135 results about "Bending vibration" patented technology

The invention discloses a stator blade shape-following frequency modulation design method based on a bending vibration mode and application, belongs to the field of vibration design of stator blades of aero-engines and gas turbines, and is suitable for vibration frequency modulation design of non-cantilever type stator structure blades (such as fans and gas compressor stators) with inner rings and outer rings in the aero-engines or the gas turbines. According to the method, firstly, static frequency and dynamic frequency modal analysis is carried out through finite element modeling, and dangerous resonance points and corresponding vibration modes in a working rotating speed range are recognized by combining a Campbell diagram; based on a vibration mode amplitude normalization result, setting a vibration degree parameter and a scale factor, selecting a high response node and carrying out directed disturbance, and updating a structure model to improve a target vibration mode frequency; and through frequency amplification verification and iterative optimization, geometric reconstruction and frequency modulation confirmation are finally completed in combination with aerodynamic performance and processing requirements. The method can realize rapid and accurate frequency modulation of a specific bending vibration mode, avoids introduction of new resonance, and has the advantages of high efficiency, strong adaptability and the like.

The present invention discloses a method and device for simultaneously measuring the bending vibration and torsional vibration of a rotating machinery shaft. The gear disk is installed on the shaft to be measured, and the gear disk is driven to rotate by the shaft to be measured. An alternating voltage signal is output by the eddy current sensor and converted into a digital signal by the software part, so as to obtain the original vibration signal. The maximum value finding method is used twice to extract the bending vibration and torsional vibration of the shaft. Through the above method, the simultaneous measurement of the torsional vibration and bending vibration of the shaft can be realized. The same set of sensors and instruments are used for the two types of vibration measurements, and the cost is relatively low.

A piezoelectric device includes a piezoresonator body and a set of electrodes disposed on the piezoresonator body. The piezoresonator body includes a bulk region and a contact element integral with and protruding from the bulk region, and further includes opposing first and second surfaces. A pair of excitation electrodes are disposed on the first surface. A common electrode is disposed on the second surface. The piezoresonator body is characterized by a longitudinal axis and a transverse axis, and further characterized by a natural resonant frequency (v1) of first-order longitudinal standing vibrations along the transverse axis and a natural resonant frequency (v2) of second-order bending standing vibrations along the longitudinal axis, with v1 < v2 ≤ 1.1v1.

The invention provides a double-constraint radial transduction ultrasonic motor, which comprises an annular rotor and a plurality of stators distributed in the annular rotor in an annular array, and is characterized in that each stator comprises a metal elastomer, a left fixing hole, a right fixing hole, a left piezoelectric ceramic, a right piezoelectric ceramic and an elastic blade group for forming pre-pressure on the annular rotor, the working vibration mode of the stator is first-order standing wave type bending vibration, the left fixing hole and the right fixing hole are formed in the metal elastic body and are formed in the two wave node positions of the first-order standing wave type bending vibration respectively, namely, the amplitude is zero during vibration, and the elastic blade set comprises a left-end elastic blade, a middle elastic blade and a right-end elastic blade. The vibration asymmetry of the metal elastomer can be effectively improved, the structural rigidity of the motor can be improved, the output torque of the motor can be improved, the energy transmission efficiency and the driving capacity can be improved, and the overall performance of the motor can be remarkably improved.

A method for determining variables influencing a total zero point error of a Coriolis mass flow meter comprises: exciting a vibration of a bending vibration mode; measuring a first total zero point error T at a flow of zero; ascertaining a first damping value D of the vibration of the bending vibration mode; measuring an exciter-independent zero point error I during a decaying vibration of the bending vibration mode at a flow of zero; ascertaining a first exciter-dependent contribution E to the first total zero point error T based on the first total zero point error T and based on the exciter-independent zero point error I; and ascertaining a sensitivity factor S for the bending vibration mode based on the first exciter-dependent contribution E to the total zero point error T and based on the first damping value D.

Disclosed is a multi-modal and multi-degree-of-freedom piezoelectric active vibration isolation platform and a working method therefor. The piezoelectric active vibration isolation platform includes an upper platform, a lower platform, a control module, and four vibration isolation modules, where the vibration isolation module includes a passive vibration isolation unit and an active vibration isolation unit; the passive vibration isolation unit includes an upper connector, a lower connector, a cross Hooke hinge, and a first acceleration sensor; the active vibration isolation unit includes a fixed beam, a pre-tightening bolt, a second acceleration sensor, and a driving component; the platform can provide active vibration isolation for the longitudinal (axial) vibration and the bending vibration in any radial direction of a vibration isolation object, and has the advantages of fast response, resistance to electromagnetic interference, and light weight.

The invention discloses a longitudinal bending composite type six-degree-of-freedom piezoelectric active vibration isolation platform and a working method thereof. The vibration isolation platform adopts a modular structural design, a vibration isolation connecting platform and a base platform are sequentially arranged from top to bottom and are connected through four uniformly distributed vibration isolation modules, and each vibration isolation module forms a multi-stage vibration transmission structure through a fixed base, a transducer base, a piezoelectric transducer, an amplitude-change pole, a pre-tightening bolt and a small flexible hinge. The control module collects feedback signals of a first acceleration sensor arranged on the vibration isolation connecting platform and feedforward signals of a second acceleration sensor arranged on the base platform, and outputs 12-channel control signals to the piezoelectric transducers of the vibration isolation modules after signal processing. The piezoelectric transducer is driven to generate a composite motion mode of longitudinal vibration and multidirectional bending vibration, and active suppression of longitudinal vibration and radial bending vibration in any direction of a vibration isolation object is achieved. The device has the advantages of multi-degree-of-freedom vibration isolation, compact structure, lightweight design, independent control, high stability and the like, and has important application value in the fields of space reflecting mirrors, micro-nano manufacturing equipment vibration control and multi-degree-of-freedom vibration isolation systems.

The utility model provides a small medical ultrasonic amplitude transformer. The small medical ultrasonic amplitude transformer comprises a base cylinder, a nose cylinder and a cutter bar cylinder. The base cylinder is provided with an internal thread and is used for being detachably connected with a transducer or other external components. The nose portion cylinder axially extends from the front end of the base portion cylinder, two symmetrical and parallel flat portions are arranged on the circumferential face of the nose portion cylinder, and the flat portions are used for being matched with the whole transducer to be installed, so that accurate positioning of the direction of the tool bit is guaranteed, and pre-tightening and fixing during assembly are facilitated. The cutter bar cylinder extends from the front end of the nose cylinder, the front portion of the cutter bar cylinder is of an arc-shaped structure, the vibration mode of the cutter head can be adjusted, bending vibration is overlaid on the basis of longitudinal vibration, and a longer effective cutting line is formed. The cutting edge limited by the multiple cutting faces is arranged on the arc-shaped front portion of the cylindrical cutter bar, the edge width and the cutting area of the cutting edge are larger, and better blood coagulation and sealing effects can be achieved. The cutting face where the cutting edge is located is perpendicular to the extending plane of the flat part so that the vibration direction of the arc-shaped front part can be accurately controlled.

A cell detachment apparatus that detaches cells placed on a culture surface of a culture container for cells by applying vibration to the cells includes a vibrator and a vibrating plate, wherein the vibrator, the vibrating plate, an acoustic transmission medium, and the culture container are stacked in this order, wherein a bending vibration is excited on the culture container when a vibration of the vibrating plate is transmitted to the culture container via the acoustic transmission medium, and wherein the acoustic transmission medium and the culture container come into contact with each other at a region including an antinode of the bending vibration and do not come into contact at a node of the bending vibration.

Coriolis mass flowmeter and / or density meter (100) comprising: at least two measuring tubes (110) which are bent in the rest position, wherein the measuring tubes (110) have measuring tube center lines which run in pairs mirror-symmetrically to a first mirror plane (Syz) which extends between the measuring tubes (110), wherein the measuring tube center lines each run mirror-symmetrically to a second mirror plane (Sxy) which extends perpendicular to the first mirror plane (Syz); at least one excitation arrangement (140) and at least one sensor arrangement (142); a collector (120) on the inlet side and an outlet side, wherein the measuring tubes (110) are fluidically combined with one of the collectors (120) on the inlet side and the outlet side; a support body (124) which rigidly connects the inlet-side collector (120) and the outlet-side collector (120); and at least one plate-shaped coupler (132, 134) on the inlet side and the outlet side, wherein the measuring tubes (110) are connected to one another in pairs by means of the couplers (132, 134) in order to form an oscillator, wherein the couplers (132, 134) are arranged symmetrically to the first mirror plane (Syz) and in pairs symmetrically to the second mirror plane (Sxy), wherein the excitation arrangement (140) is designed to excite a bending vibration mode between the two measuring tubes (110) of the respective oscillator, wherein the sensor arrangement (142) is adapted to detect oscillations of the respective oscillator, wherein the measuring tube center lines of the measuring tubes (110) of at least one oscillator between the second mirror plane (Sxy) and the collectors (120) each have a first bent section (114), a second bent section (118) and a straight section (116) arranged between the bent sections (114, 118), to which the two bent sections (114, 118) adjoin, wherein the first bent section (114) and the second bent section (118) are bent in opposite directions, wherein the second bent section (118) is arranged on the side of the straight section (116) facing away from the second mirror plane (Sxy), wherein the projection of the measuring tube center line between the intersection point with the second mirror plane (Sxy) and the transition between the straight section (116) and the second bent section (118) onto the second mirror plane (Sxy) Arch height (h) defined,wherein twice the distance between the second mirror plane (Sxy) and the measuring tube center line at the transition between the straight section (116) and the second curved section (118) defines an arc width (w), wherein the quotient of the arc height (h) divided by the arc width (w) defines a relative arc height (h, r ) which is not less than 0.65, where the relative arch height (h r ) is not more than 1.0, wherein the first curved sections (114) between the second mirror plane (Sxy) and the straight section (116) each have a plurality of stiffening bodies (151, 152, 153, 154) which surround the respective measuring tube (110) in a ring shape, wherein at least one of the couplers (132, 134) on the inlet side and the outlet side has a tuning opening surrounded by a closed edge between the measuring tubes (110) connected by the coupler (132, 134) for influencing the oscillation properties of the respective oscillator, wherein the tuning opening in the first mirror plane (Syz) has an extension of at least 70% of the diameter of the measuring tubes (110).

The invention discloses a sandwich type piezoelectric driving double-shaft output mobile robot and a working method thereof.The sandwich type piezoelectric driving double-shaft output mobile robot comprises a sandwich type piezoelectric transducer, a pre-pressure applying mechanism, a driving wheel unit, a first output shaft, a second output shaft, a base body frame and a connecting plate, and a clamping mechanism is not arranged on a stator base body of the sandwich type piezoelectric transducer; a single pin of the pre-pressure applying mechanism and a through hole in the middle of a stator node beam are used for restraining, automatic rolling transmission of contact force is achieved under the condition of matching of the pin hole, and pre-pressure transmitted by the pre-pressure applying mechanism achieves force balance under the counter-acting force generated when a first driving foot and a second driving foot of the sandwich type piezoelectric transducer make contact with the curved surface of an output shaft. The elliptical motion trail direction of the stator driving foot can be controlled by controlling the electric signal phase difference of the longitudinal vibration piezoelectric ceramic set and the bending vibration piezoelectric ceramic set, forward and reverse motion of the first output shaft and the second output shaft is achieved through friction contact, and the mobile robot achieves forward, backward and rapid locking motion.

The present invention discloses a bending vibration type inertial ultrasonic motor and its control method, which relates to the technical field of ultrasonic motors. The bending vibration type inertial ultrasonic motor includes: a stator, a piezoelectric ceramic, a carbon fiber tube, a rod, a slider and a housing. The stator is a circular ring metal sheet, and there are uniformly distributed fixing structures along the outer edge of the circular ring, which are connected to the housing; the piezoelectric ceramic is a flat circular ring sheet, and one sheet is respectively attached to the upper and lower surfaces of the stator; the carbon fiber tube and the rod form a pair of friction pairs, converting the bending vibration of the stator into the up and down movement of the rod; the rod is fixedly connected to the slider and can drive the slider to move. The present invention can provide sufficient rotational speed output and torque output while ensuring the small size of the motor and meeting the structural requirements of the micro zoom system.

The invention provides a resonance type compliant cavity composite structure pressure-resistant bending disc transducer which comprises a simply-supported ring, composite pressure-resistant assemblies are symmetrically arranged on the simply-supported ring up and down, the composite pressure-resistant assemblies and the simply-supported ring form an air cavity, and each composite pressure-resistant assembly comprises a watertight layer, a piezoelectric ceramic piece, a metal bending disc and a resonance type compliant pressure-resistant shell. The shell is arranged in the simply-supported ring, the metal bent disc is arranged above the shell, a medium cavity is formed between the shell and the metal bent disc, water permeable holes are formed in the side wall of the medium cavity, and the exterior of the transducer is communicated with the medium cavity. And a watertight layer covers the outer side. According to the composite shell structure, a pressure bearing structure and a driving structure are designed separately, pressure balance between driving force and a driving element is achieved through a coupling medium, and the anti-pressure capacity is improved; the shell is a bending vibration shell with the working frequency consistent with that of the transducer, the driving impedance is low, and the static pressure resistance is high.

The invention provides an ultrasonic transducer and ultrasonic cleaning equipment, the ultrasonic transducer comprises a piezoelectric exciter and a vibration radiant panel, the vibration radiant panel is fixed on the piezoelectric exciter, a power supply is electrically connected with the piezoelectric exciter, so that the piezoelectric exciter can generate longitudinal vibration, and the longitudinal vibration of the piezoelectric exciter can excite bending vibration of the vibration radiant panel. The longitudinal vibration sandwich type piezoelectric ultrasonic transducer solves the defects that an existing longitudinal vibration sandwich type piezoelectric ultrasonic transducer is small in radiation area, weak in longitudinal displacement amplitude, long in longitudinal size and the like to a great extent, and has the advantages of being small in space needed by operation, large in sound radiation area and sound radiation power, small in size and the like. The ultrasonic transducer can be widely applied to the application requirements of miniaturization and thinning of the installation space of the ultrasonic transducer. Meanwhile, the longitudinal bending displacement amplitude conversion ratio of the ultrasonic transducer can be influenced by the length, and / or the width and / or the thickness of the vibration radiant panel, so that the longitudinal bending displacement amplitude conversion ratio of the ultrasonic transducer is further improved through the size of the vibration radiant panel.

The invention provides a multi-dimensional vibration platform with oppositely-arranged double-sandwich piezoelectric actuators and an excitation method of the multi-dimensional vibration platform, and belongs to the technical field of high-frequency vibration engineering and micro-nano machining.The vibration platform comprises a center platform, the two oppositely-arranged piezoelectric actuators, two end covers and two bolts, wherein the center platform is integrated with the tail end platform, the two flexible hinges and the two amplitude-change poles, and the center platform is slender and is in mirror symmetry about the longitudinal symmetry plane of the tail end platform. The piezoelectric actuator comprises a longitudinal vibration ceramic group, a bending vibration ceramic group around the Y axis and a bending vibration ceramic group around the Z axis, translation along the X / Y / Z axis and rotation around the Y / Z axis can be realized through in-phase or anti-phase excitation different combinations under the condition of not increasing extra driving channels, and five-degree-of-freedom high-frequency micro-vibration output can be achieved at most. The structure has high symmetry, low parasitic vibration, compact size and high integration, and is suitable for precise engineering scenes such as micro-nano processing, laser-assisted manufacturing, cell manipulation and active vibration suppression.

The present invention relates to the technical field of inertial sensors, and particularly relates to a MEMS inertial vibration system with a self-measuring function of motion posture and a preparation method, including: an inertial vibration platform that moves with multi-directional degrees of freedom, and the direction conforms to the cooperative bending vibration generated by the inertial vibration platform under a voltage excitation signal; a PMUT array that is arrayed at a preset interval on the bottom surface of the inertial vibration platform and is bonded to the bottom surface of the inertial vibration platform. The PMUT array includes a plurality of transmitting sub-arrays and a plurality of receiving sub-arrays, and the transmitting sub-arrays and the receiving sub-arrays correspond one by one. Each of the transmitting sub-arrays and the receiving sub-arrays includes a plurality of PMUT single tubes, and the plurality of PMUT single tubes are connected to each other to form a transmitting sub-array or a receiving sub-array. The beneficial technical effects of the present invention include: being able to perform self-monitoring of the motion state of the MEMS inertial vibration platform, providing a reference for the self-calibration of the MEMS inertial sensor, and simplifying the implementation method of self-calibration.

The invention discloses a magnetostrictive ultrasonic longitudinal-bending dual-mode cutting device and an operation method, the longitudinal-bending dual-mode cutting device is provided with a longitudinal-bending dual-mode main body, the front end of the longitudinal-bending dual-mode main body is provided with a stepped-shaft-shaped tool apron, chamfers or fillets are arranged between steps, the front end of the stepped-shaft-shaped tool apron is provided with a tool mounting part, and the front end of the stepped-shaft-shaped tool apron is provided with a tool holder; a threaded connection hole is formed in the cutter mounting head part, and the cutter is matched with the threaded connection hole and is fixed on the cutter mounting head part through a cutter fixing bolt. Free switching between the longitudinal vibration mode and the bending vibration mode of the machining device can be achieved by adjusting the direct current of the bias coil at the bias coil rack according to the working condition and the machining requirement of a workpiece, and the precision of the machined surface and the flexibility of a machining tool are improved.

The present invention discloses a low-frequency, multi-directional, broadband vibration absorber for pipelines, comprising a frame, an elastic element, a base mass, an additional mass, and a mounting fixture. The frame is in the shape of a ring, and a plurality of layers of periodically arranged circular holes are provided on the surface, and the diameters of the circular holes in each layer are different. The elastic element is composed of an inner ring, an outer ring, and a connecting beam. A connecting beam is provided between the inner ring and the outer ring. The outer ring is embedded in the circular hole of the frame and its size corresponds one-to-one to the circular hole on the frame. The base mass is detachably installed in the inner ring. The additional mass is attached to the base mass. By selectively installing the base mass and the additional mass, the resonant frequency of the vibration absorber can be adjusted to achieve regulation of the vibration absorption frequency band; by rotating the elastic element as a whole in the circular hole of the frame to change the bending vibration direction of the connecting beam, the vibration reduction direction of the vibration absorber and the coordinated control of multi-directional vibration can be achieved. The present invention has a compact structure, occupies a small space, is simple to process, has a low manufacturing cost, and has good low-frequency, multi-directional, broadband vibration reduction capabilities.

The application discloses a patch type ultrasonic motor vibrator, a method and an ultrasonic motor of composite vibration, which comprises a vibrating body and a PZT plate group; the PZT plate group comprises a torsional PZT plate and a bending PZT plate; the top of the vibrating body is provided with a driving leg; the top surface and the bottom surface of the vibrating body are provided with the torsional PZT plates, the torsional PZT plates are polarized along the thickness direction of the vibrating body, and the polarization directions of two adjacent torsional PZT plates are opposite; the bending PZT plates are arranged at the nodes corresponding to the bending vibration on the two sides of the vibrating body, and the polarization directions of the bending PZT plates are the same. The four-foot vibrating body of the torsional / bending composite vibration type is designed, and the torsional excitation mode of the'reverse polarization and synchronous excitation' is designed, so that the electromechanical coupling degree of the linear ultrasonic motor is improved, and the problems of small driving force and low mechanical output caused by the vibration mode of the traditional vibrator are solved.

The application provides a tension-compression-bending vibration fatigue and force-position characteristic integrated testing device and system of a micro elastic element, and belongs to the technical field of micro elastic element testing. The device and system solve the problems of single function of the existing elastic element testing equipment, dependence of vibration fatigue testing and force-position characteristic testing on independent professional systems, and difficulty in adapting to millimeter-level micro elastic elements and difficulty in realizing multi-dimensional deformation loading. The device and system comprise a Y-direction displacement platform fixed on a base, an X-direction displacement platform provided with an adapter platform between the Y-direction displacement platform, a force sensor provided on the base along an axis parallel to the Y-direction displacement platform and connected with a displacement amplification mechanism, and a vibration exciter fixed on the base and connected with the displacement amplification mechanism. One end of a test spring is connected to the X-direction displacement platform, and the other end of the test spring is provided with two stations. A first station is connected with the force sensor, a second station is connected with the displacement amplification mechanism, and a laser displacement sensor detects the displacement of the displacement amplification mechanism.

The utility model relates to carbon tape processing technical field, and disclose a kind of carbon tape base ink dip-dyeing device, including dip-dyeing box, the left and right ends of dip-dyeing box are respectively provided with input and output for carbon tape base to pass in, and the inner bottom side of dip-dyeing box is provided with abutting roller, and the upper portion of dip-dyeing box is provided with bending vibration subassembly corresponding abutting roller;The bending vibration subassembly includes the cross frame being arranged on the top of dip-dyeing box.This carbon tape base ink dip-dyeing device, carbon tape base enters dip-dyeing box inside under the conveying effect of external conveying mechanism, when carbon tape passes through dip-dyeing box, utilize hydraulic rod elongation to drive link plate and press frame to move down, and carbon tape base is abutted and bent between abutting roller and press roller, utilize bending effect to extend dip-dyeing path and time, and utilize exciter to drive press frame and press roller vibration, vibration rolling is carried out to carbon tape base, to further shake out the fine bubble adhered to the surface of carbon tape base, improve the contact effect of ink and carbon tape base, to further improve dip-dyeing quality.

The invention discloses a dynamic supporting lead screw device and a working method thereof, and belongs to the field of lead screw equipment. According to the technical scheme, the dynamic supporting lead screw device comprises a main lead screw and a plurality of sets of auxiliary lead screws, a supporting assembly is installed on a nut base of each auxiliary lead screw, and the supporting assemblies are supported on the lower portion of the peripheral face of the main lead screw; a detection mechanism is arranged on the main lead screw, and the detection mechanism can detect deformation data of the main lead screw in real time; the device further comprises a control module, the control module is electrically connected with the detection mechanism and the multiple sets of auxiliary lead screws, and the control module can receive main lead screw deformation data detected by the detection mechanism and control the auxiliary lead screws to enable the supporting assembly to move to a proper position. The control module drives the auxiliary lead screw to dynamically adjust the position of the supporting assembly, real-time matching of the supporting point position, lead screw deformation and load distribution is achieved, the defect that a traditional fixed support cannot be matched with dynamic loads is thoroughly overcome, the operation stability and positioning precision of the main lead screw are remarkably improved, and bending vibration and droop deformation are effectively restrained.

The present invention discloses a multi-elastic modulus measurement system based on self-mixing interference. The optical unit includes two optical groups, and each optical group includes a semiconductor laser, a collimating lens, and a photoelectric receiver. The semiconductor laser is used to emit an initial optical signal to a sample, so that the initial optical signal is reflected or scattered by the sample excited by an external excitation signal to form a feedback optical signal. The feedback optical signal returns to the laser resonator of the photoelectric receiver and undergoes a self-mixing interference effect with the initial optical signal. The excitation unit is used to excite the sample with an external excitation signal to cause the sample to generate bending vibration and shear vibration. The calculation module is used to perform a fast Fourier analysis on the electrical signal to obtain the bending resonance frequency and shear resonance frequency of the sample, so as to calculate the Poisson's ratio and bulk modulus of the sample. The present invention realizes the simultaneous and high-precision measurement of the bending resonance frequency and shear resonance frequency of the specimen in one measurement, and further achieves the goal of obtaining multiple elastic moduli.

A resonance device includes: a resonator and a first substrate. The resonator includes a vibration part, a frame disposed at at least a portion of a circumference of the vibration part, and a supporting arm configured to connect the vibration part and the frame. The first substrate includes a first bottom plate configured to have a first gap to the vibration part in a thickness direction. The vibration part includes a vibration arm configured to perform out-of-plane bending vibration. The vibration arm includes a tip-end part with a base-end-side portion and a tip-end-side portion that is closer to an open-end side of the vibration arm than the base-end-side portion, the base-end-side portion has a first surface that includes a metal film facing the first bottom plate, the tip-end-side portion has a second surface that includes silicon facing the first bottom plate.

The invention relates to a vibronic measurement recorder (100) for measuring mass flow, comprising a line inlet portion (18); a vibratable measuring tube line (10) which is curved in a measuring tube line plane in its resting position and has an S-shaped directrix; a line outlet portion (19); a vibration exciter (53) for exciting a bending vibration use mode; two vibration sensors for detecting measuring tube line vibrations; a carrying body (30); two bearing bodies (21; 22) which connect the measuring tube line to the carrying body (30); wherein the measuring tube line (10) has, in the bending vibration use mode, two vibration nodes; wherein the measurement recorder (100) furthermore has two stop bodies (76; 86; 88) each of which at least partially surrounds the measuring tube line (10) in order to limit deflections of the measuring tube line (10) perpendicularly to the directrix, wherein the stop bodies (76; 86; 88) each have a centre of gravity, wherein in each case a cross-sectional plane extending perpendicularly to the directrix and in which the centre of gravity is located is no further than two outer diameters of the measuring tube line (10) away from a position at which, when the measuring tube line is filled with water, the next of the vibration nodes of the bending vibration use mode is located.

The present invention discloses a method for eliminating the natural frequency splitting of a circular periodic structure based on grouping characteristics. The method includes: constructing an additional mass block distribution function based on grouping characteristics in the inertial polar coordinate system, including the in-group uniform distribution and the in-group progressive distribution methods; applying Hamilton's principle in the inertial polar coordinate system to establish a dimensionless partial differential vibration equation for the out-of-plane bending vibration of the circular periodic structure; using Galerkin discretization and classical vibration theory to solve and obtain an analytical expression of the dimensionless natural frequency corresponding to the vibration wave number n, and determining the frequency splitting elimination condition; based on the frequency splitting elimination condition, determining specific elimination rules for the two in-group distribution methods. The present invention intuitively gives the natural frequency in an analytical form of the circular periodic structure, which can be substituted with actual parameters to directly solve and verify whether the natural frequency splits, and has characteristics such as universality, economy, and high efficiency.

The utility model discloses a three-rectangular-plate parallel connection type linear moving platform driven by a piezoelectric stator. The three-rectangular-plate parallel connection type linear moving platform comprises a support assembly, a stator assembly, a moving table assembly and a pre-tightening force adjusting assembly. The stator assembly is fixed on a boss of the base, and the top end of the triangular driving foot is in contact with the friction plate; a moving guide rail and a sliding block in the pre-pressure adjusting mechanism form a moving pair, a spring and a gasket are pressed between a pre-tightening bolt and a bolt bracket, and the tightness of the spring is controlled to realize the adjustment of the pre-tightening force between the triangular driving foot and the friction plate; when the linear moving platform device works, a specified electric signal is applied to the piezoelectric ceramic piece, a first-order longitudinal vibration mode and a second-order bending vibration mode of the stator assembly are excited at the same time, through coupling of the longitudinal vibration mode and the bending vibration mode, the triangular driving foot can generate elliptic motion, and under the action of pretightening force, through friction coupling between the driving foot and the friction plate, the linear moving platform device is driven to move. And the moving plate is pushed to linearly move. The utility model has the advantages of compact structure, simple installation and large thrust.

A first amplitude-change pole body and a second amplitude-change pole body are coaxially arranged, the projection of the second amplitude-change pole body along the central axis of the second amplitude-change pole body is located in the first amplitude-change pole body, and a containing cavity is formed in the end, away from the first amplitude-change pole body, of the second amplitude-change pole body. The positioning rod body is arranged at the end, away from the second amplitude-change rod body, of the first amplitude-change rod body and is coaxial with the first amplitude-change rod body, the flange structure is arranged on the side wall of the first amplitude-change rod body, and a gap is formed between the flange structure and the side wall of the second amplitude-change rod body. The adjusting block extends into the gap, at least part of the adjusting block is connected to the end, close to the second amplitude-change pole body, of the first amplitude-change pole body, and the adjusting block abuts against part of the side wall of the second amplitude-change pole body. The adjusting block can enable vibration to act on the second amplitude-change pole body to enable the second amplitude-change pole body to achieve polarization, the bending vibration effect is achieved through the combined action of longitudinal vibration and polarization, and motion of a cutter is better facilitated.

The present invention discloses a mobile robot based on a multi-degree-of-freedom piezoelectric actuator and an excitation method thereof, wherein the piezoelectric robot includes a rotor, a stator, four connecting rods and four support members. The support member includes a limit cylinder, a spring and a support ball. The stator is wrapped around the outer surface of the rotor. The stator is made of piezoelectric ceramics. The present invention applies a specific combination of electrical signals to the stator to excite a radial bending vibration mode and two vibration modes of the stator in two orthogonal axial bending vibration modes, thereby coupling to form a slight elliptical motion on the driving surface, and driving the rotor to rotate around three axes through friction, thereby realizing translation and rotation in two directions of the piezoelectric robot. The present invention can realize translation and rotation in two directions, and has the advantages of simple and compact structure, no electromagnetic interference, self-locking when power is off, and easy miniaturization. It is suitable for fields such as robot transportation technology, target tracking technology and precision positioning platform.

The invention belongs to the technical field of material mechanical property testing, and discloses a dynamic Young modulus measuring method and device based on a frequency sweeping mode. The method comprises the following steps: carrying out sweep frequency excitation on a standard test rod through a non-contact vibration exciter to enable the standard test rod to generate bending vibration; synchronously acquiring vibration response data in a non-contact manner by adopting a laser vibration meter, and performing spectrum analysis through a signal acquisition and processing system to obtain an amplitude response spectrum; identifying at least one harmonic peak of bending vibration from the frequency spectrum, and accurately acquiring a corresponding resonant frequency; and dynamically calculating the Young modulus of the material according to the measured resonant frequency in combination with the geometric and physical parameters of the test rod and the corresponding vibration mode. According to the invention, non-contact excitation and measurement, a sweep frequency mode and an accurate spectrum analysis technology are combined, additional mass and rigidity errors introduced by contact measurement can be avoided, and the method has the advantages of high measurement precision, high speed, good repeatability, huge automation potential and the like.