each sub-region, synchronously acquiring actual signals, calculating relative differences with simulation data, evaluating detection priorities by combining historical fault times, forming a detection sequence according to the priorities, and sequentially performing sound-vibration coherence analysis and coherence function calculation to obtain a sound-vibration coherence detection result; according to the method, noise frequency bands are classified into structural noise and air noise, order tracking analysis is performed on the structural noise obtained through classification, an amplitude stability index and an amplitude change gradient are calculated, automatic classification and identification of electromagnetic noise and mechanical noise are realized based on a preset threshold value, and the efficiency and accuracy of fault processing are remarkably improved.

The invention discloses an airspace guiding covariance matrix self-adaptive beam forming method based on sound pressure and vibration velocity combined processing, belongs to the field of underwater acoustic detection, and particularly relates to the airspace guiding covariance matrix self-adaptive beam forming method. The objective of the invention is to solve the problem that when sound pressure and vibration velocity three-channel data are used, the SSTCM algorithm cannot carry out azimuth estimation in a specific angle range. The method comprises the following steps: 1, constructing a vector double-row array receiving data model; 2, obtaining a combined vibration velocity Vc (t); 3, based on the combined vibration velocity Vc (t) and the sound pressure channel data P (t), constructing a sound pressure and vibration velocity covariance matrix in a (P + Vc) (P + Vc) combined form; 4, calculating an airspace guiding covariance matrix based on the sound pressure vibration velocity covariance matrix and the observation orientation; and 5, estimating a direct current component in the airspace guiding covariance matrix as an orientation estimation result.

The invention discloses an underwater sound absorber with low-frequency broadband sound absorption and high pressure bearing performance and a design method of the underwater sound absorber. The sound absorber comprises a plurality of hexagonal honeycomb units which are spliced in sequence. Each honeycomb unit is composed of a hexagonal metal honeycomb framework, a rubber coating, a special-shaped embedded neck part and a cavity. The hexagonal honeycomb framework forms a hexagonal cylindrical cavity, the side wall and the bottom plate of the honeycomb framework are coated with the rubber coating, the acoustic impedance of the rubber coating is matched with the underwater acoustic impedance, and sound wave energy can be effectively absorbed. The special-shaped embedded neck part is embedded into the cavity of the honeycomb framework, and the neck part structure protrudes inwards, so that the vibration velocity and the hot sticking loss of sound waves are remarkably improved. The cavity is formed by a honeycomb framework and a rubber coating and used for storing sound energy and providing a resonance space. Multi-path dissipation and broadband sound absorption of sound energy are achieved through viscoelastic dissipation of the rubber coating and hot viscous loss of the special-shaped embedded neck part, and the composite material has remarkable potential application value in the field of underwater low-frequency noise control.

The invention provides a method and system for determining time delay between auxiliary hole subsection detonating network sections, and belongs to the technical field of tunnel blasting design. A single-hole blasting experiment and blasting experiments with different explosive loads are carried out to obtain the change relation of the single-hole vibration speed along with time and the relation between the explosive loads and the waveform vibration speed peak value, and the time delay of the auxiliary hole subsection detonating network sections is determined according to the change relation of the single-hole vibration speed along with the time. And determining a peak value of the explosive load based on a safe vibration velocity threshold value, meanwhile, setting inter-section delay and inter-row delay of the same row based on an auxiliary hole same-row segmentation mode, an inter-row segmentation mode of auxiliary holes and a blasting sequence, constructing a single-section blasting vibration waveform function, and carrying out superposition and calculation on multi-section vibration waveforms of the same row, so as to obtain a multi-section blasting vibration waveform. According to the method, the optimal delay time between the same-row segmental blasting segments is determined, then the optimal delay time between the rows is determined by constructing a single-row blasting vibration waveform function and carrying out multi-row vibration waveform superposition and calculation, finally, a blasting delay scheme is generated, and accurate control over blasting vibration is achieved.

Disclosed herein are embodiments of an apparatus for detecting hydraulic shock events in a fluid system, the apparatus comprising a vibration sensor operable to output a vibration sensor signal indicative of sensed vibrations of one or more components of the fluid system, and a processing unit configured to: obtain a vibration velocity signal from the vibration sensor signal, the vibration velocity signal being indicative of a vibration velocity of the one or more components of the fluid system; detect one or more peaks in the vibration velocity signal; and classify one or more of the detected peaks as a hydraulic shock event.

The invention discloses a graded blasting construction method for a shallow-buried soft rock tunnel sensitive section. The method comprises the steps that measuring points are arranged in a tunnel chamber, a ground surface non-cavity section and a cavity section, and blasting vibration data are obtained; peak vibration velocity prediction models are established in a partitioned mode, an attenuation model is adopted in a chamber, a correction term is introduced into a non-cavity section of the earth surface to correct the attenuation model, and a multivariable model is established for the cavity section through dimensional analysis by integrating the horizontal distance, the elevation difference, the explosive quantity, the rock mass density and the tensile strength; determining a ground surface vibration velocity safety threshold, and quantifying a cavity vibration velocity amplification coefficient and an influence range thereof; based on the peak vibration velocity probability distribution and a preset safety level, establishing a safe dose prediction model and a safe range model; and dividing control areas according to the model, and implementing graded construction. According to the method, the vibration propagation law can be accurately described, the cavity amplification effect can be quantified, dynamic prediction of the blasting safety explosive quantity and range is achieved, and disturbance of blasting vibration to surrounding rock is effectively controlled through hierarchical management and control.