73 results about "Harmonic response" patented technology

The invention relates to an optimization design method for a multi-fulcrum elastic ring supporting structure of an aero-engine rotor system, and belongs to the technical field of aero-engine vibration control and rotor dynamics simulation. Firstly, a finite element or lumped unit model is adopted to establish a coupling kinetic equation of a rotor and an elastic ring, and fluid-solid coupling factors such as inner and outer oil films of the elastic ring and orifice flow are considered; then, through critical rotating speed and vibration harmonic response analysis, sensitivity evaluation is carried out on rigidity and damping characteristics of different supporting positions, and target vibration reduction modes corresponding to all fulcrums are identified; then, coupling simulation and multi-objective optimization are carried out around the number of bosses of the elastic ring, the height of the bosses, the damping aperture, the thickness of a thin wall and other key structure parameters, and the optimal design meeting the vibration reduction requirement of a rotor system and the strength reliability requirement of the elastic ring is obtained through iteration; and finally, an optimization result is applied to structure manufacturing and assembling. The method can effectively reduce the vibration amplitude of the rotor when the rotor crosses the multi-order critical rotating speed.

The invention belongs to the technical field of power monitoring, and discloses a detection method for monitoring the state of a primary and secondary fusion circuit breaker, which comprises the following steps: acquiring state data of the circuit breaker, including electromagnetic waveform data, harmonic response characteristics and temperature distribution gradient; obtaining circuit breaker electric field distribution fingerprints through nonlinear segmented harmonic analysis, constructing a multi-dimensional permeation characteristic matrix, and establishing a micro-scale electrothermal coupling map; performing impedance distortion analysis to obtain a nonlinear region situation table, performing multi-frequency response analysis to obtain a harmonic penetration curve, and constructing a high-frequency harmonic penetration path spectrum; a micro-region diagnosis algorithm is established, nonlinear impedance calibration is carried out, and a multi-level protection instruction sequence is generated; adjusting the operation state of the circuit breaker to obtain a circuit breaker medium steady-state index, and performing risk analysis to obtain a harmonic penetration early warning report; according to the invention, accurate identification and early warning of the abnormal-state area in the circuit breaker are realized, and the safe and stable operation capability of the primary and secondary fusion circuit breaker is improved.

The invention relates to the technical field of real-time monitoring and early warning, in particular to a real-time monitoring and early warning method and system for house safety, and the method comprises the following steps: obtaining a dominant frequency amplitude and an inclination change rate, screening abnormal nodes through combining a distance, correlating temperature to eliminate thermal interference, analyzing a phase and energy to recognize an abnormal region, and evaluating aging influence through combining harmonic waves and stress. And analyzing the conduction relationship to generate early warning information. According to the method, the abnormal recognition accuracy is improved through linkage judgment of the vibration dominant frequency and the inclination change rate, space aggregation screening is achieved in combination with the node spacing, thermal disturbance misjudgment is effectively eliminated through dominant frequency offset and temperature gradient joint analysis, and the regional continuous abnormal recognition capacity is enhanced through vibration phase and energy difference coupling analysis; harmonic response is compared with material aging data to establish conduction analysis of a degradation determination path, a phase difference, inclination and temperature change to strengthen structure chain type risk identification, and risk identification precision and early warning effectiveness are integrally improved.

The invention discloses a sensorless galloping starting control method for a CAES high-voltage frequency converter. The sensorless galloping starting control method comprises the steps of collecting output voltage and stator current data of the frequency converter; harmonic analysis is carried out on the normalized data, and a position estimation dead zone is identified through sensitivity evaluation; designing a quadrature phase modulation sequence for the dead zone; applying a modulation sequence to generate a harmonic interference mode; calculating harmonic response differential fingerprints, and extracting enhanced position features; meanwhile, torque fluctuation in the modulation process is predicted and compensated, and the system stability is guaranteed; and realizing stable galloping starting based on the accurate position. The position estimation dead zone problem is solved through the phase interference principle, the position precision is improved to + / -3.5 degrees, and the starting reliability is remarkably improved.

A first acoustic wave device can have a piezoelectric layer between a first electrode and a second electrode. The first acoustic wave device can have a first shape and a first area. A second acoustic wave device can be coupled to the first acoustic wave device to at least partially cancel a second harmonic response of the first acoustic wave device. The second acoustic wave device can have a piezoelectric layer between a first electrode and a second electrode. The second acoustic wave device can have a second shape that is different from the first shape and a second area that is within a threshold amount of the first area.

The invention belongs to the field of gas storage safety evaluation, and particularly relates to a method for calculating the vibration mode and harmonic response process of a gas storage pressurization area pipeline. Comprising the following steps: dividing grids for a fluid domain and a solid domain of a three-dimensional model of a supercharged area pipeline and setting constraints; a pre-stress coupling wet mode method is adopted to carry out fluid-structure interaction statics analysis to obtain initial pre-stress, and then a multi-order vibration wet mode is calculated; and applying external excitation based on a wet mode result, and obtaining deformation and stress concentration conditions during vibration by using a direct complete harmonic response method. According to the method, multi-load coupling is considered, fine modeling is conducted on dangerous positions such as welding seams and supports and a high-pressure container, self-adaptive grid division and high-precision constraint are adopted, the pre-stress wet mode and a direct complete harmonic response analysis method are innovatively combined, the calculation accuracy is greatly improved, and the method is suitable for large-scale popularization and application. Powerful support is provided for design optimization, safety evaluation and maintenance of the pipeline in the pressurization area, the safety risk is reduced, and the system reliability is improved.

The present invention discloses a method for calculating the harmonic response of a magneto-electro-elastic structure using enhanced overlapping triangular units, which relates to the technical field of magneto-electro-elastic intelligent materials. In the process of constructing a local enhanced interpolation basis function, a composite basis function consisting of a Lagrange polynomial basis function and a plane wave basis function is used for construction; in the process of constructing a local numerical approximation, a weighted function is constructed by introducing a mid-edge node in each enhanced overlapping triangular unit, and numerical interpolation is completed under the premise of satisfying the unit decomposition characteristics. Based on the numerical interpolation, a dynamic matrix control equation of the magneto-electro-elastic structure is established, and an enhanced overlapping finite element numerical model of the solver dynamic response is obtained. After applying appropriate boundary conditions and external excitations, a high-precision prediction of the harmonic response of the magneto-electro-elastic structure can be completed.

The invention discloses a method for measuring the dynamic stress of a vehicle cooling fan blade based on a blade tip timing method, and the method comprises the steps: building a finite element model, carrying out the modal harmonic response analysis, and obtaining a modal shape matrix and a modal stress matrix; a plurality of blade tip timing sensors are installed on the casing to measure blade tip vibration displacement; vibration parameters are extracted from the blade tip displacement data through a parameter identification method; calculating a modal coordinate vector by using the modal shape matrix and the blade tip vibration displacement; according to the invention, the blade tip vibration parameter suitable for the vehicle cooling fan blade is measured by using the non-contact method based on the blade tip timing method, and the dynamic stress of the vehicle cooling fan blade is calculated; according to the invention, the process from the blade tip vibration parameter to the dynamic stress is realized, and a set of complete testing and calculating process from the measurement result of the blade tip timing sensor to the blade tip vibration parameter to the blade dynamic stress is realized.

The invention belongs to the technical field of power equipment insulation state detection, and particularly relates to an XLPE cable water branch quantitative evaluation method and system based on frequency conversion pseudo trapezoidal wave excitation, and the method comprises the steps: applying pseudo trapezoidal wave excitation, and collecting voltage and current signals; wavelet and adaptive filtering are combined for denoising; establishing a Wiener-ANN nonlinear dielectric response model, and fitting cable response through the combination of a dynamic linear neural network module and a static neural network module; obtaining a frequency domain dielectric spectrum and extracting a multi-harmonic characteristic parameter, a loss slope, a hysteresis angle and a time domain nonlinearity; and finally, outputting a water treeing aging comprehensive index WTI through the support vector machine regression model to realize quantitative evaluation of the aging degree. The system comprises a pseudo trapezoidal wave excitation unit, a high-voltage amplification unit, a micro-current acquisition unit, a signal processing unit and an aging evaluation unit. The broadband harmonic response can be obtained through a single test, the test efficiency is improved by more than 75%, the anti-interference performance is high, the evaluation precision is high, and the method is suitable for on-site rapid nondestructive diagnosis.

This invention belongs to the field of structural vibration analysis technology and discloses an energy-averaged finite element method and system for structural random vibration analysis, including: S1, using fluid simulation software Fluent and StarCCM to perform fluid dynamics simulation to obtain the long-term turbulent pulsating pressure distribution of the structural wall in the time domain; S2, dividing the pulsating pressure obtained in S1 into segments with some overlap between segments, and performing Fourier transforms on each segment to obtain multiple sets of wall turbulent pulsating pressures in the frequency domain; S3, establishing a fluid-structure interaction dynamic model of the structure and fluid domain, applying the wall turbulent pulsating pressure loads obtained in S2 in the frequency domain, and performing steady-state dynamic harmonic response analysis on each segment; S4, based on the vibration response results of the multiple sets of harmonic response analyses in S3, taking the energy average of these results to obtain the result of random vibration analysis.

The present invention discloses a method for reconstructing the dynamic state of a multi-body system of a missile based on a model-assisted network, which has faster reasoning speed, high accuracy, and high computational efficiency. The method comprises the following steps: (10) model establishment: using a multi-body system dynamics method to establish a model of a multi-body system of a missile; (20) parameter calibration: using a finite element method to perform harmonic response analysis on the multi-body system of the missile to obtain connection relationship parameters; (30) dual extended Kalman filter construction: based on the connection relationship parameters, a dual Kalman filter is constructed based on the least squares method; (40) short trajectory multi-input GRU neural network construction: based on the GRU type neural network structure, a mature short trajectory multi-input GRU neural network is constructed and trained; (50) system dynamic state reconstruction: obtaining a dynamic reconstruction signal of the multi-body system of the missile from the output of the mature short trajectory multi-input GRU neural network.

The invention provides a transformer transportation impact damage assessment method based on a damage response surface model. According to the method, refined impact excitation is constructed, and impact simulation is carried out on a finite element model of the transformer by utilizing the impact excitation. In the simulation process, the vibration response of the finite element model is collected, the damage conditions of different parts of the finite element model are subjected to harmonic response analysis, and damage point data of the part which is damaged first is selected to construct a damage response surface model. And multi-modal influence factors of impact acceleration and impact frequency are introduced into the damage response surface model, so that the damage response surface model can accurately describe the boundary of damage of the transformer under impact. By using the damage response surface model, the damage risk in the transformer transportation process can be accurately and effectively evaluated.

The present application belongs to the technical field of power monitoring, and discloses a detection method for monitoring the state of primary-secondary fusion circuit breaker, comprising: obtaining circuit breaker state data, including electromagnetic waveform data, harmonic response characteristics and temperature distribution gradient; obtaining circuit breaker electric field distribution fingerprint through nonlinear segmented harmonic analysis, constructing a multi-dimensional penetration feature matrix, and establishing a micro-scale electric-thermal coupling atlas; obtaining a nonlinear region situation table through impedance distortion analysis, obtaining a harmonic penetration curve through multi-frequency response analysis, and constructing a high-frequency harmonic penetration path spectrum; establishing a micro-region diagnosis algorithm, performing nonlinear impedance calibration, and generating a multi-level protection instruction sequence; adjusting the operating state of the circuit breaker, obtaining the circuit breaker medium steady-state index, and performing risk analysis to obtain a harmonic penetration early warning report; the present application realizes accurate identification and early warning of abnormal regions inside the circuit breaker, and improves the safe and stable operation ability of the primary-secondary fusion circuit breaker.

A space flywheel optimization design method comprises the following steps: S1, designing an initial space flywheel based on input conditions and technical requirements of the space flywheel, and obtaining initial values of design variables of the initial space flywheel; S2, performing modal analysis and harmonic response analysis on the initial space flywheel based on the input conditions and the technical requirements, judging whether the initial space flywheel meets the design requirements, taking the mass and the harmonic amplification factor of the space flywheel as optimization objectives, and obtaining initial values of the two optimization objectives of the initial space flywheel meeting the design requirements; the space flywheel optimization design method is used for optimizing design of the space flywheel with respect to two or more evaluation index parameters or optimization objectives in conflict, and an optimal space flywheel model meeting input conditions and technical requirements required by a space environment is obtained.

The invention belongs to the technical field of vibration control, and relates to an instrument vibration reduction control method and system based on double resonance, and the method comprises the steps: determining the resonance frequency of an instrument based on an established finite element model of a pipeline system connection instrument; a resonance structure is additionally arranged on a pipeline of the finite element model to establish a retuning model; performing harmonic response analysis on the primary tuning model to obtain a peak frequency of the primary tuning model, and when the peak frequency is inconsistent with the resonant frequency, adjusting resonant structure parameters and optimizing the primary tuning model; installing a tuned mass damper on a resonant structure of the optimized single-tuning model, and establishing a double-tuning model; and carrying out harmonic response analysis on the double-tuning model to obtain the trough frequency of the double-tuning model, and when the trough frequency is inconsistent with the resonant frequency, adjusting the parameters of the tuned mass damper and optimizing the double-tuning model. The influence of specific frequency vibration on the instrument is efficiently suppressed, and the performance stability and the measurement precision of the instrument are guaranteed.

The invention discloses a characteristic influence analysis method for an impulse sound source circular tube-shaped composite receiving transducer, which relates to the related technical field of transducers, and comprises the following steps: constructing a simulation model of a 2-2 type piezoelectric composite circular tube-shaped receiving transducer through COMSOL; after harmonic response analysis is carried out on the simulation model, factors influencing the performance of the 2-2 type piezoelectric composite circular tube receiving transducer are obtained through parameters and constraint conditions of the simulation model, and design improvement is carried out on the 2-2 type piezoelectric composite circular tube receiving transducer according to the influence factors. According to the invention, an important new technical basis is provided for the research of the impulse sound source depth detection technology receiving transducer.

The invention relates to a bolted connection local contact stiffness sudden change threshold prediction method, which comprises the following steps of: 1, constructing a three-dimensional model of a bolted connection composite board, and performing finite element simulation analysis on the three-dimensional model; 2, performing preliminary screening and normalization on data obtained by modal analysis and harmonic response analysis; 3, constructing a machine learning prediction model by using the training set; 4, the precision of the machine learning prediction model is tested and verified through the test set, and evaluation is carried out through the evaluation indexes. According to the method, the time cost and complexity of manual testing are reduced, the dynamic overhaul period can be formulated according to the predicted threshold value cycle index, and the monitoring efficiency and the production efficiency are improved.

The invention discloses a radial point interpolation finite element method for linear elastic solid harmonic response and application, and belongs to the technical field of solid mechanics and engineering numerical simulation. The method comprises the following steps: discretizing a linear elastic solid problem domain into a standard finite element grid, deriving a nodal function through a radial basis function, selecting a local enhanced interpolation basis function to construct a newly added degree of freedom and complete local numerical approximation, and constructing a global interpolation format of a displacement vector field in an element in combination with unit decomposition characteristics; based on the interpolation format and a Galerkin weak form of an elastic dynamic problem, applying a displacement boundary condition to obtain a system forced vibration equation; acquiring steady-state dynamic response and frequency domain response characteristics under different frequency harmonic excitation; according to the method, high-order interpolation can be realized without increasing nodes, the numerical precision is improved, the computing resource and time consumption is reduced and a more reliable numerical solution is provided under the condition that the grid density is relatively small, and the method has important application value in engineering practice.

The present application belongs to the technical field of vibration control, and relates to an instrument damping control method and system based on double resonance, which comprises the following steps: determining the resonance frequency of an instrument based on a finite element model of a pipeline system connected to the instrument; adding a resonance structure to the pipeline of the finite element model to establish a one-tuned model; performing harmonic response analysis on the one-tuned model to obtain the peak frequency of the one-tuned model, and adjusting the resonance structure parameters to optimize the one-tuned model when the peak frequency is inconsistent with the resonance frequency; installing a tuned mass damper on the resonance structure of the optimized one-tuned model to establish a two-tuned model; performing harmonic response analysis on the two-tuned model to obtain the valley frequency of the two-tuned model, and adjusting the tuned mass damper parameters to optimize the two-tuned model when the valley frequency is inconsistent with the resonance frequency. The present application efficiently suppresses the influence of vibration at a specific frequency on the instrument, and guarantees the stable performance and measurement accuracy of the instrument.

The invention discloses a vehicle control unit shell random vibration reliability prediction method based on multi-physics field coupling, and the method comprises the steps: constructing a controller shell three-dimensional model, optimizing the grid transition form of the three-dimensional model through employing a variable density method, and generating a finite element model; loading the finite element model into Ansys software to create an analysis working condition, setting a boundary condition and a load, and defining material and unit attributes at the same time; carrying out free mode and constraint mode analysis on the controller, and identifying a dynamic rigidity weak region of the structure; a Harmonic Response module is used for carrying out frequency response analysis; creating a non-stationary random vibration field of the controller in nCode software, and calculating power spectrum density values in X, Y and Z directions; the frequency response result in the step (4) is imported into a Design Life module, and the power spectrum density value in the step (5) is added; dynamic response evaluation and data post-processing under random excitation are implemented; and determining a weak area of high-cycle fatigue failure of the controller under the extreme working condition and optimizing a reinforcement scheme.

A rocket system level structure vibration simulation and verification method, comprising: constructing a rocket system level structure finite element model based on modal superposition method, carrying out harmonic response analysis, constructing excitation-response transfer function in frequency domain, and determining dynamic load transfer path and amplification effect; combining the power spectral density of the rocket vibration environment, implementing random vibration analysis, quantifying the system level structure strength safety margin by calculating the fatigue life; selecting weak components or typical components to carry out targeted vibration test, and verifying the reliability of the system level vibration simulation method in the above steps through test data. The method can effectively improve the vibration environment prediction accuracy and structure design reliability.

The invention relates to the field of gas turbine engine gas compressor design, and discloses a gas compressor rotor blade asynchronous vibration response numerical simulation method and system, and the method comprises the steps: obtaining the asynchronous airflow excitation frequency of a gas compressor rotor blade tip and the surface pressure load of a blade at different moments through CFD full-cycle unsteady numerical simulation; the vibration mode and the inherent frequency of the rotor blade are obtained through finite element modal simulation, and the vibration mode and the inherent frequency of asynchronous vibration are determined according to the minimum frequency difference; the aerodynamic damping of the rotor blade under the excitation of the asynchronous airflow is calculated based on a dynamic grid technology, the surface pressure loads, the aerodynamic damping and the like at different moments are applied to harmonic response analysis, the vibration stress and the vibration frequency of the rotor blade under the excitation of the asynchronous airflow are obtained, and the numerical simulation evaluation of the asynchronous vibration response of the rotor blade of the gas compressor is completed. The analysis method can be used for evaluating the asynchronous vibration of the rotor blade of the gas compressor in the initial design stage of the gas compressor, and has good practical value and wide application prospect.

This invention discloses a method for predicting the multi-physics coupled vibration response of a pump set based on the superposition of frequency domain excitation spectra. The method includes: performing closed-loop flow field calculations of the pump set to extract the time-domain fluid excitation force on the surface of the pump set's flow-through components; performing numerical simulation calculations of the motor's electromagnetic field to extract the time-domain electromagnetic excitation force; establishing a calculation model of the pump's rotor system, applying the rotor system's mass imbalance, time-domain fluid excitation force, and time-domain electromagnetic excitation force, performing transient dynamic calculations of the rotor system, and extracting the time-domain mechanical excitation force; performing modal calculations of the entire pump set to obtain a numerical simulation calculation model of the entire pump set; converting the time-domain fluid excitation force, time-domain electromagnetic excitation force, and time-domain mechanical excitation force into frequency domain excitation spectra using FFT, applying them to the coupling surfaces of the pump body, and performing harmonic response analysis of the pump set under multi-source excitation in the frequency domain to obtain the coupled vibration response results of the pump set. This invention enables rapid and accurate prediction of the multi-physics coupled vibration response of a pump set.

The invention provides a method for evaluating the vibration fatigue life of a disc pump under the action of internal flow, and belongs to the technical field of offshore oil engineering. Comprising the following steps: establishing a disc pump model; transient fluid-solid coupling calculation is carried out on the pump body structure to obtain a pump body internal flow pulsating pressure time domain load, and the pump body internal flow pulsating pressure time domain load serves as input to obtain a pump body displacement time domain load through ANSYS calculation; the pump body displacement time domain load is processed through software, and the pump body acceleration power spectral density is obtained; aNSYS is used for harmonic response analysis, and a pump body acceleration load frequency response curve is obtained; and evaluating the fatigue life of the pump body based on the pump body acceleration power spectral density and the material SN curve. According to the method, the model between vibration and fatigue caused by the internal flow pulsating pressure is established, the fatigue life of the disc pump is accurately evaluated through a finite element software simulation calculation method, the design quality of the disc pump can be improved, the maintenance cost can be reduced, and the service life of the disc pump can be prolonged.

The invention discloses an electric drive spline NVH optimization method, which comprises the following steps of: constructing an electric drive system three-dimensional model containing key parts of a motor and a speed reducer by using multi-body dynamics software, dividing a finite element mesh and refining a gear contact surface; spline macroscopic parameters are input, and spline excitation and harmonic response are calculated; setting a plurality of groups of tooth crowning quantities, and comparing and selecting the optimal modification scheme with the lowest vibration response; and the sample preparation piece is tested and verified by a rack after being assembled. The method can recognize the NVH risk in advance, reduces the spline contact stress and load fluctuation, saves the research and development cost, and is suitable for spline-connected shafting structures such as motors, generators and transmissions.

The present application relates to the field of petrochemical industry, and specifically proposes a method, system, device and medium for optimizing heating furnace pipes based on flow heat-induced vibration. The method comprises: determining fluid domains and solid domains according to a preset three-dimensional geometric model of a convection section and its pipe bundle of a heating furnace, and performing grid division on the fluid domains and the solid domains; calculating pressure load through a CFD solver based on the grid division result of the fluid domains; performing modal analysis and harmonic response analysis on the pipe bundle based on the pressure load and the grid division result of the solid domains; and optimizing the design of the heating furnace pipe arrangement according to the result of the harmonic response analysis. The present application assists in optimizing the design of the pipe bundle of the heating furnace in the design experiment and operation stage, effectively reduces the vibration level of the pipe system by improving the pipe structure design and optimizing the fluid flow process, avoids the occurrence of resonance phenomenon, significantly reduces the safety hazards caused by vibration, and improves the reliability and safety of the heating furnace.

The application discloses a kind of welded structure harmonic response structural stress fatigue life prediction method, comprising the following steps: step 1: build the finite element model of welded structure containing weld;Step 2: using unit external load to the finite element model of welded structure harmonic sweep frequency obtains node response displacement;Step 3: according to external load coefficient obtains the unit stiffness matrix and node displacement under external load, as follows: step 4: calculate the simple harmonic response structural stress and equivalent structural stress of structure.The welded structure harmonic response structural stress fatigue life prediction method of the application: (1) compared with traditional quasi-static method, can solve the problem that quasi-static method cannot be carried out vibration fatigue evaluation, (2) compared with frequency domain structural stress method, can solve the problem that frequency domain structural stress method cannot evaluate simple harmonic vibration fatigue, (3) compared with traditional transient structural stress method, the method of the application is more efficient, and the result error is very small.

The present application relates to the field of gas turbine engine compressor design, and discloses a kind of compressor rotor blade non-synchronous vibration response numerical simulation method and system, obtain the non-synchronous airflow excitation frequency of compressor rotor blade tip and the surface pressure load of blade at different time by CFD full circumference unsteady numerical simulation, obtain the vibration mode and natural frequency of rotor blade by finite element modal simulation, determine non-synchronous vibration mode and natural frequency according to minimum frequency difference;Non-synchronous airflow excitation under the aerodynamic damping of rotor blade is calculated based on dynamic mesh technology, and surface pressure load at different time, aerodynamic damping and the like are applied to harmonic response analysis, obtain the vibration stress and vibration frequency of rotor blade under non-synchronous airflow excitation, complete compressor rotor blade non-synchronous vibration response numerical simulation evaluation.The analysis method of the present application can be used for compressor rotor blade non-synchronous vibration evaluation in the initial design stage of compressor, and has good practical value and broad application prospect.

The invention discloses a thermal coupling simulation and vibration analysis method for an eccentric main shaft of a slicing machine. The method comprises the following steps: constructing a finite element geometric analysis model; determining a thermal load and a thermal boundary condition; calculating a temperature field, a stress field and a deformation field; importing the calculated stress field into a modal analysis module considering thermal stress, and calculating first six-order modals and harmonic response; according to the method, the convective heat transfer coefficient of the cooling water channel is calculated based on fluent, and compared with an empirical formula, the calculation precision is higher, and the method is suitable for cooling water channels of various geometric types; a thermal coupling method is adopted to analyze a temperature field, a stress field and a deformation field when the main shaft works, a theoretical reference can be provided for the structural design of the main shaft, and the method has important significance in guaranteeing the stability of the operation of the main shaft; the modal analysis of the thermal prestress and the harmonic response analysis are adopted, and the modal result is more in line with the real working condition compared with the modal analysis without considering the thermal effect.

This invention discloses a method for calculating noise through direct coupling between a worm gear structure and its acoustic field, belonging to the field of noise prediction technology for mechanical transmission systems. The method includes: decomposing the time-domain torque into DC and AC components; establishing a structure-acoustic field coupled finite element model with a matching layer (PML); solving for steady-state prestress using the DC component; treating the AC component as a disturbance under prestress, and directly solving the coupled dynamic equations through harmonic response to obtain the full-field sound pressure response in one step; finally, extracting the sound pressure level distribution to achieve noise prediction. This invention overcomes the shortcomings of the traditional "two-step method" (cumbersome process, neglecting the acoustic radiation of the worm gear itself) by linearizing the prestress and using a one-step direct coupling solution, achieving fast and high-fidelity noise prediction under steady-state conditions, significantly improving computational efficiency and accuracy.