210 results about "Damping ratio" patented technology

The invention discloses a harbor shore power system oscillation damping suppression method based on heuristic probability optimization. According to the method, sliding window preprocessing is carried out on an alternating current bus side current time domain oscillation signal, modal decomposition is carried out based on a Prony algorithm, and modal energy is calculated to judge an oscillation mode; the discriminated oscillation modes are aggregated and mapped into equivalent circuit elements, a corresponding three-order circuit state matrix is constructed, and the damping ratio of each mode is determined according to the characteristic value of the matrix; taking a damping ratio as an evaluation index, introducing an influence factor to construct a multi-objective optimization function, parameterizing the parallel adjustable impedance, and limiting an adjustable range; and searching the control parameters by adopting a heuristic probability optimization strategy to obtain final damping control parameters, and downloading the final damping control parameters to the parallel adjustable impedance device to realize online dynamic adjustment. According to the method, multi-modal identification, physical magnitude mapping and online adaptive optimization can be realized, and the suppression capability and the operation stability of the shore power system on sub / super synchronous oscillation are improved.

The invention relates to a large-span bridge flutter critical wind speed prediction method based on an L-P perturbation method. The method comprises the following steps that S1, physical characteristics and aerodynamic parameters of a bridge are obtained through a wind tunnel test to serve as basic data; s2, establishing a bridge motion control matrix equation based on modal displacement; s3, deriving an explicit solution of the modal frequency, the damping ratio and the modal characteristic of each modal branch based on an L-P perturbation method; s4, iteratively solving the modal frequency, directly solving the damping ratio, the amplitude ratio and the phase difference on the basis, observing the change of the modal damping ratio xi in each direction along with the wind speed U, and determining the flutter critical wind speed; the problems that an explicit closed solution of an existing three-degree-of-freedom flutter starting condition needs to carry out multiple times of iterative calculation on modal frequency, damping ratio and vibration mode, the influence of structural parameters and pneumatic parameters on pneumatic instability is difficult to clearly explain, and the flutter critical wind speed of a large-span bridge cannot be well predicted are solved.

The invention discloses a wind turbine generator blade damage judgment method and detection system based on voiceprint detection, and belongs to the technical field of wind turbine generator blade detection. The damage judgment method comprises the following steps: acquiring environmental parameters of a wind power plant, and establishing a sound velocity correction model based on the environmental parameters; acquiring a blade resonance sound signal, and correcting the blade resonance sound signal based on the sound velocity correction model to obtain a blade resonance sound signal with a high signal-to-noise ratio; performing FFT spectrum analysis on the blade resonance sound signal with the high signal-to-noise ratio, identifying the peak position of the first three-order natural resonance frequency of the blade, and performing analysis to obtain the current modal frequency, damping ratio and sub-band energy distribution entropy value of the blade; historical baselines of the modal frequency, the damping ratio and the sub-band energy distribution entropy of the blade in the healthy state are obtained, and the modal frequency offset, the damping ratio change rate and the acoustic impedance spectrum entropy of the blade are obtained; and wind turbine generator blade damage determination is carried out by using a high-precision time difference detection technology.

The invention belongs to the field of structural modal identification, and particularly relates to an automatic modal parameter identification method based on a multi-scale space, which comprises the following steps: collecting a vibration data sample from a target structure, the vibration data sample comprising an acceleration signal of the structure; selecting power spectrum calculation parameters including a window function and a fast Fourier transform (FFT) length; performing frequency spectrum estimation on the acceleration signal by using interpolation power spectrum estimation to obtain frequency spectrum data; analyzing the spectrum data by using a multi-scale space algorithm, and detecting a peak value in the spectrum data to obtain a peak value frequency; through a frequency domain decomposition method, according to the peak frequency, modal parameters of the structure are calculated, the modal parameters comprise the modal frequency and the damping ratio, interpolation power spectrum estimation and a multi-scale space algorithm are innovatively combined, automatic and accurate identification of the modal parameters is achieved, and the identification precision and efficiency are remarkably improved.

The invention belongs to the technical field of working modal analysis, and discloses a current-carrying pipeline complex modal parameter identification method and system. The method comprises the following steps: acquiring vibration responses of a plurality of measuring points on a current-carrying pipeline under load excitation; calculating a vibration response correlation function of each measuring point and the reference point; decomposing the vibration response correlation function into a series of independent intrinsic mode functions by using variational mode decomposition; dividing the intrinsic mode functions into two types: intrinsic mode functions with variable amplitude and constant amplitude; eliminating an intrinsic mode function with a constant amplitude, and establishing an intrinsic mode function matrix; performing Hilbert transformation on the intrinsic mode function matrix, and combining the intrinsic mode function matrix with a Hilbert transformation matrix thereof to obtain a signal analysis matrix; and identifying the amplitude and the phase of the complex modal shape of the current-carrying pipeline and the inherent frequency and the damping ratio of the current-carrying pipeline based on the signal analysis matrix. According to the invention, the complex mode parameters of the current-carrying pipeline in the operation state can be identified.

The utility model discloses a damping performance testing device for a particle damper, which is characterized in that a fixed end of a particle damper mounting substrate of the testing device is arranged on a fixed bracket, and a free end of the particle damper mounting substrate is arranged far away from the fixed bracket; an excitation unit is used for being connected with an excitation input point of a particle damper mounting substrate so as to send an excitation signal to the particle damper mounting substrate; a detection unit is arranged on a particle damper mounting substrate and is used for detecting acceleration change generated by an excitation signal; the control unit is used for obtaining a first modal damping ratio of the particle damper mounting substrate and a second modal damping ratio after the particle damper to be tested is placed according to a vibration frequency response curve obtained by the acceleration change. By applying the scheme, the first modal damping ratio and the second modal damping ratio are compared, so that the test precision can be effectively improved, and a good technical guarantee is provided for evaluating the damping performance of the particle damper.

The invention discloses a dynamic and static testing device and method for a flexible pressure sensor, and relates to the technical field of sensor testing. The dynamic and static testing device for the flexible pressure sensor comprises a bracket, a pressure applying mechanism, a pressure applying head assembly, a pressure applying head support frame, a sample seat and a control system, the pressure applying mechanism outputs air pressure to the pressure applying head assembly through cooperation of the vibration exciter and the air pressure rod, so that a flexible film in the pressure applying head assembly deforms and further provides pressure applying pressure for a to-be-tested sample in contact with the flexible film; controllable electric signals including constants, lines, trigonometric functions or mutual combination are conveyed to the vibration exciter through the control system, and the electric signals can be converted into corresponding pressure waves through the vibration exciter and are applied to the sample to be tested, so that multi-waveform and multi-mode self-defined pressure waves are output to the sample to be tested; and dynamic parameters such as frequency response, resonant frequency and damping ratio of the flexible pressure sensor can be accurately tested.

The invention discloses an ultrasonic welding quality online detection system and method, and belongs to the technical field of laser non-contact measurement. According to the invention, the laser vibration measurement probe is rigidly coupled to the welding head to construct a follow-up-common-optical-path measurement unit, so that synchronous acquisition of vibration signals with zero mass loading is realized; further extracting an attenuation section after welding is finished from the signal, and inverting an equivalent modal damping ratio representing an interface energy dissipation state based on an exponential attenuation model; meanwhile, multi-dimensional physical indexes such as an energy transfer efficiency index Itrans and an input stability index Iin are calculated, and in combination with an energy absorption state index, collaborative fusion is carried out through a weighted fusion formula to obtain a comprehensive quality score; and finally, realizing quality attenuation early warning based on time sequence trend analysis of a scoring sequence. On-line sensing of the deep dynamic state in the welding process is achieved, the early defect recognition sensitivity and the system anti-interference capacity are remarkably improved, and the predictive maintenance capacity of quality degradation is achieved.

The invention provides a damping method for stay cables and a main beam based on damper mounting positions, which comprises the following steps of: establishing a finite element model about the main beam and each stay cable, and performing modal analysis on the finite element model to obtain a vibration mode of each stay cable and a vibration response characteristic of the main beam; aiming at the target stay cable, determining a standard mounting interval of an external damper arranged between the target stay cable and the main beam; in the standard installation interval, the additional damping ratios of the main beam at different positions are calculated by adjusting the position of the external damper and combining the vibration amplitude change of the main beam, and the maximum value of the additional damping ratios of the main beam is selected as a target installation position; according to the step of determining the target installation position of the target stay cable, the target installation position corresponding to each external damper is obtained, and the external dampers are arranged according to the corresponding target installation positions. The installation positions of the external dampers between the stay cables and the main beam are determined, and vibration of the main beam and the stay cables is relieved most effectively.

The invention discloses a passivity-based weak power grid phase-locked loop parameter adaptive optimization method, which comprises the following steps of: (1) establishing a dynamic coupling model of a phase-locked loop and a converter system under a weak power grid condition, and analyzing an influence mechanism of phase-locked loop parameters on system stability; (2) deriving a real-time calculation method of the equivalent short-circuit ratio of the system based on a passivity theory, and constructing a short-circuit ratio-parameter sensitivity relation matrix; and (3) adaptively adjusting the bandwidth coefficient and the damping ratio parameter of the phase-locked loop by dynamically sensing the change of the short-circuit ratio of the power grid, and eliminating the harmonic oscillation or instability risk caused by the fixed parameter. According to the method, stable operation of the system under the full working condition is ensured, and the dynamic stability and robustness of the wind turbine generator under the low-short-circuit-ratio weak-power-grid working condition can be remarkably improved.

The invention provides a bearing outer ring fault diagnosis test parameter setting optimization method, which comprises the following steps of: firstly, accurately acquiring structural parameters of a bearing by utilizing a measuring tool; secondly, testing and calculating the inherent frequency and the damping ratio of the bearing in the installed state through a modal experiment; selecting test working condition parameters according to the actual operation environment of the bearing, and calculating the fault characteristic frequency of the bearing; bearing fault simulation signal band-pass filtering processing is constructed; meanwhile, constructing a fault signal equivalent model; carrying out resonance demodulation analysis on the equivalent model, extracting an envelope spectrum and evaluating a fault diagnosis effect; and finally, circularly adjusting working condition parameters, iteratively optimizing the test working conditions, and selecting the working condition with the maximum fault characteristic frequency amplitude and the minimum noise interference as the optimal test condition. According to the invention, the accuracy and reliability of bearing outer ring fault detection are effectively improved, and powerful support is provided for fault diagnosis of mechanical equipment.

The invention belongs to the technical field of low-frequency vibration control, and discloses a low-frequency low-damping tuned mass damping device which is mainly composed of a rigid support, a first sling, a rotating arm, a cable hole, a first arc guide groove, a second arc guide groove, a lock pin, a second sling, a first mass block, a spring, a second mass block and a damping element. The flexible suspension rotation replaces the bearing or ball screw support, so that the damping is obviously reduced; the long rotating arm is combined with the equivalent large-diameter arc guide groove, so that the low-frequency low-damping tuned mass damping device can achieve large vertical displacement at a small rotating angle, and damping is reduced. The low-frequency low-damping tuned mass damping device innovatively adopts double-mass-block configuration, so that static force borne by a spring is generated by mass difference, and static deformation of the spring is remarkably shortened. According to the method, low-frequency operation can be achieved under the condition that the space is limited, the low-damping characteristic is kept, it is guaranteed that the requirement for the optimal damping ratio is met, and therefore a new technical approach is provided for control over low-frequency vortex vibration of a large-span bridge.

The invention discloses a zero-damping magnetic suspension wind tunnel segment model test device, and relates to the technical field of bridge wind resistance experiments, the zero-damping magnetic suspension wind tunnel segment model test device comprises a segment model, a laser displacement meter, an adjusting device and a guide rail device, the adjusting device comprises a damping adjusting device and a magnetic suspension adjusting device, the damping adjusting device is connected with four corners of the segment model, the magnetic suspension adjusting device is arranged below the segment model, the damping adjusting device is connected with the guide rail device in a clamping manner, and the guide rail device is fixed on a top plate and a bottom plate of a wind tunnel laboratory. Magnetic suspension replaces traditional spring suspension, zero-damping suspension of the segment model in a wind tunnel test is achieved, and therefore dampers can be flexibly arranged according to test requirements, and the test damping ratio can be adjusted in a stepless mode; in addition, according to the testing device, the section proportion of the supporting device is greatly reduced, interference to airflow is smaller, and the quality of an obtained wind field is better.

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 discloses a PLC-based high-pressure-ratio magnetic suspension centrifugal heat pump control method and system, and the method comprises the steps: carrying out the self-adaptive sampling rate adjustment through collecting operation data and PLC configuration information, generating a dynamic signal matrix, recognizing a key pressure ratio control loop, and extracting vibration envelope and surge precursor frequency to generate early warning characteristic parameters; reversely adjusting the rigidity damping ratio of the magnetic bearing to determine an anti-surge protection boundary; fin temperature difference detection information is monitored, a partition defrosting map is generated through asymmetric frosting rate analysis, and minimum energy consumption analysis is executed to determine a reversing valve switching time sequence; performing operation characteristic and oil-gas migration coupling analysis to generate oil-gas separation optimization parameters, adjusting a magnetic suspension gap to extract a zero-power-consumption suspension interval, and constructing layered energy-saving control configuration; a preventive maintenance time window is generated through magnetic bearing current ripples, a fault-tolerant degradation operation mode and a self-adaptive control strategy are established, a heat pump control instruction is finally generated, and intelligent control over the high-pressure-ratio magnetic suspension centrifugal heat pump is achieved.

The invention provides a blade fault diagnosis method and device based on vibration of a wind generating set, and relates to the technical field of blade fault diagnosis of vibration of the wind generating set. The first-order modal frequency and damping ratio of the blade under different working conditions are accurately recognized through phase compensation and frequency response function calculation, modal parameters of a plurality of working condition points are connected in sequence to construct a dynamic response track, and a local mode feature vector is formed by calculating relative vectors of each point and other points in the track. And further integrating into a global mode feature matrix, obtaining a trajectory mode deviation index by calculating the Frobenius norm of the to-be-monitored matrix and the reference matrix, and judging the structural damage according to the statistical law that the index continuously exceeds the threshold.

The invention discloses a bridge modal parameter identification method based on random subspace and biaxial vehicle response, belongs to the technical field of bridge health detection, and solves the problem of precision misalignment when a traditional indirect detection method synchronously identifies the inherent frequency, vibration mode and damping ratio of a bridge. And the technical bottleneck that the modal shape is easily interfered by bridge damping is overcome. The method comprises the following steps: eliminating vehicle frequency interference based on a double-axle vehicle-bridge contact point response algorithm, identifying the frequency and damping ratio of a bridge of detection data by using a random subspace method, and identifying a bridge modal shape by using a spatial relationship between front and rear contact point responses; contact point response signals are obtained through a double-axle vehicle-bridge contact point response algorithm, interference of vehicle frequency can be effectively removed, front and back contact point response signals are processed through a random subspace method, the accurate frequency and damping ratio of a bridge can be obtained, and when the vibration mode of the bridge is recognized, the vibration mode of the bridge is recognized. And the influence of bridge damping on bridge vibration mode identification can be effectively eliminated.

The present application provides a kind of transmission conductor negative stiffness damper, provides damping by another connection damper, negative stiffness device increases damping ratio, realizes conductor model damping effect;Main components are arranged side by side by fixed magnet and movable magnet, the interaction force between its magnets is basically linear increase, that is, it can guarantee constant negative stiffness value, damping effect is obvious and model loss is small, and durability is strong;Light weight, convenient transportation, easy to install and maintain;Transmission conductor negative stiffness damper is rigidly connected with insulator string as a whole, and can effectively transmit the vibration of conductor galloping;The present application is novel and unique in design, has wide range of application, and has good popularization and application value and economic benefits.

The application discloses an inverter power three-phase short-circuit fault current analytic method considering a phase-locked loop and a current inner loop transient process, and belongs to the technical field of photovoltaic grid-connected system fault analysis. The application studies the transient process of SRF-PLL under different damping ratios, analyzes the influence of the transient process of SRF-PLL on the coordinate transformation of PCC point voltage and current, finally considers the influence of the transient process of SRF-PLL and the current inner loop on the fault current, introduces a correction coefficient, and decomposes the phase current component expressions of the inverter port fault current into the phase current components of the inverter port current under the first influence condition and the phase current components of the inverter port current under the second influence condition. Through the application, the transient characteristics of the IIDG can be more accurately analyzed, the short-circuit characteristic analysis of the IIDG is perfected, and a reference basis is provided for the fault characteristic analysis of the IIDG.

This invention discloses a method for correcting the phase difference between aerodynamic and displacement signals in wind tunnel tests based on self-excited vibration characteristics. The method includes: independently acquiring wind pressure and vibration displacement signals from the structural surface; integrating the wind pressure signal to obtain the self-excited aerodynamic time history; identifying the vibration frequency and the total system damping ratio from the displacement signal; filtering the aerodynamic time history to extract the fundamental frequency component; establishing an analytical relationship between the aerodynamic out-of-phase component coefficient and the total system damping based on the structural dynamic equilibrium principle; and iteratively shifting the aerodynamic time history using the displacement signal as a reference until the out-of-phase components satisfy the analytical relationship, thereby determining and correcting the system delay. This invention also discloses a system and storage medium for correcting the phase difference between aerodynamic and displacement signals in wind tunnel tests based on self-excited vibration characteristics. This invention requires no additional hardware and can accurately compensate for electrical triggering and physical transmission delays, effectively improving the reliability of aerodynamic parameter identification.

The application discloses a new energy base phase modifier synchronous instability analysis method and system, and belongs to the technical field of power system stability analysis. The method comprises the following steps: obtaining a training data set covering multi-dimensional power grid parameters and fault scenes, calculating dominant degree factors based on the coupling dynamic index of inverters, and dividing multiple dominant degree factor intervals to represent the control dominance of different types of inverters; a risk guardrail set containing a power coupling index and a damping ratio change amount is constructed, and a differentiated threshold is set for each interval; the control parameters of the inverters are extracted and a candidate boundary line set is generated, the performance of the candidate boundary line set is evaluated through transient simulation, the priority value is calculated by comprehensively considering the deployable proportion, the time benchmark ratio and the safety coefficient, and the optimal target boundary line is selected; finally, the target boundary line parameters are mapped into adaptive control gears, and the coordinated control of the phase modifier and the inverter is realized in combination with the real-time risk state, so that the synchronous instability risk is effectively inhibited.

The invention discloses a bridge frequency and damping identification method based on single position acceleration quadratic integral, and relates to the technical field of bridge monitoring, and the method comprises the steps: reconstructing a displacement signal of a bridge through quadratic integral operation for an original acceleration signal of a single acceleration sensor; performing modeling analysis on the original acceleration signal by using a physical information neural network model, and subtracting the displacement signal to obtain a vibration signal; and analyzing the vibration signal by using a fourth-order autoregression model, extracting and selecting conjugate complex poles which conform to the main vibration mode characteristics of the bridge, and obtaining the inherent frequency and damping ratio of the bridge. Only a single acceleration sensor is needed, and the system cost is greatly reduced. Secondly, the signal quality is greatly improved through the physical information neural network model, the inherent frequency and the damping ratio of the inherent frequency can be accurately extracted even if the four-order autoregression model is applied to a single-point response signal, and the method has the advantages of being high in noise robustness, accurate in calculation and the like.

The present application belongs to the technical field of low-frequency vibration control, aiming at the problems of high damping ratio, instability, low vibration control efficiency and unsuitable for large-scale engineering of existing inertial damper, a low-damping tuned inertial damper device is provided, which provides the possibility for the whole system to realize the required optimal damping ratio, and further efficiently controls low-frequency resonance. Unlike traditional rigid support and transmission mode, the device adopts economical, reliable and convenient flexible suspension support and transmission mode to realize low frequency and stable low damping of the system. The flexible support part and the rigid inertial device are in contact transmission around, which eliminates the high damping caused by high energy consumption due to instability caused by friction and collision in traditional inertial tuned mass damper, so as to ensure that the large inertial system realizes stable low damping ratio, meets the needs of realizing optimal control effect, and is directly applied to large engineering structure resonance control.

The invention belongs to the field of spacecraft modal testing, and particularly relates to a modal testing method based on dynamic modal decomposition in an unfolded state of a large flexible solar wing, which comprises the following steps of: S1, exciting the solar wing by adopting a pre-tightening force release method, and synchronously acquiring displacement attenuation data of different positions of the solar wing through a plurality of laser displacement sensors in a testing device; s2, performing fast Fourier transform calculation on each group of displacement attenuation data, and processing all fast Fourier transform calculation results to generate an average frequency response curve; s3, processing the displacement data by adopting a Monte Carlo delay embedding dynamic mode decomposition algorithm to obtain Q groups of fundamental frequencies, damping ratios and vibration mode results; and S4, arithmetic average is carried out on Q groups of results, and a final fundamental frequency, a modal damping ratio and a vibration mode are output. According to the method, the modal parameters are identified by adopting the Monte Carlo dynamic modal decomposition method, the fundamental frequency, the modal damping ratio and the vibration mode of the unfolded state of the large flexible solar wing can be identified, and meanwhile, the reliability of an identification result is ensured.

The present application relates to building energy dissipation and shock absorption technical field, disclose a kind of based on optimal additional damping ratio viscous damper parameter design method, including the following steps: the first-order natural frequency of non-damping structure is calculated;The vertex displacement amplitude of structure under the action of frequently occurring earthquake is calculated;The inter-story displacement amplitude of the i floor of structure arranged with damper and the corresponding inter-story displacement amplitude average are calculated;The first-order equivalent modal stiffness of viscous damper connecting component is calculated;The traversal numerical solution of damper damping index is calculated;The value of damping coefficient when additional damping ratio obtains maximum is calculated and so on step.The present application can calculate the specific value of viscous damper damping coefficient and damping index when additional damping ratio obtains maximum according to the basic parameter of structure, and the corresponding maximum value of additional damping ratio is calculated, and it has important significance to damage control and optimization design of damper parameter of viscous damper shock absorption structure under the action of earthquake.

The invention discloses a multiple-input-multiple-output bridge modal parameter identification method and device based on a corrected periodogram method power spectrum, and the method comprises the steps: obtaining a section of multi-point input excitation and multi-point output response, and equally dividing the excitation and response data according to the dimension of an excitation vector; the equant excitation and response data are substituted into a response power spectrum matrix calculation formula for separating excitation, singular value decomposition is carried out on the obtained matrix to obtain a maximum singular value curve and a singular vector, the frequency corresponding to the peak value of the curve is the inherent frequency of the bridge, the corresponding singular vector is the vibration mode of the bridge, and the maximum singular value curve is obtained. The frequency corresponding to the half of the peak value of the curve is a half-power point, and the half-power point is substituted into a damping ratio calculation formula to obtain the damping ratio of the bridge. And substituting the damping ratio, the vibration mode and the inherent frequency into a vibration mode scaling coefficient calculation formula to obtain the vibration mode scaling coefficient of the bridge. In the bridge operation modal parameter identification process, the problem that an excited autopower spectrum ill-conditioned condition is difficult to invert is solved, and the identification precision of the bridge modal parameters is improved.

The invention discloses a power system oscillation parameter identification method based on improved TVF-EMD, and the method comprises the steps: carrying out the preprocessing of an original PMU data stream, calculating a local cut-off frequency LCF through B-spline approximation, solving a signal local mean value through B-spline approximation, completing the time-varying filtering empirical mode decomposition, namely TVF-EMD decomposition, screening an effective IMF based on a correlation coefficient after the verification of a stop criterion, and carrying out the recognition of the oscillation parameter of a power system. Extracting an instantaneous frequency and a damping ratio through the TKEO; the method combines TVF-EMD with TKEO, can accurately estimate the modal parameters of the power system under the normal operation condition, including frequency and damping ratio, has robustness for the instantaneous mode characteristics in the power system under the condition of low calculation complexity, reduces the problems of modal aliasing and discontinuity easily occurring in the traditional EMD method, and improves the reliability of the power system. The method provides better performance in the aspects of predefined parameters and time-varying cut-off frequency, and is suitable for analysis of non-stationary signals.

The invention relates to the technical field of earthquake resistance of bridge engineering, and particularly discloses a railway beam bridge damping system based on metal damper coordination and a design method.The railway beam bridge damping system adopts direct displacement design based on equivalent linearization and comprises the steps that firstly, shock insulation displacement and an initial equivalent damping ratio are set as design parameters; the design displacement target is achieved within the reasonable range of the two parameters, accurate calculation can be conducted according to specific structural requirements, blind accumulation only based on the number of existing dampers in previous design is avoided, and design pertinence and scientificity are effectively improved. On the premise that different metal dampers are combined, the independent design of the equivalent damping ratio and the equivalent rigidity is achieved, the flexibility of the damping design is improved, the damping design of a common railway beam bridge is optimized, and the cost of the damping device is reduced.

The invention provides a power distribution network harmonic instability critical damping dynamic early warning method and system. The method comprises the steps that harmonic voltage and harmonic current of key nodes of a target power distribution network are acquired every first preset time; identifying the harmonic voltage and the harmonic current according to a first preset rule so as to obtain equivalent harmonic impedance under a preset harmonic frequency according to an identification result; calculating a system damping ratio corresponding to a preset harmonic frequency according to the equivalent harmonic impedance; judging whether the system damping ratio is smaller than or equal to a preset damping ratio threshold value; and if the system damping ratio is smaller than or equal to the preset damping ratio threshold value, generating a harmonic instability early warning signal. According to the invention, the accuracy and practicability of early warning can be effectively improved.

The application relates to an electromagnetic damping vibration damper, which comprises a wire clamp, a sleeve, permanent magnet hammers and springs. One end of the sleeve is fixedly connected with the wire clamp, the inside of the sleeve is provided with a buffer cavity, and the inner wall of the buffer cavity is entirely covered with an eddy current copper plate. The permanent magnet hammers are arranged in the buffer cavity along the axial direction of the sleeve, the permanent magnet hammers can slide along the axial direction of the sleeve, and a working gap is arranged between the permanent magnet hammers and the eddy current copper plate. One end of the spring is fixedly connected with the permanent magnet hammer, and the other end is fixedly connected with the permanent magnet hammer or the end of the buffer cavity. Four permanent magnet hammers and two adjacent springs are matched to form four groups of electromagnetic energy dissipation units, the natural frequencies of the four groups of electromagnetic energy dissipation units are F1, F2, F3 and F4, and the damping ratio of the four groups of electromagnetic energy dissipation units is between 0 and 1. Each group of electromagnetic energy dissipation units corresponds to an independent natural frequency, four discrete resonance frequency points are formed, and the core frequency band 0-150Hz of the overhead transmission line wind vibration is covered.