67 results about "Mechanical dynamics" patented technology

A method for detaching and recovering the electronic elements and solder from the rejected circuit board includes uniformly heating said circuit board until the solder is molten, sucking the electronic elements from the molten solder, and solidifying the solder.

The invention discloses an online test method for a characteristic parameter of a bearing-rotor system. The online test method comprises the steps of: installing a signal acquisition system on the bearing-rotor system supported by a sliding bearing; regulating the rotation speed of a main shaft, and starting a drive motor and a signal acquisition instrument; acquiring vibration signals of specific positions in real time by an eddy current displacement sensor, and storing the vibration signals by the signal acquisition system; establishing a bearing-rotor system model by adopting a finite element method; and applying a characteristic parameter optimization method of the bearing-rotor system based on combination of machinery dynamics modeling with a genetic algorithm to ensure that a theoretical vibration state obtained through the simulation model is close to an actual measurement value, thereby realizing online solving of the rigidity and damping coefficient of the sliding bearing, the off set of a rotor and the like of the bearing-rotor system. Compared with the traditional method, the online test method disclosed by the invention has the obvious advantages that external excitation or multiple machine start/stop does not need to be performed on the bearing-rotor system, and the online test method is simple and reliable and has the characteristics of high efficiency, high stability and high precision.

The invention belongs to the technical field of mechanical dynamics, and relates to a determination method for the inherent frequency of a rotor-blade coupled system. The determination method saves the cost of a sensor, an amplifier and a display or record instrument needed by experimental tests and can obtain the higher-order inherent frequency and the inherent frequency in a rotating state. The inherent frequency of the rotor-blade coupled system can be obtained just by modifying the structural size of the system without repeated modeling, the bending and torsion influence on a complex stepped rotating shaft of the coupled system, the gyroscopic effect of a shaft and a disc, centrifugal rigidifying, rotary softening and the Coriolis force influence on blades are considered so that a more accurate result can be obtained; in addition, imbalance responses, blade tip rub-impact and other faults of the rotor-blade coupled system can be analyzed, so that the system structure is optimized.

The invention relates to a redundant parallel robot system. The redundant parallel robot system is characterized by comprising a static platform, wherein four drive motors are fixedly arranged on the static platform; the four drive motors are in common connection with a controller; each drive motor is fixedly connected with a driving lever respectively; each driving lever is connected with a driven lever through a revolute pair to form a branched chain respectively; each driven lever is fixedly connected with a sensor respectively; and each sensor is in common connection with a moving platform through a revolute pair respectively. The redundant parallel robot system has the advantages of simple structure, large work space, high stiffness and high dynamic property, and can be used for manufacturing a plurality of types of mechanical equipment such as manipulators, machine tools, experimental platforms for researching force control and the like, so the redundant parallel robot system has a wide application prospect and a development potentiality in the fields of machining, assembly, mechanical kinetics scientific research and the like.

An apparatus and method to isolate downhole components within a downhole tool from shock and vibration typically experienced during handling and use of the downhole tool. The apparatus and method include a series of interlocking hooks and loops that are bondable to the downhole component and dampingly secure the downhole component within the downhole tool. The material comprising the interlocking hooks and loops is a high temperature material whose performance is not affected by high temperatures.

The invention relates to the technical fields of machinery dynamics and vibration measurements, in particular to a super-miniature rotor dynamic balancing measuring method and equipment for complementing the super-miniature rotor dynamic balancing measuring method. The method includes the following steps: (1) arranging a damping device on a bearing device, wherein the damping device is a single freedom degree damping device, and arranging the bearing device at the position of a resonance point of a dynamic balancer through a bearing piece; (2) arranging a to-be-tested super-miniature rotor on the bearing device; (3) driving and connecting a motor for the to-be-tested super-miniature rotor; (4) starting the dynamic balancer and the motor; (5) adjusting a damping coefficient of the damping device, stiffness of the bearing device, and balance revolving speed of the to-be-tested super-miniature rotor so as to enable resonance frequency and amplitude of the to-be-tested super-miniature rotor to reach a set value; (6) measuring a vibration signal of the to-be-tested super-miniature rotor and then after the vibration signal is amplified, analyzed and processed, transmitting the vibration signal to a computer; and (7) obtaining a measured result processed by the computer. The method and the equipment can achieve measurement to dynamic balance of the super-miniature rotor under the lower speed.

The invention belongs to the technical field of mechanical dynamics, and particularly relates to a method for calculating time-varying mesh stiffness of a bevel gear pair. The method includes: S1, acquiring basic parameters of the bevel gear pair; S2, separating a bevel gear pair model into N independent and uniform laminar straight gears along a tooth width direction; S3, determining whether the N laminar straight gears participate in meshing or not at the meshing position j; S4, calculating the time-varying mesh stiffness for every laminar straight gear; S5, summing the time-varying mesh stiffness of all the laminar straight gears to obtain the time-varying mesh stiffness of the bevel gear pair. The method for calculating the time-varying mesh stiffness of the bevel gear pair has the advantages that nonlinear contact is taken into consideration, influences of base body stiffness and extended meshing are corrected, an analyzing model is improved, and calculating precision is improved.

The invention belongs to the technical field of mechanical dynamics, and particularly relates to a gear pair abrasion loss prediction method based on dynamic meshing force, which comprises the following steps: S1, acquiring basic parameters of a gear pair; S2, calculating the time-varying meshing stiffness and static load distribution coefficient of the worn gear pair according to the acquired basic parameters of the gear pair and a gear tooth bearing contact analysis method; S3, introducing the time-varying meshing stiffness obtained through calculation into a gear rotor system dynamic modelto calculate a dynamic meshing force and a dynamic load distribution coefficient of the gear pair; and S4, adopting an Archard wear theory, a wear coefficient empirical formula, the dynamic meshing force of the gear pair and the dynamic load distribution coefficient to calculate and obtain the tooth surface wear loss of the gear pair. According to the gear pair abrasion loss prediction method based on the dynamic meshing force, prediction efficiency and prediction precision are both considered.

The invention belongs to the technical field of mechanical dynamics, and particularly relates to a meshing characteristic analysis method of stripping bevel gear pair which is corrected by considering substrate rigidity. According to the method, firstly the gear tooth of a bevel gear pair is divided into N independent and uniform thin-sheet straight gears in the tooth width direction, and based on the known stripping size and position parameters, the stripping condition of each straight gear is determined; through a potential energy method, a finite element substrate rigidity correction coefficient is introduced to calculate the time-varying meshing rigidity of each single stripping straight bevel gear; based on ANSYS software parameterized programming, a three-dimensional finite element stripping bevel gear contact model is established, the time-varying meshing rigidity is solved and obtained, and analysis and comparison with an analysis method result are conveniently achieved. Based on an analysis and finite element solution method, the influence of the stripping width ws, the stripping length as, the stripping axial position and the stripping tooth-direction position on the bevel gear time-varying meshing rigidity is analyzed, and the influence of axial multi-stripping and tooth-direction multi-stripping on the bevel gear meshing rigidity is considered at the same time.

The invention belongs to the technical field of mechanical dynamics, and particularly relates to a bolt connection cylindrical shell structure frequency response function uncertainty analysis method with a flange. According to the method, eight-node degradation shell unit is adopted, and a kinetic model of bolt connection flange-cylindrical shell is established through a finite element method; bolt connection is simulated through discretizing modeling by using a spring unit, and the effectiveness of the built model is verified through a modal test; the uncertainty of the bolt connection stiffness is considered, the frequency response function interval range when the connection stiffness in five directions under a cylindrical coordinate system is an uncertainty parameter is solved based ona Chebyshev polynomial agent model and an interval analysis method, and under the deterministic inherent frequency, the Monte-Carlo sampling method is used for solving the frequency response functioninterval range, and the solving precision and efficiency of the two methods are compared; and finally, the multi-parameter uncertainty system frequency response function interval range is solved.

The invention belongs to the technical field of mechanical dynamics, and particularly relates to an aviation pipeline modeling and vibration characteristic analysis method considering bolt connection.The method comprises the following steps: establishing an entity contact finite element model constrained by a pipeline clamp, and correcting the elasticity modulus of a pipeline through a free modaltest to obtain a corrected pipeline model; Carrying out simulation calculation on the inherent frequency under the set tightening torque, and verifying the simulation calculation by adopting a modaltest and a basic excitation response test; And analyzing the rule of the influence of the bolt tightening torque, the clamp span and the pipe body length on the inherent frequency of the double-clamppipeline system. According to the method, a finite element contact model is adopted and is combined with a test to carry out comparative study, and the modeling method is accurate in calculation result and conforms to the actual structure.

The invention provides a wind magnetic suspension cabin suspension control method which aims at a nolinear wind cabin suspension system with strong interference and heavy suspended matter and can reasonably divide a control task from interference suppression. The method includes the steps that cabin suspension is divided into two parts including suspension mechanical dynamics and converter currenttracking, the suspension mechanical dynamics completes suspension air gap control and sets converter suspension current reference, and the converter current tracking completes suspension current reference tracking; the suspension mechanical dynamics adopts a suspension steady-state controller and an interference compensator to complete suspension current reference setting in a coordinated manner;and the converter current tracking adopts a current tracking steady-state controller and a self-adaption counter electromotive force compensator to cope with influences of counter electromotive forcechanges caused by suspension air gap fluctuation and converter parameter changes caused by suspension temperature rise on current tracking in a coordinated manner. The wind magnetic suspension cabinsuspension control method improves the steady state performance and the interference suppression capability of the cabin suspension system, and lays a foundation for wind alignment of wind turbine cabin yaw.

The invention discloses an active and passive vibration reduction device based on piezoelectric ceramics and a six-degree-of-freedom vibration reduction system, and belongs to the technical field of mechanical dynamics. The active and passive vibration reduction device comprises a load connector, active and passive vibration reduction mechanisms, a middle mass block, a speed sensor, a piezoelectric ceramic actuator, a displacement amplification mechanism, a foundation platform and a controller; one end of the passive vibration reduction mechanism is connected with the load connector, and the other end of the passive vibration reduction mechanism is connected with the middle mass block; the lower part of the middle mass block is connected with the displacement amplification mechanism; the speed sensor collects the movement speed of the middle mass block and feeds back a speed signal to the controller, and the controller calculates a voltage signal applied to the piezoelectric ceramic actuator according to the speed signal so as to enable the piezoelectric ceramic actuator to generate deformation displacement in the horizontal direction; and the displacement amplification mechanism converts the horizontal displacement into vertical displacement and drives the middle mass block to realize vibration reduction. According to the active and passive vibration reduction device, an active control system and a passive vibration reduction system are combined, so that the device can effectively restrain low-frequency resonance and isolate low-frequency vibration and has a good high-frequency vibration reduction effect.

The invention discloses a method for dynamically correcting and calculating the meshing stiffness of a straight gear under a fluctuation load working condition, and belongs to the technical field of mechanical dynamics. The method comprises the following steps: synthesizing time-varying meshing stiffness of a transmission gear pair in a gear transmission system under a constant load working condition by using an energy method, calculating average meshing stiffness of each pair of gear pairs, substituting the average meshing stiffness into a bending-torsion coupling model of the gear transmission system, and loading an external fluctuation load to solve transverse vibration and torsional vibration responses of the system; analyzing the influence of transverse vibration and torsional vibration responses on the actual meshing state of each transmission gear pair under the fluctuation load working condition; and the straight gear meshing stiffness under the external fluctuation load working condition is dynamically corrected. The method has the advantages that the actual meshing state of the straight gear pair is reflected more truly; different from a traditional straight gear meshingstiffness calculation method, the method considers that the center distance, the meshing angle and the coincidence degree of a meshing gear pair are changed instead of being constant, and the method is closely related to the vibration state of a driving wheel and a driven wheel.

The invention discloses a portable self-sealing rock SHPB test confining pressure pressurization device, which belongs to the field of rock mechanics dynamics indoor test measurement. The cylinder body of the confining pressure device is provided with an oil inlet and an exhaust port, and there are cover plates at both ends. There are concentric circular holes of equal size in the center of the cover plate. The size of the hole can be changed according to the size of the test rock sample. The U-shaped synthetic rubber holster, the hydraulic oil is filled between the holster and the cylinder body, and the test rock sample is placed in the double U-shaped synthetic rubber holster. The whole system adopts the hydraulic oil self-sealing principle, and the oil inlet is connected to the pressurized system through the high-pressure oil pipe, and the confining pressure in the cylinder can be monitored in real time through the pressurized system. The invented portable self-sealing rock SHPB test confining pressure device can apply a stable confining pressure value of more than 100MPa in the radial direction in a relatively short period of time, and the rock sample can be pasted with strain gauges and drawn out from the round hole of the cover plate with wires for real-time monitoring The deformation process of the rock under the impact load, and the system has the advantages of simple operation, stable confining pressure, and easy portability.

The invention discloses a multi-objective optimization design method for dynamic characteristics of a feeding system. The multi-objective optimization design method comprises the following steps: (1)establishing rigidity and flexibility-electromechanical coupling feed system dynamic characteristic simulation analysis model; (2) determining initial parameter setting of multi-objective optimizationof the rigidity and flexibility-electromechanical coupling feed system dynamic characteristic simulation analysis model; (3) obtaining test sample points in a design variable range by using a full factor design method; (4) constructing a nonlinear input/output mapping rule between the multi-objective optimization design variable based on the BP neural network and the dynamic characteristic evaluation index; (5) optimizing rigidity and flexibility by using a cyclic approximation optimizing technology of a genetic algorithm; and the dynamic performance evaluation index of the electromechanicalcoupling feeding system is used for obtaining the Pareto optimal solution of the dynamic performance evaluation index of the feeding system. According to the method, control parameter characteristicsand mechanical and dynamic characteristics of a feeding system and the influence law of the coupling effect between the control parameter characteristics and the mechanical and dynamic characteristicsare explored.

The invention discloses a robust finite time control method of a permanent magnet synchronous motor servo system, with input saturation constraints. The robust finite time control method includes thefollowing steps: establishing a mechanical dynamic model of the permanent magnet synchronous motor servo system; and designing an anti-saturation finite time sliding mode control law. The invention provides a robust finite time control method with input saturation constraints, for solving the problem of tracking and control of the permanent magnet synchronous motor servo system has a non-linear nondeterminacy factor of model parameters and input saturation constraints. The robust finite time control method of a permanent magnet synchronous motor servo system achieves the effect of short adjusting time and high robustness, and can effectively eliminate the adverse influence of input saturation constraints on the system tracking control performance.

The invention discloses a rotary blade-box rub-impact force determining method and belongs to the technical field of machinery dynamics. The method includes the following steps of establishing a function equation Ue+Uc=W between a blade and a box at a certain moment according to the conservation law of mechanical energy; establishing the force equilibrium relation between the blade and the box and obtaining the expression of the radial force Fn in the position of a blade tip; decomposing the blade tip radial force Fn according to the normal direction and the tangential direction of the blade tip according to the bending deformation of the blade, wherein -FL=-Fncos[v'(L,t)], and -FT=Fnsin[v'(L,t)]; and finally, composing the stress on the blade tip.

The invention provides a clearance space-contained manipulator simulation device and relates to a simulation device, particularly a clearance space-contained manipulator simulation device. The device solves the problem in the prior art that no special simulation device for studying the influence of a spatial manipulator gear backlash on the mechanical dynamics is available. The device comprises a test bench, an air-floating platform, an arm rod, a mass-adjustable load mechanism, a base, and three joints. One end of the arm rod is connected with the base through one joint. The base is fixedly mounted on the test stand. The other two joints are mounted on the arm rod. The other end of the arm rod is connected with the mass-adjustable load mechanism. The mass-adjustable load mechanism and the lower ends of the other two joints are respectively provided with one air-floating mechanism. The mass-adjustable load mechanism and the other two joints are capable of floating on the air-floating platform through air-floating mechanisms. The device of the invention belongs to the field of aerospace.

The invention provides a bolt connection cylindrical shell structure dynamic characteristic calculation and analysis method, and belongs to the technical field of mechanical dynamics. The method comprises the following steps: establishing a cylindrical shell energy equation according to a plate-shell theory; establishing a load excitation equation according to the external load condition; establishing a bolt connection mechanical equation according to the bolt connection characteristics; solving bolt connection equivalent stiffness and equivalent damping according to first-order Fourier decomposition; accurately expressing different load characteristics through component force in each vibration displacement direction; obtaining a forced vibration differential equation of the bolt connection cylindrical shell structure through a Lagrange equation; and solving the dynamic characteristics of the bolted connection cylindrical shell structure by applying an incremental harmonic balance method. The method starts from the establishment of a bolted connection equivalent mechanical model, is applied to a cylindrical shell structure, achieves the solving of the vibration response according to the demands of different actual working conditions, simplifies the modeling and calculation process, is high in precision, is high in universality, and the like.

The invention discloses a device and a method for testing dynamic contact kinetic parameters between a silk yarn package and a contact roller. The invention relates to the field of polyester filamentproduction equipment and mechanical dynamics. According to the testing device and method, in the rotating state, the dynamic contact rigidity and the contact damping value between a package and a contact roller are tested according to the mechanical dynamics principle. A spindle shaft package and a contact roller are driven by a servo motor to rotate, an air cylinder is adopted for pressurizing tokeep the contact roller in contact with the package and have certain contact pressure, an electric vibration table is adopted for providing system exciting force, vibration signals of the package andthe contact roller are tested respectively, and dynamic contact rigidity and contact damping are calculated and obtained. The dynamic contact stiffness and the contact damping value under different rotating speeds, different package diameters and different contact pressures can be accurately tested. The defects of inaccurate design parameters, access of analysis results and actual measurement andthe like caused by long-term use of static rigidity and damping and even use of estimated parameters to design a winding system are overcome.

The invention discloses an electromechanical coupling hybrid modeling method for an electric drive system. The method comprises the following steps: 1) establishing a mechanical dynamics model based on a viscoelastic macro-unit, establishing a one-dimensional hybrid dynamics model composed of the viscoelastic macro-unit and discrete vibrators, modeling a flexible rotor shaft system by adopting thecontinuous viscoelastic macro-unit, and characterizing support and inertia of a rotor bearing elastically attached to the shaft by utilizing the discrete vibrators; 2) establishing Park electric model of an electric drive system under alpha-beta dq rotation orthogonal coordinates; assuming that magnetomotive force generated by the asynchronous motor is distributed along an air gap according to asine rule, and obtaining voltage and current in a three-phase asynchronous motor winding; and 3) establishing electromechanical coupling deep hybrid modeling of the electric drive system based on theharmonic balance method. The method solves the problem of deep fusion modeling among multiple physical quantities of rotation speed, current, flux linkage and load, and can provide a more accurate model for electromechanical coupling control of the electric drive system.

The invention provides a magnetic suspension bearing metal rubber ring combined bearing high-speed rotation system device, belonging to the field of magnetic suspension technique; the device comprises a rotor component, a radial magnetic suspension bearing component, an axial magnetic suspension bearing component and a driving motor, wherein, the radial magnetic suspension bearing is supported by a radial magnetic bearing seat; the device is characterized in that: the radial magnetic suspension bearing seat is supported by a metal rubber ring seat through a metal rubber ring; the magnetic suspension bearing metal rubber ring combined bearing component can effectively reduce the vibration when a rotator crosses the first-order bending modal frequency and improve the dynamic performance of the system. The technical proposal is simple and feasible and has good effect; the requirement of high-speed, heavy-load and slightness development of the rotation mechanical rotor leads the mechanical dynamics problems to be outstanding increasingly; the research result of the device can provide clews and references for solving relative practical problems.