1394 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 a rotor blade dynamic field rapid reconstruction method based on a deep neural network model, and the method comprises the steps: firstly collecting a BTT signal containing blade vibration information, then designing a deep neural network model, and training the deep neural network model through a training data set; processing the actually measured BTT signal by using the trained deep neural network model, and reconstructing a blade vibration displacement signal; performing spectral analysis on the reconstructed blade vibration displacement signal, and identifying vibration frequency, amplitude and phase parameters; then establishing a finite element model of the blade, and determining the inherent frequency and modal shape of the blade through modal analysis; and finally, quickly calculating a displacement field, a strain field and a stress field of the blade in a vibration state based on a modal superposition theory by utilizing the identified vibration parameters and modal analysis results. According to the invention, the vibration displacement and stress condition of the blade can be known in real time, so that real-time decision is supported, and the safety, reliability and durability of a rotating machine are improved.

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 relates to an unmanned aerial vehicle wing deformation monitoring sensor layout method based on modal analysis, and the method comprises the steps: determining the modal parameter detection of a wing under different working conditions through modal analysis, and employing a modal component sum index to recognize a key degree of freedom so as to optimize the position of a sensor; the method is mainly used for verifying the deformation of the wing part in the overall design process of the unmanned aerial vehicle in a laboratory. According to the method, the modal shape and the inherent frequency are obtained through finite element analysis, the modal amplitude and the participation factor of each degree of freedom are calculated, the optimal arrangement position of the sensor is further optimized through an iterative algorithm, and the arranged fiber bragg grating sensor can accurately monitor the deformation information of the wing. The data processing unit collects data and evaluates wing performance by applying a data analysis algorithm. The method improves the accuracy and comprehensiveness of deformation measurement, and provides guarantee for the flight safety and efficiency of the unmanned aerial vehicle.

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.

To provide a box shaped high performance air filter which can inhibit deformation of a container during earthquake and achieve high pressure resistance to decompression.SOLUTION: A box shaped high performance air filter 1 includes: a filter body 10 which filters air passing therethrough; a hexahedron container 20 which houses the filter body 10 and has an inlet nozzle 32 (1) for introducing air, and an outlet nozzle 32 (2) for discharging air which has been filtered by the filter body 10 and is located on a surface opposite to the inlet nozzle 32 (1); and a reinforcement material 40 fastened to the container 20. The filter body 10 is adhered to an inner surface of the container 20 and the natural frequency is 20 Hz or higher.SELECTED DRAWING: Figure 1

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 parameter determination method of a flexible support and a related device, and relates to the photovoltaic field. In the application, after the excitation force is applied to the preset excitation position in the flexible bracket, the flexible bracket freely vibrates according to the inherent frequency, and the damping influence and the free vibration are continuously attenuated in the vibration process of the flexible bracket, so that the inherent frequency and the damping can be calculated by using the time history data during the free vibration of the flexible bracket; the problem that parameters of the flexible support need to be determined urgently is solved.

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 invention relates to a non-contact recognition method for a global three-dimensional vibration mode of a structure, which comprises the following steps of: acquiring a two-dimensional displacement field of the structure based on a left camera and a right camera in each view field through a full-field optical flow method based on frequency domain characteristics, and calculating according to the two-dimensional displacement field to obtain a sub-pixel displacement field; wherein each view field is subjected to video acquisition by the same binocular camera in a time-sharing manner, and two adjacent view fields have an overlapping region; for each independent view field, projecting a sub-pixel two-dimensional displacement field of the structure to a three-dimensional displacement field according to the parallax between the left image and the right image of the binocular camera, and smoothing the three-dimensional displacement field; converting the three-dimensional displacement field of each view field from the time domain to the frequency domain, and extracting the inherent frequency of the structure and the operation modal shape of each view field under the global coordinate system; and splicing the operation modal shape of each view field based on feature point detection and matching of the overlapping region to obtain a three-dimensional global operation modal shape of the structure. The global vibration mode of the structure can be covered, and the reliability of the recognition result is ensured.

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.

To provide a method, device, equipment and medium for identifying a vibration limit exceeded failure of an offshore wind turbine.SOLUTION: A method for identifying a vibration limit exceeded failure of an offshore wind turbine, includes: when a resonance limit exceeded failure occurs in an offshore turbine, executing Fourier spectrum analysis on first vibration acceleration data before the vibration limit exceeded failure occurs, second vibration acceleration data in a vibration limit exceeded failure stage, and third vibration acceleration data in a turbine stop stage; determining an excitation frequency of the turbine in an impeller normal rotation stage, an excitation frequency of the turbine in the vibration limit exceeded failure stage, and a natural frequency in a stop stage; and determining whether the resonance limit exceeded failure occurs in the offshore turbine on the basis of a first deviation value between the excitation frequency and the natural frequency of the turbine in the impeller normal rotation stage, a second deviation value between the excitation frequency and the natural frequency of the turbine in which the vibration limit exceeded failure occurs, and a preset deviation value. This method solves the problems in related techniques such as wasted resources and unnecessary outage due to manual troubleshooting.SELECTED DRAWING: Figure 1

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 belongs to the related technical field of ship vibration and noise reduction, and discloses a method and system for determining vibration of a beam structure containing an acoustic black hole damping layer. The method comprises the following steps that S1, for a beam structure attached with an acoustic black hole damping layer in a ship, a coupling system comprising a uniform beam and the acoustic black hole damping layer is selected as a research object, the research object is simplified into two layers of beams which are connected in a coupling mode, and material attributes and section forms of the two layers of beams are different; s2, constructing a motion control equation of the coupling system; and S3, solving the motion control equation of the coupling system, and respectively obtaining the inherent frequency of the coupling system under free vibration and the vibration response of the coupling system under external excitation. According to the invention, the problems of low efficiency and poor economical efficiency of rapid prediction of the inherent frequency and the vibration response of the beam structure containing the acoustic black hole damping layer are solved.

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.