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63 results about "Modal superposition" patented technology
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In-plane-control-based active vibration control method for wrinkled film
ActiveCN108897213AReduce vibrationImprove anti-disturbance abilityAdaptive controlControl orientedIn plane
The invention relates to an in-plane-control-based active vibration control method for a wrinkled film. On the basis of the analysis on the influence on dynamic characteristics of a film structure bya wrinkle form, a dynamic model of a wrinkled film is established; according to a modal superposition method, a space vector based on a natural mode of vibration is obtained and dynamic models of thewrinkled film under different loads are established; condensation polymerization is carried out on the dynamic models according to contributions to system vibration deformation by all orders of modes,so that a control-oriented film structural dynamic model is established; and with a model reference adaptive controller, a PID-MRAC control method based on in-plane-control multi-model switching is proposed. According to the method provided by the invention, no actuator needs to be pasted on the surface of the film; the out-of-plane vibration of the film is suppressed effectively; the characteristics of the film are not affected; the high stability of the film structure is ensured; and compared with the conventional PID control method, the in-plane-control-based active vibration control method enables the vibration time to be shortened by about 39.7%.
Owner:BAOJI UNIV OF ARTS & SCI +1
Elastic motion modeling method of trailing edge rudder gliding aircraft
ActiveCN105629725AGuarantee task progressIncrease awarenessAdaptive controlElastic vibrationEngineering
The invention belongs to the technical field of aircraft elastic motion modeling, and specifically relates to an elastic motion modeling method of a trailing edge rudder gliding aircraft. The method comprises the following steps: (1) converting an elastic body transverse free vibration into superposition of various mutually independent main vibrations by utilizing modal orthogonality; (2) according to a linear small disturbance hypothesis, under the action of external forces, still describing the transverse vibration of an elastic body approximatively by utilizing modal superposition, and determining a vibration mode function by structural characteristics (rigidity and quality distribution) of the elastic body and a boundary condition of the elastic body; (3) establishing a vibration differential equation according to the d'almbert's principle and other methods; and (4) analyzing the external forces, which comprise an aerodynamic force, a rudder surface control force, a posture jet pipe control force, a rudder surface swinging inertia force and the like, influencing an elastic vibration of the gliding aircraft. A traditional elastic motion modeling method is corrected and improved.
Owner:BEIJING LINJIN SPACE AIRCRAFT SYST ENG INST +1
Control-orientated large antenna modeling method
The invention relates to a control-orientated large antenna modeling method which comprises the steps of ansvs modal analysis, relevant vibration mode selection, modal parameter calculation, input and output matrix conversion, decomposition of each order of modality, calculation of the norm of each order of modality, modal polycondensation and modal superposition. The method has the advantages that due to the fact that antenna flexibility information is established in a control model, the model is closer to the reality and pointing error calculation is more accurate; due to the fact that a rigid model and a flexible model are both in a decoupled state, rigid corners and flexible deviation can be output by the rigid model and the flexible model respectively, and output processing can be conducted respectively.
Owner:XIDIAN UNIV
Dual-modal equation-based dynamic response analysis method for random noise environment
ActiveCN107748815AImprove dynamic response prediction efficiencyShorten the design cycleGeometric CADSubsonic/sonic/ultrasonic wave measurementRandom noiseStructural coupling
The invention provides a dual-modal equation-based dynamic response analysis method for a random noise environment. The method comprises the following steps of (1) dividing a structure and a vocal cavity in an acoustic-structural coupling system into different subsystems; (2) calculating modes of the structure subsystem and the vocal cavity subsystem; (3) calculating coupling parameters between the modes in the adjacent subsystems; (4) establishing a dual-modal equation of the coupling system; (5) through preprocessing, obtaining a cross-power spectrum of generalized force loads on the modes of the subsystems under the action of random loads; (6) calculating the dual-modal equation to obtain a cross-power spectrum of participation factors of all the modes; and (7) through modal superposition, calculating a random acoustic-structural coupling response of the system. The random dynamic response analysis method provided by the invention is the dual-modal equation-based dynamic response analysis method for the random noise environment. According to the method, the system is divided into the continuous coupling subsystems, and random vibration of the system is described by using the modes of the subsystem in a limited frequency band; and the analysis efficiency of the method is higher than that of a conventional finite element method.
Owner:SOUTHEAST UNIV
Method for analyzing random response of non-proportional damping structure under earthquake action
ActiveCN110083920AImprove response calculation efficiencyAvoid redundant calculationsDesign optimisation/simulationSpecial data processing applicationsModulation functionRandom vibration
The invention discloses a method for analyzing a random response of a non-proportional damping structure under an earthquake effect. The method comprises the following specific steps: 1, acquiring a unit impulse response of the structure about any excitation; 2, based on a random vibration theory, establishing a direct convolution formula responding to power spectrum calculation; 3, performing PODfeature orthogonal decomposition on the non-uniform modulation function excited by each point; and 4, calculating an evolution frequency response matrix by using FFT, and further determining an evolution power spectrum matrix and a variance matrix of the structure response. According to the method, the response statistics is explicitly represented as the convolution form about the pulse response,and the convolution is calculated by using the FFT technology, so that the response calculation efficiency is greatly improved; the method is suitable for a linear structure, is also suitable for a nonlinear structure, and can also be used for a linear system subjected to order reduction through a modal superposition method.
Owner:SOUTHWEST JIAOTONG UNIV
Blade vibration response analysis method based on fluid-solid interaction
PendingCN111523182ASmall amount of calculationGuaranteed solution accuracyGeometric CADDesign optimisation/simulationEngineeringMechanical engineering
The invention discloses a blade vibration response analysis method based on fluid-solid interaction. The blade vibration response analysis method comprises the following steps of: firstly, carrying out unsteady analysis on a flow field in a blade flow channel by adopting a nonlinear harmonic method to obtain unsteady load distribution on the surface of a blade, and extracting a load correspondingto a key frequency by adopting Fourier transform to obtain a pneumatic exciting force borne by the blade; secondly, carrying out fluid-solid interaction analysis on the blade and the flow field in theflow channel of the blade, analyzing aerodynamic work applied to the blade by the aerodynamic force when the blade vibrates, and acquiring modal aerodynamic damping ratios of all orders of vibrationof the blade in the flow field according to an energy equivalence principle; and finally, loading the aerodynamic exciting force and the modal aerodynamic damping ratio of each order onto the blade, and performing vibration response analysis on the blade by adopting a modal superposition method. The blade vibration response analysis method can efficiently and accurately analyze the vibration response of the blade under the action of the unsteady aerodynamic force, and provides support for the safety guarantee and design work of an engine.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
Turbine last-stage long blade torsional vibration stress obtaining method based on finite elements
InactiveCN112648024AAvoid accidentsMachines/enginesDesign optimisation/simulationStress distributionPower grid
The invention discloses a turbine last-stage long blade torsional vibration stress obtaining method based on finite elements, relates to the field of turbine design, and aims to solve the problem that a dynamic stress value obtained in the prior art cannot predict the safety of a turbine last-stage blade when a shafting is subjected to torsional vibration. Due to the fact that the torque value T of the shafting is closely related to long blade dynamic stress distribution caused by torsional vibration when a power grid is in transient imbalance, finite element solving is conducted on the stress of the whole circle of blades and the corresponding rotor structure at the working rotating speed; a stress-strain distribution value of each node is obtained, and first n-order frequencies f1-fn of the system are extracted by utilizing a Lanczos method; and the torque value T of the shafting is applied to the system as excitation when the transient state of the power grid is unbalanced, a modal superposition method is applied, and the dynamic stress value of the last-stage long blade is obtained. The dynamic stress value obtained through the calculation method can predict the safety of the turbine last-stage blade when the shafting is subjected to torsional vibration, and therefore accidents are avoided.
Owner:HARBIN TURBINE
Distributed optical fiber computing method for wing strain field reconstruction based on modal superposition principle
The invention relates to a distributed optical fiber computing method for wing strain field reconstruction based on a modal superposition principle, and belongs to the field of structural health monitoring. The method comprises the following steps that 1, based on measurement of fiber grating sensor wing structure strain, calculating the strain of the surface of a wing structure through fiber grating center wavelength offset; and 2, calculating a strain mode of the wing structure, and optimizing the fiber grating sensor network layout of the wing structure through the strain mode; 3, deducinga strain matrix corresponding to the position of the measurement point of the wing structure sensor and a conversion formula between strain matrixes of all points of the wing structure; and 4, for theproblem that the strain mode matrix is uncertain, adopting a regularization method to optimize the solution of the strain mode coordinates, and reducing the strain field reconstruction error. According to the method, response signals of fiber gratings with a small number of discrete points are collected, and a wing structure strain field is deduced and calculated through a formula.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
A wind turbine tower stress state calculation method based on a modal superposition method
ActiveCN109543258AMeet the needs of real-time online monitoringData processing applicationsDesign optimisation/simulationElement modelExtended finite element method
The invention relates to a wind turbine tower stress state calculation method based on a modal superposition method, Firstly, the finite element model of the tower is established, then the truncated modal matrix of the tower is calculated by the finite element method, and the principal vibration coordinates of the tower are calculated according to the real-time vibration values at the monitoring points. Finally, the real-time stress state of the tower is calculated by the modal superposition method. Using this method, the stress states of the whole tower and flange bolts can be calculated quickly according to the real-time vibration values of the finite vibration measuring points of the tower. The method has the characteristics of high calculation accuracy and fast calculation speed, and can meet the requirements of real-time online calculation.
Owner:SOUTHEAST UNIV
Theoretical detection method for determining location of damaged fastener
The invention relates to a theoretical detection method for determining the location of a damaged fastener. The theoretical detection method includes the steps that (1) a sensitive index limiting value is calculated, specifically, a modal superposition method is adopted, ordinary differential vibration equations of a steel rail and lining can be respectively obtained through orthogonal decomposition, the ordinary differential vibration equations are combined with a train body formula, single fastener damage is introduced, the fastener rigidity is 0 at the damaged fastener location x0, and vertical acceleration of a car body when a first wheel of the car body passes above the damaged location is the sensitive index limiting value and obtained; and (2) the damaged location is distinguished. The theoretical detection method has the beneficial effects that a subway integrated track bed train track coupling model is established, an integrated track bed (tunnel lining)-soil coupling analysis model is established based on a structure dynamics theory, sensitivity index car body vertical acceleration a and the condition that the damaged fastener rigidity is 0 are introduced, and the sensitive index limiting value is calculated. The theoretical detection method can be suitable for single fastener damage and multiple fastener damage conditions.
Owner:ZHEJIANG UNIV CITY COLLEGE
Netting and floating body coupling water elasticity response analysis method
ActiveCN111274728AImprove calculation accuracyImprove accuracyGeometric CADClimate change adaptationElement modelMarine engineering
The invention relates to a netting and floating body coupling water elasticity response analysis method. The method includes: establishing finite element model for a netting by adopting a mesh super-element method; carrying out modal analysis on the structure of the breeding equipment, and considering coordinated deformation among the main floating body, the slender floating body and the netting during modal analysis to obtain corresponding stress and strain under each modal; obtaining a wave current load of the netting by a mesh super-unit method; and establishing a motion equation of the breeding equipment, obtaining modal principal coordinates of the breeding equipment structure, and calculating the total stress, strain and motion response of the breeding equipment after modal superposition according to the principal coordinates. According to the method, the stress of each mesh can be no longer calculated through a super-unit method, so that the calculation workload is greatly reduced; by introducing the entity rate, the calculation precision of the netting fluid load is improved; through the coupling analysis of the floating body and the netting, the mutual influence between the netting and the floating body is considered when the motion response is calculated, so that the accuracy of the calculation result is greatly improved.
Owner:CHINA SHIP SCIENTIFIC RESEARCH CENTER (THE 702 INSTITUTE OF CHINA SHIPBUILDING INDUSTRY CORPORATION)
Modal parameter and vibration response calculation method for rotating joint type industrial robot
ActiveCN111597657AImprove versatilityFlexible modelingGeometric CADDesign optimisation/simulationDynamic equationKinetics equation
The invention discloses a modal parameter and vibration response calculation method for a rotating joint type industrial robot, and particularly relates to vibration characteristic analysis and calculation of the rotating joint type industrial robot. The method mainly comprises the steps of breaking the overall structure of the industrial robot into parts, and splitting the parts into a pluralityof elements with the transmission relation; establishing a transfer matrix and a transfer equation of each element; forming a system total transfer matrix and a transfer equation according to the element transfer chain; determining system boundary conditions according to the state vectors of the head and tail elements; solving the system characteristic equation to obtain the inherent frequency andthe inherent vibration mode of each order of the industrial robot; and solving the vibration response of the robot by utilizing the orthogonality and modal superposition principle of the augmented feature vector. According to the robot dynamics modeling and vibration analysis method, a system overall dynamics equation is not needed, the stylized modeling degree is high, the system matrix order islow, the calculation speed is high, and vibration characteristics and responses of the industrial robot can be accurately described and quickly calculated.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
Method for predicting structural deformation by analyzing power signals in narrowband range
InactiveCN102402647ACalculation speedImprove the accuracy of recognition resultsSpecial data processing applicationsModal superpositionFrequency domain
The invention discloses a method for predicting structural deformation by analyzing power signals in a narrowband range, which comprises the following steps that: the structure reaction power signals are observed by an impact vibration test of a civil structure, and a frequency domain transfer function of the structure is obtained by Fourier transform and spectral analysis; the whole frequency space of the frequency domain transfer function is divided into two to five continuous narrow subspaces; the modal parameter of each subspace is identified; and according to the modal superposition theory, the identification results of the subspaces are superposed, and the structural modal parameters are calculated and further the overall flexibility matrix is calculated. In the method, firstly, the overall frequency domain is divided into a plurality of narrowband regions, and the experimental data are analyzed in each narrowband region, and finally the analysis results of each narrowband region are integrated to identify the flexibility matrix of the structure, and thus the structural deformation of the structure under any static load is predicted. The method has the characteristics of short calculation time and high accuracy of predicted results, and is suitable for the health diagnosis and the security assessment for various engineering structures, especially the civil structure.
Owner:SOUTHEAST UNIV
Vibration noise numerical simulation method for piston engine
InactiveCN111241734ASimplify the modeling processImprove computing efficiencyDesign optimisation/simulation3D modellingKineticsElement model
The invention discloses a vibration noise numerical simulation method for a piston engine. The method includes: establishing a three-dimensional entity simulation model and a finite element model of the three-dimensional entity simulation model for the plate-type structure on the surface of the piston engine, and performing vibration modal analysis of the plate-type structure on the three-dimensional entity simulation model to obtain a surface modal result set and a surface node coordinate file of the plate-type structure; performing multi-body dynamics analysis on the three-dimensional entitysimulation model in combination with a finite element model to obtain a plurality of different exciting forces of the piston engine; applying different exciting forces to the plate-type structure ofthe three-dimensional entity simulation model, and calculating dynamic response results of the plate-type structure under different exciting forces by utilizing a modal superposition principle; solving a frequency range requirement of an acoustic physical quantity according to the acoustic boundary element model, and performing roughening processing on the finite element model to obtain an envelope surface grid and a node coordinate file; endowing the dynamic response result to boundary element grid nodes of the node coordinate file, and calculating and obtaining acoustic physical quantity ofacoustic radiation of the plate-type structure.
Owner:上海索辰信息科技股份有限公司
Numerical model method for solving ship horizontal motion response divergence in oblique waves
The invention relates to a numerical model method for solving ship horizontal motion response divergence in oblique waves. Specifically, the method comprises the following steps: step 1, on the basisof a PID (proportional integral and derivative) autopilot basic control equation, establishing a rudder force component expression on swaying motion and yawing motion in a matrix mode; step 2, including the force (moment) in a rigid / elastic hull motion equation; step 3, respectively solving each coefficient and acting force in the equation; step 4, finally, based on a Runge-Kutta method, solving an equation to obtain a hull motion response, and obtaining an elastomer load response by means of a modal superposition principle. According to the method, the defect of response divergence caused bysolving of the hull horizontal time domain motion equation in oblique waves can be fundamentally overcome, the method is suitable for load calculation of ships and ocean platforms, and a foundation can be provided for load response prediction of random waves.
Owner:HARBIN INST OF TECH AT WEIHAI
Design method for solving strong nonlinear time domain water elasticity problem based on improved moving particle semi-implicit method and modal superposition method
InactiveCN110750833ASolve processing problemsGeometric CADSustainable transportationTime domainEngineering
The invention discloses a design method for solving a strong nonlinear time domain water elasticity problem based on an improved moving particle semi-implicit method and a modal superposition method.The method is based on a fluid dynamic solver of an improved moving particle semi-implicit method (MPS) and a structural response solver of a mode superposition method based on a coupling rigid body and an elastic mode, and the fluid dynamic solver and the structural response solver achieve strong coupling in a time domain in an iterative mode. According to the method, the defect that the traditional potential flow-based water elasticity calculation cannot directly simulate the severe deformation of the free surface and the slamming phenomenon of the ship body is overcome, and the problem of mutual influence between the rigidity of the structure and the flexible motion mode is considered.
Owner:DALIAN UNIV OF TECH
Micro-miniature robot mobile mechanism design method based on collision driving
The present invention discloses a micro-miniature robot mobile mechanism design method based on collision driving. The method comprises the following steps: the first step: cutting off a high-order vibration mode based on the modal analysis result and the modal superposition theory, and constructing a multi rigid body finite freedom degree of a flexible foot aiming at the mode of vibration and the frequency of the low-order mode; the second step: establishing a collision model of the flexible foot and the walking surface based on the Hertz contact theory and the Coulomb friction theory; the third step: building an experiment system to measure the changing of the flexible foot motion parameter caused by the collision, combining parameters for analysis and integration, and performing identification of the collision model parameters. according to the micro-miniature robot mobile mechanism design method based on the collision driving, the mobile mechanism employs the elastic deformation and vibration of the flexible foot to realize movement, the flexible foot can have collision with the walking surface while vibration under the restraint effect of the walking surface, and a matrix, the flexible foot and the walking surface form a collision vibration system.
Owner:HARBIN INST OF TECH GENIUS INTELLIGENTTECH
Sensor measuring point optimization method for reducing strain field reconstruction error
InactiveCN111931395AEfficient solutionReduce reconstruction errorDesign optimisation/simulationSpecial data processing applicationsElement modelEngineering
The invention relates to a structure strain sensor measuring point optimization method. The invention particularly relates to a sensor measuring point optimization method for reducing a strain field reconstruction error. The layout advantages of fiber grating sensors are utilized to overcome the defects in the prior art, strain field reconstruction of a structure can be realized based on a strainfield reconstruction method of a modal superposition idea. The method comprises the following steps: step (1), firstly, establishing a finite element model of an actual structure, and performing modelcorrection on the established finite element model to ensure that the established finite element model has precision meeting requirements; (2) selecting a modal order required by strain field reconstruction, and extracting a strain modal matrix of the finite element model of the structure for the corrected finite element model; and (3) constructing a function relationship between the local strainmeasurement information and the overall strain field as shown in the specification: {epsilon all}=[T]{epsilon loc}, wherein [T] is a conversion matrix, {epsilon all} is a strain field vector, and {epsilon loc} is a local measurement point matrix.
Owner:JIANGSU UNIV OF TECH
Irregular closed space noise model and construction method and application thereof
PendingCN110276117AGet rid of dependenceDesign optimisation/simulationSpecial data processing applicationsEngineeringSound pressure
The invention belongs to the technical field of computer aided design, and discloses an irregular closed space noise model and a construction method and application thereof. An impedance-admittance and Green function method is adopted to establish a theoretical model of irregular closed space structure-acoustic coupling analysis, and the theoretical model is converted into a numerical analysis model, so that compared with a previous model, dependence on a substructure analytical solution is thoroughly eliminated, and the method can be used for an actual closed space without the analytical solution. Based on the response expression of the sound pressure and the plate vibration velocity of the irregular closed space structure-sound coupling analysis, a coupling coefficient calculation formula is found by using a modal superposition method, so that the structure-sound coupling calculation becomes possible. The interaction force between the piezoelectric film and the thin plate is calculated, and the rule that the static bending moment of the piezoelectric film acting on the thin plate under the constant electric field changes along with the thickness of the film can be derived.
Owner:SHENZHEN INSTITUTE OF INFORMATION TECHNOLOGY
A simply supported beam vibration experiment demonstration instrument
InactiveCN106448364BConvenient teachingObserve intuitivelyEducational modelsDegrees of freedomCantilever
The invention aims to provide a demonstrating instrument for a simply supported beam vibration experiment. In a physics teaching process, vibration of an infinite-degree-of-freedom object is usually demonstrated through vibrations of simply supported beams or cantilever beams. The simply supported beams in the demonstrating instrument vibrate under vibration excitations of vibration exciters, when the vibration excitation frequency equals to an inherent frequency of a specific phase, the beams resonate, and the vibrating form is approximate to a corresponding principal vibration mode. When the vibration excitation frequency of the vibration exciters is increased slowly, variation of the beams from a first-phase principal vibration mode to a second-phase and a third-phase principal vibration mode can be shown. The demonstrating instrument for the simply supported beam vibration experiment has the advantages that by amplifying displacement and vibration of the simply supported beams by directly demonstrating the principal vibration modes in various phases of the simply supported beams, experimental explanation in modeled teaching for the infinite-degree-of-freedom object vibration is facilitated, and by comparing and observing the multi-phase vibration modes, understanding to modal superposition on vibration is enhanced.
Owner:厉子宁
Dynamic response reconstruction method and system based on EMD and model polycondensation, and storage medium
ActiveCN112507585AImprove computing efficiencyReduce dimensionalityDesign optimisation/simulationComplex mathematical operationsTime domainElement model
Owner:CENT SOUTH UNIV
Demonstrating instrument for simply supported beam vibration experiment
InactiveCN106448364AConvenient teachingObserve intuitivelyEducational modelsDegrees of freedomVibration exciter
The invention aims to provide a demonstrating instrument for a simply supported beam vibration experiment. In a physics teaching process, vibration of an infinite-degree-of-freedom object is usually demonstrated through vibrations of simply supported beams or cantilever beams. The simply supported beams in the demonstrating instrument vibrate under vibration excitations of vibration exciters, when the vibration excitation frequency equals to an inherent frequency of a specific phase, the beams resonate, and the vibrating form is approximate to a corresponding principal vibration mode. When the vibration excitation frequency of the vibration exciters is increased slowly, variation of the beams from a first-phase principal vibration mode to a second-phase and a third-phase principal vibration mode can be shown. The demonstrating instrument for the simply supported beam vibration experiment has the advantages that by amplifying displacement and vibration of the simply supported beams by directly demonstrating the principal vibration modes in various phases of the simply supported beams, experimental explanation in modeled teaching for the infinite-degree-of-freedom object vibration is facilitated, and by comparing and observing the multi-phase vibration modes, understanding to modal superposition on vibration is enhanced.
Owner:厉子宁
Subsynchronous oscillation analysis method based on EEMD and Prony methods
ActiveCN111523231ASolving Modal Mixing ProblemsSolving the modal overlay problemGeometric CADDesign optimisation/simulationAlgorithmNoise
The invention discloses a subsynchronous oscillation analysis method based on EEMD and Prony methods, and belongs to the technical field of subsynchronous oscillation of power systems. The method comprises: firstly, using EEMD to decompose a noise-containing signal, removing a high-frequency noise component in the noise-containing signal, meanwhile, solving the modal mixing problem during EMD denoising, and after a stable signal is obtained, accurately recognizing characteristic parameters of subsynchronous oscillation through Prony. Centralized empirical mode decomposition (EEMD) denoising and Prony identification are combined so that the problem of modal superposition in EMD is effectively solved; because the Prony method is sensitive to noise signals, the result of the denoised signalsis more accurate by using Prony identification, the dominant mode of subsynchronous oscillation can be identified, the method is crucial for analyzing the source of oscillation and proposing inhibition measures, and the method has the advantages of strong noise immunity and high accuracy.
Owner:HUANENG CLEAN ENERGY RES INST
Aluminum plate impact load positioning analysis method based on acoustic mode superposition
ActiveCN112666261ARealize monitoringHigh precisionProcessing detected response signalSustainable transportationExternal irradiationModal analysis
The invention provides an aluminum plate impact load positioning analysis method based on acoustic mode superposition. The aluminum plate impact load positioning analysis method comprises the steps of radiation mode analysis of an aluminum plate, establishment of a radiation sound field of the aluminum plate, measurement of local sound field information and inversion of a load impact signal. The radiation modal analysis of the aluminum plate takes a rectangular thin plate as a research object, and the inherent frequency and modal shape function of the aluminum plate can be calculated according to a free vibration differential equation of the thin plate. And according to an acoustic mode superposition method, an external radiation sound field of the aluminum plate can be obtained, and a corresponding relation between the radiation sound field and a load impact signal is established. The microphone array is reasonably arranged on the aluminum plate, so that certain local sound field information can be measured. The inversion of the load impact signal adopts a near-field acoustic holography theory, the information of the whole sound field is inverted from the local sound field information, the position of the load impact is positioned according to the corresponding relation between the radiation sound field and the load impact signal, and the load impact characteristic is inverted.
Owner:HOHAI UNIV
Strain field reconstruction method and system based on Bayesian finite element model correction
PendingCN114580080AStrain monitoring results are accurateHigh precisionGeometric CADSustainable transportationElement modelFull field strain
The invention discloses a strain field reconstruction method based on Bayesian finite element model correction, and the method comprises the steps: carrying out the modal test of a crossbeam structure, and obtaining the modal data; constructing a posterior probability density function of the beam structure finite element model by using a Bayesian formula; to-be-corrected parameters of the finite element model are selected, and a corrected finite element model is obtained through calculation; performing fiber bragg grating sensor arrangement on the cross beam structure to obtain a strain response column vector, and establishing a finite point strain matrix and a full-field strain response matrix by using the corrected finite element model; the strain response column vector and the finite point strain matrix obtained through simulation are used for solving modal coordinates; and multiplying the modal coordinates by the full-field strain response matrix to obtain a full-field strain value under a static load working condition, and realizing strain field reconstruction. According to the method, uncertain finite element model correction and a strain field reconstruction method based on a modal superposition method are combined, and the strain monitoring result of the cross beam structure is more accurate.
Owner:SHANDONG UNIV
Modeling method for telescopic vibration characteristics of arm support of straight arm type aerial work platform
ActiveCN110298129AImprove calculation accuracyModeling Method of Precise Dynamic Characteristics of Telescopic BoomDesign optimisation/simulationSpecial data processing applicationsVibration controlCurve fitting
The invention discloses a modeling method for telescopic vibration characteristics of an arm support of a straight arm type aerial work platform when the straight arm type aerial work platform does telescopic motion. According to the method, a cantilever crane is segmented according to the combination condition and the section property between cantilever sections, and the whole cantilever crane isequivalent to a multi-cantilever-section variable-length cantilever beam with the end face provided with concentrated mass and rotational inertia. A Newton's second law is adopted to establish a motion differential equation of each arm section during telescoping, according to the boundary connection, a cantilever crane boundary condition and a transfer condition between the cantilever crane sections are obtained; a boom vibration mode at a series of moments by using a modal superposition method is colved; curve fitting is carried out on the relationship between the change parameters and the arm length; an actual vibration mode is replaced by approximation, a motion differential equation of each arm section is converted into a state space equation about generalized coordinates by means ofan orthogonal relation between the vibration modes and a Galerkin truncation method, and dynamic simulation is carried out under the environment of visual simulation software to obtain dynamic response of the head of the arm support. The method can provide theoretical reference for the telescopic vibration control of the boom.
Owner:HOHAI UNIV CHANGZHOU
a transient acceleration calculation method in an OLTC contact collision process based on a point sound source
ActiveCN109598022ADesign optimisation/simulationSpecial data processing applicationsCircular discSound sources
Owner:HOHAI UNIV
External rotor axial magnetic flux hub motor vibration and noise analytical calculation method
PendingCN113868929AFast Prediction of Electromagnetic VibrationsFast predictive noiseDesign optimisation/simulationSpecial data processing applicationsMotor vibrationElectric machinery
The invention discloses an outer rotor axial magnetic flux hub motor vibration and noise analytical calculation method, which belongs to the technical field of motor vibration and noise calculation and comprises the following steps of: S1, establishing an air gap magnetic field model and calculating electromagnetic force; S2, calculating modal parameters and vibration modes of an end cover; S3, calculating the vibration response of the end cover; S4, acquiring the overall sound power level of the magnetic flux motor; and S5, verifying a result. Based on the modal superposition method, the method can calculate the vibration response of any point on the surface of the end cover, rapidly predicts the electromagnetic vibration and noise in the whole speed range, provides a theoretical basis for the optimization design of the vibration noise of the axial flux motor, and is worthy of popularization and application.
Owner:ANHUI UNIVERSITY
Flexible baseline dynamic prediction method based on fiber grating sensor and wing mode
ActiveCN111475940AHigh measurement accuracyConvenient and accurate fixationSustainable transportationDesign optimisation/simulationFiberReal-time data
The invention discloses a flexible baseline dynamic prediction method based on a fiber grating sensor and a wing mode. According to the invention, the method comprises: employing a modal superpositionprinciple based on structural strain response to calculate structural displacement and a base line variable between child nodes, and then predicting a base line quantity change condition at a futuremoment by a base line dynamic model established based on flexible base line real-time data; employing the modal method to reduce the calculation amount and employing dynamic modeling to predict the flexible baseline in advance so as to solve the problem of real-time transfer alignment time delay caused by time consumption of resolving from the actual measurement dependent variable to the base linevariable, thereby facilitating the realization of high-precision pose real-time transfer alignment of child nodes. The method can be used for remarkably improving the real-time performance of transfer alignment and making up for the defects of previous baseline solution and estimation method research.
Owner:BEIHANG UNIV
Anti-seismic calculation mode superposition method of hybrid structure
PendingCN112528528AQuick judgmentAccurate judgmentGeometric CADDesign optimisation/simulationElement analysisFinite elemente analyse
The invention discloses an anti-seismic calculation mode superposition method of a hybrid structure, which comprises the following steps: S1, establishing a finite element analysis model of the structure, and further obtaining a motion equation, a mass matrix M, a rigidity matrix K and a damping matrix G of the structure; s2, obtaining a circular frequency omega j, a feature vector and a componentmodal internal force vector rj (j = 1... L) through regular modal calculation of the structure, and further calculating a damping coefficient gji (j, i = 1... L) through an equation; and S3, performing calculation by utilizing frequency domain iterative solution or time domain iterative solution to obtain node displacement x (t) or component internal force R (t), wherein t represents time. By implementing the invention, the damping matrix is clear in physical significance and simple in construction process, only one calculation result is provided, the uncertainty of the calculation result when classical damping assumption exists is avoided, and the calculation result is closer to an accurate value.
Owner:SHENZHEN INSTITUTE OF INFORMATION TECHNOLOGY
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