124 results about "Harmonic response" patented technology

The invention discloses a transformer electromagnetic vibration noise calculating method based on the finite element method. The transformer electromagnetic vibration noise calculating method comprises the steps of 1, establishing a structured grid model and an acoustics grid model according to a three-dimensional geometrical model of a transformer; 2, conducting transient electromagnetic simulation on the structured grid model to obtain transient electromagnetic force waves borne by each phase winding and an iron core; 3, conducting FFT on the transient electromagnetic force waves borne by each phase winding and the iron core to obtain the frequency domain distribution of electromagnetic force borne by each phase winding and the iron core; 4, conducting harmonic response analysis on the structured grid model to obtain the vibration displacement data of nodes on the surfaces of the windings and the iron core; 5, conducting sound field calculation on the acoustics grid model to obtain the radiation noise distribution of the transformer. According to the transformer electromagnetic vibration noise calculating method, all noise influence factors are considered, and calculation results are accurate and reliable. The transformer electromagnetic vibration noise calculating method can be used for winding short circuit vibration deformation analysis and the like and can also provide method and basis for motor noise analysis.

A wireless sensing system monitors the level, temperature, magnetic permeability and electrical dielectric constant of a non-gaseous material in a container. An open-circuit electrical conductor is shaped to form a two-dimensional geometric pattern that can store and transfer electrical and magnetic energy. The conductor resonates in the presence of a time-varying magnetic field to generate a harmonic response. The conductor is mounted in an environmentally-sealed housing. A magnetic field response recorder wirelessly transmits the time-varying magnetic field to power the conductor, and wirelessly detects the harmonic response that is an indication of at least one of level of the material in the container, temperature of the material in the container, magnetic permeability of the material in the container, and dielectric constant of the material in the container.

The invention discloses a vibration analysis method for dry frictional damping mistuned blades with tendons and shroud bands. The method comprises the steps of for actual mistuned states of the blades of a steam turbine, performing three-dimensional contact finite element analysis firstly to obtain support reactions of nodes of contact surfaces of the tendons and the shroud bands of the entire circle of the blades; secondly establishing a contact surface relationship by adopting spring damping units, considering positive pressures, areas and frictional coefficients at the spring damping units, and building a dry frictional damping mistuned vibration analysis model based on a Mindlin micro-sliding friction model and a harmonic balance method; thirdly considering a pre-stress and adopting harmonic response analysis for obtaining convergency values of vibration responses of the blades through iterative solving; and through cyclic calculation, obtaining vibration amplitude response curves of the dry frictional mistuned blades, and performing further extraction to obtain an inherent frequency and a vibration mode. The method is of important significance for dry frictional damping mistuned analysis of the blades and improvement of mistuned bladed disk vibration.

A wireless sensing system monitors the level, temperature, magnetic permeability and electrical dielectric constant of a non-gaseous material in a container. An open-circuit electrical conductor is shaped to form a two-dimensional geometric pattern that can store and transfer electrical and magnetic energy. The conductor resonates in the presence of a time-varying magnetic field to generate a harmonic response. The conductor is mounted in an environmentally-sealed housing. A magnetic field response recorder wirelessly transmits the time-varying magnetic field to power the conductor, and wirelessly detects the harmonic response that is an indication of at least one of level of the material in the container, temperature of the material in the container, magnetic permeability of the material in the container, and dielectric constant of the material in the container.

The invention provides a method and a system for predicting random vibration life of a PCB solder point. Based on a sinusoidal vibration test and harmonic response simulation analysis, a stress-life curve of the PCB solder point is determined; According to a stress-time curve of a random vibration fatigue dangerous part of the PCB solder point or a strain-life curve of a PCB, the cycle number, stress amplitude and mean distribution of the random vibration fatigue dangerous part of the PCB solder point are determined with a rain-flow counting method; the random vibration fatigue loss of the PCB solder point is determined; and finally based on a Miner rule, according to the random vibration fatigue loss of the PCB solder point, the random vibration life of the PCB solder point is predicted. The whole process is based on precise data processing, the operability is strong, and a stress and time response signal is subjected to cycle number statistics and sorting with the rain-flow counting method, so that the data acquisition accuracy in the process for predicting the random vibration life of the PCB solder point is ensured.

A wireless tamper detection sensor is defined by a perforated electrical conductor. The conductor is shaped to form a geometric pattern between first and second ends thereof such that the conductor defines an open-circuit that can store and transfer electrical and magnetic energy. The conductor resonates in the presence of a time-varying magnetic field to generate a harmonic response. The harmonic response changes when the conductor experiences a change in its geometric pattern due to severing of the conductor along at least a portion of the perforations. A magnetic field response recorder is used to wirelessly transmit the time-varying magnetic field and wirelessly detecting the conductor's harmonic response.

The invention proposes a method and system for applying a time-domain tracking filter technique in a conventional audio measurement unit for measuring the audio response parameter of a sound producer. The present invention adopts a special signal to excite the sound producer to be tested; after testing the voltages at both ends of the sound producer and the sound pressure signals, the invention can use the time-domain tracking filter to track the base frequency variation in the audio response; the invention can obtain various audio response parameter results curve such as base frequency response, each harmonic response, total harmonic distortion+noise response, total harmonic distortion response and the like by processing such as equivalent low pass filtering, band-pass filtering, band elimination filtering, high-pass filtering and the like. The invention has superiority which lies in that it can separate and obtain the base frequency and subfrequency response in the audio response ofthe sound producer to be tested in a short time based on the time-domain, which can greatly enhance the test efficiency to the audio response parameter of the sound producer in the R&D stage and the quality management stage.

The invention relates to a method for virtual vibration and impact tests of electromechanical control equipment of a ship. The method comprises the steps that a geometric model of the equipment is built; a finite element model is built; boundary conditions are applied to the finite element model, a modal analysis method is determined, and a virtual modal test is performed on the basis of setting the frequency range of modal analysis; the boundary conditions are applied to the finite element model, a vibration harmonic response analysis method is determined, and a virtual vibration test is performed on the basis of setting the frequency range of vibration analysis; a contact type and a contact parameter between components are defined, and a virtual impact test is performed on the basis of applying the boundary conditions and impact loads on the finite element model; a test result of the dynamic characteristics of the electromechanical control equipment is combined to adjust the parameter for a virtual retest until the error between the virtual test result and test data meets the requirements. Accordingly, the vibration and impact response characteristics of the electromechanical control equipment can be quickly and conveniently predicted, and designing hidden dangers of the electromechanical control equipment are revealed through dynamic property optimization design of the equipment.

The invention discloses a failure frequency sensitivity based method for arranging a vibrating sensor of a helicopter gearbox, comprising the following steps of: (1) constructing a three-dimensional model of the helicopter gearbox; (2) establishing a finite element model of the helicopter gearbox; (3) analyzing the modality of the finite element model of the helicopter gearbox; (4) analyzing the harmonic response of the finite element model of the helicopter gearbox; and (5) determining the installation position of the vibrating sensor of the helicopter gearbox. The invention can rapidly and precisely determine the optimum arrangement position of the vibrating sensor for the traditional gearbox, also has the directive function on reserving the installation position of the sensor for the gearbox in design, and has the important significance on fully acquiring the early failure signals of the gearbox for early failure diagnosis.

Embodiments of the invention disclose a magnetic circuit method and finite element method-based motor noise optimization method and apparatus, which is used for solving the technical problems of relatively high noise measurement precision and cost of a permanent magnet synchronous motor and difficulty in adjusting parameters of the permanent magnet synchronous motor in a measurement process to achieve the purpose of optimizing motor noises in the prior art. The method comprises the steps of simplifying a magnetic field of the motor to a magnetic circuit through magnetic circuit method design, and generating a preliminary design model of the motor; analyzing parameters influencing cogging torque of the motor in the preliminary design model of the motor according to a finite element method, and selecting numerical values of parameters capable of reducing the cogging torque of the motor; performing radial electromagnetic force wave solving on the motor, working out radial force waves on stator teeth of the motor, and performing harmonic response analysis on an obtained solving result; and outputting vibration acceleration obtained by the harmonic response analysis to a stator shell of the motor, and performing sound field analysis to obtain a noise distribution condition around the motor.

A wireless system for collecting data indicative of a tire's characteristics uses at least one open-circuit electrical conductor in a tire. The conductor is shaped such that it can store electrical and magnetic energy. In the presence of a time-varying magnetic field, the conductor resonates to generate a harmonic response having a frequency, amplitude and bandwidth. A magnetic field response recorder is used to (i) wirelessly transmit the time-varying magnetic field to the conductor, and (ii) wirelessly detect the harmonic response and the frequency, amplitude and bandwidth, associated therewith. The recorder is adapted to be positioned in a location that is fixed with respect to the tire as the tire rotates.

The invention discloses a method of acoustics simulated analysis and optimization for a cabin of a passenger plane. The method comprises the following steps that the cabin of the passenger plane is used as a prototype, a free meshing method is adopted based on HYPERMESH software, a cabin structure grid model containing seats is established, the cabin structure grid model is led into ANSYS in a *.cdb format, a Block Lanczos method is used for carrying out vibration mode analysis, a mode superposition method is used for carrying out harmonic response analysis, the vibration frequency response features of the cabin structure are obtained, a vibration frequency response feature destination file is led into SYSNOISE as an boundary incentives condition in a *.fre format which is capable of being recognized by the SYSNOISE, a direct boundary element method is used for finally obtaining sound pressure frequency response characteristics in the cabin, the cabin structure parameters are selected as design variables, and a lowest sound pressure order in the cabin is used as a design goal to carry out sound field optimization of civil aircraft cabins. According to the method of the acoustics simulated analysis and optimization for the cabin of the passenger plane, not only is the advantage that a finite element method is prone to obtaining vibration performance used, but also the advantage that the boundary element method obtains acoustic properties fast is brought in to full play, and therefore calculation speed is accelerated.

The invention discloses a dynamic property optimization design method for foundation major parts of a machine tool. The method includes the steps that a machine tool assembly is simplified according to the dynamics simulation analysis requirement, and the simplified assembly is imported into ANSYS / Workbench for mesh generation, material setting and boundary condition setting to complete modal analysis of the machine tool assembly; in harmonic response analysis, the maximum amplitude response values of the end of a spindle box of the machine tool assembly under the action of simple harmonic force in the X direction, the Y direction and the Z direction are obtained by simulating the actual working state of a tool; finally, experiment design of quality characteristic parameters of the foundation major parts is carried out with the parametric analysis technology, and a response surface model between the dynamic property response values of the machine tool and the quality characteristics of the foundation major parts is obtained through fitting. By analyzing the response surface model, the weak link of the foundation major parts in the dynamic property of the machine tool can be qualitatively found out, the tendency of influences of changes of the foundation major parts on the dynamic property of the machine tool can be quantitatively predicted, and the precision of machine tool design can be improved.

The invention relates to the field of finite element simulation. For solving the problem that the optimization direction of the existing compressor piping system is not clear, the invention presents asimulation optimization method of compressor piping vibration of a constant frequency air conditioner. The method comprises the steps of performing modal analysis and harmonic response analysis fora finite element model, determining the peak frequency corresponding to the stress peak in the stress frequency response curve; judging whether the result of harmonic response analysis accords with the evaluation standard of pipe harmonic response analysis; if yes, trial-manufacturing the compressor piping, otherwise, selecting the peak frequency with the smallest absolute value difference from the working frequency of the compressor and recording the same as the peak frequency one, selecting the natural frequency with the smallest absolute difference between the peak frequency and the naturalfrequency and obtaining the natural vibration mode corresponding to the natural frequency and denoting the same as the natural vibration mode one; according to the natural vibration mode to determinethe part of the finite element model with the largest vibration amplitude and the vibration direction of the part, adjusting the mass of the part and / or adjusting the stiffness of the part in the vibration direction. The invention is suitable for optimizing the piping system of the compressor.

An optimization method of CSP solder joint structural parameters for reducing stress in power cycle-harmonic response coupling is disclosed. The method includes: 1) establishing a simulation analysismodel; 2) obtaining the thermal stress value of the solder joint; 3) determining the influencing factors of thermal stress value; 4) determining the parameter level value of the influencing factors; 5) obtaining an experimental sample; 6) obtaining a functional relationship between the influence factors and the thermal stress value; 7) carrying out regression analysis on that functional relation;8) establishing the correctness of the function relation; 9) generating an initial population in a random manner; 10) obtaining the current iterative number and the optimal fitness value; 11) performing crossover operation, mutation operation and evolutionary reversal on that individual; 12) selecting the optimal individual of fitness value; 13) re-judging aft population updating. The method combines a response surface and a genetic algorithm to reduce the stress in the CSP solder joint under power cyclic harmonic response coupling loading, exhibits excellent robustness, is simple in calculation ,and greatly brings convenience for optimization design of the structural parameters of the CSP solder joint in the later period.

The invention relates to a system for monitoring the condition of elongate structural elements and more particularly but not exclusively, to a system for monitoring and detecting cracks and breaks in railway rails. The invention furthermore extends to the methodology of designing and developing such a system. The method includes the steps of identifying modes of propagation and signal frequencies that can be expected to travel large distances through an elongate structural element; selecting a suitable mode of propagation and frequency of operation; designing a transducer that is adapted to excite the selected mode at the selected frequency; numerically modelling the transducer as attached to the elongate structural element; and analyzing a harmonic response of the selected mode of propagation to excitation by the transducer in order to validate the transducer design.

Rejection of local oscillator alias response is provided in a mixing circuit by (1) a switching mixer producing an output that changes at least twice between two states (e.g., high-low-high or low-high-low) during each local oscillator period, and (2) a charge integrator integrating current output from the switching mixer over the local oscillator period. The switching mixer and charge integrator produce a sampled data format, double sideband signal with serial cancellation of the switching mixer's alias responses. An extension unit connected in series with the switching mixer and charge integrator, and implementing a transform function computing a difference between consecutive samples, produces a cascading effect with the switching mixer and charge integrator, optionally producing additional nulls suppressing alias response at frequencies near the local oscillator frequency. A harmonic gating circuit between the switching mixer and charge integrator, controlled at a multiple of the local oscillator frequency, suppresses harmonic responses of the switching mixer.

The invention discloses a piezoelectric actuator hysteresis neural network compensation method for helicopter body vibration active control, and belongs to the field of helicopter vibration control. Aiming at the problems that the helicopter body vibration has the vibration characteristic of multi-order harmonic response, and the control effect becomes poor due to higher harmonic response caused by hysteresis nonlinearity of a piezoelectric actuator in the active control process of helicopter body vibration driven by the piezoelectric actuator, based on a neural network and a nonlinear autoregressive exogenous (NARX) input model, a piezoelectric actuator hysteresis nonlinear neural network and a nonlinear compensation neural network under the driving of two-order harmonic signals are provided, and the nonlinear compensation neural network is used in a helicopter body vibration active control system driven by a piezoelectric actuator. The piezoelectric actuator hysteresis neural networkcompensation method provided by the invention can obviously improve the control effect of the helicopter body vibration active control system.

A detection system and method uses an implantable magnetic marker comprising at least one piece of a large Barkhausen jump material (LBJ). The marker is deployed to mark a tissue site in the body for subsequent surgery, and the magnetic detection system includes a handheld probe to excite the marker below the switching field for bistable switching of the marker causing a harmonic response to be generated in a sub-bistable mode that allows the marker to be detected and localised. The marker implanted may also be shorter than the critical length required to initiate bistable switching of the LBJ material.

The invention relates to an algorithmic method used for analyzing vibration of a large-scale turbonator stator iron-core through numerical simulation on a computer and can be used for the vibration performance study of a turbonator stator iron-core. The invention is characterized by the simplified model of the large-scale turbonator stator iron-core, the calculation and conversion for magnetic pull force of the turbonator stator iron-core, the loading method of function and the result processing after harmonic response analysis, besides, displacement response of the stator iron-core in radial direction, tangential direction or other direction in frequency multiplication area or other frequency area can be directly obtained, the frequency response curve of the radial direction displacement, tangential direction displacement or algebra displacement can also be obtained. Compared with the prior algorithmic method, the invention has a more rapid and accurate result due to using function to load, the sustained momentum property of the large-scale turbonator stator iron-core can be forecasted by calculating the steady state vibration of the stator iron-core through the harmonic response analysis technology, testing and verifying whether the design can successfully overcome harmful effects caused by resonance, fatigue and other forced vibrations.

A method for calculating vibration and noise of an ultra-high voltage shunt reactor is provided. The method comprises the following steps: a process of generating vibration and noise of reactor is considered, and a reactor electromagnetic-structure-noise full process simulation process of multi-field coupling is established based on the finite element theory of multi-physical field coupling, andthe vibration noise of reactor is calculated. Various sizes and related parameters of UHV shunt reactor are obtained, and the three-dimensional model of the reactor with real data is established. In the transient magnetic field, the electromagnetic force acting on the reactor windings and the iron core is calculated by the imaginary displacement method. The frequency, amplitude and phase of the electromagnetic force acting on the reactor are obtained by FFT transformation. Taking the FFT transform electromagnetic force as the load excitation, the modal analysis and harmonic response analysis are carried out, and the vibration velocity and vibration characteristics of the reactor are obtained. Taking the reactor vibration velocity as the load excitation, the noise distribution of the reactor is obtained by noise analysis. The invention provides a theoretical basis for vibration suppression and noise reduction of the ultra-high voltage shunt reactor, and has good application value.

The invention provides a dynamic stiffness modeling method for a flexible support gear transmission device, belongs to the field of gear system dynamic modeling, and aims to divide a common single-layer vibration isolation gear system into a transmission system, a box body, a vibration isolator and a basic module. The method comprises the steps of establishing a concentrated mass model of the transmission system, and converting to obtain a dynamic stiffness equation; establishing a box body finite element model, and obtaining box body dynamic stiffness parameters through harmonic response analysis; simplifying the vibration isolator into a Timoshenko beam, and obtaining a dynamic stiffness equation through a wave equation; obtaining dynamic stiffness parameters by a foundation through a test; by assembling the dynamic stiffness equations of the subsystems, obtaining a complete dynamic stiffness model of the gear transmission device, and hybrid modeling of theoretical parameters / test parameters can be achieved. The modeling method can greatly improve the modeling efficiency of gear transmission device analysis and the accuracy of calculation results.

An accurately quantitative calculation method for near-field ultrasonic levitation force can be used for modeling, designing and optimizing of a non-contact type ultrasonic levitation system and a transmission positioning system. The accurately quantitative calculation method includes: building a finite element model of an ultrasonic generating device, performing model analysis and harmonic response analysis, building one-to-one mapping relation of driving input and output, building an extrusion gas-film kinetic model considering inertia of gas and determining parameters of the model; obtaining a specific format of numerical solution of the parameters of the model according to difference scheme; and acquiring gas pressure and levitation force of an extrusion gas film by the numerical solution. By the accurately quantitative calculation method, accuracy in modeling and solving is improved as compared with that of the prior art. Besides, the accurately quantitative calculation method is accurate and feasible for production design and optimization of ultrasonic equipment.

The invention relates to the piping field of a compressor of a fixed frequency air conditioner. The invention solves the problems that the piping mode analysis of the fixed frequency air conditioner can not be quantified and the natural frequency point of the pipe which is close to the operation frequency of the compressor can not be accurately judged according to the piping mode analysis, and a simulation evaluation method of the compressor piping vibration of the constant frequency air conditioner is presented. The main points of the technical scheme are as follows: firstly, the accurate finite element model of the compressor pipe is determined; secondly, the boundary conditions are applied to the finite element model and the modal analysis is carried out; then, whether the modal analysis result accords with the evaluation standard of piping modal analysis is judged, if so, the compressor pipe is trial-manufactured, otherwise, boundary conditions and load excitation are applied to the determined finite element model, and harmonic response analysis is performed; then whether the harmonic response analysis result accords with the piping harmonic response analysis evaluation criteria is determined, if so, the compressor pipe is trial-manufactured, otherwise, the finite element model is re-determined after pipe structure optimization.

The invention provides a method for accurately calculating the optimal horizontal stiffness and damping value of dynamic vibration absorption type high pier-beam connection and provides a scientific theoretical basis and specific practical guidance for the calculation of the bearing stiffness and damping value of the dynamic vibration-absorbing high pier beam bridge. The method comprises the following steps: 1. establishing a seismic finite element analysis model of the dynamic vibration-absorbing high-rise beam bridge; 2. initially determining the horizontal connection stiffness k and dampingc of the pier-beam elastic connection device; 3, applying a harmonic response analysis load at the pier top joint, and drawing the amplitude / frequency curve corresponding to the displacement or acceleration dynamic result of the pier top; 4. in the top displacement or acceleration amplitude frequency curve, determining whether there are two vertices (P point and Q point), and adjusting the pier-beam connection stiffness and carrying out repeated testing if there don't have obvious double vertices; 5, determining whether the two points P and Q are equal, if the P and Q points are not equal, continuously adjusting the pier-beam connection stiffness for repeated trials until the P and Q points are equal, at this time the connection stiffness is the optimal horizontal connection stiffness; and 6. adjusting the pier-beam connection damping for trial and error, so that the two points P and Q become the peak points on the amplitude-frequency curve. At this time, the connection damping is theoptimal horizontal connection damping.

The invention disclose an split-ring coupling band-pass filter based on microstrip capacitance load, which includes input feeding line, output feeding line and split-ring coupler, and which is characterized in that the terminal of each split-ring of the split-ring coupler is respectively cascaded connected to a pair of microstrip capacitance load which is disposed inward the split-ring. The invention reduce the area of the filter, by means of the character of slow wave, in a manner of cascaded connecting microstrip capacitance load to the terminal of the split-ring based on traditional split-ring coupling band-pass filter. Meanwhile, for the microstrip capacitance load effect, the bandgap suppression ratio of the filter greatly increases and the harmonic response of the traditional split-ring coupling band-pass filter can be eliminated. The invention can be used in any microwave frequency, and is fit for making substrate material for various microwave circuit.

The invention discloses a micro-strip dual-mode filter with intensified coupling and harmonic suppression characteristics, which is a microwave band-pass filter with high performance. A microwave dielectric substrate comprises a square ring resonator (1), an L-shaped coupling structure, a perturbation element (3) and a 50-ohm incoming and outgoing feeder, wherein, the L-shaped coupling structure at the input end (21) and the L-shaped coupling structure at the output end (22) are symmetrically distributed corresponding to a diagonal of the square ring resonator (1); the L-shaped coupling structure at the input end (21) is connected with the 50-ohm incoming feeder (41); the L-shaped coupling structure at the output end (22) is connected with the 50-ohm outgoing feeder (42); the perturbation element (3) is positioned on a corner of the square ring resonator (1) and is connected with the square ring resonator (1). The dual-mode micro-strip band-pass filter is applicable to the design of mobile communication radio frequency (RF) front end, can obtain greater port coupling quantity than traditional micro strip, thereby reducing the insertion loss, and very effectively suppressing the higher harmonic response simultaneously.