103results about How to "Additional mass is small" patented technology

The invention belongs to the technical field of vibration test, in particular to a thin-walled structure part vibration test device and a method based on a piezoelectric ceramic vibration exciter. The device comprises a signal generator, a piezoelectric ceramic drive power supply, a piezoelectric ceramic vibration exciter, a feedback attenuator, a laser vibration meter, a data acquisition analyzer and an upper computer. The method comprises the steps of performing modality test on a thin-walled structure part, determining a linear relationship between excitation voltage and critical excitation frequency of the signal generator and calibrating an excitation force of the piezoelectric ceramic vibration exciter based on a cantilever theory. According to the device and the method, an excitation signal can be effectively acquired; the magnitude of the excitation force when the piezoelectric ceramic vibration exciter excites the structure part is defined; the stable designated excitation force and the linear excitation signal of the excitation frequency can be generated; influencing factors of non-linear piezoelectric ceramic excitation are effectively eliminated; the piezoelectric ceramic vibration exciter is adopted to realize high-frequency vibration excitation; additional mass is low; and the device is convenient to use.

The invention relates to the field of low-frequency or ultralow-frequency vibration isolators, in particular to a disc spring quasi-zero stiffness vibration isolator which is applied to ground vibration tests of spacecrafts. In order to overcome the defects that an existing quasi-zero stiffness vibration isolator is low in bearing capacity, complex in structure, and relatively short in effective stroke nearly zero-stiffness, the invention provides the quasi-zero stiffness vibration isolator. The quasi-zero stiffness vibration isolator comprises a disc spring, a pressing piece, a rigid casing, a linear spring and a linear spring length regulator, wherein the outer edge of the disc spring is connected with the rigid casing through the pressing piece; the center of the disc spring is fixedly connected with the top of the linear spring; the bottom of the linear spring is fixedly connected with the linear spring length regulator; and the linear spring length regulator is in threaded connection with the rigid casing. Compared with the existing low-frequency vibration isolator, the quasi-zero stiffness vibration isolator disclosed by the invention has the advantages of being small in added mass, high in bearing capacity, adjustable in bearing capacity, small in size, simple in structure, easy to maintain, high in reliability and the like.

The invention relates to bran finisher double-turned mass dampers, a combined vibration reduction and isolation device and an implementation method. The double-turned mass damper consist of double-cantilever beams and turned mass blocks at two ends of the double-cantilever beams; the combined vibration reduction and isolation device consists of a vibration isolation system and a tuned mass damper; the vibration isolation system consists of rubber vibration isolators, a vibration isolation steel plate and a steel spring vibration isolator; the rubber vibration isolators are installed on the upper surface of the vibration isolation steel plate; the steel spring vibration isolator is arranged on the upper bottom surface of the vibration isolation steel plate; the rubber vibration isolators are arranged at four corners of a bran finisher; and the double-turned mass dampers are arranged at two ends of the vibration isolation steel plate and are symmetrically arranged by a central line of the vibration isolation steel plate. According to the combined vibration reduction and isolation method, the upper and lower vibration isolation structures (the rubber vibration isolators and the spring vibration isolator) cooperate with the turned mass damper, so that additional mass of the vibration isolation structure is reduced, and a good vibration isolation effect can be achieved due to the small mass of the vibration isolation structure.

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 discloses a pipeline vibration active control system with a band gap characteristic, and belongs to the technical field of vibration control in the field of machinery. The system adoptsthe band gap characteristic of a periodic structure and an intelligent damping material to control pipeline vibration. The system comprises a pipeline, a piezoelectric sensor, a signal conversion unit, an upper computer, an active controller, a voltage amplifier, a viscoelastic damping layer and piezoelectric ceramic, wherein the viscoelastic damping layer is periodically attached to the outer wall of the controlled pipeline. The piezoelectric sensor receives a vibration signal of the pipeline, the vibration signal is input to the active controller and the upper computer through the signal conversion unit to be calculated to obtain a feedback signal, the feedback signal is transmitted to the piezoelectric ceramic piece attached to the outer wall of the controlled pipeline through the voltage amplifier, and the piezoelectric ceramic piece deforms to enable the viscoelastic damping material to generate shear deformation. Due to the band gap characteristic of the periodic structure, the propagation of vibration of a specific frequency is attenuated in the structure. The two effects are combined to reduce the vibration amplitude of the pipeline.

The invention discloses a portable thermal loading device for a temperature-acceleration composite environment test, comprising a radome having one end open and the other end closed, electric heating membranes and a fan. The radome is in connection with a centrifuge arm through main body bolts; a testpieces is installed on the centrifuge arm through a table top, and is located in the radome; in the radome, a thermal insulation layer is arranged between an outer wall and an inner wall; a plurality of electric heating membranes are uniformly bonded on the inner wall; the fan is installed on the inner wall and is close to the inner bottom center, and the air supply direction just faces the inner bottom center of the inner wall. The portable thermal loading device employs bonded electric heating membranes to realize heating, thereby synchronously controlling the temperature and acceleration, and improving the simulation capability of a temperature-acceleration composite environment test; the radome is of a three-layer structure, thereby reducing the overall mass, and improving insulation effects; the radome is internally provided with the fan, thereby improving the temperature uniformity and the convection heat exchange efficiency of a heating source.

The invention relates to an improved aircraft electronics cooling system for an aircraft having a liquid cooling system (2), the aircraft electronics cooling system providing a thermal coupling between an electronic device (40a, 40b, 40c, 40d, 42, 44) to be cooled and the liquid cooling system (2) of the aircraft. A coolant delivered by the liquid cooling system (2) may flow through a board of the electronic device (40a, 40b, 40c, 40d), through a heat sink on which the electronic device (42) is arranged and/or through a housing in which the electronic device (44) is arranged. The coolant may be permanently in the liquid state in a cooling circuit. The coolant may vaporize at least partially while cooling the electronic device.

The invention relates to a vertical frequency adjustment mass damper for a model test and a design method of the vertical frequency adjustment mass damper. The vertical frequency adjustment mass damper comprises a top plate, a bottom plate and a mass block. The top plate and the bottom plate are connected through connection threaded rods. The vertical frequency adjustment mass damper is provided with straight tracks which are fixedly connected with the top plate and the bottom plate. Springs are arranged between the top plate and the mass block as well as between the bottom plate and the mass block. The mass block is connected with sliding blocks which slide up and down along the straight tracks. The mass block makes simple harmonic motion along the straight tracks under the action of the springs. The vertical frequency adjustment mass damper is concise is design, the mass of an additional device is low, a bolt is arranged on the top plate, and thus mounting and dismounting are convenient; the number of the springs can be increased or decreased according to requirements, mounting and dismounting are easy and fast, positioning is symmetrical and accurate, and the model test requirements are met; and the side faces of the mass block are installed on the straight tracks, the gravity is borne by the compression springs, the friction force is small during vertical reciprocating high-frequency motion, influences on the frequency of the damper can be neglected, and the accuracy of frequency adjustment of the vertical frequency adjustment mass damper is guaranteed.

The invention relates to a topological optimization method for constraining and damping blades of an aeroengine. The method comprises the following steps: taking lightweight aluminum foil as a constraining material, sequentially sticking a viscoelastic material and the constraining material onto the surface of each blade of the aeroengine, carrying out constraining and damping processing on the blades, and establishing finite element models of the constrained and damped blades; carrying out modal analysis on the constrained and damped blades according to the finite element models of the constrained and damped blades, and filtering sensitivity of constrained and damped cell units by adopting an independent grid filtering technology; solving an optimization model by adopting an asymptotic optimization algorithm, programming an optimization program, searching for the optimal layout of a constraining and damping material on each blade, and cutting and regularizing optimized layout, so as to adapt to engineering application. The method has the advantages that the aim of achieving the maximal aeroengine blade damping vibration reduction effect with the minimal damping material additionally-added amount is realized, so that the vibration stress of the blades of the aeroengine is remarkably lowered, and the fatigue damage resistance of the blades is improved.

The invention discloses a two-dimensional development zero-gravity simulation device and method based on a constant force spring. The device comprises a constant force lifting component composed of afixed end mandrel component, a movable end mandrel component, guide sliding rails, a guide rail fixing piece and the constant force spring, a tackle and a longitudinal guide rail; the fixed end mandrel component is fixedly connected with the guide sliding rails; the guide sliding rails penetrate through guide sliding blocks on the movable end mandrel component in a sliding mode; the bottom ends ofthe guide sliding rails are fixedly connected with the guide rail fixing piece; the constant force spring is installed between the fixed end mandrel component and the movable end mandrel component; and the upper end of the constant force lifting component is fixedly connected with the tackle, and the tackle is installed on the longitudinal guide rail and can horizontally move along the longitudinal guide rail. The problem that ground two-dimensional development zero-gravity simulation is difficult for existing aerospace mechanism products is solved, and the device has the beneficial effects of being high in response speed, small in additional mass, small in additional resistance, small in system energy loss and the like.

The invention provides a damping ring device used for controlling vibration of compressor blades. The damping ring device comprises the blades, a rim and damping rings. The blades and the rim are integrally formed. The blades are arranged on the outer side of the rim. The rim comprises a first structural part and a second structural part. The second structural part is arranged inside the first structural part. The first structural part comprises two grooves shaped like the Arabic number '7'. The grooves are located in the inner side of the end face of the upstream end of the first structural part and the inner side of the end face of the downstream end of the first structural part. The two damping rings are arranged on the inner sides of the first structural part by being embedded in the grooves respectively. The damping ring device does not make direct contact with the blades. The blades do not need to be machined. Only the procedure of machining wedge-shaped faces or rectangular faces in the rim is needed. The damping ring device is convenient to install and has the advantages of being simple in process, convenient to install, small in added mass, simple in design and high in reliability.

The invention provides a steel rail dynamic damping composite vibration absorber and a manufacturing method thereof. The composite vibration absorber is connected with a steel rail, and the compositevibration absorber is arranged between any two adjacent sleepers; the composite vibration absorber comprises a vibration reduction part and a fixing device, the vibration reduction part is arranged inthe fixing device, and a containing space is formed between the vibration reduction part and the fixing device; the rail bottom and at least part of the rail web of the steel rail are arranged in thecontaining space; and the vibration reduction part comprises a dynamic vibration absorber and a particle damper; According to the steel rail dynamic damping composite vibration absorber and the manufacturing method thereof, the rail bottom and at least part of the rail web of the steel rail are wrapped, and the dynamic vibration absorber and the particle damper of the vibration reduction part arecombined into a whole to form the composite vibration absorber together, so that the advantage that the dynamic vibration absorber effectively inhibits resonance is utilized, and the advantages thatthe particle damping vibration absorber is small in additional mass and good in broadband vibration reduction effect are also utilized; and the vibration of the steel rail and the generated radiationnoise can be effectively inhibited and attenuated.

The invention relates to the technical field of material testing, particularly to an integrated tester and testing method for shock absorption, noise reduction and impact resistance of a composite material. The tester comprises a reverberation box, an anechoic box, an upper box body and lower box body supporting and connecting table body, a high-power high-pitch horn, a front power amplifier, a pure post-power amplifier, a plurality of groups of piezoelectric ceramics, a piezoelectric ceramic driving power supply, a projectile centrifugal acceleration ejection device, and a plurality of groupsof projectile sensors, a telescopic support frame, a snake-shaped telescopic thin tube, a laser displacement sensor, a high-speed camera, a plurality of sound pressure sensors, a projectile recoverydevice and a data acquisition instrument. The integrated tester can meet the integrated test requirements for shock absorption, noise reduction and impact resistance of the composite material at the same time, has comprehensive test indexes, has the advantages of high efficiency and mobility, is convenient for on-site test, and objectively evaluates the shock absorption, noise reduction and impactresistance of the composite material.

The invention provides a design method of a static aeroelasticity test model. The design method comprises the following steps: firstly, through a similarity relationship, calculating the section rigidity of the model, and utilizing relevant three-dimensional modeling software to carry out model section design, wherein the designed model section comprises the leading edge, the trailing edge and a windward side of a wing so as to realize a purpose on improving leading and trailing edge model rigidity; using rigid form to fill a metal girder so as to guarantee the aerodynamic configuration of the model; and painting the surface of the model to guarantee the surface flatness of the model. Through an integrative structural model, the deformation of the surface of the model in a wind tunnel test can be effectively reduced, and influence on wing aerodynamic force due to the deformation of the surface of the model is eliminated. In addition, since the leading edge and the trailing edge of the model are made of metal materials, the strength of the model is greatly improved.

The invention discloses an active vibration control system of a flexible structure based on a voice coil motor and a method thereof, wherein the system comprises a main support rod fixed on the ground, a rail is fixed on the main support rod, left and right oblique rods on both sides of the rail are symmetrically fixed to the main support rod, left and right large displacement actuators adjacent to the left and right oblique rods are fixed on both sides of the main support rod when the rail is as a symmetry axis, both sides of the other end of the rail are symmetrically fixed with stationary fixtures on which fixed pulleys are mounted, and the top of the rail is provided with the flexible structure; the other ends of the left and right oblique rods are connected with positioning fixtures on which hole bolts are mounted, the fixed pulleys, the hole positions of the hole bolts and the left and right oblique rods are located on the same plane, and a rigid rope passes through the left large displacement actuator, the fixed pulleys and the holes of the hole bolts; besides, the invention further discloses a control method of the system; the active vibration control system outputs large displacement and greater control force through the voice coil motor, a control direction is shifted by the pulleys such that the active modal vibration control of the flexible structure can be realized.

The invention relates to a multilevel control anti-dive automobile seat. The multilevel control anti-dive automobile seat comprises a seat back, a seat basin framework, a cushion arranged on the seat basin framework, and an anti-dive mechanism, wherein the anti-dive mechanism comprises multiple anti-dive units. Each anti-dive unit comprises a first connection piece assembly and a second connection piece assembly arranged on the two sides of the seat basin framework respectively, a connection rope which is located under the cushion and penetrates each connection piece of the first connection piece assembly and the second connection piece assembly at intervals, and a winding mechanism which is arranged on one side of the two sides of the seat basin framework and used for winding or releasing the connection rope; one end of the connection rope is connected with one side of the two sides of the seat basin framework, and the other end is connected with the winding mechanism. According to the anti-dive mechanism of the multilevel control anti-dive automobile seat, the rigidity of the cushion is controlled by the connection rope stretching regulation through the winding mechanisms; the structure is simple, the arrangement is flexible, the added mass is small, and the seat comfortableness during a normal ride is not influenced.

The invention relates to a power supply device for a tunnel monitoring system, and belongs to the technical field of new energy. The device mainly comprises a rack, a swing frame, a coupler, an elastic vibrator and an isolator; an electric control cavity and two transduction cavities are formed in the rack, the swing frame is composed of a seat plate, a swing arm and an excitation cavity shell, and a magnet is embedded in the inner wall of the excitation cavity shell; the isolator is composed of a wedge body and a cambered surface body; an end cover is arranged at the end part of the transduction cavity and extrudes the isolator and the elastic vibrator in the transduction cavity; the fixed end of the elastic vibrator and the wedge surface of the isolator extrude each other; the elastic vibrator is composed of a substrate and transduction pieces bonded to the two sides of the substrate; when the transduction plate is a movable friction plate, a fixed friction pair is embedded in the sinking cavity of the isolator, and the fixed friction pair is an independent fixed electrode plate or is formed by bonding the fixed electrode plate and a fixed friction plate; the swing frame is arranged on the rack through a reed, and the coupler is arranged on a seat plate of the swing frame; and when airflow flows through, the coupler drives the swing frame and the magnet to swing in a reciprocating mode, and the elastic vibrator generates reciprocating bending deformation under the action of the magnet and converts mechanical energy into electric energy.

The invention discloses a high-rigidity and high-damping satellite platform configuration, which belongs to the field of overall design of spacecrafts and comprises a satellite-rocket butt joint ring used for being in butt joint with a rocket adapter; a mounting plate, wherein one side of the mounting plate is fixedly connected with the satellite-rocket butt joint ring, the other side of the mounting plate is fixedly connected with an optical load plate, and the optical load plate bears an optical load; damping layers which are laid on the outer surface of the optical loading plate and the outer wall of the satellite-rocket butt joint ring; a restraint layer which is laid on the outer surface of the damping layer; the mounting plate comprises a butt joint plate, a partition plate, an outer plate and an optical load plate; the partition plate is of a #-shaped structure, the outer plate is arranged on the periphery of the partition plate, the butt joint plate, the partition plate, the outer plate and the optical load plate are all aluminum honeycomb sandwich plates, and embedded parts are embedded in the single-machine equipment installation position and the rigidity reinforcing position of the aluminum honeycomb sandwich plates. The high-rigidity and high-damping satellite platform configuration has advantages of convenient single equipment configuration and installation, and high space utilization ratio. On the premise that the system is high in rigidity and small in additional mass, structural damping is effectively increased so as to attenuate vibration response of all components of the system.

The invention relates to a method for reducing regenerative chatter in that a workpiece (1) rotates in relation to a tool head (2) having at least one chip-removal tool (3, 3a, 3b, 3c) arranged at one end of the tool head (2), the tool head (2) machines walls of the workpiece (1) by means of the at least one chip-removal tool (3, 3a, 3b, 3c), the tool head (2) is vibrationally excited during the machining, a loose additional mass (mz) is moved by the vibration, which additional mass randomly touches the tool head (2) in first positions or randomly has no connection to the tool head (2) in second positions, and thus the total mass of the tool head (2) is randomly changed by the amount of the additional mass (mz) and the vibrational behavior of the tool head (2) is changed because of the mass change and thus counteracts regenerative chatter, and in that a receptacle (51), by means of which the tool head (2) can be exchangeably placed onto a spindle, is arranged at another end of the tool head (2) opposite the one end.

The invention discloses a damping component of a large self-unfolding satellite antenna, and aims to solve a problem of profile precision errors caused by vibration in an unfolding process of an existing unfolding antenna mechanism and in a posture adjusting process after unfolding. The component comprises a multi-finger-petal friction damper, a self-resetting elastic support friction damper, an elastic driving hinge and a satellite structure rod piece. The multi-finger-petal friction damper controls transverse vibration of the satellite unfolding antenna and comprises a multi-finger-petal rodwhich is pressed on a structural rod piece through an adjustable pressing ring. The self-resetting elastic support friction damper controls axial vibration and comprises a metal rubber, a guide rod,an SMA pull wire and an outer sleeve. The elastic driving hinge provides unfolding power through a volute spring, and an unfolding speed and synchronism are controlled through a gear. The satellite structure rod piece is fixedly connected with other assemblies so that integrity of the unfolded antenna is ensured. The component is used for satellites and space detectors.