CN111006830A - Mouse cage type vibrating plate coupled particle bed experimental device and experimental method - Google Patents
Mouse cage type vibrating plate coupled particle bed experimental device and experimental method Download PDFInfo
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- CN111006830A CN111006830A CN201911093410.4A CN201911093410A CN111006830A CN 111006830 A CN111006830 A CN 111006830A CN 201911093410 A CN201911093410 A CN 201911093410A CN 111006830 A CN111006830 A CN 111006830A
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Abstract
A squirrel-cage vibrating plate coupled particle bed experimental device and an experimental method thereof comprise an outer drum, a vibration exciter and a vibration exciting rod; outer cask and vibration exciter pass through bolt and workstation fastening connection, the coaxial cover in the vibration exciter outside is equipped with the squirrel cage, and squirrel cage one end is fixed with the workstation through the location tang, and the other end links to each other with vibration board, and the upper surface coupling of vibration board has the granule bed, excitation rod one end is connected with the vibration exciter, and the other end is connected with vibration board, the last force sensor of installing of excitation rod, force sensor links to each other with the power collector that is located the outer cask outside through first wire, post the foil gage on the arc spoke of squirrel cage, the foil gage passes through the second wire and links to each other with the strain collector that is located the outer cask outside. The squirrel-cage structure can provide smaller rigidity for the vibration plate while ensuring the axial motion stability of the vibration plate, further generate vibration amplitude meeting the research requirement, and meet the test requirement of nonlinear dynamic response of the vibration plate-particle material coupling system.
Description
Technical Field
The invention belongs to the technical field of engineering test devices, and particularly relates to a mouse cage type vibrating plate coupled particle bed experimental device and an experimental method.
Background
The particle substances are closely connected with the life of people, the motion of single particles in the particle substances obeys Newton's law and energy conservation law, and the research methods of various mechanical behaviors are mature. When a large number of particles are stacked together to form a particle bed, the particle bed moves integrally or flows under the action of external force to form a particle flow, the particle flow shows complex solid-liquid phase change-like characteristics, and the characteristic and mechanism research of the particle bed faces many challenges and becomes a research hotspot of researchers in related fields in recent years. The particle flow phenomenon is widely existed in human activities and natural disasters such as transportation, coal mining, pharmacy, agriculture, debris flow, avalanche and the like. In recent years, a number of qualitative and quantitative theoretical methods have been established through extensive research on particulate matter. However, due to the particularity of the particulate matter, the traditional mechanical theory still cannot well explain the complex mechanical characteristics of the particulate matter. The particle substances are further studied, the mechanical mechanism of the particle substances is explored, and the particle substances are beneficial to further promoting production practice, reducing and preventing disasters and the like.
The plate structure is widely applied to the fields of buildings, bridges, aerospace and the like. In many practical engineering applications, slab structures do not exist alone and are often coupled with particulate media, such as foundations, bridges, etc. buried deep in soil, gravel, etc. Meanwhile, the plate structure is often subjected to different forms of external excitation during operation, so that the plate structure in the granular medium vibrates, and very complex vibration characteristics are presented. Aiming at the complex dynamic behavior research of the excited vibration plate coupled particle material, the rheological characteristic mechanism of the particle substance under the complex excitation of the boundary can be newly known, and theoretical support and technical guidance can be provided for the engineering practice in the related field.
The plate structure moves at variable speeds during the coupling process with the particle medium, and the driving force exerted on the plate structure does not only work for increasing the kinetic energy of the plate but also work for increasing the kinetic energy of the surrounding particles. Thus a plate with mass m will acquire an acceleration a and the force F exerted on it will be greater than the product of the plate mass m and the acceleration a, this added part of the mass being called the additional mass. The additional mass can make the observed mass of the structure body surface different from the actual mass, and the concept of the apparent mass has application in the research fields of physics, chemistry, material science and the like, and is called effective mass. When the effective mass varies with the frequency of the excitation force, it is also referred to as a frequency-dependent dynamic effective mass. However, the present invention is still blank for the mechanism analysis of the dynamic effective mass and the nonlinear dynamic behavior of the particle-plate coupled system, and therefore, the present invention provides a testing apparatus and method for vibrating plate coupled particle bed, which is particularly important.
Disclosure of Invention
The invention provides a squirrel-cage vibration plate coupled particle bed experimental device and an experimental method thereof, which are simple and convenient to operate and reliable in principle, can not only explore the change rule and mechanism of the dynamic effective mass of a vibration plate and analyze the nonlinear dynamic behavior of the vibration plate, but also can simultaneously obtain the basic rule of the phase state transition of the particle bed, and provide more theoretical supports and technical guidance for the engineering practice field.
In order to achieve the purpose, the invention adopts the following technical scheme:
a squirrel-cage vibration plate coupled particle bed experimental device comprises an outer drum, a vibration exciter, a vibration plate, a squirrel cage, a vibration exciting rod, a force sensor, a strain gauge, a particle bed and a locking nut; the outer barrel and the vibration exciter are tightly connected with the workbench through bolts, the vibration exciter is positioned in the inner cavity of the outer barrel, the vibration exciter and the outer barrel are axially overlapped, a squirrel cage is coaxially sleeved outside the vibration exciter, the squirrel cage is positioned in the inner cavity of the cylindrical barrel, one end of the squirrel cage is fixedly connected with the workbench through a bolt, the other end of the squirrel cage is connected with the vibrating plate, the upper surface of the vibrating plate is coupled with a particle bed, one end of the excitation rod is connected with the vibration exciter, the excitation rod and the vibration exciter are coaxially arranged, the other end of the excitation rod is connected with the vibration plate, the excitation rod is provided with a force sensor, the output end of the force sensor is connected with one end of a first lead, the other end of the first lead penetrates through one of lead holes on the side wall of the outer drum and is connected with the input end of the force collector, and a strain gauge is pasted on the arc spoke of the squirrel cage, the output end of the strain gauge is connected with one end of a second wire, and the other end of the second wire penetrates through another wire hole on the cylindrical barrel to be connected with the input end of the strain collector.
Two wire holes on the lateral wall of the outer drum are symmetrically arranged and have the diameter of 3 mm.
The squirrel cage comprises an upper ring, a lower ring and a plurality of arc-shaped spokes, wherein the upper ring and the lower ring are connected into a whole through the arc-shaped spokes.
The strain gauge adopts a half bridge consisting of small strain gauges with the length of 3mm and the width of 2mm, and the small strain gauges can reduce the arc surface effect at the position of the squirrel cage spoke paster.
The vibration board is the rigid plate, and is provided with the clearance between vibration board and the excircle bucket internal surface, and the size in clearance is less than the particle diameter setting of granule.
The outer barrel is made of transparent organic glass.
A squirrel-cage vibration plate coupled particle bed experimental method adopts a squirrel-cage vibration plate coupled particle bed experimental device, and comprises the following steps:
step 1, static calibration of a system: weighing the mass of the vibrating plate, and statically calibrating the relation between the strain output and the displacement of the vibrating plate under the condition that no particle bed exists on the upper surface of the vibrating plate to obtain a fitting equation;
In the formula: a. the1Amplitude of the exciting force signal, theta1Is the phase angle of the excitation force signal, A2Being amplitude of acceleration signal, theta2I is an imaginary unit in the complex number, which is the phase angle of the acceleration signal.
Due to the adoption of the technical scheme, the invention has the following advantages:
1. the squirrel-cage structure introduced by the invention replaces a spring and a damper to provide rigidity and damping for the system, the symmetrical distribution of the squirrel-cage structure and the arc-shaped design of squirrel-cage spokes can ensure the axial motion stability of the vibrating plate, provide smaller rigidity for the vibrating plate and further generate a vibration amplitude meeting the research requirement, and meet the test requirement of nonlinear dynamic response of the vibrating plate-particle material coupling system;
2. the outer barrel is made of transparent organic glass materials, so that visual research is facilitated, and phase change of a particle bed in the barrel is conveniently observed; the open design facilitates the replacement of the particle bed;
3. the invention adopts a small-sized strain gage group half bridge with the size of 3mm long and 2mm wide at the outer side of the squirrel cage spoke. The small strain gauge can reduce the arc surface effect at the mouse cage spoke patch, the half bridge can amplify the output strain signal, the characteristics of high frequency response, high deformation identification sensitivity, mature testing technology, high cost performance and the like of the strain gauge are fully utilized, and the real-time signal acquisition of the axial displacement of the vibrating plate is realized. In addition, all there is the half-bridge on four spokes of squirrel cage, can monitor whether the plate structure vibrates along vertical direction, gets the mean value with four half-bridges during the processing data, reducible experimental error.
4. The invention adopts the calibration relation between the squirrel cage spoke strain and the displacement measured by the displacement sensor to obtain the displacement of the vibrating plate under the actual working condition, and the method and the device thereof are suitable for the conditions that the displacement sensor cannot be installed and used under the actual working condition, such as filling particles in the lower side area of the vibrating plate, high-temperature fluid (the strain testing technology under the medium and high temperature environments is relatively mature) or other complex working conditions.
5. The method is simple and convenient to operate and reliable in principle, can monitor the phase change of the particle bed in real time, provides a test means for researching the change rule and mechanism of the dynamic effective mass of the vibrating plate-particle bed coupling system, and analyzes the nonlinear dynamic behavior of the vibrating plate-particle bed coupling system through phenomena of plate displacement bifurcation, chaos and the like in the coupling system.
Drawings
FIG. 1 is a schematic view of the structural assembly of the experimental device of the squirrel-cage vibrating plate coupled particle bed of the present invention;
FIG. 2 is a front view of the squirrel cage structure of the experimental apparatus with the squirrel cage vibration plate coupled with the granular bed;
FIG. 3 is a three-dimensional schematic diagram of a squirrel-cage structure of a squirrel-cage vibrating plate coupled particle bed experimental apparatus;
FIG. 4 is a partial graph of the excitation force signal collected in step 2 of the embodiment;
FIG. 5 is a partial graph of the displacement signal converted in step 3 according to the embodiment;
FIG. 6 is a spectrum diagram showing the displacement of the vibrating plate in step 3 according to the embodiment;
FIG. 7 is a phase diagram showing the displacement of the vibration plate in step 3 of the embodiment;
1-outer barrel; 2-a vibrating plate; 3-a force sensor; 4-exciting a vibration rod; 5, vibration exciter; 6-positioning a spigot; 7-locking the nut; 8-a particle bed; 9-a strain gauge; 10-mouse cage; 11-a workbench; 12-a force harvester; 13-a strain collector; 14-wire guide.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
As shown in fig. 1 to 3, a squirrel-cage vibration plate coupled particle bed experimental device comprises an outer cylinder 1, a vibration exciter 5, a vibration plate 2, a squirrel cage 10, a vibration exciting rod 4, a force sensor 3, a strain gauge 9, a particle bed 8 and a locking nut 7; the vibration exciter is characterized in that the outer barrel 1 and the vibration exciter 5 are fixedly connected with the workbench 11 through bolts, the vibration exciter 5 is positioned in an inner cavity of the outer barrel 1, the vibration exciter 5 and the outer barrel 1 are axially overlapped, a squirrel cage 10 is coaxially sleeved outside the vibration exciter 5, the squirrel cage 10 is positioned in the inner cavity of the outer barrel 1, one end of the squirrel cage 10 is fixed on the workbench 11 through a positioning spigot 6, the squirrel cage 10 is prevented from moving under the vibration of the vibration exciter 5, the other end of the squirrel cage 10 is connected with the vibration plate 2, the upper surface of the vibration plate 2 is coupled with a particle bed 8, one end of the vibration exciting rod 4 is connected with the vibration exciter 5, the vibration exciting rod 4 and the vibration exciter 5 are coaxially arranged, the other end of the vibration exciting rod 4 is connected with the vibration plate 2 through a locking nut 7 positioned at the circle center of the vibration plate 2, the force sensor 3 is arranged on the vibration exciting rod 4, the strain gauge 9 is adhered to the arc-shaped spoke of the squirrel cage 10, the output end of the strain gauge 9 is connected with one end of a second wire, and the other end of the second wire penetrates through another wire hole 14 in the outer barrel 1 to be connected with the input end of a strain collector 13.
The two wire holes 14 on the side wall of the outer drum 1 are symmetrically arranged and have a diameter of 3 mm.
The squirrel cage 10 comprises an upper ring, a lower ring and four arc-shaped spokes, wherein the upper ring and the lower ring are connected into a whole through the four arc-shaped spokes, and the four arc-shaped spokes are uniformly distributed along the circumferential direction.
The strain gauge 9 adopts a half bridge formed by small strain gauges 9 with the length of 3mm and the width of 2mm, and the small strain gauges 9 can reduce the arc surface effect at the spoke paster of the squirrel cage 10.
The vibrating plate 2 is a rigid plate, a gap is arranged between the vibrating plate 2 and the inner surface of the outer barrel 1, and the size of the gap is smaller than the particle size of the particles; the existence of clearance guarantees that no friction produces between vibration board 2 and cask 1, and then avoids producing the influence to the experimental result.
The outer barrel 1 is made of transparent organic glass.
A squirrel-cage vibration plate coupled particle bed experimental method adopts a squirrel-cage vibration plate coupled particle bed experimental device, and comprises the following steps:
step 1, static calibration of a system: weigh vibration board 2 quality and be 1.14Kg through weighing sensor, and under the 8 states of vibration board 2 upper surface no granule bed, place experimental apparatus on universal electronic test machine test bench, axial load to 500N are applyed in grades to vibration board 2 through universal electronic test machine's loading head, keep axial load unchangeable, simultaneously through peripheral hardware displacement sensor measurement vibration board 2 displacements, gather the meeting an emergency of squirrel cage 10 spoke through strain collector 13, the strain signal of gathering through computer record strain collector 13, the displacement signal of gathering through the manual record displacement sensor of experimenter, the fitting equation who obtains meeting an emergency and vibration board 2 displacement is y ═ 32518.6x +415.7, in the formula: y represents strain; x represents displacement in mm;
To obtain a dynamic effective mass of the vibrating plate 2
In the formula: a. the1Amplitude of the exciting force signal, theta1Is the phase angle of the excitation force signal, A2Being amplitude of acceleration signal, theta2I is an imaginary unit in the complex number, which is the phase angle of the acceleration signal.
The depth, the particle size, the exciting force frequency, the exciting force amplitude and other parameters of the particle bed 8 are changed to construct different working conditions. By observing and recording the phase state change of the particle bed 8 under different excitation working conditions, and drawing a time domain graph, a frequency spectrum graph, a phase graph and the like of the vibration plate 2 and the mass center of the particle bed 8, the mechanism of the dynamic effective mass change and the corresponding nonlinear dynamic behavior can be analyzed.
Claims (7)
1. A squirrel-cage vibration plate coupled particle bed experimental device is characterized by comprising an outer barrel, a vibration exciter, a vibration plate, a squirrel cage, a vibration exciting rod, a force sensor, a strain gauge, a particle bed and a locking nut; the outer barrel and the vibration exciter are tightly connected with the workbench through bolts, the vibration exciter is positioned in the inner cavity of the outer barrel, the vibration exciter and the outer barrel are axially overlapped, a squirrel cage is coaxially sleeved outside the vibration exciter, the squirrel cage is positioned in the inner cavity of the cylindrical barrel, one end of the squirrel cage is fixedly connected with the workbench through a bolt, the other end of the squirrel cage is connected with the vibrating plate, the upper surface of the vibrating plate is coupled with a particle bed, one end of the excitation rod is connected with the vibration exciter, the excitation rod and the vibration exciter are coaxially arranged, the other end of the excitation rod is connected with the vibration plate, the excitation rod is provided with a force sensor, the output end of the force sensor is connected with one end of a first lead, the other end of the first lead penetrates through one of lead holes on the side wall of the outer drum and is connected with the input end of the force collector, and a strain gauge is pasted on the arc spoke of the squirrel cage, the output end of the strain gauge is connected with one end of a second wire, and the other end of the second wire penetrates through another wire hole on the cylindrical barrel to be connected with the input end of the strain collector.
2. The experimental device of claim 1, wherein the experimental device comprises: two wire holes on the lateral wall of the outer drum are symmetrically arranged and have the diameter of 3 mm.
3. The experimental device of claim 1, wherein the experimental device comprises: the squirrel cage comprises an upper ring, a lower ring and a plurality of arc-shaped spokes, wherein the upper ring and the lower ring are connected into a whole through the arc-shaped spokes.
4. The experimental device of claim 1, wherein the experimental device comprises: the strain gauge adopts a half bridge consisting of small strain gauges with the length of 3mm and the width of 2mm, and the small strain gauges can reduce the arc surface effect at the position of the squirrel cage spoke paster.
5. The experimental device of claim 1, wherein the experimental device comprises: the vibration board is the rigid plate, and is provided with the clearance between vibration board and the excircle bucket internal surface, and the size in clearance is less than the particle diameter setting of granule.
6. The experimental device of claim 1, wherein the experimental device comprises: the outer barrel is made of transparent organic glass.
7. A squirrel-cage vibration plate coupled particle bed experimental method, which adopts the squirrel-cage vibration plate coupled particle bed experimental device as claimed in claim 1, and is characterized by comprising the following steps:
step 1, static calibration of a system: weighing the mass of the vibrating plate, and statically calibrating the relation between the strain output and the displacement of the vibrating plate under the condition that no particle bed exists on the upper surface of the vibrating plate to obtain a fitting equation;
step 2, signal acquisition: starting a vibration exciter to excite a vibration plate under the state that the vibration plate is coupled with the particle bed, collecting an excitation force signal of the vibration plate through a force collector, collecting a strain signal output by a squirrel cage spoke patch through a strain collector, and recording the whole process through a high-speed camera for analyzing the phase state change of the particle bed;
step 3, data processing: converting the strain signal obtained in the step (2) into a displacement signal by using a strain output-displacement fitting equation obtained in the step (1); drawing a frequency spectrum graph and a phase graph of the displacement signal; then, an acceleration signal is obtained through calculation of the displacement signal, and Fourier transformation is respectively carried out on the excitation force signal and the acceleration signal to obtain the amplitude A of the excitation force signal1Phase angle theta of sum excitation force signal1And amplitude A of the acceleration signal2And the phase angle theta of the acceleration signal2Calculating the dynamic effective mass of the vibrating plate by using the formula (1)
In the formula: a. the1Amplitude of the exciting force signal, theta1Is the phase angle of the excitation force signal, A2Being amplitude of acceleration signal, theta2I is an imaginary unit in the complex number, which is the phase angle of the acceleration signal.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113532818A (en) * | 2021-06-17 | 2021-10-22 | 武汉理工大学 | Shafting test bed based on particle damper |
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2019
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| CN203722443U (en) * | 2014-03-03 | 2014-07-16 | 武汉大学 | Miniaturized squirrel-cage asynchronous motor structure for vibration noise research |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113532818A (en) * | 2021-06-17 | 2021-10-22 | 武汉理工大学 | Shafting test bed based on particle damper |
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