24 results about "Frequency ratio" patented technology

The invention discloses a rigid rod frequency ratio method axial force identification method. The method comprises the following steps: (1) according to engineering data, obtaining whether a rigid rod is a pressure rod or a pull rod, and obtaining related parameters of the rigid rod: the linear density m of the rigid rod, the length L of the rigid rod and the flexural rigidity EI of the rigid rod; (2) vibration signals of the rigid rod are collected on site through a vibration sensor, and multi-order frequency of the rigid rod is obtained through analysis; (3) selecting a corresponding method to calculate the frequency ratio of the rigid rod according to whether the rigid rod is a compression rod or a pull rod and boundary conditions, and calculating the axial force of the rigid rod through a frequency ratio method; and (4) checking the relative flexural rigidity xi of the rigid rod, and evaluating the axial force identification precision of the rigid rod. According to the method, a unified calculation method for identifying the axial force of the rigid pull rod and the pressing rod is established through a frequency ratio method, the method is easy to use and has good precision, and a practical new method is provided for identifying the axial force of the rigid rod.

The invention discloses a vibration control method for lifting construction of a target object, and the method comprises the steps: measuring the height of the target object at any moment, determining the mass of a damping box body, and determining the optimal frequency ratio and the optimal damping ratio of a TMD and a bearing structure based on the mass of the damping box body, the TMD comprises the damping box body and a lifting device used for lifting the damping box body, the bearing structure comprises a lifting target object and a distance measuring device for measuring the height of the target object, the suspension length of the damping box body is determined based on the height of the target object under the condition that the optimal frequency ratio and the optimal damping ratio serve as constraint conditions, and the damping box body is lifted according to the suspension length, so that the damping box body is lifted at the moment t; the suspension length of the damping box body is matched with the height of the target object so as to eliminate or weaken the vibration influence. In the construction process of lifting the target object, vibration, caused by wind loads, of the target object can be eliminated or weakened, and the construction safety is improved.

The invention provides a bridge vortex-induced vibration and flutter control TMDI parameter optimization method, which comprises the following steps of: according to a selected inertia mass ratio, obtaining optimal values of parameters under a control target by adopting a GBO optimization algorithm, wherein the optimal values are a TMDI mass ratio, a frequency ratio and a damping ratio; according to the optimization algorithm, the target function Fs converges to the minimum individual, namely the minimum TMDI mass ratio, and the minimum TMDI mass ratio and the corresponding optimal parameter, namely the optimal combination parameter. The invention further provides equipment, a storage medium and a program product. Compared with the prior art, the method has the advantages that the most economical TMDI optimization parameters can be obtained while effectiveness and robustness are considered.

The invention belongs to the technical field of bridge vibration reduction, and discloses a TMD parameter design method for modal dense bridge multi-modal vortex vibration control. Modal analysis is carried out on the target bridge, and modal frequency, vibration mode and modal mass where vortex vibration possibly occurs are extracted; then based on a modal shape amplitude threshold, screening significant extreme points of each order of modal, calculating the number of the significant extreme points, and determining the priority of TMD design according to the number from small to large; for a mode with the number of extreme points being 1, the TMD is installed at the unique position; for a mode with the number of extreme points exceeding 1, the TMD mass is split and arranged at symmetrical positions meeting the mode decoupling condition, and therefore mode coupling caused by improper installation positions is avoided. And finally, determining the frequency ratio and the damping ratio of each TMD based on a Den Hartog empirical formula. The method does not need a complex optimization algorithm, is simple in design process, and is suitable for engineering practice; and modal coupling can be effectively inhibited, and the multi-modal vortex vibration control efficiency is improved.

The application provides an alarm method, comprising the following steps: a. filtering a vibration signal to obtain a first noise signal; b. judging whether the maximum amplitude of the first noise signal is greater than a preset amplitude threshold value, and if yes, recording the first noise signal and performing step c; c. obtaining the vibration signal before the first noise signal as a background noise signal, establishing an AR model of the background noise signal, and calculating the residual error of the first noise signal and the predicted signal of the AR model; d. calculating the sequential probability ratio test parameter of the residual error, and judging whether the sequential probability ratio is greater than a preset probability ratio threshold value for multiple times, and if yes, recording the time when the sequential probability ratio is greater than the probability ratio threshold value for the first time as a suspected time; e. calculating the amplitude probability density function of the residual error, and calculating the correlation coefficient of the amplitude probability density function of the residual error and the probability density function of a standard signal; and f. obtaining a frequency ratio according to the self-power density spectrum of the first noise signal at the suspected time.

A torsional damper having reduced radiated noise from a hub is provided. The torsional damper has a value of a spring ratio relative to a resonance frequency ratio of a hub and a ring of 0.9 or more.

The invention discloses a dangerous rock mass stability evaluation method and system based on an amplitude ratio and a frequency ratio, and relates to the technical field of geological disaster risk assessment, and the method comprises the steps: collecting dangerous rock three-way vibration data and bed rock three-way vibration data in the same time interval; the dangerous rock three-dimensional vibration data and the bedrock three-dimensional vibration data are synthesized into dangerous rock one-dimensional amplitude data and bedrock one-dimensional amplitude data respectively, and the ratio of the dangerous rock amplitude standard deviation to the bedrock amplitude standard deviation is calculated to obtain an amplitude ratio; calculating the ratio of the dangerous rock peak frequency to the bedrock peak frequency to obtain a frequency ratio; and inputting the amplitude ratio and the frequency ratio as inputs into a trained dangerous rock mass stability evaluation model, and identifying the stable state of the dangerous rock mass. According to the method, the problem that the accuracy of a stability evaluation result is insufficient due to excitation and equipment temperature drift in dangerous rock mass vibration monitoring in the prior art is solved.

The present invention discloses a method for measuring the elevation of a cross-sea bridge under a surge environment. A stable measuring station platform is used to measure the elevation of the bridge. The stable measuring station platform includes a shell, a plurality of springs, and a mass block. The mass block is located in the shell, and the spring is fixed to the periphery of the mass block and the inner wall of the shell. The method specifically includes the following steps: S1, setting the frequency ratio of the horizontal vibration frequency of the completed structure to the horizontal vibration frequency of the stable measuring station platform to be ≥3; S2, measuring, based on and, setting; S3, based on the spring stiffness k and, obtaining the mass m of the mass block, based on m, designing the volume of the mass block; S4, assembling the stable measuring station platform, the stable measuring station platform is fixed on the completed structure of the conventional construction of the bridge, and adjusting the damping ratio of the mass block to 0.6≤≤0.7; S5, setting a measuring instrument at the reference point of the mass block, and measuring the bridge elevation by the measuring instrument. The present invention can realize fast and accurate real-time monitoring of offshore elevation, and significantly improve economic efficiency.

The present invention discloses a method for identifying axial forces of rigid rods using a frequency ratio method. The steps are as follows: (1) Based on engineering data, determine whether the rigid rod is a compression rod or a tension rod, and obtain relevant parameters of the rigid rod: the rigid rod linear density m, the rigid rod length L, and the rigid rod bending stiffness EI; (2) Use a vibration sensor to collect the vibration signal of the rigid rod on-site and analyze the multi-order frequencies of the rigid rod; (3) Select a corresponding method to calculate the frequency ratio of the rigid rod based on whether the rigid rod is a compression rod or a tension rod and the boundary conditions, and calculate the axial force of the rigid rod using the frequency ratio method; (4) Verify the relative bending stiffness ξ of the rigid rod and evaluate the accuracy of the axial force identification of the rigid rod. The method of the present invention establishes a unified calculation method for identifying the axial forces of rigid tension rods and compression rods using the frequency ratio method. The method is easy to use and has good accuracy, providing a practical new method for identifying the axial forces of rigid rods.

This invention belongs to the field of charging management technology, specifically relating to an autonomous docking magnetic charging management system and method. First, real-time data from a magnetic field sensor and accelerometer are acquired to determine the current environmental interference intensity. Then, based on the interference intensity, the magnetic field direction of the magnetic attraction component is dynamically adjusted, and the corresponding magnetic torque compensation value is calculated to counteract external interference. Furthermore, this method monitors the real-time displacement and current changes at the docking interface to determine if a preset docking threshold has been reached. Based on the interference intensity and displacement change, a vibration frequency ratio is calculated to further optimize the magnetic torque compensation value. When the new compensation value causes the current change rate to be below the interference threshold for three consecutive cycles, the magnetic attraction component is locked, and docking is completed. This method significantly improves the docking success rate and charging stability in complex environments, and is particularly suitable for high-precision, low-tolerance docking interface designs.

This void ratio acquisition method includes: a measurement results acquisition step of acquiring measurement results by measuring, over a predetermined time period, the voltage in a gas-liquid two-phase flow by using a probe; a frequency distribution creation step of creating a frequency distribution indicating the frequency of voltage values; a phase discrimination step of determining, as a liquid phase level voltage, the value of the voltage of a first peak which is the most frequent; a noise acquisition step of acquiring, as noise, the frequency of the value of the voltage having a small absolute value with respect to the liquid phase level voltage; and a void ratio acquisition step of taking the difference of noise from the frequency of the value of a voltage having a large absolute value with respect to the liquid phase level voltage, acquiring a frequency, from which the noise was removed, as a frequency ratio of the gas phase in the gas-liquid two-phase flow, and acquiring a frequency ratio of the gas phase as a void ratio.

The present disclosure provides a system for automatic conversion of musical pieces to natural tuning based on contextual analysis, comprising a context input module configured to receive musical context information including note distribution, melodic motifs, harmonic content, temporal dependencies, metadata, and instrument data. The system includes a learning processor configured to process the musical context information using statistical and rule-based models to identify patterns linking musical context with natural tuning relationships, incorporating harmonic relationships as dependencies under a predetermined prime-limit constraining numerical complexity of frequency ratios. The system includes an inference module connected to the context input module and learning processor, configured to convert input notes from equal-tempered tuning to corresponding natural tuning frequencies based on identified patterns and musical context information, generating output comprising natural tuning frequencies expressed as whole number relationships.

The invention discloses a frequency tuning scheme optimization method, system and equipment of a variable stiffness vibration absorber, and relates to the field of mechanical system vibration reduction. The method comprises the following steps: establishing a main vibration system dynamic model containing a variable-stiffness vibration absorber; analyzing an influence rule of a ratio of the inherent frequency of the variable stiffness vibration absorber to the external excitation dominant frequency on a main vibration system response dynamic amplification coefficient based on a main vibration system dynamic model; based on the analyzed influence rule, segmenting and intercepting the ratio of the external excitation dominant frequency to the inherent frequency of the main vibration system between 0 and 2.0 to obtain a plurality of cut-off intervals; a quadratic linear programming optimization method is adopted, the dynamic amplification coefficient serves as an optimization target, and the optimal frequency ratio of each cut-off interval is calculated to form an optimized frequency tuning scheme of the variable stiffness vibration absorber; the optimized frequency tuning scheme is adopted to carry out dynamic tuning vibration elimination on the main vibration system, and the optimal vibration reduction effect can be achieved.

The invention discloses a direct-current magnetic bias fault diagnosis method and related device for vibration signals of a high-frequency transformer, and belongs to the technical field of direct-current magnetic bias fault diagnosis. The method comprises the following steps: collecting vibration signals of the surface of a clamping piece of the high-frequency transformer under different working conditions; performing fast Fourier transform on the vibration signal to obtain the amplitude of the vibration signal under each frequency; calculating the frequency proportion of the vibration signal, the odd-even harmonic ratio of the vibration signal and the vibration entropy of the vibration signal; calculating a direct current bias judgment characteristic value based on the frequency proportion, the odd-even harmonic ratio and the vibration entropy; and comparing the direct-current bias judgment characteristic value with a preset threshold value, and judging the direct-current bias state of the high-frequency transformer. According to the method, the complexity of detection and maintenance is reduced, online monitoring can be realized under the normal operation condition of the transformer, potential fault hidden dangers can be found in advance, the defects of magnetostriction and vibration monitoring caused by direct current magnetic bias in the prior art are overcome, and the feasibility of direct current magnetic bias hidden danger detection is improved.

This optical scanning device comprises a mirror part, a first actuator, a second actuator, a first angle sensor, and a processor. The processor performs processing for deriving a first phase difference between a first drive signal and an output signal of the first angle sensor on the basis of the output signal of the first angle sensor, and changing a first drive frequency and a second drive frequency while maintaining the ratio between the first drive frequency and the second drive frequency along a preset frequency ratio line so that the first phase difference falls within a first target range. The frequency ratio line is a line representing a frequency ratio corrected on the basis of the amount of change of the ratio between a first resonance frequency in a case where the mirror part is swung around a first axis and a second resonance frequency in a case where the mirror part is swung around a second axis.

The invention discloses a mobile measurement trolley based on bridge frequency measurement and damping tuning, which comprises a system pre-starting and parameter initialization stage: a first pass pre-scanning and parameter coarse identification stage: in the stage, the trolley passes through a bridge at a constant speed, collects a vibration signal, position information and a suspension state, and extracts a bridge fundamental frequency estimated value through FFT analysis; in the damping parameter dynamic tuning stage, tuning is carried out based on the fixed point principle, the optimal frequency ratio and the optimal damping ratio are calculated, and the damping parameters are adjusted; a secondary passing fine measurement and verification stage: performing high-precision data acquisition on the trolley through the bridge again in the stage, calculating a difference value, and judging the frequency stability; in the cycle tuning and convergence judgment stage, when the frequency change rate is larger than a threshold value, the mobile measurement trolley starts a new round of tuning-measurement cycle until the requirement is met, and the technical obstacles that a traditional passive mass damper is limited by space and weight, insufficient in controllability and the like in mobile vehicle scene application are overcome.

The invention relates to the technical field of electromagnetic shielding, and provides a variable-frequency-ratio metasurface absorber which is characterized in that a first metal sheet and a second metal sheet are arranged on the upper surface and the lower surface of a substrate respectively, the second metal sheet is grounded, and the first metal sheet receives electromagnetic waves and is connected with an absorption circuit so as to selectively absorb target electromagnetic waves through the absorption circuit; the first metal sheet is provided with a fishbone-shaped groove, the fishbone-shaped groove comprises a first main groove, a second main groove and a plurality of secondary grooves, and the first metal sheet is symmetrical in the transverse direction and the longitudinal direction; the second main grooves are arranged on two sides of the first main groove and are separated from the first main groove through the connecting branches. The first main groove and the secondary groove are isolated through the second main groove and the connecting branch knot, resonance interference between the first main groove and the secondary groove is reduced, and therefore when the corresponding target absorption frequency is adjusted by adjusting the length of the secondary groove, interference on the absorption frequency corresponding to the first main groove can be reduced, and the absorption efficiency of the device is improved. And the design cost of absorption frequency adjustment is reduced.

The invention discloses a high-precision piano rhythm dividing method based on pure pitch group inspection, which comprises the following steps: S1, based on different natural pitches, selecting a pure pitch group and an actual slow frequency pitch related to a pitch to be inspected, the pure pitch group being composed of known sounds and target sounds, and the actual slow frequency pitch being composed of the known sounds and the target sounds; calculating the frequency of the target tone in the pure tone group through a target tone frequency calculation formula f01 = f02 / n; s2, based on different natural ranges, substituting the frequency of the target tone obtained in the step S1 into a natural range beat frequency calculation formula f = (f03 * a)-(f04 * b) to calculate the beat frequency of a theoretical slow frequency range; when f03 represents the frequency of the target sound, f04 is the frequency of the sound to be tested; a represents a numerator in the natural pitch frequency ratio, and b represents a denominator in the natural pitch frequency ratio; and S3, comparing the beat frequency of the theoretical slow frequency interval calculated in the step S2 with the actual slow frequency interval in the step S1, and verifying the accuracy of the to-be-verified sound by taking the theoretical slow frequency interval and the sum sound interval of the to-be-verified sound as comparison data.

The invention discloses a method for judging internal instability of a large-span suspension bridge, which belongs to the technical field of bridge engineering and comprises the following steps of: 1, acquiring section parameters and modal parameters of a bridge, and constructing a vertical-torsional coupling dynamic model of a main cable-suspender-main beam system of the large-span suspension bridge; 2, on the basis of bridge section parameters and modal parameters, vertical modal inherent frequencies of all orders and torsional modal inherent frequencies of all orders are calculated; 3, for the combination of any one vertical mode and any one torsional mode, calculating a frequency ratio, and judging whether the frequency ratio falls into a sensitive frequency ratio range of internal instability or not; 4, if the frequency ratio falls into a sensitive frequency ratio range, calculating a critical span interval corresponding to the modal pair according to an internal instability condition; 5, based on the critical span interval of each modal pair, establishing a segmented envelope line of internal instability; and 6, judging the internal instability risk of the bridge according to the subsection envelope line indexes. By the adoption of the method, the vibration risk of the large-span suspension bridge under the non-external resonance condition can be effectively recognized.

The invention belongs to the technical field of charging management, and particularly relates to an autonomous docking magnetic attraction charging management system and method.The autonomous docking magnetic attraction charging management method comprises the steps that firstly, the current environment interference intensity is determined by obtaining real-time data of a magnetic field sensor and an accelerometer, then the magnetic field direction of a magnetic attraction assembly is dynamically adjusted according to the interference intensity, and a corresponding magnetic attraction moment compensation value is calculated; therefore, the external interference is counteracted. In addition, the method also monitors the real-time displacement and current change of the docking interface, judges whether the real-time displacement and current change reach a preset docking threshold value or not, calculates the vibration frequency based on the interference intensity and the displacement change to generate a frequency ratio, and further optimizes the magnetic attraction moment compensation value. And when the new compensation value enables the current change rate to be lower than the interference threshold value in three continuous periods, locking the magnetic attraction assembly to complete butt joint. According to the method, the docking success rate and the charging stability in a complex environment are remarkably improved, and the method is particularly suitable for high-precision and low-tolerance docking interface design.

This invention discloses a vibration control method for lifting a target object during construction. The method includes: measuring the height of the target object at any given time and determining the mass of a damping box; determining the optimal frequency ratio and optimal damping ratio of a damping device (TMD) and a load-bearing structure based on the mass of the damping box; the TMD including a damping box and a lifting device for lifting the damping box; and the load-bearing structure including the target object being lifted and a distance measuring device for measuring the height of the target object. Under the constraints of the optimal frequency ratio and optimal damping ratio, determining the suspension length of the damping box based on the height of the target object; and lifting the damping box according to the suspension length, such that at time t, the suspension length of the damping box matches the height of the target object, thereby eliminating or reducing the vibration impact. This invention can eliminate or reduce the vibration caused by wind loads on the target object during the lifting process, improving construction safety.

The invention relates to the technical field of pipeline vibration reduction, in particular to a parameter optimization method of a tuned mass pipeline vibration reduction device and the vibration reduction device. The method comprises the following steps: establishing a dynamic amplification coefficient calculation model responded by a controlled pipeline structure, and applying the calculation model to obtain a simple harmonic load frequency ratio of the controlled pipeline, a frequency ratio of a plurality of shock absorbers and a corresponding relation between a damping ratio of the plurality of shock absorbers and the dynamic amplification coefficient; the frequency ratio and the damping ratio of each shock absorber are in one-to-one correspondence to form a parameter column of each shock absorber, and a dynamic amplification coefficient, the simple harmonic load frequency of the controlled pipeline and a target function associated with a parameter combination are established through a parameter combination formed by parameter column sets of a plurality of shock absorbers; and optimizing the parameter combination through an optimization algorithm. According to the method, the optimal parameters of the detector can be obtained through optimization so as to ensure that the shock absorber achieves the optimal shock absorption effect.

The invention discloses an electric pole burial depth measuring method, system and device based on knocking vibration echoes and a medium, and the method comprises the steps: applying knocking excitation to a part, exposed out of the ground, of an electric pole, and collecting a vibration response signal excited by the knocking excitation; performing spectral analysis to obtain fundamental frequency information and high-order frequency information; calculating to obtain frequency ratio information; and pre-storing frequency ratio-burial depth mapping relation information, matching the frequency ratio information with the pre-stored frequency ratio-burial depth mapping relation information, and outputting an electric pole burial depth result. Through an innovative algorithm based on frequency ratio information, the defects that a traditional method depends on archives and is low in efficiency and poor in precision are overcome; standardized excitation and vibration response signal acquisition, spectrum analysis and query output are combined, the objectivity, reliability and engineering practicability of detection are improved, the method is suitable for large-scale field general survey, and rapid, accurate and lossless burial depth measurement under the condition that the total length of the electric pole is unknown is achieved.

The present invention relates to the field of ultrasonic transducer technology, and in particular to an ultrasonic transducer driving method, device, equipment and storage medium, the method comprising: generating an initial sine wave according to excitation frequency information and a preset excitation frequency ratio, and obtaining an excitation frequency ratio according to the initial sine wave; comparing the excitation frequency ratio with the preset excitation frequency ratio to obtain a comparison result; adjusting the initial sine wave based on the comparison result, and driving a target ultrasonic transducer according to the adjusted sine wave. Since the present invention first determines the excitation frequency ratio of the initial sine wave, compares the excitation frequency ratio with the preset excitation frequency ratio, and then adjusts the initial sine wave based on the comparison result, compared to the existing square wave that carries many harmonic components, the present invention can adjust the initial sine wave based on the excitation frequency ratio of the sine wave, reduce harmonics, and thereby enable the ultrasonic transducer to operate normally and increase its service life.