58 results about "Vibration transmissibility" patented technology

The invention relates to a vertical vibration isolation system of single freedom and ultra-low frequency, comprising a mass block, a middle mass block, a zero point generator, a zero stiffness apparatus and a stiffness base. The zero stiffness apparatus invents the dynamic stiffness values of the system at a low cost, which greatly decreases the natural frequency of the system and realizes the passive vibration isolation within the range of ultra-low frequency. The zero point generator reduces the vibration transmissibility in the range of the ultra-low frequency and improves the efficiency of vibration isolation; otherwise, the parameters of the zero point generator can be changed to regulate the system vibration transmissibility according to the actual amplitude and frequency requirements of the vibration isolation. The existing relationship between the zero point generator and the zero stiffness apparatus is: the zero stiffness apparatus decreases the dynamic stiffness value and also brings down the zero value of the zero point generator III and realizes zero within the range of ultra-low frequency.

The invention discloses an engine suspension system optimization design method capable of considering the dynamic change of rigidity and damping due to excitation force. The method comprises the following steps: firstly, establishing a dynamics model of an engine suspension system; selecting a sample point in an interval formed by a suspension vertical static rigidity design range and an excitation frequency change range, calculating a dynamic rigidity and damping value corresponding to the sample point, carrying out data fitting, and establishing a prediction model; then, according to a multi-degree-of-freedom vibration theory, obtaining a vibration differential equation of the suspension system; solving the differential equation to obtain the inherent frequency of a six degrees of freedom of the suspension system and corresponding dynamic response, taking an integral sum of vibration transmissibility in a vertical direction on the centroid within a vibration frequency range as an optimization target, selecting four suspension vertical static rigidity values as optimization design variables, and taking the inherent frequency of the six degrees of freedom of the suspension system as a constraint condition; adopting a genetic algorithm to carry out optimization; and finally, verifying the feasibility of the method through a specific example. The engine suspension system optimization design method has integrity and practicality.

The invention relates to the field of structural damage identification, in particular to a method for identifying structural damage based on a vibration transmissibility function and a support vector machine. The vibration transmissibility function is constructed through an accelerated speed response, the amplitude value of the vibration transmissibility function is used as an analysis signal, all frequency band signals are obtained through wavelet packet decomposition and reconstruction, the energy ENj of all the frequency band signals is obtained through calculation, the variable quantity delta ENj of the energy of the front and rear frequency band signals of the structural damage is used as damage characteristic indexes, and the mode identification function of the support vector machine is used for identifying the structural damage. The method for identifying the structural damage is not influenced by the excitation amplitude value, meanwhile, a structural damage identification method with the problems that a neural network structure is hard to determine and prone to being in local minimization is avoided, operability is strong, processing precision is improved, and the damage identification process is simplified.

The invention discloses a satellite micro-vibration isolation simulation measurement system and method. The system comprises a moving trolley, a satellite, a to-be-measured vibration isolation system,equipment subjected to vibration isolation, a vibration measurement system, a quasi-zero stiffness suspension system and a vibration exciter, wherein the vibration exciter is installed on the movingtrolley and is connected with the satellite, the satellite and the equipment subjected to vibration isolation are suspended on the quasi-zero stiffness suspension system, and the to-be-measured vibration isolation system is arranged between the satellite and the equipment subjected to vibration isolation; the moving trolley simulates the weightlessness and on-orbit motion state of the satellite inspace; the to-be-measured vibration isolation system isolates the vibration of the satellite from being transmitted to the equipment subjected to vibration isolation; the quasi-zero stiffness suspension system simulates a zero gravity state; the vibration measurement system measures vibration signals of the vibration exciter and the equipment subjected to vibration isolation; vibration attenuation is obtained by comparing the vibration signals of the vibration exciter and the equipment subjected to vibration isolation, and the vibration transmissibility is obtained by calculating the ratio ofvibration signal amplitudes of the vibration exciter and the equipment subjected to vibration isolation. According to the invention, the performance of the micro-vibration isolation device on the satellite is simulated and measured on the ground, and the on-orbit operation state of satellite related equipment is evaluated.

The invention relates to a test method capable of realizing vibration characteristics physical separation of a stator and a rotor. A reduction sleeve is additionally arranged between a motor stator and an end cover fixed with a rotor base, after the reduction sleeve is detached, the vibration physical separation between the motor stator and the rotor can be realized, therefore, the decoupling between the stator and the rotor excitation can be realized, the electromagnetic excitation, the mechanical excitation and the vibration transmissibility of the motor can be obtained by arranging proper vibration acceleration sensor, and the test of the influence of the motor stator and rotor eccentricity on the motor vibration can be implemented. The method provides necessary original parameter and vibration and noise reduction measure for the analysis of motor vibration and the motor design and provides a technical support for the development of the low noise motor.

The invention discloses a damping-adjustable polyurethane material and its preparation method and an application thereof and belongs to the technical field of high molecular materials. According to the invention, the technical problem that high inherent frequency of a magnetorheological elastomer in the prior art results in that resonance frequency moves to higher frequency and high-frequency damping effect is poor is solved. The damping-adjustable polyurethane material provided by the invention comprises: by weight, a polyurethane performed polymer with isocyanate index being 2-8%, 2-10 parts of a chain extender, 5-80 parts of magnetic particles and 0.1-2 parts of a coupling agent. Under the influence of a magnetic field of 0-0.3T, damping of the damping-adjustable polyurethane material is increased from 0.12 to 0.32. According to a vibration damper prepared by the use of the damping-adjustable polyurethane material, the high-frequency damping effect is guaranteed, and vibration transmissibility of a resonance region can be reduced effectively. The damping-adjustable polyurethane material has a wide application prospect in the fields of automobile engine vibration damping and the like which require wideband vibration damping.

The invention discloses an integral metal spring type active vibration reduction table. The integral metal spring type active vibration reduction table comprises a bottom plate (10) and an upper panel (60). Passive vibration isolation units and active vibration isolation units are arranged at the four corners of the bottom plate (10) correspondingly. The passive vibration isolation units are used for achieving high-frequency attenuation of the vibration reduction table and each comprise a metal spring assembly, vibration isolation rubber (50) and a structural damper. The active vibration isolation units are used for achieving active control over the vibration reduction table and each comprise a feedback speed sensor, a feedforward speed sensor, a Lorentz motor and a controller. According to the vibration reduction table, the vibration reduction technique combining passive vibration isolation with active vibration reduction is adopted, high-frequency vibration can be isolated comprehensively, low-frequency vibration can be effectively restrained, and the transmission rate of low-frequency vibration is ensured; and meanwhile, high attenuation rate of high-frequency vibration is achieved, full decoupling under six-degree of freedom control can be achieved, and application is flexible.

The invention discloses a motor for a ship and a vibration and noise reduction method thereof. A three-phase asynchronous motor for the exiting ship is improved from two aspects of reducing the electromagnetic exciting force and preventing the superposition of the frequency of the electromagnetic exciting force with the inherent frequency of a motor stator core, so that the low-frequency vibration generated by the electromagnetic exciting force is maximally avoided or weakened, and the high-frequency vibration is reduced. According to a principle that if the underground vibration frequency is lower, the vibration transmissibility is stronger, the low-frequency vibration acceleration level and the total vibration level of the three-phase asynchronous motor for the exiting ship can be greatly reduced, so that the mute ability of the ship is improved, and the distance of the ship discovered by sonar equipment is reduced.

The invention relates to the field of structural damage identification, in particular to a structural damage warning method based on confidence of the principle component of a vibration transmissibility function. The transmissibility function is constructed by using accelerated speed response, the transmissibility function is free of the influence of excitation amplitude, and the structural damage warning can be free of the influence of the excitation amplitude by taking the amplitude of the transmissibility function as analysis signals; the principle component of the vibration transmissibility function is extracted through the analysis of the principle component, correlation analysis is carried out on the principle component, the confidence of the principle component is computed according to the modal confidence criteria, evaluation is carried out on structural states by using the confidence of the principle component, and the influence of noise can be restrained or eliminated. The structural damage warning method based on the confidence of the principle component of the vibration transmissibility function is free of the influence of the excitation amplitude, capable of effectively restraining or eliminating the influence of noise, small in computing amount, extremely suitable for online monitoring, and strong in operability, and improves processing precision and warning accuracy.

The invention relates to a method for predicting the vibration condition of an aircraft structure under a specific working condition, and the method comprises the steps: enabling the time domain information of a vibration response point to be easily and directly measured under the specific working condition on the aircraft structure under a test working condition, and enabling the time domain information of the vibration response point to be not easily and directly measured under the specific working condition; based on the time domain information of the vibration response point which is easy to directly measure on the airplane structure under the specific working condition and the vibration transmissibility matrix under the airplane structure test working condition, calculating the time domain information of the vibration response point which is not easy to directly measure on the airplane structure under the specific working condition, under a test working condition and a specific working condition, vibration response points on an airplane structure are easy to directly measure, and a cross-power spectral density matrix between the vibration response points is not easy to directly measure; in a test working condition, a cross-power spectral density matrix between vibration response points is easy to directly measure on an airplane structure under a specific working condition.

The invention provides a computer shock absorbing platform. The computer shock absorbing platform comprises an equipment mounting frame, at least four variable damping shock absorbers and a shock absorbing device. The variable damping shock absorbers are evenly arranged between the equipment mounting frame and the shock absorbing device. Computer equipment is arranged on the equipment mounting bracket. The top ends of the variable damping shock absorbers are connected with the bottom of the equipment mounting frame. The bottom ends of the variable damping shock absorbers are connected with theshock absorbing device. An acceleration sensor is arranged in the position, close to each variable damping shock absorber, of the bottom of the equipment mounting frame. By cooperating the variable damping shock absorbers with the shock absorbing device, the damping can be adjusted in real time within the working frequency range. The anti-vibration performance of a computer can be effectively improved, damping is increased in an amplification area to reduce resonance, and damping is decreased in a vibration isolation area to reduce the vibration transmission rate. When the center of gravity of the equipment does not match the layout centers of the shock absorbers, the stability of the equipment in the vibration process can be ensured by controlling the output of each variable damping shock absorber.

The invention relates to a damping flexible connection method for spacecrafts, which can improve the affect of the rail heat distortion and high-frequency vibration of spacecrafts on the working performance of sensitive instruments and the stability of spacecraft control systems. The damping flexible connection method for spacecrafts uses a damping flexible connection device (1) on a joint having high internal stress and/or high vibration transmissibility on a spacecraft. The method has the following advantages that: on the one hand, the flexibility of the damping flexible connection device (1) is utilized to absorb the load produced by structural heat distortion, so as to reduce the static distortion of a mounting structure of a sensitive instrument (2); on the other hand, the damping of the damping flexible connection device (1) is utilized to improve the overall damping level of a spacecraft structure or the local damping level of the sensitive instrument, so as to play a role in inhibiting high-frequency vibration.

The invention discloses a multi-dimensional structure damage identification method for convolutional neural network processing of mass vibration transmissibility data. The method specifically comprises the steps: collecting mass structure acceleration response data through a sensor system; dividing the data into a reference response and a non-reference response, calculating the transmissibility between the reference response and the non-reference response, and forming a mass sample data set based on the vibration transmissibility; establishing a convolutional neural network model, and performing training by using the transmissibility data set; after N times of training, enabling the convolutional neural network to reach convergence, carrying out structural damage identification by using the trained convolutional neural network, and outputting a damage mode of the convolutional neural network. Compared with a traditional method, the built damage identification method integrating the vibration transmissibility and the convolutional neural network can eliminate the excitation interference and the method has the advantages of being high in damage sensitivity, high in damage identification accuracy and high in noise resistance, and can efficiently process massive high-dimensional data.

A machine tool health monitoring method which is to use a predetermined plurality of vibration sensors on a plurality of components of a machine tool and to drive motors of the machine tool to excite the machine tool using an electronic device while the health status of the machine tool is good, and then to perform a diagnostic process to obtain a characteristic cluster consisting of a plurality of modals, and then to define the characteristic cluster as a sample health characteristic cluster. The diagnostic process includes the procedures of vibration transmissibility obtaining, singular value decomposition, curve fitting and modal establishing. In addition, excite the machine tool and proceed the diagnosis process to obtain a current health characteristic cluster. Finally, the current health characteristic cluster is compared with the sample health characteristic cluster to judge whether the machine tool is healthy or not.

The invention discloses a high-stability zero-rigidity micro-vibration isolation device based on a magneto-rheological technology. The vibration isolation device comprises a horizontal vibration isolation supporting frame and a vertical vibration isolation mechanism, wherein the vertical vibration isolation mechanism is fixed on a horizontal vibration isolation table of the horizontal vibration isolation support frame, a workbench is arranged over the vertical vibration isolation mechanism and is connected with the vertical vibration isolation mechanism through a screw rod, and magneto-rheological fluid is poured into the positions below the horizontal vibration isolation table of the horizontal vibration isolation platform, in the center of the vertical vibration isolation mechanism, andin a center circular ring of the vertical vibration isolation structure below the workbench, so that liquid damping is changed by changing the current intensity. According to the vibration isolation device, an ultra-low horizontal and vertical direction inherent frequency is achieved, a good vibration isolation effect is achieved, the contradiction between high bearing capability and low inherentfrequency is well solved, the whole mechanism has the characteristics of high stability and zero rigidity, the extremely low vibration transmission rate is achieved, and the vibration isolation devicehas the advantages of being small in size, simple and compact in structure, stable in performance and the like.

The invention discloses a seat vibration comfort testing method and device.A seat vibration comfort testing system adopted by the seat vibration comfort testing method comprises a to-be-tested seat and a data analysis platform, the to-be-tested seat is provided with an acceleration sensor, the acceleration sensor is connected with the data analysis platform, and the data analysis platform is connected with the acceleration sensor. The method is applied to the data analysis platform and comprises the steps that after a user sits on the to-be-tested seat, the to-be-tested seat vibrates according to a plurality of sets of preset excitation signals in different directions, each set of excitation signals corresponds to an excitation acceleration, and for each set of excitation signals, each set of excitation acceleration corresponds to a set of excitation acceleration; and acquiring a vibration acceleration corresponding to the following vibration of the to-be-tested seat under the excitation signal, calculating the vibration transmissibility of the to-be-tested seat according to the vibration acceleration and the excitation acceleration, and generating a comfort test result according to a plurality of vibration transmissibility calculated under the plurality of groups of excitation signals in different directions.

The invention belongs to the technical field of automobile suspensions and particularly relates to an oil cavity interconnecting two-stage vibration isolation balanced suspension. The suspension comprises an automobile frame and two-stage shock absorbers. The two two-stage shock absorbers are arranged oppositely and connected with the automobile frame. Each two-stage shock absorber comprises a balance swing frame and oil cylinders. The middle portions of the balance swing frames are rotationally connected with the automobile frame. The two ends of each balance swing frame are connected with the automobile frame through the corresponding oil cylinders. The two ends of each oil cylinder are hinged to the automobile frame and the corresponding balance swing frame. Swing arms are hinged to thetwo ends of each balance swing frame. Dampers are arranged between the swing arms and the balance swing frames. The two ends of each damper are hinged to the corresponding swing arm and the corresponding balance swing frame. First-stage vibration isolation suspension systems are composed of the swing arms, the balance swing frames and the structures between the swing arms and the balance swing frames. Second-stage vibration isolation suspension systems are composed of the balance swing frames, the automobile frame and the structures between the balance swing frames and the automobile frame. The suspension has the low vibration transmission rate and the large suspension stroke, vibration of a ground-tire system can be further fully filtered, and a better vibration isolation effect is provided for upper installed parts such as a compartment.