226 results about "Nonlinear vibration" patented technology

The invention relates to an arrangement and a method for converting an input signal v into an output signal p(r_a) by using an electro-mechanical transducer and for reducing nonlinear total distortion p_d in said output signal p(r_a), whereas the nonlinear total distortion p_d contains multi-modal distortion u_d which are generated by nonlinear partial vibration of mechanical transducer components. An identification system generates distributed parameters P_d of a nonlinear wave model (N_d) and lumped parameters P_l of a network model (N_l) based on electrical, mechanical or acoustical state variables of transducer measured by a sensor. The nonlinear wave model distinguishes between activation modes and transfer modes, whereas the activation modes affect the transfer modes, which transfer the input signal u into the output signal p. A control system synthesizes based on the physical modeling and identified parameters P_d and P_l nonlinear distortion signals v_d and v_l which are supplied with the input signal v to the transducer and compensate for the distortion signals u_l and u_d generated by the transducer nonlinearities.

Systems for flowably dispensing dry powders include means for generating a first non-linear vibration input signal, the first non-linear input signal comprising a carrier frequency modulated by a plurality of different selected frequencies that correspond to a first dry powder formulation whereby first meted quantities of the first dry powder are serially dispensed to a receiving member. Related devices and computer program products for dispensing dry powders are also described.

The invention provides an engineering nonlinear vibration inspection method. The method adopts a wavelet nonlinear threshold value filtering wave to filter wide-frequency background noise of a three-direction acceleration signal and to remove DC bias so as to get the treated acceleration signals after frequency domain filtering and removal of trend term. Then speed signals and displacement signals are obtained after the acceleration signals is subject to a first time and second time integrals and removal of trend term. The characteristics and types of the nonlinear vibration are determined through a three-dimensional phase space diagram and other calculations of a reconstructed phase space tested by the three-dimensional phase space diagram. The invention adopts three-direction low resistance piezoelectricity acceleration meter to measure the vibration accelerations of three orthogonal directions. The invention has convenient installation, easy usage and reliable analysis, overcomes the problems of drifting, delay and aberration of the actual acceleration signals after passing through analog integration or digital integration. The invention plays an important role in the engineering nonlinear vibration inspection for mechanical mechanisms, bridges, dams and buildings, etc.

Methods for flowably dispensing dry powders from a hopper having a dispensing port and a dry powder flow path can include: (a) generating a first non-linear vibration input signal, the first non-linear input signal comprising a plurality of different selected frequencies that correspond to a first dry powder formulation; (b) applying the first non-linear vibration input signal to a dispensing hopper having at least one dispensing port while the first dry powder formulation is flowing therethrough; and (c) dispensing a first meted quantity of the first dry powder through the dispensing port to a receiving member. Related devices and computer program products for dispensing dry powders are also described.

The present invention discloses a vibration fault diagnosis method based on confirming the learning theory. The method comprises the following steps: (1) executing learning exercise to the normal mode and fault mode of the diagnosed system; (2) establishing a mode database (comprising a normal mode and a fault mode); (3) establishing a dynamic estimator; (4) comparing the state of the dynamic estimator with the state of the detected system to generate a residual error; and (5) evaluating the residual error thereby discovering and eliminating the fault. The method is suitable for diagnosing the fault of complicated unknown non-linear vibration system. The unknown normal mode and fault mode can be studied to establish a mode database thereby executing fast failure discovery and elimination.

The invention provides a fluid power sound source excitation method of a piezoelectric generator. By means of change characteristics generated by air flow after the air flow flows through a pipeline and the characteristic that sound waves cause structure vibration when spreading in a cavity and a pipe hole, a novel air flow induced sound piezoelectric power generation forced vibration device free of movable parts is provided. The device is provided with a non-linear vibration mechanical system capable of mechanically and automatically adjusting air flow to excite a fluid power sound source, can meet the requirement of self-power-supply of application systems in various fields such as automobiles, unmanned vehicles, weapon application systems, aerospace and aviation systems, robots and city or community illumination, fully uses clean renewable energy sources and has important theoretical value and engineering mentoring meaning.

The invention relates to a vibration response simulation analyzing method for a rolling bearing with single-point failures. On the basis of a Hertz contact theory, related knowledge about kinematics and kinetics are utilized to establish a five-degree-of-freedom nonlinear vibration mode of a rolling bearing and kinetic differential equations of the rolling bearing while influencing factors like slipping of rolling balls, oil slick rigidity and the like are taken into consideration, according to that the rolling balls change due to contact deformation is caused when the rolling balls roll through partial failures, a partial failure model of the rolling bearing is introduced into the kinetic differential equations of the rolling bearing, and the single-point failures of the rolling bearing are classified according to length-width ratios of the failures and size ratios between the failures and the rolling balls so as to establish different failure shape functions; the differential equations are solved by an ode solver in MATLAB (matrix laboratory) software, and vibration responses of the rolling bearing are simulated when an inner ring, an outer ring and the rolling balls of the rolling bearing are suffered from the single-point failures. By the aid of the vibration response simulation analyzing method, vibration responses of the bearings with failures in different sizes can be simulated. Compared with traditional methods for acquiring vibration responses of failed bearings, the vibration response simulation analyzing method has the advantages that an experimental period is short and experimental cost is saved. The computation for the vibration responses for the failed rolling bearings can lay the foundation of late failure diagnosis for the rolling bearings.

The invention discloses a two-dimensional nonlinear vibration-isolating suspension frame of seats of an off-road vehicle. The two-dimensional nonlinear vibration-isolating suspension frame consists of a vertical vibration-isolating part and a transverse vibration-isolating part, which are respectively used for achieving vibration isolating effects in the vertical direction and the transverse direction, and are fixed by virtue of a bolt. The two-dimensional nonlinear vibration-isolating suspension frame has vibration isolating effects in the vertical direction and the transverse direction, adopts the non-linear vibration isolating principle, and is suitable for various off-road vehicles, especially the off-road vehicles, such as excavators, with very great transverse vibration.

The invention discloses a positioning and detection method and a system for crack positions of a wind turbine blade. The positioning and detection method comprises the following steps: marking the wind turbine blade, and determining a plurality of mark point positions; collecting a non-cracking nonlinear vibration response signal of each mark point position when the wind turbine blade is not cracked and a cracked nonlinear vibration response signal of each mark point position when the wind turbine blade has a crack for a same piece of wind turbine blade under a same working state; calculatinga mutual information entropy of nonlinear vibration response signals before and after crack damage occurs at each mark point position according to the non-cracking nonlinear vibration response signaland the cracked nonlinear vibration response signal; calculating a vibration response nonlinear degree change amount before and after crack damage occurs at each mark point position according to the mutual information entropy; and determining the crack position according to the vibration response nonlinear degree change amount. The positioning accuracy of the crack position of the wind turbine blade can be improved by adopting the positioning and detection method and system provided by the invention.

The invention discloses a method for constructing a dynamic model of a nonlinear mechanical system. The method includes the steps of constructing an oscillatory differential equation containing uncertain parameters; actually measuring vibration data to form a data sample; resampling data samples; using a particle swarm algorithm to identify the uncertain parameters and obtain uncertain parameter estimation samples; applying a machine learning algorithm to train the uncertain parameters, and continuously correcting the uncertain parameters; and examining precision and accuracy of the established model. According to the method, first the nonlinear oscillatory differential equation is established, and then the improved particle swarm algorithm is applied; the uncertain parameter estimation samples of the nonlinear mechanical system are obtained based on measured data identification, the uncertain parameter estimation samples are trained through an on-line learning algorithm, equation error correction function samples are trained through a neutral network learning algorithm, accuracy of the uncertain parameters is greatly improved, and the shortcoming that the established model is sufficient in precision is overcome.

The invention relates to a loaded tooth surface contact analysis method direct at epicycloid bevel gear errors, and belongs to the field of theory of non linear vibration. Gear pair elastic deformation, support system torsion, gear processing errors and machine tool setting errors are taken into consideration to derive a novel error loaded contact analysis method. When analyzing one loaded tooth surfaced contact, real situation can be closer. The loaded tooth surface contact analysis method is usually used for setting parameters and machine tool parameters via V-H-J (V is the longitudinal set parameter of a gear pair, and the upward direction of a small gear is active; H is a coordinate set parameter of the gear pair, and the direction facing towards the big end of the small gear is active; J is the adjusting parameter along a coordinate direction, and the direction, distant from a big gear, of the small gear is active) within a real contact area under the conditions of loading and delivering errors and simulated load distribution and processing, so that impact of the errors is compensated to improve delivering performance and correct size and position of the contact area.

The invention discloses a helicopter rotor abnormity detecting method which comprises the steps of analyzing and processing original vibration data; extracting a helicopter rotor state characteristic; training a support vector data model by means of a rotor data characteristic in a normal state; and finally performing abnormity detection on the rotor according to the established model. The helicopter rotor abnormity detecting method is advantageous in that the effective fault characteristic is extracted for aiming at non-smooth and nonlinear vibration data; and on condition that only normal state data are available, the helicopter rotor abnormity detecting method according to the invention satisfies a requirement of abnormal characteristic data in a routine method.

The invention provides a satellite attitude anti-interference fault-tolerant control method based on T-S fuzzy modeling. Firstly, performing modeling on the nonlinear vibration interference generatedby an orbiting satellite flywheel through a T-S fuzzy model, and constructing a T-S fuzzy interference observer to estimate and cancel the interference generated by the flywheel vibration; secondly, estimating time-varying actuator failures in the system through designing a fault diagnosis observer, and performing reconstitution in composite control; and finally, combining the T-S fuzzy interference observer, the fault diagnosis observer, a robust (the formula is as shown in the specification) state feedback controller and a convex optimization algorithm to construct a composite layered anti-interference fault-tolerant controller and solve a control gain and an observer gain, therefore, the control accuracy is improved on the basis of ensuring system safety and stability. The invention hasthe advantages of strong robustness to interference, high reliability, convenient design, and the like, and can be used for the attitude control system of a spacecraft or a satellite.

Methods, systems, and computer program products flowably process dry powders using a non-linear vibratory signal individualized or customized to a target dry powder undergoing processing to facilitate fluidic flow through a flow channel.

The invention discloses a wind array type magnetic nonlinear piezoelectric power generation device, and relates to the field of electromagnetic driving and new energy utilization. The wind array typemagnetic nonlinear piezoelectric power generation device has the advantages of being simple in structure, low in cost, wide in resonance frequency band and the like. The device is composed of a generator casing, L-shaped supporting beams, linear supporting beams, ceramic piezoelectric plates, magnets, a driving shaft, bearings, fan blades and a base. The ceramic piezoelectric plates, the L-shapedsupporting beams and the magnets form L-shaped piezoelectric vibrators; the L-shaped piezoelectric vibrators and the base form a stator part of a generator; the linear supporting beams, the ceramic piezoelectric plates and the magnets form linear piezoelectric vibrators; the linear piezoelectric vibrators, the driving shaft and the blades form a rotor part of the generator; and power is input to the rotor through the blades, the rotor is driven to rotate in the stator by the power of the blades, and meanwhile, the L-shaped piezoelectric vibrators and the linear piezoelectric vibrators generatenonlinear vibration. The device is used for meeting the energy requirements of low-energy-consumption electronic products.

The invention discloses an electrostatic control device for a resonator nanometer beam. The electrostatic control device is composed of a driving device, a single extraction device and a control device. The character that the resistance value of a graphene film sensor is changed along with bending deformation of the nanometer beam is used, changed voltage signals of the graphene film sensor serve as control input signals, and nonlinear vibration of the nanometer beam is controlled through axial control force produced by an axial parallel plate controller. The electrostatic control device aims at avoiding the harmful nonlinear phenomenon caused by electrostatic driving of the resonator nanometer beam, and therefore the vibration of the nanometer beam is similarly-linear stable vibration.

The invention discloses a testing method and a testing system for nonlinear internal resonance representation of fiber composite boards. The method includes selecting internal resonance inherent frequencies of two steps of a composite board, and pre-determining dimension parameters and material parameters, for forming internal resonance of the composite board, according to an integral-multiple coordination method; processing the composite board; testing the internal resonance inherent frequencies of the two steps of the composite board; judging whether the internal resonance inherent frequencies of the two steps are in integral-multiple relation or not, and if not, adjusting the clamping position of the composite plate slightly and retesting the internal resonance inherent frequencies of the two steps of the composite board to enable the internal resonance inherent frequencies of the two steps to have integral-multiple relation; performing internal resonance representation testing on the composite board under different stimulation conditions, analyzing vibration characteristics of nonlinear internal resonance, and concluding change rules of nonlinear vibration response. By the testing method, an integral-multiple coordination theory is provided to calculate the inherent frequency of the composite board, specific parameters of the composite board are determined, and accordingly,testing accuracy and efficiency are high.

The invention discloses a piecewise nonlinear vibration isolator and a design method therefor. The method comprises: firstly, adopting an analytic method, i.e., an average method to obtain an amplitude frequency expression of vibration response of the piecewise nonlinear vibration isolator; secondly, according to the amplitude frequency expression, obtaining a relationship expression of an extreme response value and each parameter of a vibration system, adopting a numerical solution to obtain correct solutions and the number of solutions of the extreme response value, and obtaining a changing rule that the number of extreme response values changes with the parameters of the vibration system; thirdly, analyzing main structural parameters of the piecewise nonlinear vibration isolator, such as an influence of different measurement values of damping ratio and the value of base excitation on a frequency island and a changing rule of the number of the extreme response values, and if the number of the extreme response values is larger than 1, determining that the vibration response possibly causes a frequency island phenomenon, or otherwise, determining that the frequency island phenomenon does not occur; and finally, according to the values of the base excitation and the damping ratio, determining the structural parameters of the segmental nonlinear vibration isolator, so that the segmental nonlinear vibration isolator that avoids the frequency island phenomenon is designed. According to the method, the condition for removing frequency islands can be conveniently obtained; and the method is high in operability.

The invention discloses a disc-shaped nonlinear low-frequency vibration isolator based on the positive and negative stiffness parallel connection principle. The disc-shaped nonlinear low-frequency vibration isolator is composed of a power input part, a tension spring system, a pressure spring system and a shell. Positive stiffness is achieved through the tension spring, negative stiffness is achieved through the pressure spring system, and the tension spring and the pressure spring system are combined, so that a system static force-displacement curve represents a quasi zero stiffness feature. The excellent vibration isolation performance of the nonlinear vibration isolator is continued; and meanwhile, through adjustment of a threaded structure and increasing or decreasing of the number of tension sets, the applicable vibration isolation mass range of the vibration isolator can be broadened greatly, and the defect that the vibration isolation mass range of an ordinary nonlinear vibration isolator is small is overcome.

The invention provides a multi-freedom-degree low-frequency large-load all-metal passive vibration isolator. The vibration isolator is composed of a load mounting tray, horizontal vibration isolation press rods, a lower bearing tray, a vertical main bearing shaft, a vertical guide rail, an upper auxiliary platform, vertical supporting beams, negative stiffness adjustors, rolling bearings, a supporting bottom tray, machine feet and the like. Based on the Euler press rods and a negative stiffness mechanism, the three-direction nonlinear vibration isolator which is heavy in load and low in inherent frequency is provided, and the vibration isolation frequency with the minimum of 1.5 Hz can be achieved; and the all-metal structure is adopted, and the environmental adaptation to high temperature is good.

The invention relates to a fiber composite thin plate nonlinear vibration characterization test method based on vibration measurement with laser, First, the inherent frequency and modal shape of a fiber composite thin plate needs to be obtained accurately. Then, a nonlinear vibration characterization test is carried out according to a test idea of from a time domain to a frequency domain and thento a time-frequency domain. The specific steps are as follows: testing inherent frequency of each order of the fiber composite thin plate; testing the modal shape of each order of the fiber compositethin plate according to the inherent frequency; carrying out a harmonic distortion nonlinear characterization test; carrying out a nonlinear time-varying damping characterization test; carrying out ahard/soft rigidity nonlinear characterization test; carrying out a characterization test of amplitude dependent on nonlinear damping; carrying out a nonlinear jump characterization test; carrying outan ultraharmonic/subharmonic resonance nonlinear characterization test; and carrying out an internal resonance nonlinear characterization test. The method provided by the invention can obtain variousnonlinear vibration characterization of the fiber composite thin plate through one-time testing, a test result is relatively accurate, the test efficiency is improved, and an important reference is provided for establishing a method system for a nonlinear vibration test of a composite structure of this type.

The invention discloses a vibration isolation device for a vehicle with Mecanum wheels. The vibration isolation device comprises a supporting part, two vibration isolation units, a moving part and a spring; a first boss is arranged on the top of the supporting part, and a second boss is arranged at the bottom of the moving part and is positioned above the first boss; the two vibration isolation units are fixedly connected to the top of the supporting part and are symmetrically arranged along the center line of the supporting part; the moving part is positioned between the two vibration isolation units and is respectively movably connected with the two vibration isolation units; and the spring is sleeved on the second boss and the first boss, the top of the spring is fixedly connected with the bottom of the moving part, and the bottom of the spring is fixedly connected with the top of the supporting part. The vibration isolation device has the advantages that the requirement on a nonlinear vibration isolation function can be met in a complicated engineering work environment; the vibration isolation device in a static state is high in rigidity, namely the bearing capacity; and when moving, the vibration isolation device is low in rigidity, in other words, a low-frequency vibration isolation effect is realized, and the vibration isolation device is good in vibration isolation effect.

The invention discloses a BP-neural-network-technology-based improved method of a spherical harmonic function of an ionized layer. The method comprises the following steps: S1, obtaining a puncturingpoint geographic longitude, a puncturing point geographic latitude and an electronic content in the vertical direction of the puncturing point of an observation point of a region; S2, on the basis ofa spherical harmonic function model format of an ionized layer, establishing an ionized layer error compensation model and calculating an electronic content of the puncturing point in the vertical direction and a residual value of the ionized layer error compensation model; S3, carrying out model compensation on a spherical harmonic function by using a BP neural network technology and establishinga fusion model; and S4, with the newly established fusion model, predicting a vertical total ionized layer electronic content residual by spherical harmonic function model fitting, thereby improvingthe model compensation precision. According to the invention, the nonlinear vibration characteristics of the delay information of the ionized layer with time is described accurately; the space-time changing characteristics of the regional ionized layer are simulated well; and compared with the pure spherical harmonic function model, the provided spherical harmonic function model enables the precision to be improved.