259 results about "Dynamic stiffness" patented technology

The invention discloses a wind turbine generator hoisting construction tower drum operation system and a construction method thereof, and relates to the technical field of intelligent control. The problems that in the prior art, a static tension balance mechanism cannot restrain bending moment abrupt change, steel-concrete interface stress concentration causes microcrack propagation, the wave dynamic load compensation capacity is insufficient, and dynamic rigidity attenuation early warning is lacked are solved. Comprising a dynamic load prediction module, a multi-mode vibration suppression module, an offset compensation module and a digital twinborn decision module, a hoisting load is solved in real time through a multi-physics field coupling model and an improved time sequence deep learning algorithm, and interface crack propagation is suppressed in combination with traveling wave offset control and sweep frequency vibration. An improved Morison equation is adopted to drive a two-stage hydraulic servo to compensate a wave dynamic load, and a digital twin closed-loop correction mechanism is constructed based on a 5G URLLC protocol; the tower drum hoisting precision, the structural safety and the operation reliability under the complex working condition are remarkably improved.

The invention relates to the technical field of mechanical vibration testing, in particular to a method for testing dynamic rigidity and damping characteristics of an engine support, which comprises the following steps of: 1, simulating a boundary; step 2, double-source excitation loading is carried out; step 3, dynamic response acquisition: arranging vibration measurement points in the main shaft direction of the rigidity of the support to acquire acceleration signals in three directions, synchronously acquiring excitation force signals, and recording all the signals at a set sampling rate after anti-aliasing filtering; 4, constructing a frequency response matrix: performing time-frequency transformation on the exciting force signal and the acceleration signal, and calculating a cross-point frequency response function matrix; 5, parameter decoupling calculation is carried out, wherein parameter decoupling is achieved through cross iterative optimization; and 6, outputting parameters. Through the decoupling calculation of the low frequency band and the high frequency band, the cross iteration optimization method can effectively reduce the calculation error, improves the parameter decoupling precision, and guarantees the reliability of the test result under different frequency bands.

The invention relates to a low-frequency vibration isolator with a wide quasi-zero stiffness interval. The low-frequency vibration isolator comprises a bearing platform, a base, a first negative stiffness assembly, a second negative stiffness assembly and a linear vibration isolation assembly. The bearing platform and the base are arranged in parallel and are both provided with bolt holes and limiting holes; a linear vibration isolation assembly is installed between the bearing platform and the base. The first negative stiffness assemblies are symmetrically distributed with the center point connecting line of the bearing platform and the base as the symmetry axis. The top of the first negative stiffness assembly is connected with the bearing platform, and the bottom of the first negative stiffness assembly is connected with the base. The two ends of the second negative stiffness assembly are connected with the two first negative stiffness assemblies correspondingly. The low-frequency vibration isolator has the characteristics of high static rigidity and low dynamic rigidity, the contradiction between the bearing capacity and the vibration isolation performance of a linear vibration isolation system is effectively solved, and the effective low-frequency vibration isolation effect on a vibration-isolated object is achieved while the bearing capacity of the vibration isolator is guaranteed.

The invention relates to a rigid-flexible trans-mass self-adaptive robot force position and rigidity collaborative optimization method and system, and relates to the technical field of robot control, and the method comprises the steps: firstly, carrying out the linearization processing of a robot dynamic model through a semi-implicit integral method, and obtaining a robot dynamic model; and in combination with an extended Kalman filter, stiffness parameters in the contact operation process are estimated in real time, a dynamic stiffness sensing model is constructed, and the system response capability is effectively improved. Then, a rigidity parameter is embedded into a Hertz contact model, the dependence of a traditional model on prior information of a contact surface is broken through, a dynamic interaction model between the robot and an operation object is established, and high-precision real-time sensing of normal force and friction force is achieved. And finally, under a nonlinear model predictive control framework, multi-dimensional physical constraints are constructed based on the contact force, the position and the contact rigidity, an optimal control model is obtained, control input is dynamically and adaptively updated through rolling optimization, and the stability and the control precision of the robot in rigid-flexible heterogeneous contact operation are improved.

The invention relates to the technical field of mechanical arm control, and discloses a bionic self-adaptive variable-stiffness mechanical arm joint control method. The method comprises the steps that multi-source biological signals such as electromyographic signals, tendon tension signals and joint angle signals during joint operation are collected; constructing a stiffness feature vector based on the myoelectricity and tendon tension signals, and generating a motion trail sequence according to the joint angle signals; extracting a corresponding stiffness feature vector for each track point, and calculating stiffness sensitivity; constructing a bionic stiffness reference model containing a mapping relation between the stiffness feature vector and a joint angle signal, and dynamically weighting and adjusting the mapping relation by using stiffness sensitivity; predicting a joint stiffness change sequence based on the adjusted model and the real-time signal, and fusing the sequence with the current joint angle signal to generate a dynamic stiffness parameter; and calculating a driving torque correction amount according to the dynamic stiffness parameter and a preset safety threshold range, iteratively updating the model weighting parameter until the correction amount meets a convergence condition, and outputting a driving torque instruction to an execution mechanism.

The invention discloses a grooving machine rigidity dynamic adjusting system and method based on material image recognition, and relates to the technical field of grooving machine rigidity dynamic adjusting, and the method comprises the following steps: obtaining a material surface and subsurface image sequence of a grooving machine processing area; inputting the image sequence into a pre-trained depth vision analysis model, and outputting a material characteristic parameter set in real time; converting the material characteristic parameter set into a target rigidity value based on a rigidity demand mapping model; within a preset regulation and control window period before the cutter makes contact with the target machining area, the initial rigidity adjustment amount is obtained according to the target rigidity value, and a rigidity adjustment instruction is generated and sent to a rigidity adjustment execution mechanism for dynamic adjustment; in the cutting process, fusion of feedback data and an image analysis result is obtained, and the initial rigidity adjustment amount is corrected; dynamic, accurate and predictive active adjustment of the rigidity of the grooving machine is achieved, and therefore the machining adaptability, intelligence and stability of the grooving machine are effectively improved.

The invention discloses a flexible structure 3D printing support control method combined with a resistor, and relates to the technical field of 3D printing, and the flexible structure 3D printing support control method comprises the following steps: generating a continuous density field and a dynamic damping parameter field of a support structure based on multi-target topological optimization of dynamic stiffness constraint and material distribution; quantifying the contact probability of the support structure and the target model through a membership function, and constructing a nonlinear gradient field of a contact interface; the stress coupling relation between the supporting structure and the model interface is defined based on the mixed constitutive tensor, the interface stress transfer coefficient is adaptively updated based on the material shrinkage rate difference, multi-physics field collaborative optimization is achieved in combination with regularization constraint, the key part of the supporting structure is recognized, and the resistor is integrated to the key part of the supporting structure. Through multi-target topological optimization, membership construction and adaptive stress transfer coefficient updating, the material consumption is reduced, the printing efficiency is improved, stress concentration at an interface is inhibited, the forming defect risk is reduced, and the structural reliability is improved.

The invention relates to the technical field of robots, in particular to a redundancy-driven variable-stiffness ankle joint structure which comprises an ankle assembly connected to a shank main body through a central hinge shaft; the dual-drive unit comprises a first drive unit and a second drive unit which are independently controlled, and the first drive unit and the second drive unit are fixedly mounted in the shank main body; the traction system comprises a first eccentric wheel and a second eccentric wheel which are coaxially connected with the output ends of the first driving unit and the second driving unit respectively; by means of a redundant drive framework and a variable rigidity adjusting mechanism, elastic buffering and dynamic rigidity adjusting can be achieved, the impact adaptability is improved, the dual-drive unit can be prevented from being directly impacted, and the service life of the dual-drive unit is prolonged. Damage to a motor gear is reduced, the rigidity can be quickly reduced for buffering in an impact scene, and the rigidity is improved for maintaining the posture during stable supporting.

The invention relates to the technical field of industrial robots, in particular to a dynamic simulation damping parameter solving method based on a gravity compensation mechanism, which comprises the following steps of: acquiring a joint basic parameter set of a to-be-tested industrial robot, and determining a test boundary condition according to the joint basic parameter set, and constructing a test task sequence based on the test boundary conditions. According to the method, the fusion weight of the static stiffness and the dynamic stiffness is intelligently adjusted according to the characteristics of the movement speed, the acceleration or the force control frequency band in a specific application task, and the limitation of a single parameter under complex and changeable working conditions is avoided. According to the parameter fusion mechanism aiming at the specific task characteristics, the generated joint comprehensive rigidity parameters can truly reflect the physical response of the robot in different operation stages, and the prediction error between the physical simulation environment and the actual physical operation is reduced; and the strict requirements of high-precision scenes such as semiconductor packaging and the like on micron-level positioning precision and force control stability are met.

The invention relates to an anti-falling device integration method and system based on light guide rail coupling and deformation control, and the method comprises the following steps: carrying out the stress distribution scanning of a light guide rail through a laser interference measurement system, and obtaining a guide rail stress distribution map; based on the guide rail stress distribution map, carrying out dynamic rigidity analysis on the light guide rail to obtain a guide rail rigidity characteristic curve; carrying out coupling calculation on the light guide rail based on the guide rail rigidity characteristic curve to obtain guide rail coupling parameters; based on the guide rail coupling parameters, structural design and layout optimization are conducted on the anti-falling device, and an anti-falling device integration scheme is obtained; and performing virtual assembly and performance simulation on the integration scheme of the anti-falling device to obtain a performance evaluation report of the anti-falling system, thereby solving the technical problem that the integrated design of the anti-falling system generally lacks in-depth analysis on the mechanical characteristics of the guide rail body, so that potential safety hazards are difficult to find and correct in time.

The invention discloses a nonparametric prediction method for the fatigue life of a steel-FRP composite bar, and belongs to the field of fatigue performance evaluation of civil engineering materials and structures, and the nonparametric prediction method comprises the following steps: initializing component material attributes, load conditions and initial states of the steel-FRP composite bar, the component materials comprising an inner core steel bar and an FRP layer; according to an equivalent stiffness distribution principle, fatigue stresses of the component materials are calculated respectively; according to the fatigue stress of the component material, theoretical fatigue life of the component material is obtained in combination with the S-N curve relation, and cyclic jumping is executed; calculating accumulated fatigue damage of the component materials respectively based on results after cyclic jumping; and circularly updating the dynamic stiffness and the equivalent cycle number of the component material until the accumulated fatigue damage of any component material reaches a critical threshold value, judging that the component material is invalid, and outputting the fatigue life. According to the method, the fatigue life of the steel-FRP composite rib can be efficiently and accurately predicted, and the test cost is remarkably reduced.

The invention relates to a train-rail coupling vibration analysis method and device, computer equipment, a storage medium and a computer program product. The method comprises the following steps: dividing a plurality of track units, constructing a motion differential equation of a steel rail in the track units in a frequency domain, and solving to obtain a relation between longitudinal displacement and frequency on nodes at two ends of the steel rail and a relation between stress and frequency on the nodes at the two ends of the steel rail; constructing a steel rail dynamic stiffness matrix for the steel rails in the rail units, and constructing a rail dynamic stiffness matrix for the rail units according to the steel rail dynamic stiffness matrix; assembling to obtain an integral dynamic stiffness matrix of the train-rail system, and constructing a transfer matrix of a rail; and determining a track irregularity excitation power spectrum, and solving to obtain a dynamic response index of the train-track system on each degree of freedom under the track irregularity excitation power spectrum according to the transfer matrix and the overall dynamic stiffness matrix. By adopting the method, the calculation efficiency of the dynamic response index can be improved.

The invention relates to the field of air floating spindles, in particular to a critical rotating speed calculation method of an air static pressure spindle, which comprises the following steps: S1, calculating dynamic rigidity and dynamic damping of an air static pressure spindle bearing by utilizing a finite difference method according to structural parameters of the air static pressure spindle bearing; s2, calculating the critical perturbation frequency of the aerostatic spindle according to the dynamic stiffness and dynamic damping of the aerostatic spindle bearing; s3, according to the dynamic rigidity and the dynamic damping of the aerostatic spindle bearing, the inherent frequency of the aerostatic spindle core is calculated through a finite element method; and S4, a curve corresponding to the inherent frequency of the shaft core of the air static pressure main shaft and a curve corresponding to the critical perturbation frequency of the air static pressure main shaft are drawn under the rotating speed-perturbation frequency coordinate system through a drawing method, and when the two curves intersect, the abscissa where the intersection point is located is the critical rotating speed of the air static pressure main shaft. The method has the advantages of being high in prediction precision, simple in implementation method, suitable for air static pressure main shafts of different structures and the like.

The invention relates to the technical field of monitoring and alarming, in particular to an intelligent orthopedic rehabilitation training monitoring system based on multi-modal sensing, which comprises a basic data synchronous acquisition module, a dynamic stiffness differential analysis module, a defensive contraction judgment module and a load boundary dynamic reconstruction module. According to the method, a time sequence is constructed by synchronously collecting joint angle and moment data, an instantaneous dynamic stiffness change trend is analyzed by combining a moment and angle difference value, a Savitz-golay filter is used for carrying out second-order differential processing on dynamic stiffness to capture a stiffness second-order derivative mutation point, and the critical moment when defensive contraction pain occurs to the joint of a patient is recognized. The maximum activity angle upper limit is dynamically reconstructed based on the critical angle and the safety buffering difference value, a control instruction is directly fed back to a driving end to execute reverse braking, crossing from single-position monitoring to multi-dimensional mechanical state sensing is achieved, it is ensured that the activity boundary is automatically adjusted according to real-time physiological feedback of a patient, and the safety performance of the patient is improved. And secondary injury caused by forcibly breaking through a pain threshold value is prevented.

The invention discloses a lightweight piston thermal-structure coupling stability gradient design method, and relates to the technical field of internal combustion engine pistons, and the lightweight piston thermal-structure coupling stability gradient design method comprises the following steps: constructing an asymmetric load adaptive gradient structure, establishing a multi-physical field coupling stability criterion system, and implementing an intelligent response type gradient design process; according to the method, the limitation of traditional symmetric design and static analysis is broken through by constructing an asymmetric load adaptive gradient structure, establishing a multi-physics coupling stability criterion and combining an intelligent response type closed-loop design process based on a convolutional neural network, and the stability of the multi-physics coupling stability criterion is improved by utilizing mechanisms such as negative Poisson's ratio dynamic softening, inertial mass tuned damping and cross-scale interface strengthening. And deformation energy homogenization and dynamic stiffness self-adaptive regulation and control are achieved, the problems of local-overall response mismatch and steady-state-dynamic model disjunction are solved, real-time feedback regulation is introduced for the first time, and the thermal-structural coupling stability of the lightweight piston under the asymmetric working condition is improved through structural function integration.

The invention provides a variable load quasi-zero stiffness vibration isolator based on an electromagnetic actuator, and belongs to the field of low-frequency vibration isolation. Comprising a supporting structure composed of a shell and a bearing platform, a positive stiffness element, a negative stiffness element and an electromagnetic actuator, the positive stiffness element, the negative stiffness element and the electromagnetic actuator are coaxially installed in the supporting structure, load gravity on the bearing platform is detected in real time through a force sensor, and output force of the electromagnetic actuator is dynamically adjusted through a control circuit according to load changes. And the rigidity of the system at the balance position is zero so as to complete self-adaptive variable load compensation. According to the parallel structure, the dynamic stiffness is remarkably reduced while high static stiffness is guaranteed, and the problems that a traditional quasi-zero stiffness vibration isolator is non-adjustable in load and narrow in zero stiffness interval are solved.

The invention belongs to the field of machining, and discloses a modeling calculation method and system for dynamic rigidity of a cutter handle-main shaft combination part, and the method comprises the following steps: S1, modeling a geometric structure and dynamic displacement of the combination part; s2, performing multi-scale modeling on the contact surface morphology and solving the normal spacing variation of the joint part; s3, joint surface micro-convex body contact characteristic modeling is carried out; s4, modeling the non-linear stiffness of the infinitesimal junction surface; and S5, constructing an integral dynamic stiffness matrix of the joint part. According to the modeling calculation method for the dynamic stiffness of the cutter handle-main shaft combination part, high-precision modeling of the dynamic characteristics of the cutter handle-main shaft combination part is achieved through a step Timoshenko straight beam model and a distributed nonlinear spring layer in combination with a slicing method and a fractal contact theory. The method is suitable for high-precision nonlinear dynamic modeling of a numerical control machine tool, a machining center and the like, and vibration, deformation and stability problems in the machining process can be effectively predicted.

The embodiment of the invention provides an MPV servicing vehicle body dynamic stiffness analysis method, device and equipment and a computer readable storage medium. The method comprises the following steps: acquiring a first system matrix of a reordered MPV servicing vehicle body and a reordered first external steady-state excitation vector; converting the first system matrix into a second system matrix through a constructed projection model; converting the first external steady-state excitation vector into a second external steady-state excitation vector based on the position of a non-zero element in the first external steady-state excitation vector; calculating a residual vector based on the second system matrix and a second external steady-state excitation vector; calculating a global residual vector based on the residual vector; based on the global residual vector, dynamic stiffness analysis of the MPV servicing vehicle body is completed, in this way, efficient scheduling and solving of large-scale residual vector tasks under hundreds of working conditions are achieved, and the overall calculation efficiency and the resource utilization rate of frequency response analysis are remarkably improved.

The invention discloses a method for calculating broadband consistent damping force in time-domain dynamic analysis, which comprises the following steps of: constructing a finite element model of a hydroelectric plant, endowing the model with material attributes, and then obtaining an initial stiffness matrix of the hydroelectric plant by adopting a finite element method; idealizing the finite element model as a main spring, and connecting a plurality of combined elements consisting of sticky kettles and springs in parallel to form an idealized model; according to the initial stiffness matrix, the dynamic stiffness model of the combined element and a damping ratio in time domain dynamic analysis, calculating a stiffness coefficient of each combined element by adopting a least square method; when the dominant frequency of the combined element is uniformly distributed in the broadband range, calculating the viscosity coefficient of the combined element according to the dominant frequency of the combined element and the target damping ratio; and according to the rigidity coefficient and the viscosity coefficient, a time domain damping force model is adopted to calculate the consistent damping force of the hydroelectric plant in the broadband range.

The utility model discloses a quasi-zero stiffness shock absorber for a camera, and belongs to the field of shock absorption. The quasi-zero stiffness shock absorber comprises a mounting seat, at least one group of disc spring shock absorption units are arranged on the mounting seat, a bottom cylinder is arranged below the mounting seat, a spring fixing column is arranged below the bottom cylinder, a spring is arranged on the spring fixing column, each disc spring shock absorption unit comprises a disc spring, one side, close to the mounting seat, of the disc spring is the inner side, and the other side of the disc spring is the outer side. A rubber inner ring and a metal inner ring are sequentially arranged on the inner side, a rubber outer ring and a metal outer ring are sequentially arranged on the outer side, the rubber inner ring is in contact with the disc spring, and the metal inner ring is in contact with the mounting seat. The positive stiffness structure and the negative stiffness structure are connected in series, so that the system has high static stiffness, low dynamic stiffness, large bearing capacity and low inherent frequency, and the purpose of broadband vibration isolation of the system is achieved.

The invention relates to the technical field of data processing, in particular to a structure dynamic stiffness analysis method based on frequency response function polycondensation substructure impedance coupling, which comprises the following steps: acquiring node information, unit connection relation and material attribute based on a global finite element model; defining a focus point set, a boundary point set and an internal point set according to the unit connection relationship; partitioning the global quality matrix, the stiffness matrix and the damping matrix to obtain a partitioned system matrix; introducing an inertia compensation term to construct a transformation matrix based on the block system matrix and the highest analysis frequency of the system, condensing the system matrix until only the freedom degrees of a concern set and a boundary point set are reserved, and calculating a dynamic stiffness matrix in a frequency domain; a dynamic stiffness result of a focus set is extracted through inverse operation of a dynamic stiffness matrix, the calculation scale is remarkably reduced through system matrix condensation, meanwhile, the inertia effect and the stiffness coupling effect of a far-field structure are strictly reserved, and the contradiction between low calculation efficiency of a global model and precision distortion of a local substructure method is effectively solved.

A tuning element that can be integrally formed with a resilient body of a bush and configured to reduce dynamic stiffness increases associated with eigenmodes of the resilient body within a predetermined operational vibration frequency range. The tuning element may resemble an upstanding wall or wing on an outer surface of the resilient body. The resilient body may comprise a plurality of radial arms having axial passageways therebetween. The tuning element may bridge the passageways. A bush configured in this way may be particular suitable for use in scenario where the operational vibration frequency range comprises high frequency, such as an engine mount for an electric vehicle.

The invention discloses a digital twinning full life cycle management method and system based on machining, and belongs to the technical field of digital twinning in intelligent manufacturing, and the method comprises the steps: 1, obtaining a vibration spectrum of equipment, converting the vibration spectrum into a time sequence waveform, and constructing a multi-scale waveform database; 2, calculating a dynamic stiffness coefficient and a damping ratio based on the multi-scale waveform database, and generating a behavior feature vector; 3, constructing a local correction engine, detecting whether the behavior feature vector deviates from a preset reference threshold value, triggering local grid reconstruction of the digital twin model when the behavior feature vector deviates from the preset reference threshold value, and adjusting model parameters; 4, constructing a virtual load simulator, simulating equipment response based on the adjusted model parameters, and comparing the simulation response with the time sequence waveform; dynamic self-adaptive adjustment of the parameters of the digital twin model can be realized, the mapping precision of the digital twin model to the nonlinear and multivariable coupling state of the equipment is improved, and the timeliness and reliability of a prediction result are guaranteed.

This utility model discloses a suspension decoupling membrane structure for reducing dynamic stiffness, relating to the field of automotive suspension technology. The device includes a diaphragm body located within a flow channel decoupling membrane groove. The diaphragm body has several first buffer ribs evenly distributed along its length on its upper and lower surfaces. Between adjacent first buffer ribs, several second buffer ribs are evenly distributed along their width on the diaphragm body, with the length direction of the second buffer ribs perpendicular to that of the first buffer ribs. The sides of the first and second buffer ribs away from the diaphragm body respectively abut against the top cover plate and the bottom of the flow channel decoupling membrane groove. This utility model enables the suspension decoupling membrane to maintain low dynamic stiffness not only under high-frequency micro-amplitude vibrations but also to provide a large damping angle under low-frequency large-amplitude vibrations, thereby effectively suppressing abnormal noises and improving in-vehicle quietness.

The invention discloses a high-speed heavy-load working condition bearing dynamic stiffness testing device and testing method, and relates to the field of bearing testing. The invention solves the problems that the existing bearing dynamic stiffness test technology and equipment only can load in a single direction, cannot simulate axial and radial composite loading, depends on contact transmission, is insufficient in heavy load bearing, lacks system vibration error suppression measures, and is poor in reliability. And the high-precision test requirement of the independent rolling bearing under the high-speed heavy-load composite working condition is difficult to meet. A shafting supporting module is arranged on the upper portion of a test bench support, a measuring module is located over the shafting supporting module, an axial loading module and a radial loading module apply axial force and radial force to a tested bearing respectively, and a driving module drives a supporting shaft and an inner ring of the tested bearing to rotate. Axial and radial composite loading under the high-speed heavy-load working condition can be achieved, axial and radial displacement can be monitored synchronously, system errors are reduced, and high-precision measurement of the dynamic stiffness of the bearing is achieved.

According to the forecabin reinforcing structure, three triangular frame structures are adopted, reinforcing ribs are evenly distributed on all frames, a left shock absorber support and a right shock absorber support are connected with a front wall assembly to form a firm cage type structure, a force transmission path is increased, and therefore the torsional rigidity and the modality of a body in white and the dynamic rigidity of shock absorber installation points in all directions are greatly improved; the frame structures are all made of aluminum alloy materials, are formed through casting, and are light in weight, simple in manufacturing process and high in manufacturing precision.

The invention relates to the field of design and manufacturing of numerical control machine tools, and discloses a method for determining four-point main support positions of a horizontal machining center lathe bed, which comprises the following steps of: firstly, constructing an alternative position set according to the structural characteristics of the bottom surface of the lathe bed, and dividing the alternative position set into a stand column working area subset and a turntable working area subset based on a gravity center projection constraint principle; then establishing a multi-working-condition complete machine finite element model containing different position combinations of the moving part, and designing a test scheme by using an orthogonal table; in the simulation process, the bearing rigidity is dynamically updated by adopting an iterative correction mechanism based on a bearing reaction power function relation for each group of tests, and the response of the whole machine is solved and obtained; on the basis, a comprehensive evaluation index fusing the flatness and the inherent frequency of the guide rail is constructed; and finally, determining an optimal horizontal combination as four main support positions through index mean value analysis. According to the method, the influence of non-linear contact rigidity and gravity center drifting of the whole machine is fully considered, and the static precision retentivity and the dynamic rigidity characteristic of the whole machine are effectively improved.

The invention discloses an oil-immersed transformer vibration noise rapid simulation method based on multipath coupling and dynamic stiffness correction. The method comprises the following steps: step 1, shell unit FEM modeling and winding vibration calculation; 2, oil tank vibration calculation considering fluid and structure coupling; step 3, noise calculation; according to the method, by optimizing an electromagnetic force loading strategy, a modal screening mechanism and dynamic stiffness modeling, the calculation efficiency and prediction precision are remarkably improved, and efficient and reliable technical support is provided for transformer noise control and structure optimization design in scenes such as a hydropower station and a transformer substation.

This invention relates to the field of wind tunnel aerodynamic measurement technology for hypersonic vehicles, and discloses a method for evaluating and optimizing the dynamic load testing accuracy of a wind tunnel force measurement system. The evaluation method involves: equating the force measurement system to a multi-degree-of-freedom spring and mass model; constructing a dynamic differential equation and performing a Laplace transform; then, combining the dynamic stiffness matrix to construct a frequency response function matrix; defining the output of the force measurement channel of a rod-type strain balance and solving for the transfer function from the excitation point to the force measurement channel; combining the reference transfer function and the actual load, calculating the identified load and performing a Fourier transform to obtain the relative identification error of the force measurement system at the excitation point; finally, calculating the power spectrum weighted average identification error at the excitation point and comparing it with the engineering allowable error to determine whether the system has undergone stiffness optimization. This invention not only accurately identifies the dynamic load of the force measurement system but also achieves stiffness optimization, improving the accuracy of unsteady aerodynamic force measurement.

The present application belongs to the technical field of performance test of aero-engine parts, and particularly relates to an elastic ring dynamic stiffness testing device considering extrusion oil film characteristics under rotary excitation, comprising a rotary excitation driving assembly, an elastic ring assembly, a plurality of force sensor assemblies and an outer shell. An annular chamber of the extrusion oil film is formed between the inner and outer bushings of the elastic ring assembly, the elastic ring assembly is installed between the inner and outer bushings, and the outer bushing is fixed to the outer shell through the force sensor assembly; the inner bushing is used for tight fit with the bearing outer ring. The present application can accurately simulate the elastic ring extrusion oil film characteristics under rotary excitation, apply rotary excitation load by using an unbalanced rotor system with adjustable unbalance, directly measure the excitation force amplitude by cross-arranged dynamic force sensors, measure the rotor displacement response by high-precision laser displacement sensors, and further realize accurate testing of dynamic stiffness considering the elastic ring structure and oil film characteristics, thereby providing strong support for elastic ring design.