1130 results about "Natural frequency" patented technology

The invention discloses a large-span bridge vibration response prediction method based on data driving, and relates to the technical field of bridge vibration response prediction, and the method comprises the following steps: arranging a plurality of sensors at a plurality of key structure parts of a bridge, collecting vibration response data of the bridge during operation in real time based on an initial sampling frequency set based on the inherent frequency of the bridge structure; performing frequency domain analysis on the collected vibration response data, extracting a main excitation frequency component under the current working condition, and constructing a current excitation frequency spectrum; the method comprises the following steps: calling structural modal parameters obtained in a design stage, a static load test or a modal test of a bridge, extracting the natural vibration frequency of each order of structure, and constructing a bridge inherent frequency feature library; according to the method, the resonance state is dynamically identified through frequency domain analysis and the fuzzy risk index, the sampling frequency is intelligently adjusted, high-frequency response accurate capture and resource efficiency optimization are realized, and the sensitivity, the real-time performance and the safety of a bridge health monitoring system are remarkably improved.

The invention relates to the technical field of road surface detection, in particular to a road surface skid resistance detection system based on multi-feature fusion, which comprises the following steps: applying broadband sweep frequency excitation by using a frequency modulation vibration sensor, matching with the inherent frequency of road surface texture to generate local resonance, and collecting the temperature, humidity and rainfall of a road surface in real time; performing fast Fourier transform on the collected vibration signals to obtain a resonance response spectrum, extracting key parameters through Gaussian fitting, and fusing frequency domain, material and environment data to form a comprehensive feature set; the frequency domain features are converted into three-dimensional energy distribution of pavement microtextures, the actual contact area ratio is calculated according to the three-dimensional energy distribution, an environment temperature and humidity compensation factor is introduced, and a dynamic friction attenuation coefficient is calculated; and comparing the calculated dynamic friction attenuation coefficient with a third-level safety threshold, and outputting a corresponding anti-skid performance level. Multi-source data fusion enables a detection result to be more fit with an actual driving scene, and misjudgment caused by single data is avoided.

The invention discloses a curtain wall structural adhesive damage detection method and device based on modal difference and digital twinning, and belongs to the technical field of digital twinning structural adhesive damage detection and evaluation. The problem that in the prior art, a traditional glass curtain wall structural adhesive damage detection and evaluation method based on the first-order inherent frequency is not sensitive to local boundary adhesive failure, and consequently the specific damage position cannot be positioned is solved. The method comprises the following steps: acquiring vibration data of a group of hidden framing glass curtain walls to be detected and a group of hidden framing glass curtain walls in a lossless state to obtain normal acceleration time history data; primarily screening second-order and third-order inherent frequencies, and judging whether the structural adhesive is damaged or not according to a difference constraint condition; further positioning the damage by using the boundary relative curvature modal difference, and judging whether the current measuring point is a damage point or not; and constructing a digital twinborn model and damage early warning, and outputting a parameter report and a visual damage evaluation result. The method effectively improves the boundary damage positioning precision, and can be applied to glass curtain wall structural adhesive damage detection.

The invention discloses an ML-based rear subframe structure lightweight and modal optimization target design method, which comprises the following steps: (1) through three-dimensional modeling, statics analysis and modal analysis, constructing a mathematical model corresponding to the weight of a rear subframe and first-order inherent frequency simulation; (2) generating a population based on a Maximin criterion and a Latin hypercube, and establishing a radial basis function machine learning model; (3) generating candidate offspring individual vectors by adopting a Pbest-driven DPM evolutionary strategy based on an Eplison function; (4) constructing a minimum and maximum Pareto front lifting function to screen real offspring individual vectors; and (5) performing simulation evaluation on a real offspring individual vector, adaptively switching the reference vector type based on a reverse generation distance updating condition, returning to the step (3) until an optimization target meets a design requirement, and outputting an optimal optimization design parameter value. According to the method, the evolution direction is adaptively adjusted according to the population simulation result, and the optimization design effect on the two targets of lightweight and modal optimization is good.

The invention discloses a continuous feeding manipulator control method which comprises the following steps: constructing a finite element simulation model aiming at each joint of a mechanical arm and a tail end execution structure, acquiring inherent frequency distribution data of the structure under different load states and posture working conditions, and generating a frequency sensitive area parameter set based on the data. The method has the advantages that the track segment exciting the resonance risk can be recognized before the path is executed, the inherent frequency of the structure is effectively avoided through frequency matching and path reconstruction, the dynamic adaptability is improved, and pose offset and structural fatigue caused by resonance are prevented. Meanwhile, the system has the self-adaptive closed-loop optimization capacity, disturbance injection testing and periodic response verification are combined, the structure state can be monitored in real time, path re-optimization can be triggered, the stability and precision of the mechanical arm in continuous high-frequency operation are ensured, and the overall reliability and intelligent level of a production line are improved.

A computer implemented method for on-line monitoring a structure, the method comprising: receiving (151) at least dynamics data (204) of dynamic variables representing a dynamic response of the structure from a plurality of sensors (10), the dynamic response of the structure being generated when the structure has been subjected to an excitation; detecting an impulse (152) created by said excitation by identifying a free load response (208) of the structure from said at least dynamic data (204); obtaining (153) a set of poles (210) comprising pairs of a natural frequency and a damping factor of the structure from the free load response (208); generating (154), using a non-supervised machine learning algorithm, a probability-based baseline model for the structure using a plurality of said poles (210) obtained along a certain period of time, the probability-based baseline model associating in a probabilistic way the dynamic variables affecting the structure and providing a plurality of baseline parameters (214); every time a new impulse is detected and a new set of poles (211) are obtained from the free load response of said impulse, feeding (155) the new set of poles (211) to a concept drift algorithm to obtain a KPI (217) of the structure.

The invention relates to the technical field of flutter, and particularly provides a flutter stability prediction method and device, equipment, a storage medium and a program product. The flutter stability prediction method comprises the following steps: dividing a flow field grid and a solid grid based on a gas compressor geometric model; on the basis of the solid grid, finite element modal analysis is executed to obtain intrinsic mode data, and the intrinsic mode data comprises inherent frequency and intrinsic mode distribution thereof; based on the flow field grid, the intrinsic mode data and preset circumferential air inlet distortion parameters, executing unsteady numerical simulation so as to determine first aerodynamic work under single-node diameter vibration; based on the phase angle between the blades and the first aerodynamic work, second aerodynamic work under all node diameter vibration is determined, and aerodynamic damping under all node diameter vibration is determined based on the second aerodynamic work; based on the aerodynamic damping, flutter stability is predicted. According to the technical scheme, the prediction speed of the flutter stability can be increased.

The invention provides an acoustic coalescence elimination method for hydrogen bubbles in molten aluminum, and belongs to the technical field of molten aluminum bubble elimination. According to the method, sound field collaborative focusing is achieved by arranging a phase control array transducer set in a molten aluminum smelting furnace, primary gathered sound waves and efficient coalescence sound waves are applied in stages according to bubble size evolution in a double-frequency scanning mode, and the hydrogen bubbles in the molten aluminum are eliminated. A target frequency is dynamically adjusted in combination with a bubble resonance frequency optimization model to match the inherent frequency of a bubble, a sound-bubble coupling dynamic tracking system is used for monitoring bubble evolution triggering stage switching in real time, and a sound field focus point dynamically scans and covers a three-dimensional space area through phase delay control. A delay detection method is adopted to eliminate cavitation bubble interference and accurately measure the hydrogen content, sound intensity and frequency parameters are optimized according to a sound field parameter self-adaptive regulation and control model, and the technical problem that hydrogen bubbles in a molten aluminum deep area are difficult to be effectively driven by sound waves and cannot be fully coalesced and eliminated is solved.

The invention discloses a method for correcting a predicted value of inherent frequency of a bridge under an operation condition, and belongs to the technical field of bridge monitoring, and the method comprises the following steps: S1, collecting bridge data; s2, data preprocessing; s3, environment and load interference decoupling is carried out; s4, constructing a model; s5, correcting the AI driving model; s6, verifying and iterating the mechanism; according to the method, breakthrough is made in three aspects of environmental interference stripping, parameter dynamic optimization and intelligent algorithm iteration, so that the prediction precision is improved, the engineering efficiency is optimized, the safety is ensured, the environmental interference stripping technology can effectively eliminate external environmental noise, and the accuracy of prediction data is ensured; a parameter dynamic optimization technology can dynamically adjust model parameters according to real-time data, so that a prediction result is closer to reality; the intelligent algorithm iteration continuously optimizes the model through machine learning and improves the intelligent level of prediction, and the method of updating posteriori distribution through Bayesian is adopted, so that the prediction model can be continuously corrected according to newly acquired data, and the prediction accuracy is ensured.

The invention provides a ship weld joint stress deduction and fatigue damage evaluation method and system, and the method comprises the steps: firstly building a finite element model of a container ship, calculating the inherent frequency of the finite element model and a corresponding vibration mode through employing a Lanczos algorithm, and forming a plurality of free vibration modes of the finite element model; the inherent frequency of each free vibration mode is compared with a preset frequency range, and the free vibration mode in the preset frequency range is reserved and serves as a basic mode; calculating a theoretical stress distribution field of the whole ship structure in each basic mode based on the vibration mode through a strain-displacement relation equation and a material constitutive equation, arranging a plurality of stress monitoring points and weld joint evaluation points, and performing inversion by adopting a mode superposition method to obtain stress values of the weld joint evaluation points; and finally, calculating a total fatigue damage value by adopting a rain flow counting method and combining a fatigue evaluation method, and evaluating whether the total fatigue damage value is reliable or not, thereby facilitating the realization of long-term fatigue life management of the welding seam area.

The invention discloses a structural damping ratio identification method and device considering frequency spectrum leakage error compensation. The method comprises the following steps: firstly, obtaining a cut-off free attenuation signal under impact vibration, and carrying out Fourier transform on an autocorrelation function and a cross-correlation function of the signal to obtain a response power spectral density matrix influenced by a spectrum leakage error; singular value decomposition is carried out on the response power spectrum density function through a frequency domain decomposition method to obtain a damping ratio and an inherent frequency, a spectrum leakage error is calculated through the calculated inherent frequency and the damping ratio, and the error obtained through calculation is substituted into an output power spectrum. And the inherent frequency and the damping ratio are identified by using the power spectrum after the frequency spectrum leakage error is compensated, and the above process is iterated for multiple times, so that the frequency spectrum leakage error in damping ratio identification can be compensated. When the free attenuation data is used for identifying the damping ratio, spectrum leakage errors caused by data truncation can be made up, the signal-to-noise ratio of the data can be improved, the influence of noise can be reduced, and the identification precision of the damping ratio is improved.

The application discloses a curtain wall structure adhesive damage detection method and device based on modal difference and digital twinning, and belongs to the technical field of digital twinning structure adhesive damage detection and evaluation. The application solves the problem that the traditional glass curtain wall structure adhesive damage detection and evaluation method based on the first-order natural frequency cannot locate the specific position of damage due to the insensitivity to local boundary delamination. The application collects vibration data of the test group of hidden frame glass curtain walls and the non-damage state group of hidden frame glass curtain walls to obtain normal acceleration time history data. The second-order and third-order natural frequencies are preliminarily screened, and whether the structure adhesive is damaged is judged through the difference constraint condition. The boundary relative curvature modal difference is used to further locate the damage, and whether the current test point is a damage point is judged. A digital twinning model and damage early warning are constructed, and a parameter report and a visual damage evaluation result are output. The application effectively improves the boundary damage positioning accuracy and can be applied to glass curtain wall structure adhesive damage detection.

The invention relates to a composite vibration feeding device and method suitable for a seed color sorter, and the composite vibration feeding device comprises a stock bin, a feeding device arranged below the stock bin, and a vibration device for promoting the feeding device to vibrate; the feeding device comprises a receiving disc and a feeding disc; the driving end of the vibration device is connected with the material receiving disc; one end of the feeding disc is connected to the receiving disc through an elastic structure, and the other end of the feeding disc is a free end. The feeding disc is provided with a plurality of sets of conveying channels arranged in the direction perpendicular to the conveying direction of materials. The difference value between the vibration frequency output by the vibration device and the inherent frequency of the feeding device is controlled to be within the preset range so as to excite modal resonance of the feeding device, and the modal resonance and the vibration effect of the vibration device are coupled to form composite vibration. The materials are promoted to be converted into a single-layer and single-row arrangement state from a stacked state through the compound vibration, and meanwhile the materials continue to move towards a discharging port of the feeding device.

The embodiment of the invention relates to a modeling and nonlinear vibration analysis method for a cone-column combined shell connected by a bolt and a flange. The method comprises the following steps: establishing a three-dimensional model of the bolt flange connection cone-column combined shell, performing simulation pretreatment on the model to obtain a finite element model of the bolt flange connection cone-column combined shell, setting parameters, applying acceleration excitation, and performing state setting; simulating calculation is conducted on the inherent frequency, the vibration mode and the structural vibration response under different excitation amplitudes under the set tightening torque, and a simulation result is verified through a modal test and a basic excitation response test; the dynamic softening phenomenon of an amplitude-frequency curve is explained from the two aspects of contact stress and contact state of a bolt flange connection interface; and analyzing the influence rule of the excitation amplitude, the bolt pre-tightening force and the flange thickness on the nonlinear vibration characteristic of the structure. According to the method, a finite element model is adopted and is combined with a test for comparative research, the modeling method is accurate in calculation result, and the modeling requirement of a complex actual structure can be met.

A method for rapidly calculating the interface slip of a steel-concrete composite beam under vehicle dynamic loads relates to the technical field of bridge construction. The method comprises the following steps: calculating the first n natural frequencies of a simply supported steel-concrete composite beam based on basic bridge parameters; calculating the circular frequency of vehicle dynamic loads; calculating the bridge's natural frequencies and critical damping frequencies taking into account the influence of damping; calculating the introduction parameters; calculating the interface slip under vehicle dynamic loads taking into account the first n vibration modes; determining convergence; and calculating the interface slip under multiple vehicle dynamic loads. Based on the Timoshenko beam theoretical model, and taking into account the material, cross-section, and connector stiffness, a formula for calculating the interface slip of a simply supported steel-concrete composite beam under vehicle dynamic loads is proposed. This formula enables rapid and accurate calculation of interface slip without relying on numerical simulation or field testing.

The invention discloses a damping-controllable low-impact inerter vibration reduction device and a control method, the damping-controllable low-impact inerter vibration reduction device comprises a low-impact inerter, a shell, a ball screw device and a controllable electromagnetic damper, the sudden change working condition of instantaneous reversing of a traditional inerter often induces obvious impact, and then the vibration reduction performance is deteriorated. Therefore, the invention provides the double-flywheel inerter structure with different rotating directions, and the double flywheels work independently, so that the problem that large impact is generated due to sudden change of reversing is effectively solved. Besides, the controllable electromagnetic damper and the low-impact inerter are integrally designed, the inerter overcomes the defect that the damper cannot change the inherent frequency of a system and can provide large inerter, a control method is provided, the controllable electromagnetic damper can be adjusted to output expected electromagnetic damping force according to the needed ideal torque, and the electromagnetic damping force can be adjusted to be larger than that of the low-impact inerter. Therefore, the vibration damping device can obtain more excellent vibration damping performance.

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 relates to the technical field of air conditioners, in particular to a fixing structure for an air delivery pipeline of an air conditioner compressor and an air conditioner, and aims to solve the problem that the air delivery pipeline and a fixing piece fluctuate greatly due to the fact that resonance is generated between the compressor of the existing air conditioner and the air delivery pipeline and the fixing piece in the frequency conversion process. In order to achieve the purpose, the fixing structure for the air delivery pipeline of the air conditioner compressor comprises a body, the body comprises a first part and a second part which are detachable, and the first part and / or the second part are / is used for fixing the air delivery pipeline and form a combined body with the air delivery pipeline. The first part and the second part can be combined or separated to change the size of the assembly, so that the inherent frequency of the assembly is changed. When the operation frequency of the compressor is consistent with the inherent frequency of the combination body of the fixed structure body and the gas conveying pipeline, the inherent frequency of the combination body can be adjusted by combining or separating the first part and the second part of the body, and resonance with the compressor is avoided.

The invention relates to the technical field of packing scale equipment, and provides a special packing scale for powdery sodium cyanide and a control method thereof.The special packing scale comprises a feeding hopper and a vibration table which are distributed up and down, a connecting flange coaxially fixed to a discharging opening of the feeding hopper, and a receiving hopper which is coaxially connected to the connecting flange in a sleeving mode, and the outer wall of the receiving hopper is annularly provided with a driving gear and is driven by a motor on the feeding hopper; at least one concave cavity is formed in the side wall of the receiving hopper, a rod body is hinged in the concave cavity, a replaceable balancing weight is arranged at the free end of the rod body, when the receiving hopper rotates, the rod body is unfolded under the action of centrifugal force and knocks a ton bag sling, meanwhile, the vibration table acts on the bottom of a ton bag, and the vibration table and the receiving hopper cooperatively excite the standing wave effect of the ton bag. The rod body periodically knocks the sling under the action of centrifugal force, and the frequency can be adjusted through the balancing weight. When the knocking frequency is close to the inherent frequency of the ton bag, vibration of the hanging belt can be transmitted to the whole bag body, the resonance phenomenon is caused, the vibration table at the bottom is matched to excite the standing wave effect, and loosening and even distribution of materials are achieved.

The invention provides an inhaul cable self-vibration fundamental frequency automatic identification method and system based on a harmonic product spectrum, and relates to the technical field of structure monitoring, and the method comprises the steps: receiving vibration acceleration data of an inhaul cable, carrying out the windowing processing of the vibration acceleration data through employing a Hanning window, and generating a windowed signal; carrying out fast Fourier transform on the windowed signal, and improving the frequency resolution by implementing zero filling to obtain an initial frequency spectrum; smoothing the initial frequency spectrum to form a smooth frequency spectrum; performing passband clipping on the smooth frequency spectrum to zero the passband outer amplitude to form a clipped frequency spectrum; calculating the signal-to-noise ratio of the frequency spectrum after cutting, and comparing the signal-to-noise ratio with a preset threshold value; if the signal-to-noise ratio is lower than a preset threshold value, judging that the signal quality is unqualified and terminating the processing flow; and if the signal-to-noise ratio is equal to or higher than the preset threshold value, continuing the normal processing flow. According to the invention, automatic and high-precision identification of the self-vibration fundamental frequency of the inhaul cable can be realized.

The invention relates to a mobile phone elastic piece resonant frequency optimization method in the field of mobile phone elastic pieces, which comprises the following steps: acquiring elastic piece material and structure design parameters, and establishing a relation model of elastic piece resonant frequency, material and structure; according to the working frequency range of the mobile phone and the target interval of the resonant frequency of the preset elastic sheet, determining the optimization direction of the elastic sheet material and the structural design; a finite element analysis method is adopted to simulate vibration modes of the elastic sheet under different materials and structural designs, and the inherent frequency and vibration characteristics of the elastic sheet are obtained; if the inherent frequency of the elastic sheet exceeds the target interval, adjusting the material thickness or structural design parameters of the elastic sheet, and performing finite element analysis again until the inherent frequency falls into the target interval; verifying whether the resonant frequency and the vibration mode of the elastic sheet accord with a preset target or not through an experimental test, and obtaining comparative analysis of experimental data and a simulation result; and according to the optimized elastic sheet material and structural design parameters, elastic sheet manufacturing process parameters are generated and used for accurate manufacturing in the actual production process.

The invention discloses a rapid calculation method for electromagnetic vibration of a permanent magnet synchronous motor, and belongs to the technical field of electromagnetic field calculation. According to the method, a magnetic potential and magnetic conductance method is innovatively combined with an improved sub-domain method, the problem of complexity of electromagnetic field distribution of a nonlinear material is effectively solved through the magnetic potential and magnetic conductance method, and the capture precision of electromagnetic field changes is remarkably improved by dividing a computational domain into a plurality of sub-domains through the improved sub-domain method. According to the method, the influence of the tangential electromagnetic force wave and the harmonic current is fully considered, and high-precision calculation of the electromagnetic force can be realized. On the basis, a stator core shell equivalent theoretical model is established, the inherent frequency of the stator is calculated by adopting an energy method, and the accuracy of the model is verified through a modal experiment. Furthermore, by determining the frequency response function of the stator in the low-order mode, the acceleration spectrum and electromagnetic force wave distribution of the prototype stator in each mode are obtained based on the linear superposition principle. Compared with a traditional electromagnetic-structure coupling finite element model, the method has the advantages that the calculation efficiency is remarkably improved while the calculation precision is guaranteed, the calculation time is shortened by 59.3%, and efficient and reliable technical support is provided for optimization design of electromagnetic equipment.

The invention discloses an intelligent regulation and control method and system for the environmental comfort degree of a central air conditioner terminal, and relates to the technical field of air conditioner regulation and control. The intelligent regulation and control method comprises the following steps that a pressure fluctuation track generated by aerodynamic disturbance is collected in the operation process of a draught fan, and the pressure fluctuation track is converted into energy spectrum distribution in a time sequence; establishing dynamic energy representation of the fan frequency; based on dynamic energy representation of fan frequency, a sound vibration field is projected in a spatial range, excitation response of inherent frequency is synchronously recorded through a room structure sensing array, and instantaneous energy coupling fingerprints of a room structure are formed. Through dynamic energy characterization and structural response coupling analysis, real-time identification and quantitative control of the standing wave noise risk are realized, a phase drift mechanism is introduced at a risk critical point, a fan disturbance phase is actively adjusted, standing wave superposition is effectively blocked, and acoustic safety and operation stability of a tail end environment are improved.

The invention relates to the technical field of hydraulic control, and discloses a hydraulic motor constant torque self-adaptive PID (Proportion Integration Differentiation) control system which comprises a controller and a hydraulic driving unit, the controller performs frequency domain separation on the pressure signal by using a signal preprocessing module, and extracts an average pressure difference representing the driving force and a ripple amplitude representing the fluid rigidity; the state observation module estimates an instantaneous volume elastic modulus based on the ripple amplitude, corrects a compression item in a flow continuity model by using the elastic modulus, and calculates an instantaneous leakage coefficient of the motor in real time; the self-adaptive control module establishes dynamic mapping of PID gain and physical parameters, the proportional gain is adjusted by using a leakage coefficient to match system damping, the integral gain is adjusted by using a volume elastic modulus to adapt to inherent frequency, and a control instruction is synthesized by combining feedforward compensation. According to the method, the problem of model mismatch caused by oil characteristic change and motor abrasion is effectively solved, and the whole-life-cycle control precision of the system is improved.

An active system is provided that changes the mechanical stiffness of a BHA during drilling to prevent / reduce damage to a BHA due to vibrations. The active system uses a combination of mechanical and electronic systems to change the physical characteristics of a BHA that govern the natural frequencies thereof. The active system can change the mechanical stiffness of a BHA by switching between two different coupling modes for connecting sections or portions of the BHA. An active torsional isolator and damper (ATID) can be used to switch between the different coupling modes. In one example, the ATID includes: (1) a dynamic coupler configured to connect a first portion of a BHA to a second portion of the BHA according to different coupling modes, and (2) a processor configured to control switching of the dynamic coupler between the different coupling modes during a drilling operation of a drill bit.

To set specifications while suppressing antiresonance in a vibration control device having a plurality of tuned mass dampers.SOLUTION: A method for setting specifications of a vibration control device 10 having a plurality of tuned mass dampers 14 includes a step of assuming that the plurality of tuned mass dampers 14 are sequentially installed on a structural material 52, setting a natural frequency of the tuned mass damper 14 assumed to be first installed to a primary natural frequency of the structural material 52, and then obtaining a frequency of antiresonance generated by one or a plurality of tuned mass dampers 14 assumed to be previously installed; Is repeated.SELECTED DRAWING: Figure 6

The invention provides a dumping type slope dangerous rock body inherent frequency analytical calculation method and system, and relates to the technical field of geotechnical engineering and geological disaster prevention and control. The method comprises the following steps: acquiring basic parameters of the toppling slope dangerous rock mass; according to the basic parameters, the safety coefficients of the gravity center of the toppling type slope dangerous rock body inside and outside the toppling point are determined; based on a modified Timoshenko beam theory, constructing a beam model; according to the beam model, analytic calculation is conducted on the toppling type side slope dangerous rock mass, and the inherent frequency of the toppling type side slope dangerous rock mass is determined; constructing a dynamic model of the toppling type slope dangerous rock mass; determining the relationship between the inherent frequency and the relative depth of the crack according to the dumping type slope dangerous rock mass dynamic model; according to the relation between the safety coefficient and the inherent frequency and the relative depth of the crack, a dumping type slope dangerous rock mass stability evaluation model is constructed; and carrying out stability analysis on the dumping type slope dangerous rock mass through the dumping type slope dangerous rock mass stability evaluation model.

The invention relates to the technical field of material grading equipment, in particular to a screen with a novel beating mode and a screening device. The screen with the novel beating mode comprises a screen assembly and a beating assembly. The screen assembly comprises a first screen frame and a flexible screen arranged in the first screen frame. The beating assembly is arranged below the screen assembly and comprises a plate spring and a beating tool bit. One end of the plate spring is fixedly arranged and the other end is provided with a striking cutter head; a plurality of adjusting holes are formed in the surface of the plate spring to adjust the inherent frequency of the plate spring; when the screen assembly vibrates, the plate spring vibrates along with the screen assembly, so that the beating tool bit can repeatedly beat the flexible screen. Due to the fact that the flexible screen has the characteristic of flexibility, under repeated knocking of the striking tool bit, the flexible screen can generate extra vibration besides vibration under the action of external force, then materials attached to the flexible screen are separated from the flexible screen, screen holes of the flexible screen are prevented from being blocked, and the screening efficiency is improved.

The invention relates to the technical field of switching device monitoring, and discloses an intelligent monitoring method and system for a vacuum circuit breaker. The method comprises the following steps: synchronously acquiring an operation mechanism vibration signal and an arc extinguish chamber arc current signal during opening and closing; the inherent frequency band energy ratio of the opening spring is extracted through wavelet packet decomposition to serve as a mechanical degradation factor; extracting an arc fluctuation factor based on the time domain integral of the current first-order derivative; the two factors are input into a multi-physics field correlation model, a coupling vector of the contact abrasion depth and the resistance moment of the transmission mechanism is output, and according to the method, a timestamp alignment mechanism that the current rising edge of the opening coil triggers the double-channel acquisition card is used, and synchronization of a vibration signal and a current signal is achieved. The system comprises corresponding function modules and an early warning mechanism. The problem of mechanical / electrical signal time domain splitting is solved, and the state monitoring precision of the vacuum circuit breaker is remarkably improved.

The invention relates to the technical field of linear motors, and particularly discloses a linear driver and a hair cutting device.The linear driver comprises a mounting frame, the mounting frame comprises an electromagnet mounting part and two magnet set mounting parts, and the two magnet set mounting parts are oppositely arranged at intervals; the electromagnet mounting part is located between the two magnet group mounting parts, the two ends of each magnet group mounting part are elastically connected with the corresponding ends of the electromagnet mounting part through elastic connecting parts, each magnet group mounting part is connected with a driving arm, and at least one output shaft is arranged on each driving arm; the number of the output shafts on one magnet group mounting part is greater than that of the output shafts on the other magnet group mounting part, and each output shaft is connected with a load; each magnet group mounting part, the driving arm on the magnet group mounting part, the output shaft, the load and the elastic connecting parts at the two ends of the magnet group mounting part form a whole, and the inherent frequencies of the two whole bodies are the same, so that the function of a product applied to the linear actuating device is achieved.