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38 results about "Transfer-matrix method (optics)" patented technology
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The transfer-matrix method is a method used in optics and acoustics to analyze the propagation of electromagnetic or acoustic waves through a stratified medium. This is for example relevant for the design of anti-reflective coatings and dielectric mirrors.
Method for analyzing shafting torsional vibration of turbo-generator set
InactiveCN101603855AAccurate moment of inertiaSolve nonlinear problemsVibration measurement in solidsMatrix methodNewmark-beta method
The invention discloses a method for analyzing the shafting torsional vibration of a turbo-generator set, which belongs to the technical field of power and large rotating machinery manufacture. The method comprises the following steps: firstly, segmenting a shafting body, and determining the external diameter, internal diameter and length of each shaft segment; secondly, calculating equivalent parameters of a shafting, including the rotation inertia and stiffness of each shaft segment; thirdly, calculating the rotation inertia of blades by finite integration technique; fourthly, modeling the shafting of which the shafting body is segmented into a concentrated mass block-spring model; fifthly, calculating the external torque of a shafting torsional vibration model; and finally, calculating shafting torsional vibration response by a Newmark-beta method and a Riccati increment transfer matrix method. The method takes non-linear factors into account during the analysis of shafting torsional vibration, and avoids the influences of the change of torsional vibration patterns with time and space on an analysis result.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)
Pipe excitation source identification and prediction method of vibration response to pipe excitation source
ActiveCN103049670AIncrease flexibilityFast recognitionSubsonic/sonic/ultrasonic wave measurementSpecial data processing applicationsVibration accelerationMeasurement point
The invention aims at providing pipe excitation source identification and a prediction method of vibration response to a pipe excitation source. The steps are collecting a pipe wall acceleration signal and transforming the collected time domain signal into a frequency domain signal through Fourier transform, performing excitation source identification and equivalence and using a linear system superposition method to determine the size of the pipe system equivalent excitation source through comparing the experimental data with the pipe system dynamics calculation result, and using a transfer matrix method for predicting the dynamic response to the vibration of any optional position of the pipe according to the equivalent excitation. According to the pipe excitation source identification and the prediction method of vibration response to a pipe excitation source, an appropriate measuring point easy to measure is chosen according to the specific arrangement of the pipe for the excitation source size identification and the pipe vibration prediction, so that problem of the pipe system excitation source characteristics and the difficult vibration measurement of some portions of the pipe and others can be solved, the experimental measurement points arrangement can be reduced and the flexibility of the pipe vibration measurement can be increased.
Owner:HARBIN ENG UNIV
Dynamic coupling time varying failure rate analysis method of on-orbit space flexible gear mechanism
ActiveCN104008240AAvoid the problem of low reliability calculation accuracySuitable for highly nonlinear situationsSpecial data processing applicationsFailure rateEngineering
A dynamic coupling time varying failure rate analysis method of a on-orbit space flexible gear mechanism comprises the seven steps that firstly, according to the fact that a shaft in the on-orbit space flexible gear mechanism is an elastic body, a kinetic equation of the flexible shaft is built, and the finite element method is adopted for analysis; secondly, a gear kinetic equation is built; thirdly, a nonlinear kinetics equation of coupling of the flexible shaft and a gear in the on-orbit space flexible gear mechanism is built; fourthly, transmission stimulation analysis is performed on the space flexible gear mechanism; fifthly, the Newmark algorithm is adopted to calculate a dynamic load coefficient; sixthly, a gear bending stress reliability limit state function is built in the on-orbit space flexible gear mechanism; seventhly, dynamic reliability and failure rate analysis are performed on the space flexible gear mechanism. The method solves the problem that reliability calculating accuracy is low because of nonlinear factors of a traditional transfer matrix method and mode superposition method, and has engineering practical value for improving reliability of the on-orbit space flexible gear mechanism and other spacecrafts. The method is also suitable for other flexible gear mechanisms.
Owner:BEIHANG UNIV
Statistical energy analysis-based ship cabin noise forecasting method
ActiveCN107944108AImprove efficiencyHigh precisionDesign optimisation/simulationSpecial data processing applicationsVibration accelerationStatistical analysis
The invention provides a statistical energy analysis-based ship cabin noise forecasting method. The method comprises the steps of 1, preliminarily building a statistical energy analysis-based ship cabin noise forecasting model by utilizing ship drawing data; 2, performing local detail optimization on an emphatically assessed cabin and load region in the built model, and constructing an external auxiliary sound cavity; 3, determining a vibration acceleration load and a sound power load of equipment by utilizing an experimental test; 4, performing calculation by utilizing the experimental test or a formula to determine loss factors in a steel plate and the sound cavity; 5, building a microacoustic analysis model of an outfitting material structure by utilizing a transfer matrix method, and obtaining acoustic parameters of an outfitting material through sound absorption and insulation analysis; 6, setting frequency response analysis as a 1 / 3 octave frequency, and setting a calculation frequency to be 31.5Hz-8kHz; and 7, performing ship cabin noise forecasting analysis by applying statistical energy analysis. The efficiency and precision of ship cabin noise forecasting can be effectively improved; and the method can be applied to ocean platform and ship cabin noise forecasting and control.
Owner:HARBIN ENG UNIV
Multi-cavity direct-through dual-layer perforating silencer capable of eliminating wide-band noise
InactiveCN106837625ACompact structureLarge noise reductionPipe elementsMachines/enginesTransfer matrixEngineering
The invention provides a multi-cavity direct-through dual-layer perforating silencer capable of eliminating wide-band noise. The multi-cavity direct-through dual-layer perforating silencer capable of eliminating the wide-band noise comprises an inlet end, a silencer body and an outlet end. At least two dual-layer perforating pipes are arranged in the silencer body. The dual-layer perforating pipes are connected in series and separated through partition plates. Each dual-layer perforating pipe comprises an outer pipe body and an inner pipe body, wherein through holes are distributed in the outer pipe body and the inner pipe body, a closed cavity is defined by the outer pipe body, the silencer body and the corresponding partition plate, and another closed cavity is defined by the inner pipe body, the outer pipe body and the corresponding partition plate. The silencer has the advantages that airflow circulates directly from the inlet end to the outlet end, the pressure loss is low, the size is small, the structure is simple, cost is low, and by designing the structure parameters through a multi-cavity one-dimension transfer matrix method, the high-amplitude and wide-band silencing effect can be achieved.
Owner:TONGJI UNIV
Dynamics forecasting method of random branch structure
InactiveCN102708297AIncreased number of degrees of freedomEasy to implementSpecial data processing applicationsStructural dynamicsTransfer matrix
The invention provides a dynamics forecasting method of a random branch structure. The dynamics forecasting method comprises the following steps of: (1) selecting a main transmission path, i.e. for a system which comprises the random branch structure, firstly, selecting one chain-type main transmission path from one boundary end to the other boundary end; (2) establishing each branch point model, i.e. by the influence of adsorbing each sub branch, establishing the model between state vectors of both front and rear ends of each branch point on the main transmission path; (3) establishing an integral model, i.e. establishing the integral model between state vectors of both initial and tail ends by an arrangement sequence of transfer elements and point elements of each field on the main transmission path; and (4) forecasting a structural dynamics problem, i.e. introducing a boundary condition and an external acting force which serve as definite conditions and applying a transfer matrix method to forecast the dynamics problem of a chain system. The dynamics forecasting method has wide application range, has simple and convenient implementing process, is very beneficial to programming calculating and has high forecasting accuracy; the integral solving process cannot cause the increase of a variable freedom degree value; and the forecasting efficiency is ensured high.
Owner:HARBIN ENG UNIV
Calculation verification method for torsional vibration modal of gas turbine pull-rod type rotor
InactiveCN102222123AImprove calculation accuracyReliable design basisSpecial data processing applicationsTransfer matrixEngineering
The invention discloses a calculation verification method for the torsional vibration modal of a gas turbine pull-rod type rotor, comprising the steps of: (1) establishing a transfer matrix equation of a pull-rod rotor contact section, and then introducing a contact section torsional rigidity correction coefficient in the equation; (2) calculating the torsional rigidity correction coefficient of the pull-rod rotor contact section in the equation; (3) calculating the modal frequency and the modal vibration mode of the rotor via a transfer matrix method by utilizing the transfer matrix equationand the torsional rigidity correction coefficient value of the pull-rod rotor contact section, wherein the contact effect of the rotor contact section is considered in the calculation; and (4) testing the torsional vibration modal frequencies of an experimental pull-rod rotor under different pre-tightening forces via a torsional vibration modal experiment, and comparing with the calculated result. According to the method disclosed by the invention, the influence of the contact effect on the calculation of the torsional vibration modal of the pull-rod type rotor can be efficiently considered and the torsional vibration modal frequency of the pull-rod type rotor can be more accurately calculated, thus a reliable basis is provided for reasonably designing the torsional vibration characteristics of the rotors of the type.
Owner:XI AN JIAOTONG UNIV
Truck dynamic modeling method based on transfer matrixes
ActiveCN108733917AOptimal Design StructureEasy to optimizeGeometric CADSustainable transportationDynamic modelsTransfer matrix
The invention discloses a truck dynamic modeling method based on transfer matrixes. The method comprises the steps of establishing transfer matrixes of dynamic elements in a truck dynamic model; carrying out reasonable assumption on a truck, thereby obtaining a rigid-flexible coupled dynamic model with truck features; on the basis of a transfer matrix method theory, determining truck element serial numbers, transmission directions and cutting locations; modularly establishing a transfer matrix method of the truck, scattering the elements in each module, establishing sub-module transfer matrixes, obtaining a total transfer matrix of the truck dynamic model through splicing, and establishing the truck dynamic model; and in a frequency domain, through road surface spectrum input, and carryingout inherent characteristic and dynamic characteristic analysis on the established model according to a random vibration theory. According to the method provided by the invention, the modeling efficiency and accuracy and a code reuse rate are improved, and the theoretical basis for truck ride comfort analysis is provided.
Owner:GUILIN UNIV OF ELECTRONIC TECH
Diesel engine air distribution system dynamic calculation method based on multi-body system transfer matrix
InactiveCN103034784ARealize kinetic performance calculationsEasy to set upSpecial data processing applicationsSystems researchMatrix method
The invention belongs to the field of diesel engine air distribution system researches and relates to a diesel engine air distribution system dynamic calculation method based on a multi-body system transfer matrix. The diesel engine air distribution system dynamic calculation method based on the multi-body system transfer matrix comprises the following steps of: building a cam profile Nth harmonic fitting function, selecting a state vector, a boundary condition, an initial input quantity and the like required by a multi-body system transfer matrix method, analyzing the mechanical properties of all components of an air distribution system, deducing a transfer matrix which reflects the mechanical properties, integrating all parameters to obtain a total transfer equation, solving the total transfer equation to obtain the dynamic response situation of each part, drawing the dynamic characteristic curve of each part and the like. The diesel engine air distribution system dynamic calculation method based on the multi-body system transfer matrix has the advantages that the mechanical response situations of all parts during the movement of the air distribution system can be intuitively reflected through the dynamic characteristic curves, the dynamic response results and the like of all parts, the method is suitable for air distribution systems of diesel engines with different speed types, the measuring and modeling time needed for building a three-dimensional model is greatly saved, and the obtained results are more effective than the results obtained through solution by using the traditional multi-rigid-body differential equation set.
Owner:FUZHOU UNIV
Development method of phonon crystal vibration reduction initial frequency of which is not higher than 200 Hz
InactiveCN101872612ASimple preparation processStrong designabilitySound producing devicesRubber materialManufacturing technology
The invention relates to a vibration reducing and sound insulating material, in particular to a development method of a phonon crystal the vibration reduction initial frequency of which is not higher than 200 Hz. The invention comprises the following steps. Metal material with 10e10 elastic modulus magnitude order and large density and rubber material with 10e6 elastic modulus magnitude order are chosen. The period size of the phonon crystal is 0.04m according to the stability condition. According to a transfer matrix method, equivalent density is obtained through calculation. The equivalent density method is adopted and when the vibration reduction initial frequency is lower than 200Hz, the height ratio the metal material and the rubber material is approximate to 1 to 1. The sectional areas of the metal material and the rubber material are calculated. The metal material and the rubber material are spliced periodically and then the phonon crystal the vibration reduction frequency of which is not higher than 200Hz can be obtained. The invention has the beneficial effects that the invention can obtain the band gap of low frequency when the periodical size is small, is applicable to low frequency vibration and noise reduction and has simple manufacture technology and strong designability.
Owner:UNIV OF SCI & TECH BEIJING
Linkage type row pile vibration isolation structure
InactiveCN103093055AImprove the vibration isolation effectLower amplitude ratioSpecial data processing applicationsElement modelStructural engineering
The invention relates to a linkage type row pile isolation structure. The structure is provided with a periodic row pile structure on the walking direction of row piles, and pile tops of the row piles are in mutually rigid linkage through linkage beams. Each pile in the same row of the piles is a concrete pile with arbitrary cross section, and is provided with same geometry material parameters; and piles in different rows can have different parameters. The linkage beams in the same groups have same geometry material parameters, and the linkage beams in different groups can have different parameters. Floquet transformation and a boundary element method are adopted, and a pile-soil boundary element model in a wave number domain is built. The linkage beams on the upper portion are processed through a transfer matrix method. The pile-soil boundary element model, coupling conditions and periodic conditions of the pile tops and the beams are adopted, and a calculation model of the linkage type row piles is built. Compared with free type row piles with pile tops not restricted, the linkage type row pile isolation structure can effectively reduce vibration isolation coefficients and improve vibration isolation effects.
Owner:JIANGSU UNIV
Multilayer constraining and damping implementation method for vibration damping of case of aeroengine
InactiveCN104565189AChange structureReduce vibration stressNon-rotating vibration suppressionFatigue damageTransfer matrix
The invention relates to a multilayer constraining and damping implementation method for vibration damping of a case of an aeroengine. The method comprises the following steps: (1) taking lightweight aluminum foil as a constraining material, sequentially sticking a viscoelastic material and the constraining material, carrying out multilayer constraining and damping processing on the case of the aeroengine, and establishing a multilayer constraining and damping case vibration analysis model; (2) determining the number of layers of a multilayer constraining and damping structure by adopting an improved transfer matrix method; (3) enabling the surface to be stuck of the case to keep a certain temperature; (4) gradually sticking a constraining and damping material to the case starting from one end of the constraining and damping material; (5) verifying the vibration damping effectiveness of the multilayer constraining and damping processed case. The method has the advantages that the method is simple and is easy to implement, and the vibration stress of the case can be effectively lowered, so that the fatigue damage resistance of the case is improved; multiple layers of constraining and damping have very good bonding performance and are firm in sticking, so that the case has a good vibration damping suppression effect.
Owner:AECC SHENYANG ENGINE RES INST +1
Test bench for acoustic performance development and verification of intake and exhaust system
InactiveCN109186972AAccurate noise reduction performanceGet the real transfer matrixVehicle testingMachine part testingSound sourcesTurbocharger
The invention provides a test bench for acoustic performance development and verification of an intake and exhaust system, comprising a standing wave tube assembly, a gas source system, an airflow control and acquisition system, an acoustic data acquisition system and a post-processing software platform. A sound source system is provided on both sides of the standing wave tube assembly. The gas source system, the airflow control and acquisition system are connected to the sound source system. The acoustic data acquisition system and the post-processing software platform are connected to the standing wave tube assembly. The sound source system emits sound waves, and the air source system generates airflow. The sound waves and the airflow enter the standing wave tube assembly, and the airflow is monitored by the airflow control and acquisition system. A sound signal is collected by the acoustic data acquisition system, and the obtained data is transmitted to the post-processing softwareplatform for calculation processing. According to the test bench for acoustic performance development and verification of intake and exhaust system, a proven dual source transfer matrix method is used, he frequency range of the test process can be customized, commonly used intake tuning components and exhaust mufflers are tested with low frequency, and broadband muffler of turbocharger is tested with the high frequency.
Owner:拾音汽车科技(上海)有限公司
Shafting load preadjusting method of metered spring base
InactiveCN103306302AImprove stabilityReduce low frequency vibrationFoundation testingTransfer matrixFinite element method
The invention relates to a shafting load preadjusting method of a metered spring base. The method sequentially comprises the following steps of (1) collecting the elevation hi of a rigid base bearing and a spring with the rigid Ki of a spring base corresponding to the bearing; (2) obtaining a relation between a bearing load and the elevation hi at a constant speed under the rigid base by adopting a transfer matrix method; (3) obtaining the stroke of the spring; (4) solving a reynolds equation by adopting a finite element method so as to obtain the floating amount of a shaft neck under a bearing load condition; (5) obtaining the elevation of the bearing; (6) replacing hi by use of the elevation of the bearing according to the f(hi) obtained in the step (2) so as to obtain an iterated bearing load; (7) returning to the steps (3)-(7) in due time; (8) obtaining the real load and practical elevation of the bearing at a constant speed under the spring base; and (9) obtaining the preadjusting amount delta of the elevation of the bearing. The method provided by the invention can be used for effectively improving the stability of the bearing and reducing the low-frequency vibration of the bearing and is wide in application prospect.
Owner:JIANGSU NUCLEAR POWER CORP
MultiLayered plexcitonic nanoparticles and methods of producing same for controlling plasmon-exciton distance
Multilayered nanoparticles and methods of producing same are provided for controlling plasmon-exciton distance. The nanoparticles include a silver core, a polyelectrolyte spacer layer exterior to the silver core, and a J-aggregate cyanine dye outer shell. This multilayer architecture served as a framework for manipulating the dual coupling of localized surface plasmon resonance exhibited by the silver core with the molecular exciton exhibited by the J-aggregate outer shell. The polyelectrolyte spacer layer promotes the formation of an excitonic J-aggregate while serving as a means of controlling the plasmon-exciton coupling strength through changing the distance between the core and the shell. An analytical expression based on Mie Theory and the Transfer Matrix Method is provided for describing the optical response of these multilayered nanoparticles. Computational and experimental results illustrate that the absorption wavelength of the J-aggregate form of the dye is dependent on both the distance of the dye layer from the silver core and the degree of dye aggregation.
Owner:UNITED STATES OF AMERICA
Calculation method for dynamic additional stress of roadbed under load effect of vehicles
InactiveCN109518573AAccurate solution of dynamic additional stressRoads maintainenceMatrix methodTransfer matrix
The invention discloses a calculation method for the dynamic additional stress of the roadbed under the load effect of vehicles. The calculation method includes the following steps: (1) according to actual conditions of the roadbed and surface of a road, establishing a two-dimensional elastic layered body model, and transforming stress and displacement in an elastodynamic control equation into state vectors under modal coordinates; (2) separating and eliminating a time variable in a dynamic additional stress expression; (3) subjecting the state vectors to Laplace transformation, and acquiringa stiffness matrix of layered foundations by a transfer matrix method; (4) according to initial conditions and boundary conditions, establishing a dynamic additional stress quantitative model of a layered roadbed and road surface system; (5) subjecting the model to Laplace inverse transformation by a Durbin method to obtain the dynamic additional stress of the roadbed under the load effect of thevehicles. The calculation method for the dynamic additional stress of the roadbed provided by the invention is suitable for selection of road and rail roadbed fillers and the structural combination design of the roadbed.
Owner:CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
Straight pile vertical impedance calculation method
PendingCN110598262AIn line with the actual situation of the projectImprove calculation accuracySpecial data processing applicationsVertical vibrationWave equation
The invention discloses a straight pile vertical impedance calculation method, which comprises the following steps: vertically dispersing a pile body of the straight pile and foundation soil accordingto the horizontal layering condition of a soil body, and dispersing the foundation soil in the radial direction according to the disturbance condition of soil around the pile; solving a wave equationof each soil ring layer and calculating the dynamic stiffness on the pile-soil contact surface through a radial transfer matrix method; and calculating the vertical impedance of the straight pile through a vertical transfer matrix method after solving the equation. The straight pile vertical impedance calculation method has the advantages that the vertical impedance of the straight pile under theradial heterogeneous condition of saturated soil around the pile caused by the construction disturbance effect in the layered foundation is calculated and considered; radial heterogeneity of layeredsaturated soil under a construction disturbance effect is considered through a bidirectional transfer matrix method, and meanwhile, a fractional derivative operator is adopted to describe a stress-strain relationship of foundation soil so as to improve calculation precision; and a Rayleigh rod vibration theory is adopted to describe vertical vibration of a pile body so as to consider a transverseinertia effect of pile body vibration. By means of the straight pile vertical impedance calculation method, the calculated vertical impedance of the straight pile better conforms to engineering practice.
Owner:HOHAI UNIV
Critical load calculation method of parallel-shaft tooth-typed compressor
A critical load calculation method of parallel-shaft tooth-typed compressor belongs to the field of rotating mechanical rotor dynamics and particularly includes following steps: (1) obtaining required parameters of critical loads of the parallel-shaft tooth-typed compressor; (2) calculating dynamic characteristic parameters of each gear output shaft under different powers according to the obtained parameters; (3) inputting the dynamic characteristic parameters into a dynamic equation and calculating a first-stage critical rotating speed, a second-stage critical rotating speed and a third-stage critical rotating speed of each gear output shaft under different powers through a transfer matrix method; (4) fitting the first-stage critical rotating speed, the second-stage critical rotating speed and the third-stage critical rotating speed of each gear output shaft under different powers through a polynomial to obtain fitting functions of each critical rotating speed; and (5) according to an operation rotating speed and the critical rotating speed fitting function of each gear output shaft, determining whether a critical rotating speed of each gear output shaft exists or not in design and calculating the particular critical rotating speed. The method is used for determining whether the critical load of each gear output shaft exists or not during design of the parallel-shaft tooth-typed compressor, thereby guiding a designer to optimize design of the compressor.
Owner:BEIJING UNIV OF CHEM TECH
Pointing accuracy calculation method for spaceborne deployable antenna system
ActiveCN109931917ADeployable on-orbit pointing accuracyEasy accessAngle measurementSurveying instrumentsTransfer matrixAngular error
The invention provides a pointing accuracy calculation method for a spaceborne deployable antenna system. The deployable antenna system comprises a feed source and a reflection surface, wherein the feed source is fixedly mounted on a satellite body, and the reflection surface is connected with the satellite body through M cascaded deployment arms. The method includes the following steps that: (1)a feed source body coordinate system SigmaF, each of deployment arm body coordinate systems Sigma1 to SigmaM, and a reflection surface body coordinate system SigmaA are defined; (2) with the reflection surface adopted as a datum, an ideal parabolic antenna system is established, so that the theoretical pointing of the deployable antenna system can be obtained; (3) the installation accuracy of thefeed source and the first-stage deployment arm is measured, and the actual pointing of the deployable antenna system is calculated through a transfer matrix method according to inherent error transferrelationships between various components of the deployable antenna system, inherent error being angular error which is brought by manufacturing tolerances after the deployment arms are deployed, andthe actual pointing of the deployable antenna system is determined; and (4) the actual pointing and theoretical pointing of the deployable antenna system are compared with each other, so that the pointing accuracy of the antenna system can be obtained.
Owner:CHINA ACADEMY OF SPACE TECHNOLOGY
Shafting centering calculation method of novel shafting structure under specific centering requirement
The invention discloses a shafting centering calculation method of a novel shafting structure under a specific centering requirement. The method is used for guiding selection of each bearing elevation and on-site mounting of large machine set shafting. The method is combined with a transfer matrix method, a moment balance equation which reflects the relation among a shafting structure, a bearing bending moment and the elevation is provided on the basis of a three-bending-moment equation, and a shafting centering calculation model is established. According to the centering requirement during mounting of single-supporting structure shafting, a calculation method for solving each bearing elevation of the single-supporting structure shafting under the condition that the bending moment of a shaft coupler is zero is provided. The bearing elevation of the single-supporting structure shafting is calculated by adopting the method, and the correctness of the shafting centering calculation method is verified by comparing the bearing elevation with the bearing elevation actually measured by a manufacturer. The method can provide guidance for on-side mounting of the large machine set and selection of the bearing elevation.
Owner:XI AN JIAOTONG UNIV
Multi-cavity insert tube type double-layer perforated silencer capable of eliminating broadband noise of supercharging air intake system
InactiveCN106894924ACompact structureGood noise reduction effectMachines/enginesIntake silencers for fuelBroadband noiseEngineering
The invention relates to a multi-cavity insert tube type double-layer perforated silencer capable of eliminating broadband noise of a supercharging air intake system. The silencer comprises an inlet end, silencer main bodies and an outlet end. The silencer main bodies are internally provided with at least two double-layer perforated tubes. All the double-layer perforated tubes are connected in series and partitioned through partition plates. Each double-layer perforated tube comprises an outer tube body and an inner tube body which are provided with perforated holes, the outer tube bodies, the corresponding silencer main body and the corresponding partition plate form a closed cavity, the inner tube body extends from the inlet side to the outlet side, and the inner tube body, the corresponding outer tube body and the corresponding partition plate form an unclosed cavity. The silencer is low in pressure loss, compact in structure and low in manufacturing cost, and structural parameters are designed through a multi-cavity one-dimensional transfer matrix method to achieve the high-amplitude broadband silencing effect.
Owner:TONGJI UNIV
Chinese text named entity recognition method
PendingCN110472248AImprove performanceImprove robustnessNeural architecturesNeural learning methodsFeature extractionNamed-entity recognition
The invention discloses a Chinese text named entity recognition method which comprises the following steps: when a named entity recognition request is received, analyzing the named entity recognitionrequest to obtain a to-be-recognized Chinese text; respectively extracting character features, word features and whole sentence features in each sentence of the to-be-recognized Chinese text by takingthe sentence as an analysis unit; respectively splicing the character features and the word features of each word in the Chinese text to be recognized and the sentence features of the sentence wherethe word features are located to obtain a feature sequence respectively corresponding to each word; extracting a context feature of each feature sequence to obtain a context feature extraction result;and according to a context feature extraction result, labeling each named entity of the to-be-recognized Chinese text from each word by utilizing a Markov transfer matrix method. According to the method, the named entity recognition performance is greatly improved, and the recognition accuracy is improved. The invention furthermore discloses a Chinese text named entity identification apparatus and device, and a storage medium, which have corresponding technical effects.
Owner:GUANGDONG UNIV OF TECH
Analyzing method of dynamic characteristics of biomimetic seal whisker sensor
The present invention provides an analyzing method of the dynamic characteristics of a biomimetic seal whisker sensor. The analyzing method comprises the following steps of : dividing a biomimetic seal whisker into a plurality of continuous Timoshenko beam sections; according to the kinematical equation and the dynamic balance equation of the Timoshenko beam sections, calculating the frequency-response function H00 of the linear displacement in accordance with shear force, the frequency-response function N00 of the angular displacement in accordance with the shear force, the frequency-response function L00 of the linear displacement in accordance with the bending moment, and the frequency-response function P00 of the angular displacement in accordance with the bending moment, of any point on the biomimetic seal tentacle. The analyzing method of the dynamic characteristics of the biomimetic seal whisker sensor adopts a multi-section Timoshenko beam theory and a transfer matrix method to analyze the dynamic characteristics of the biomimetic seal whisker in the free state, and reveals the influence rules of elasticity modulus, shear coefficients, damping ratios, sectional dimensions and the like on structural natural vibration characteristics, so that the analyzing method disclosed by the present invention has an important significance in the development of the biomimetic seal whisker sensor.
Owner:CHANGZHOU COLLEGE OF INFORMATION TECH
A Time-varying Failure Rate Analysis Method for Dynamic Coupling of On-orbit Space Flexible Gear Mechanism
ActiveCN104008240BAvoid the problem of low reliability calculation accuracySuitable for highly nonlinear situationsSpecial data processing applicationsFailure rateEngineering
A dynamic coupling time varying failure rate analysis method of a on-orbit space flexible gear mechanism comprises the seven steps that firstly, according to the fact that a shaft in the on-orbit space flexible gear mechanism is an elastic body, a kinetic equation of the flexible shaft is built, and the finite element method is adopted for analysis; secondly, a gear kinetic equation is built; thirdly, a nonlinear kinetics equation of coupling of the flexible shaft and a gear in the on-orbit space flexible gear mechanism is built; fourthly, transmission stimulation analysis is performed on the space flexible gear mechanism; fifthly, the Newmark algorithm is adopted to calculate a dynamic load coefficient; sixthly, a gear bending stress reliability limit state function is built in the on-orbit space flexible gear mechanism; seventhly, dynamic reliability and failure rate analysis are performed on the space flexible gear mechanism. The method solves the problem that reliability calculating accuracy is low because of nonlinear factors of a traditional transfer matrix method and mode superposition method, and has engineering practical value for improving reliability of the on-orbit space flexible gear mechanism and other spacecrafts. The method is also suitable for other flexible gear mechanisms.
Owner:BEIHANG UNIV
Dynamics forecasting method of random branch structure
InactiveCN102708297BImprove general performanceSpecial data processing applicationsStructural dynamicsTransfer matrix
The invention provides a dynamics forecasting method of a random branch structure. The dynamics forecasting method comprises the following steps of: (1) selecting a main transmission path, i.e. for a system which comprises the random branch structure, firstly, selecting one chain-type main transmission path from one boundary end to the other boundary end; (2) establishing each branch point model, i.e. by the influence of adsorbing each sub branch, establishing the model between state vectors of both front and rear ends of each branch point on the main transmission path; (3) establishing an integral model, i.e. establishing the integral model between state vectors of both initial and tail ends by an arrangement sequence of transfer elements and point elements of each field on the main transmission path; and (4) forecasting a structural dynamics problem, i.e. introducing a boundary condition and an external acting force which serve as definite conditions and applying a transfer matrix method to forecast the dynamics problem of a chain system. The dynamics forecasting method has wide application range, has simple and convenient implementing process, is very beneficial to programming calculating and has high forecasting accuracy; the integral solving process cannot cause the increase of a variable freedom degree value; and the forecasting efficiency is ensured high.
Owner:HARBIN ENG UNIV
Modal modeling method of kinematic system with spatial six degrees of freedom
The invention provides a modal modeling method of a kinematic system with spatial six degrees of freedom, which comprises the following steps: scattering a parallel kinematic system with complex spatial six degrees of freedom into a plurality of substructures; computing the modalities of the previous orders of the substructures by adopting a substructure transfer matrix method to acquire low-order modality characteristics of the substructures; constructing a modal matrix; converting physical coordinates into modal coordinates by modal coordinate conversion; establishing a modal kinematic second order differential equation for each substructure; removing the redundant degree of freedom; carrying out modal synthesis on each substructure, thereby establishing an integral modal kinematic equation of the parallel kinematic system with spatial six degrees of freedom to acquire a modal model of the parallel kinematic system with spatial butted six degrees of freedom; and finally, converting the modal model into physical coordinates through coordinate conversion to acquire a physical spatial dynamic equation. The modal modeling method of the kinematic system, which is provided by the invention, has overlarge working space, overlong kinematic routes of supporting legs and high bandwidth and accuracy requirements of the system, and overcomes the limitation of multi-rigid body modeling of a spatial butted overlarge kinematic system.
Owner:HARBIN INST OF TECH
Calculation Method of Diesel Engine Valve System Dynamics Based on Multibody System Transfer Matrix
InactiveCN103034784BRealize kinetic performance calculationsEasy to set upSpecial data processing applicationsSystems researchMatrix method
The invention belongs to the field of diesel engine air distribution system researches and relates to a diesel engine air distribution system dynamic calculation method based on a multi-body system transfer matrix. The diesel engine air distribution system dynamic calculation method based on the multi-body system transfer matrix comprises the following steps of: building a cam profile Nth harmonic fitting function, selecting a state vector, a boundary condition, an initial input quantity and the like required by a multi-body system transfer matrix method, analyzing the mechanical properties of all components of an air distribution system, deducing a transfer matrix which reflects the mechanical properties, integrating all parameters to obtain a total transfer equation, solving the total transfer equation to obtain the dynamic response situation of each part, drawing the dynamic characteristic curve of each part and the like. The diesel engine air distribution system dynamic calculation method based on the multi-body system transfer matrix has the advantages that the mechanical response situations of all parts during the movement of the air distribution system can be intuitively reflected through the dynamic characteristic curves, the dynamic response results and the like of all parts, the method is suitable for air distribution systems of diesel engines with different speed types, the measuring and modeling time needed for building a three-dimensional model is greatly saved, and the obtained results are more effective than the results obtained through solution by using the traditional multi-rigid-body differential equation set.
Owner:FUZHOU UNIV
A Calculation Method of Critical Load of Parallel Shaft Gear Compressor
Owner:BEIJING UNIV OF CHEM TECH
Quantitative calculation method and system for vibration response of complex composite shell structure in fluid medium
InactiveCN104573377BEasy to operateEasy to implementSpecial data processing applicationsCollocationTransfer matrix
The invention discloses a method and system for quantitatively calculating the vibration response of a complex combined shell structure in a fluid medium, wherein the method includes the following steps: obtaining structural parameters and excitation parameters of the combined shell system in the fluid medium; according to the obtained structural parameters and excitation parameters, Collocate points on the surface of the combined shell along the direction of the generatrix, use the fine integration method to calculate the field transfer matrix and point transfer matrix between the collocated points of the combined shell system, and calculate the external force vector; according to the boundary conditions at both ends of the combined shell system and the structural continuity conditions, establish The dynamic model of the fluid medium-combined shell system; the vibration response of the fluid medium-combined shell system is obtained by solving the Moore-Penrose generalized inverse matrix. Based on fine integration and transfer matrix method, the invention can quantitatively calculate the vibration response of the complex combination shell in the fluid medium which is generated by external excitation, and provides reference and basis for the analysis of the vibration characteristics of the underwater vehicle.
Owner:WUHAN UNIV OF TECH
A Modeling and Solving Method for Manipulator Based on Improved Transfer Matrix of Multibody System
InactiveCN104573255BSimple modelLower orderSpecial data processing applicationsProcess systemsResearch Object
The invention discloses a method for establishing and solving a manipulator model based on an improved multi-body system transfer matrix. According to the structural characteristics, motion transmission and force transmission relationship of the planar manipulator, the present invention improves the discrete-time transfer matrix method of the multi-rigid body system, establishes a unified model of n-degree-of-freedom serial manipulators, and aims at the relationship between the joint space and the operation space of the manipulator. Based on the two known motion conditions between the two, by setting the boundary conditions, the kinematics and dynamics solution method and process of the system model are proposed. The research object of the present invention is a planar serial robot system. The mathematical model established by using the improved method of the multi-body system discrete time transfer matrix not only has the characteristics of flexible modeling and small calculation scale, but also can cover the kinematics and dynamics characteristics of the system at the same time. , which is more effective than the traditional robot modeling method, embodies the superiority of the new method, and achieves the goals of clear thinking, simple programming and easy realization.
Owner:TIANJIN UNIVERSITY OF TECHNOLOGY
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