118 results about "Beam vibration" patented technology

The invention discloses a minitype composite vibration power generator belonging to the field of minitype power technology and energy-saving technology. The minitype composite vibration power generator is a cantilever beam vibration power generator compounded by piezoelectricity and electromagnetism and mainly comprises an insulating shell, a piezoelectric cantilever beam, a permanent magnet and an inductance coil, wherein the piezoelectric cantilever beam consists of a piezoelectric sheet and a supporting substrate; the piezoelectric sheet is bonded on the supporting substrate; one end of the supporting substrate is fixed on the insulating shell; the permanent magnet is bonded with a free end of the piezoelectric cantilever beam; and an inductance coil is arranged right above the permanent magnet. Under the resonant state, the power generator synchronously outputs the piezoelectric current and the electromagnetic current; the output power is improved within the finite volume; furthermore, by adopting the structure of dispersing mass blocks, the energy collecting density is improved, and the working frequency scope is enlarged simultaneously.

The invention discloses a bistable piezoelectric cantilever beam vibration energy collector. The structure of the bistable piezoelectric cantilever beam vibration energy collector is that an internal magnet is installed in a free end of a cantilever beam; a fixed end is installed on a vertical face of a right-angle base; a spring is installed on a horizontal face of the right-angle base; an external magnet is arranged on the upper end of the spring; the external magnet and the internal magnet are arranged in a manner that poles with opposite polarities are disposed face to face; and a piezoelectric plate is adhered on the fixed end of the cantilever beam, 2-3mm away from the vertical face of the right-angle base. Vibration of the cantilever beam enables the piezoelectric plate to produce electric energy. The piezoelectric plate is connected with a lead used for outputting the electric energy. As to dynamic environmental stochastic excitation vibration, electric energy conversion can be realized effectively by adopting the bistable piezoelectric cantilever beam vibration energy collector in a condition with fixed structural parameters. However, real-time adjustment of magnet intervals according to changes of environmental excitation intensity is needed constantly for a rigid support external magnet system. By arranging the bistable piezoelectric cantilever beam vibration energy collector on roadsides or in occasions with vibration excitation backgrounds, vibration energy can be converted to electric energy.

The invention discloses a passive type MEMS flow-induced vibration strengthened heat transfer apparatus and heat transfer method. Through reasonable structural design, a cantilever beam structure fixed on a heat sink can generate a deflection movement far from the heat sink when the temperature of the heat sink increases, and the deflection angle is enlarged along with the increasing of the heat sink temperature. When the deflection angle of the cantilever beam structure is enlarged, an included angle between the length direction and an inflow velocity direction is correspondingly enlarged, so that the vibration of the cantilever beam vibration part is more fierce; therefore, higher disturbance is brought to a flow field close to the cantilever beam, formation of a heat boundary layer is damaged, and strengthened heat transfer is realized finally; the strengthened heat transfer apparatus does not require manual control and external energy input; and instead, the heat dissipation intensity can be adjusted automatically according to the heat sink temperature, so that a new approach is provided to solve a high heat flux problem of modern electronic devices.

The invention relates to a rotary flexible beam rigidness and softness coupling system vibration measuring and controlling device and a method, which belong to the flexible beam vibration control field. The device comprises a counterweight flexible beam part, a vibration and vibration anti-interference signal detection part, a stepping motor driving and controlling part, and a magneto-rheological damp vibration controlling part. One end of the counterweight flexible beam is fixedly arranged on a rigid transmission shaft through a clamping device, and is driven by the stepping motor to make rotation movement. The position of a mass block on the flexible beam can be adjusted so as to change the base frequency and the moment of inertia of the flexible beam. A strain foil is plastered on the flexible beam close to the root part of a machine tightening device to detect the bending vibration of the flexible beam. The device and the method of the invention are used to simulate the vibrations caused by the driving instability of the space flexible rotation components and to measure and control the interference. Integrated with the signal feedback of multiple sensors and the magneto-rheological controllable damping vibration suppression technology and through the corresponding algorithm, the device and the method realizes the half-active control to the vibration of a low speed rotary flexible beam rigidness and softness coupling system.

The invention discloses a precise detection device and a detection method for stress of an invitro prestressed steel beam. The method comprises the following steps that magnetic induction sensors are subjected to tensioning testing machine calibration; the magnetic induction sensors and a vibration sensor are mounted; a transient loss coefficient is determined by tensioning testing; an initial prestressed steel beam stress prediction model is acquired; after steel beam tensioning is accomplished, data of the vibration sensor is tested; transient vibration data after the tensioning is obtained; the transient invitro steel beam vibration frequency after the tensioning is calculated; measured values x of the magnetic induction sensors and the data of the vibration sensor are measured according to a predetermined target and the testing time after the tensioning; and a stress value is calculated. By combining a magnetic induction effect testing method and a vibration testing method, the method overcomes the disadvantage that a stress relaxation influence of an invitro prestressed steel beam stranded wire cannot be eliminated by separately using the magnetic induction sensors and a magnetic induction acquisition device for testing analysis, and the testing precision is improved effectively.

The invention discloses a nano-electromechanical resonant sensor based on a graphene sheet layer and a manufacturing method thereof. A P-Si substrate is provided with a drain-N type doping region and a source-N type doping region; the drain-N type doping region is provided with a drain electrode; the source-N type doping region is provided with a source electrode; two SiO2 anchor regions are arranged between the drain-N type doping region and the source-N type doping region on the surface of the P-Si substrate; two ends of the graphene for fixing support beams are respectively suspended on the two SiO2 anchor regions; and one of the two ends of the graphene for fixing the support beams is provided with a top gate electrode connected with the graphene. The resonant frequency of a resonator is determined by using the change of an electric field caused by beam vibration, and a weak resonant signal can be directly amplified into a voltage signal capable of being used for detection, so that an external active circuit is avoided, the circuit is simplified, and the low-pass filter phenomenon caused by parasitic capacitance can be eliminated; and therefore, the nano-electromechanical resonant sensor is in particular suitable for detection of chemical substances with ultra-small masses.

The invention relates to the field of vibration application and electric power technology, and particularly to a right-angled piezoelectric cantilever beam vibration energy harvester. The right-angled piezoelectric cantilever beam vibration energy harvester comprises a supporting base and a horizontal metal substrate which is mounted on the supporting base. The horizontal metal substrate is provided with a piezoelectric ceramic wafer at the end which is next to the supporting base. A vertical metal substrate is adhered to the other end of the horizontal metal substrate. The horizontal metal substrate is perpendicular with a vertical metal substrate, thereby forming a right-angled cantilever beam structure. The other end of the vertical metal substrate is provided with a mass block. According to the right-angled piezoelectric cantilever beam vibration energy harvester, the right-angled cantilever beam is formed through adding an auxiliary cantilever beam at the end of the horizontal cantilever beam. Through controlling the structural dimensions of the horizontal cantilever beam and the vertical cantilever beam and the mass of the mass block, controlling for an interval between two front stages of modal frequencies is realized, thereby forming a relatively wide operation frequency band and realizing high-efficiency acquisition and conversion for environment vibration energy.

The invention discloses a double-flexible-cantilever-beam vibration measurement and control device and method based on laser binocular vision. The device comprises two flexible cantilever beams connected in series. The flexible cantilever beams are provided with piezoelectric ceramic drivers, piezoelectric ceramic sensors and accelerometers. The device also comprises a line laser, an industrial camera, a servo motor and a planetary speed reducer. The line laser generates a laser light resource, and combined with the industrial camera, in a complete non-contact mode, the bending vibration of the cantilever beams is detected. The speed of the servo motor is reduced by the planetary speed reducer, and the servo motor is used for controlling the rotation of the cantilever beams, receiving a vibration suppression signal obtained by a vibration control algorithm and suppressing the vibration of the cantilever beams at the same time. The device can be used for the vibration measurement and control of a space flexible joint, laser is used as the light resource without the affection of sun light, thus the working stability is maintained, and a reference is provided for the vibration measurement and vibration suppression of a flexible aerospace structure.

The invention discloses a cantilever beam vibration control method based on back-stepping fuzzy sliding mode control. The method comprises the following steps of building a dynamic cantilever beam mathematical model, and performing cantilever beam mathematical model conversion; designing a back-stepping sliding mode controller on the basis of a Lyapunov stability theory, and obtaining a sliding mode control law; designing a fuzzy self-adaptation system on the basis of the Lyapunov stability theory, and obtaining a fuzzy self-adaptation law; simultaneously inputting the output of the back-stepping sliding mode controller and the output of the fuzzy self-adaptation system into the cantilever beam mathematical model; feeding back the output of the cantilever beam mathematical model to the fuzzy self-adaptation system in real time, and ensuring the global stability. The method has the beneficial effects that the relying of a control system on the cantilever beam mathematical model can be avoided; the manufacturing errors and the environment interference are compensated; the parameter study and regulation can be controlled in time, and the global progressive stability of the whole control system is ensured, so that the system reliability and the parameter change robustness can be improved.

The invention discloses a branch cantilever beam vibration generator which comprises a cantilever beam, a piezoelectric element that is arranged at the root of the cantilever beam and works in a drawing compression mold state, at least one branch arranged on the cantilever beam, and counter weights arranged at the end parts of the branches and the cantilever beam. According to the generator, the branches are integrated at different parts of the cantilever beam, so that the frequency domain response characteristic of the generator is improved; and only the single piezoelectric element is used, so that electric energy management is easy.

The invention discloses a beam crack fault detection apparatus and apparatus based on frequency sweep frequency sweep excitation vibration. By use of a vibration signal excitation and data acquisition system, given sine frequency sweep excitation is applied to a beam structure, and according to the frequency change of the frequency sweep excitation, innovative re-sampling, filtering and statistical analyzing are carried out on beam vibration signals so that fault diagnosis and fault degree classification carried out on different-degree cracks of a simply supported girder are realized.

The invention discloses a device and method for eliminating the welding stress of a steel pipe ring beam by mechanical vibration. The contact reliability problem of a vibration pickup and a structure member is solved by using a steel pipe ring beam vibration supporting seat and a vibration method, and a crystal tissue of a steel pipe ring beam welding joint is changed through the process of effectively transmitting the vibration wave energy of the vibration pickup to the structure member, thereby obtaining the purpose of weakening and eliminating the welding tress of the steel pipe ring beam structure member.

The invention discloses an S-shaped piezoelectric cantilever beam vibration energy collector. The S-shaped piezoelectric cantilever beam vibration energy collector comprises a supporting seat and an S-shaped cantilever beam fixedly mounted on the supporting seat, wherein the S-shaped cantilever beam comprises a substrate section, bent sections and free sections; piezoelectric elements are mounted on the surfaces of the substrate section and the free sections for converting energy generated by the vibration of the cantilever beam into electric energy; mass blocks are mounted at the tail ends of the free sections for adjusting the resonant frequency and vibration amplitude value of the cantilever beam; and the rigidity of the bent sections is far greater than that of the substrate section and the free sections. According to the vibration energy collector provided by the invention, the front two orders of vibration modes of the system are controlled through the S-shaped piezoelectric cantilever beam and the mass blocks at the tail end to form a relatively wide working frequency band; in addition, the apparatus is easy to start oscillation, and high in recycling efficiency and the operating stability; and conversion of the environment vibration energy can be realized.

The invention provides an adjustable gap nonlinear research test bed which comprises a cantilever beam, a gap size adjusting assembly, a gap rigidity adjusting assembly, a gap position adjusting assembly, a cantilever beam supporting assembly and a base. Gaps of different positions, different sizes, different rigidities and different numbers can be obtained through a gap adjusting device and the good test bed is provided for research on influence on cantilever beam vibration by the different gaps and identification of a system with the gaps. The principle of the adjustable gap nonlinear research test bed is that gap positions can be adjusted through the method that a gap position adjusting frame moves along a guiding groove; the bending rigidity of a gap rigidity beam is equivalent to the gap rigidity and the gap rigidity is adjusted through the change of materials of the gap rigidity beam and the change of the thickness of the gap rigidity beam; different gap values are obtained through replacement of pads of different thicknesses; the number of gap adjusting devices is increased so that research on the gaps can be achieved. According to the adjustable gap nonlinear research test bed, the structure is novel, functions are multiple, operation is simple, manufacturing is easy, and the structure is compact.

The invention provides a composite beam bending vibration inherent frequency analytical method and belongs to beam vibration inherent frequency analytical methods. According to the geometric features of a composite beam, composite beam units ETE-B are established based on the classic Euler-Bernoulli (EB) beam theory and the Timoshenko beam (TB) theory; the EB beam units and the TB units in the ETE-Bs are continuously connected through boundary conditions, a dynamical model and a bending vibration equation of the composite beam are established, a parametric frequency equation of the composite beam on the boundary conditions is acquired, and finally the inherent frequency of the composite beam is determined through the one-dimensional searching method; according to the one-dimensional searching method, the feasible region of the inherent circular frequency is determined first, and then inherent frequency values are acquired in all the feasible regions through the bisection method. The method has the advantages that the physical significance involved in analysis of the dynamic characteristics of the composite beam is clear; acquisition of the inherent frequency is only related to the materials and dimensions of the beam, the established parametric frequency equation has universality, and a model test or finite element analysis under three-mode modeling is not needed.

The invention discloses a multi-flexible beam vibration control device and method based on synchronous belt drive. The device comprises a flexible beam body, a detection part and a control part. The flexible beam body comprises three flexible beams of the same size. The detection part comprises a piezoelectric sensor and an acceleration sensor, wherein the piezoelectric sensor and the acceleration sensor are respectively arranged on the flexible beams. The control part comprises a synchronous belt drive control system and a piezoelectric drive control system. The vibration signal of the flexible beam structure is detected by the piezoelectric sensor and the acceleration sensor. A synchronous belt driven by a servo motor and a piezoelectric drive are used as an actuator for suppressing vibration. The device can be used to study the influence and vibration control of gravity, synchronous belt gap characteristics, synchronous belt elasticity and other factors on the vibration of the flexible beam structure.

The invention discloses a cantilever beam vibration control method on the basis of self-adaption neural network control and is designed on the basis of filtered tracking error. A controller comprises proportional differential items and RBF neural network items. By the cantilever beam vibration control method, with unknown functions of a cantilever beam system of an RBF neural network approach, an updating algorithm of the weight of the RBF neural network is designed on the basis of Lyapunov stability theory, and overall stability of the system is guaranteed. Robust items are added into the updating algorithm, boundedness of control input is guaranteed, and the final tracking error is kept within any small range by the aid of proportional differential control items. Under the conditions of no structural or nonstructural parameters of a cantilever and with external interference, the control method is capable of accurately tracking and controlling the cantilever system, and robustness and reliability of the system are improved.

The invention discloses a three-dimensional piezoelectric cantilever beam vibration energy collection system, the structure of which is: three cantilever beams are arranged on a right angle base, one is fixed horizontally on the elevation of the base; the other two are vertically fixed on the base The horizontal plane, but the working surfaces of the two cantilever beams are perpendicular to each other, the structure constitutes a bistable vibrating beam and a monostable vibrating beam. The free end of each cantilever beam is respectively provided with three permanent magnets; the upper and lower surfaces of the fixed end are respectively provided with piezoelectric sheets, and the corresponding surfaces of the three permanent magnets have the same polarity and repel each other. The device can simultaneously collect vibration energy in a three-dimensional direction, and is superior to the energy collection effect of a similar three-dimensional linear piezoelectric cantilever beam vibration energy harvester. At the same time, it can adapt to external stimuli of different strengths, and can realize the optimization of output power without adjusting system parameters. The three-dimensional piezoelectric cantilever vibration energy harvesting system is not only simple in structure, but also suitable for random excitation vibration in any direction of the environment.

The invention discloses a bistable double-piezoelectric cantilever beam vibration energy collector. The bistable double-piezoelectric cantilever beam vibration energy collector is characterized in that two cantilever beams are oppositely arranged on a horizontal line in a left-and-right mode, an internal magnet is installed at the free end of the cantilever beam on the left side, an external magnet is installed at the free end of the cantilever beam on the right side, the fixed ends of the two cantilever beams are fixedly installed on the vertical plane of a right-angle base, the external magnet and the internal magnet are arranged in the mode that the magnetic polarity of the external magnet and the magnetic polarity of the internal magnet are oppositely rejected with each other, piezoelectric patches are pasted at the positions, 2-3mm away from the vertical plane of the right-angle base, of the fixed ends of the two cantilever beams, vibration of the cantilever beams enables the piezoelectric patches to generate electric energy, and the piezoelectric patches are connected with a lead to output the electric energy. Random excitation vibration is carried out on the variable environment, and the electric energy can be effectively converted through the bistable double-piezoelectric cantilever beam vibration energy collector under the condition that structure parameters are fixed and unchanged. Real-time adjustment on the distance of the magnets is required to be continuously carried out through the rigid supporting external magnet according to variation of environmental excitation strength. The bistable double-piezoelectric cantilever beam vibration energy collector is arranged beside a road and the field having the vibration excitation background, and the vibration energy can be converted into the electric energy.

The invention discloses a double-movement piezoelectric hinge-joint flexible beam vibration control device based on a lead screw drive. The device comprises a hinge-joint flexible beam body part, a lead screw transmission part, a bending vibration signal detection part and a bending vibration drive control part. A double-movement piezoelectric hinge-joint flexible beam structure is composed of a first flexible beam, a second flexible beam and a third flexible beam which are connected through hinges, wherein the first flexible beam and the third flexible beam are provided with free ends, and the center of the second flexible beam is fixedly connected to a moving sliding block; a piezoelectric sensor or an acceleration sensor detects bending vibration signals of the flexible beam structure; the lead screw drive driven based on a servo motor and a piezoelectric patch drive serve as actuators for vibration elimination. According to double-movement piezoelectric hinge-joint flexible beam vibration control device based on the lead screw drive, the rigid-soft coupling property of a system is better reflected, and the device can be used for simulating vibration test and control conditions in the orbital transfer process of spacecraft solar panels.

The invention discloses an automatic testing system for the vibration fatigue characteristic of a on-line micro electromechanical system beam which consists of a voltage generating module, an amplifier, a beam, a timer, a voltage detecting module, a protection circuit and a data output module. The invention adopts the technical scheme as follows: firstly using an AC voltage to load a vibration fatigue load on the micro electromechanical system beam to lead the beam to vibrate for specific times; removing the vibration fatigue load, then loading a DC measuring voltage on the beam to detect a pull-in voltage value which reflects the fatigue characteristic of the beam, finally repeating the steps to lead the loading and the measuring to be alternatively carried out to obtain a relation between the pull-in voltage value which reflects the fatigue characteristic of the beam and the vibration times of the beam. The automatic testing system integrates the loading of the vibration fatigue load and the testing of the fatigue characteristic, thereby leading the system to be simpler; besides, the measuring process is completely automatic and no persons are needed to watch the whole process.

This invention relates to one micro beam structure absorptive property test method, which is characterized by the following: when micro beam structure totally added to the structure, its structure shape and effective length change; according to vibration force principle to guide micro beam vibration with fix frequency change. This method is based on Doppler measurement system with function generator to test sample vibration and to load scan signals and to focus laser beam onto beam structure to get range property; through comparing fix frequency value and theory value to judge whether the beam structure is added with the underlay.

The invention discloses an Euler-Bernoulli beam vibration control method based on backstepping iterative learning. The method comprises a step of constructing an Euler-Bernoulli beam system accordingto dynamic characteristics of an Euler-Bernoulli beam, a step of constructing a vibration control method based on the backstepping iterative learning according to the Euler-Bernoulli beam system in combination with a Lyapunov method, wherein virtual control quantity design, backstepping item design and iterative item design are included, a step of verifying the stability of the Euler-Bernoulli beam system under the vibration control method, a step of performing digital simulation on the Euler-Bernoulli beam system by using MATLAB simulation software and verifying whether a control effect meetsexpectation or not, and a step of adjusting gain parameters of a controller according to a simulation result if not such that the controller has a relatively good control effect. According to the vibration control method based on the backstepping iterative learning provided by the invention, the vibration of the Euler-Bernoulli beam system can be effectively suppressed, so that the Euler-Bernoulli beam system works more stably.

The invention discloses a vibration energy collection device based on liquid metal. The device comprises a hollow housing with two open ends, and the two ends of the hollow housing are respectively connected with a first cover body and a second cover body which are used for covering the hollow housing. Friction nano-generator assemblies are symmetrically arranged between the first cover body and the hollow shell and between the second cover body and the hollow shell respectively, and each friction nano-generator assembly comprises electrodes sequentially arranged from outside to inside, a friction electric material and liquid metal contained in the hollow shell. The electrodes are connected with wires for transmitting charges, and the first cover body and the second cover body are providedwith through holes through which wires pass. The vibration energy collecting device provided by the present invention is good in low-frequency response and wide in working frequency domain, is suitable for multi-direction energy collection, is capable of being combined with various energy collecting structures and has good application prospect in the fields of bistable structure vibration energycollectors, cantilever beam vibration energy collectors and the like.

The invention discloses a vibration signal measurement device. The vibration signal measurement device is characterized in that a beam electrostatic excited vibration device comprises an alternating-current signal source, an electrostatic driving pole plate, a bottom plate, a cantilever beam, a side plate, acoustic waves, a switch and wires; a signal detection device with a photoelectric detectorcomprises a support circular ring block, diffraction gratings, diffracted light, incident light, diffraction order, a substrate, the photoelectric detector and a conductive thin film. The vibration signal measurement device has the advantages that the cantilever beam can be forced to vibrate under excitation effects of alternating-current signals; the acoustic waves can be generated during vibration, acoustic wave thin films can vibrate, interference effects can be realized by the diffracted light and reflected light, and accordingly beam vibration can be detected.

The invention discloses a method for outputting a measured exciting force signal of a piezoelectric vibration sensor with high sensitivity, and aims to solve the problem that a conventional cantileverbeam type piezoelectric vibration sensor cannot accurately measure a vibration signal with higher frequency. The method is realized through the following technical scheme: the method comprises the following steps: enabling piezoelectric sensitive elements to be overlapped to form a piezoelectric cantilever beam serving as a sensitive element, and enabling the to-be-measured vibration of a mass block to act on the sensitive elements, wherein the formed piezoelectric cantilever beam is provided with a damping block which is fixed to the position close to the base. The cantilever beam piezoelectric body vibrates under the action of the mass block; when the vibration frequency is close to the first-order resonance frequency of the cantilever beam piezoelectric body, the condition that the amplitude near the first-order resonance frequency point is sharply increased under the damping effect of the damping block due to resonance is effectively restrained, the formed effect is that in the frequency band lower than the second-order resonance frequency, the amplitude of cantilever beam vibration and the amplitude of measured exciting force are in a corresponding linear relation, and the high-frequency upper limit with the frequency monitoring upper limit requirement reaching high sensitivity can be obtained.

The invention relates to a variable load flexible cantilever beam vibration active control experiment system and experiment method. The system comprises a base, a cantilever beam, a load mass block, four actuating piezoelectric fiber sheets, two sensing piezoelectric fiber sheets, a multi-channel piezoelectric driving power amplifier, two charge amplifiers, an AD acquisition card, a DA output cardand two computers. Disturbance piezoelectric fiber sheets are actuated for simulating vibration of the cantilever beam subjected to external disturbance. The sensing piezoelectric fiber sheets collect a vibration signal of the cantilever beam; the computers perform calculation according to corresponding control strategies to generate an expected control signal; and the control signal is amplifiedby the piezoelectric driving power amplifier and is output to vibration suppression piezoelectric fiber sheets, so that the purpose of actively eliminating or reducing vibration response of the cantilever beam is achieved. The experimental system and method can provide an experimental verification implementation means for a vibration active control method of the flexible cantilever beam, and provide a technical implementation support for exploring further practical application of related control theory methods.

The invention discloses a fixed supporting beam vibration electromagnetic self-powered microsensor in a radio frequency receiving and transmitting assembly of the Internet of Things. The two energy collecting self-powered modules of a piezoelectric transducer and a rectifying antenna system are integrated, and the functions of collection, conversion and energy storage can be respectively achieved on mechanical vibrational energy and stray electromagnetic energy. Gallium arsenide is used as a substrate, and the microsensor is composed of an MEMS fixed supporting beam, a filter circuit, a rectifying circuit and an energy storage capacitor. Fiver layers of an upper electrode, a piezoelectric film, a lower electrode, a silicon nitride dielectric layer and a rectangular microstrip patch antenna are arranged on the MEMS fixed supporting beam from top to bottom. Integration of the two modules can complement each other, the microstrip antenna structure is used as inertia force and deformation of mass block reinforcing beam vibration, and the directivity range of energy collecting by the microstrip patch antenna can be widened along with vibration of the beam. Energy collecting efficiency and power supply capacity are improved, the effective scheme is provided for solving the self-powered problem of a low-power-consumption system, the electromagnetic compatibility performance of the system is enhanced, and the shake of the system structure is reduced.

The invention discloses a single-span beam vibration experiment system. The whole single-span beam vibration experiment system consists of eight parts: a right-angle pedestal, a beam support, a strongelectric modal exciter, a laser displacement sensor, a dynamic force sensor, a digital signal generator, a dynamic and static strain data acquisition system and a computer; a plurality of mounting holes are formed in a vertical plate of the right-angle pedestal; the supports comprise a singly supported end support and a fixed end support; an excitation signal is output by the computer, and excitation is provided for a test piece beam through a signal generator, a linear power amplifier and the exciter; and the displacement sensor and the dynamic force sensor are sequentially connected with the dynamic and static strain data acquisition system and the computer to obtain a test piece beam vibration response time course curve. The single-span beam vibration experiment system can complete a multi-form vibration experiment, an inherent frequency experiment and a complex random vibration experiment of a single-span beam by changing the restrained end form of the beam, the position of the exciter and the type of an excitation signal.

The present invention provides a folding beam structure-based multi-degree of freedom passive vibration isolation device for a spacecraft flywheel. The vibration isolation device is mainly composed of an installation platform, folded beam vibration isolation units, an installation base and the like. The vibration isolation device is installed between the spacecraft flywheel and an spacecraft body structure, and used for reducing the influence, on stability and precision of the spacecraft platform, of additional high-frequency micro-vibration disturbance generated in the working process of the flywheel under the premise of not influencing the attitude control performance of the spacecraft flywheel, and reducing the work environment noise of satellite-borne sensitive loads.