CN211528096U - Experimental device for be used for testing concrete damping ratio of permeating water - Google Patents
Experimental device for be used for testing concrete damping ratio of permeating water Download PDFInfo
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- CN211528096U CN211528096U CN201921837968.4U CN201921837968U CN211528096U CN 211528096 U CN211528096 U CN 211528096U CN 201921837968 U CN201921837968 U CN 201921837968U CN 211528096 U CN211528096 U CN 211528096U
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Abstract
The utility model discloses an experimental apparatus for be used for testing concrete damping ratio that permeates water, including the excitation unit, test piece fixed unit and data acquisition unit, the excitation unit includes the bobble, slide and support, the slide includes the slope section, circular arc section and horizontal segment, the contained angle of slope section and horizontal plane is 45, it has a plurality of height mark to mark on the slope section, test piece fixed unit sets up the place ahead at the horizontal segment, be provided with carbon paper on the table surface, the data acquisition unit includes acceleration sensor, charge amplifier and dynamic signal collection appearance, before the experiment, the cantilever beam test piece is fixed the back, acceleration sensor installs the surface of one side far away from the horizontal segment at the test piece, acceleration sensor is connected with the dynamic signal collection appearance electricity through charge amplifier. The device has controllable anchoring degree to the test piece, good anchoring effect, can control the exciting force and is easy to operate, the accuracy of the obtained damping ratio under different exciting forces is high, and the device is suitable for testing the damping ratio of permeable concrete test pieces with different sizes.
Description
Technical Field
The utility model relates to a damping ratio experimental apparatus specifically is an experimental apparatus for be used for testing concrete damping ratio that permeates water.
Background
The pervious concrete is also called porous concrete, and is a cellular concrete formed by mixing specific graded aggregate, cement and additive according to a specific proportion and adopting a special process, and the aggregate skeleton of the cellular concrete contains a large number of penetrating pores, so that the cellular concrete has excellent water permeability. In recent years, urban inland inundation has a lot of problems, and the pervious concrete is widely applied to urban roads as an environment-friendly high-permeability material. As a pavement paving material of a road, the pervious concrete has excellent damping and shock-absorbing effects besides excellent water permeability: on one hand, the reduction of the comfort of a rider caused by the abrasion of vehicle parts and vibration caused by the vibration when the vehicle runs on a road surface can be reduced, and on the other hand, the reduction of the traffic noise caused by the friction between tires and the ground can also be reduced, so that the method has special important significance in improving the urban sound environment, improving the life quality, building quiet cities and the like.
At present, a simple beam damping ratio testing device for large-size materials is developed mainly aiming at common concrete such as Oucangnu and the like at home and abroad for an experimental device for the concrete damping ratio, but the testing device is not suitable for measuring the large-size permeable concrete damping ratio. In addition, some researchers propose a free vibration attenuation method of a cantilever beam by using a heavy hammer to knock, but the excitation force and the anchoring degree of the cantilever end are not easy to control, and the anchoring operation of the cantilever end is complex and tedious, and the factors can influence the measurement value of the damping ratio.
Disclosure of Invention
The utility model aims to solve the technical problem that, to prior art not enough, provide one kind can control the exciting force and easily operate be used for testing the experimental apparatus of concrete damping ratio that permeates water again, adopt the device to obtain different exciting forces under the degree of accuracy height of the damping ratio of the concrete that permeates water, be applicable to the damping ratio test of the concrete test piece that permeates water of equidimension not.
The utility model provides a technical scheme that above-mentioned technical problem adopted does: an experimental device for testing the damping ratio of pervious concrete comprises an excitation unit, a test piece fixing unit and a data acquisition unit, wherein the excitation unit comprises a small ball, a slide way and a support, the slide way is installed on the support, the support is installed on a working table board, the slide way comprises an inclined section, an arc section and a horizontal section which are sequentially connected, the included angle between the inclined section and the horizontal plane is 45 degrees, the inclined section is calibrated with a plurality of height marks, the height marks correspond to different height positions respectively, the upper surface of the arc section is tangent to the upper surface of the inclined section and the upper surface of the horizontal section respectively, the test piece fixing unit is arranged in front of the horizontal section and is used for fixing a test piece made of the pervious concrete, and the working table board is provided with carbon paper, the data acquisition unit comprises an acceleration sensor, a charge amplifier and a dynamic signal acquisition instrument, before an experiment, the cantilever beam test piece is fixed on the test piece fixing unit and positioned right ahead of the horizontal section, the acceleration sensor is installed on the surface of one side of the cantilever beam test piece far away from the horizontal section, and the acceleration sensor is electrically connected with the dynamic signal acquisition instrument through the charge amplifier.
When the damping ratio of the pervious concrete is tested by the experimental device, after the initial position of the small ball on the slideway is determined, the small ball is placed at the height position marked with the corresponding height mark, the small ball is released in a static state, finally slides out from the horizontal section, performs projectile motion, rebounds and falls down after colliding with a cantilever beam test piece, and finally falls on the carbon paper and leaves a mark on the carbon paper.
Specifically, after the ball is released from a certain height mark on the slide without initial speed, neglecting the energy loss caused by the friction force and air resistance of the slide and the influence of the size of the ball on the falling height by the formula V0 22gH canObtaining the horizontal speed V of the highly released small balls finally sliding out of the horizontal section0Wherein g is the acceleration of gravity, H is the release height of the pellet, and the horizontal velocity V0Namely the horizontal initial speed of the projectile motion after the small ball is separated from the slide way. And adjusting and determining the horizontal distance between the horizontal section and the cantilever beam test piece so as to reduce the time for the small ball to do projectile motion to the maximum extent. The time for the small balls to do projectile motion is extremely short, and the falling heights of the small balls released at different heights after colliding with the cantilever beam test piece are close to each other, so that the collision positions of the small balls released at different heights and the cantilever beam test piece can be regarded as the same point, namely a collision point.
And applying a certain impulse to the cantilever test piece by the small ball in the collision process, and recording as I. The ball obtains a horizontal initial velocity V of projectile motion after collision0Horizontal velocity V in opposite direction1Then the horizontal initial velocity of the small ball is V1When the ball lands on the copy paper, the projectile motion of (2) can leave marks on the copy paper. Measuring the horizontal distance x between the mark and the collision point by using a ruler, recording the horizontal displacement of the small ball after colliding with the cantilever beam test piece until the small ball rebounds to fall on the carbon paper as s, recording the falling height as h, recording the elapsed time as t, and recording the diameter of the small ball as d, then:
therefore, the temperature of the molten metal is controlled,
therefore, the impulse I is calculated by the following formula:
wherein m is the mass of the pellet.
When the small balls impact the cantilever beam test piece, the acceleration sensor detects the acceleration of the cantilever beam test piece, transmits the acceleration to the dynamic signal acquisition instrument in a signal form through the charge amplifier, and the dynamic signal acquisition instrument records and converts the acceleration into time-course data and establishes an acceleration time-course curve.
Calculating the damping ratio xi of the pervious concrete test piece by utilizing a known free attenuation damping formula:
wherein, akAnd ak+1And the acceleration amplitude of any two left and right adjacent time interval periods on the established acceleration time interval curve is represented.
The impulse generated by the release of the same pellet at different height positions without initial speed is different, and the impulse generated by the release of the pellets with different quality at the same height position without initial speed is also different. By changing the mass and/or the release height of the small ball, different impulses to the cantilever beam test piece can be obtained, so that different exciting forces to the cantilever beam test piece can be realized, the exciting force is controllable in size, and the realization process of the exciting forces with different sizes is easy to operate. Under the action of different exciting forces, the damping ratios of cantilever beam test pieces obtained through experiments are different, the accuracy of the finally obtained damping ratios of the pervious concrete under different exciting forces is high, and the method is suitable for testing the damping ratios of the pervious concrete test pieces with different sizes.
The experimental device can obtain the damping ratio xi of the pervious concrete test piece, and can also calculate the impulse I applied to the cantilever beam test piece by the small ball which is not released at the initial speed under different heights according to the deduced formula, thereby researching the relation between the exciting force represented by the impulse I and the damping ratio xi.
Preferably, the test piece fixing unit comprises a press machine, the press machine comprises an upper clamping plate and a lower clamping plate, the upper clamping plate and the lower clamping plate are used for clamping one end of the cantilever beam test piece up and down, and the other end of the cantilever beam test piece is located right in front of the horizontal section. The upper clamp plate and the lower clamp plate of the press machine are used for anchoring the cantilever beam test piece, constant pressure can be applied to the cantilever beam test piece, the anchoring degree of the cantilever beam test piece can be effectively controlled, and the cantilever beam test piece can be fixed and detached simply, conveniently and quickly. The loading constant pressure of the press machine on the cantilever test piece is generally controlled to be 40% -50% of the ultimate load of the cantilever test piece.
Preferably, the press machine is a WAY-2000 electrohydraulic pressure tester, the loading range of the press machine is 0-2000kN, and the pressure accuracy is +/-1%.
Preferably, the upper surfaces of the inclined section, the arc section and the horizontal section are respectively provided with a concave arc surface. The concave cambered surface arranged on the upper surfaces of the inclined section, the arc section and the horizontal section plays a role in guiding the small ball to slide along the slide way, so that the experimental result is more accurate.
Preferably, a first cement paste clean layer is coated on the partial surface of one side, close to the horizontal section, of the cantilever beam test piece, and the first cement paste clean layer is opposite to the horizontal section. The thickness of the first cement grout layer is negligible. The position of paining on first cement clean grout layer is the collision face of cantilever beam test piece, because the cantilever beam test piece surface unevenness that the concrete that permeates water made, after the collision face sets up first cement clean grout layer, can prevent that the bobble from colliding with the cantilever beam test piece repeatedly in the experimentation and leading to the collision face phenomenon of coming off, guarantees the accuracy of experimental result.
Preferably, a second cement clean slurry layer is coated on the partial surface of one side, far away from the horizontal section, of the cantilever beam test piece, and the acceleration sensor is attached to the surface of the second cement clean slurry layer. The setting of second cement clean grout layer, acceleration sensor's the subsides of being convenient for are decided, guarantee acceleration sensor's installation and result of use.
Preferably, the support comprises a plurality of vertical steel plates which are vertically arranged and a horizontal steel plate which is horizontally arranged, the plurality of vertical steel plates are welded on the horizontal steel plate at intervals from front to back, the heights of the plurality of vertical steel plates are sequentially increased from front to back, and the bottoms of the slideways are respectively fixed at the upper ends of the plurality of vertical steel plates.
Preferably, the dynamic signal acquisition instrument is an INV3062VC dynamic signal acquisition instrument.
Compared with the prior art, the utility model has the advantages of as follows: the utility model discloses an experimental apparatus for be used for testing concrete damping ratio that permeates water, anchor degree to the cantilever beam test piece is controllable, the anchor is effectual, through the quality and/or the release height that change the bobble, can obtain the impulse of the variation in size to the cantilever beam test piece, and then realize the exciting force to the variation in size of cantilever beam test piece, and the size of exciting force is controllable, the realization process of the exciting force of variation in size is easily operated, the degree of accuracy of the damping ratio of the concrete that permeates water under the different exciting forces that finally obtains is high, be applicable to the damping ratio test of the concrete test piece that permeates water of different sizes.
Drawings
FIG. 1 is a schematic front view of the experimental apparatus in the example;
FIG. 2 is an enlarged view of FIG. 1 at A;
FIG. 3 is a schematic cross-sectional view of a slide according to an embodiment;
FIG. 4 is a top view of the cantilever test piece after being fixed in the embodiment.
Detailed Description
The present invention will be described in further detail with reference to the following embodiments.
The experimental device for testing the damping ratio of the pervious concrete in embodiment 1 comprises an excitation unit, a test piece fixing unit 4 and a data acquisition unit, wherein the excitation unit comprises a small lead ball 1, a metal slideway 2 and a metal bracket 3, the slideway 2 is mounted on the bracket 3, the bracket 3 is mounted on a worktable 5, the slideway 2 comprises an inclined section 21, an arc section 22 and a horizontal section 23 which are sequentially connected, an included angle between the inclined section 21 and a horizontal plane is 45 degrees, four height marks H1, H2, H3 and H4 are marked on the inclined section 21, the four height marks H1, H2, H3 and H4 respectively correspond to four different height positions, an upper surface of the arc section 22 is tangent to an upper surface of the inclined section 21 and an upper surface of the horizontal section 23, as shown in fig. 3, upper surface test pieces of the inclined section 21, the arc section 22 and the horizontal section 23 are respectively provided with a concave arc surface 24, the fixing unit 4 is arranged in front of the horizontal section 23, the test piece fixing unit 4 is used for fixing a cantilever beam test piece 7 made of pervious concrete, the working table surface 5 is provided with carbon paper 51, the data acquisition unit comprises an acceleration sensor 61, the dynamic signal acquisition instrument comprises a charge amplifier 62 and a dynamic signal acquisition instrument 63, before an experiment, a cantilever test piece 7 is fixed on a test piece fixing unit 4 and is positioned right ahead of a horizontal section 23, a first cement clean slurry layer 71 is coated on the local surface of one side, close to the horizontal section 23, of the cantilever test piece 7, the first cement clean slurry layer 71 is right opposite to the horizontal section 23, a second cement clean slurry layer 72 is coated on the local surface of one side, far away from the horizontal section 23, of the cantilever test piece 7, an acceleration sensor 61 is attached to the surface of the second cement clean slurry layer 72, and the acceleration sensor 61 is electrically connected with the dynamic signal acquisition instrument 63 through the charge amplifier 62.
The experimental apparatus for testing the damping ratio of the pervious concrete in the embodiment 2 is different from the experimental apparatus in the embodiment 1 in that in the embodiment 2, the test piece fixing unit 4 includes a press machine, the press machine is a WAY-2000 electrohydraulic type pressure testing machine (not shown in the figure), and the press machine includes an upper clamp plate 41 and a lower clamp plate 42, the upper clamp plate 41 and the lower clamp plate 42 are used for clamping one end of the cantilever test piece 7 up and down, the plan view of the effect after the cantilever test piece 7 is fixed is shown in fig. 4, and the other end of the cantilever test piece 7 is located right in front of the horizontal section 23. In the experimental process, the constant pressure of 50% of the ultimate load of the cantilever test piece 7 is continuously applied to the cantilever test piece 7 by the press machine.
The experimental device for testing the damping ratio of the pervious concrete in the embodiment 3 is different from the experimental device in the embodiment 2 in that in the embodiment 3, the bracket 3 comprises four vertical steel plates 31 vertically arranged and one horizontal steel plate 32 horizontally arranged, the four vertical steel plates 31 are welded on the horizontal steel plate 32 at intervals from front to back, the heights of the four vertical steel plates 31 are sequentially increased from front to back, and the bottoms of the slideways 2 are respectively fixed at the upper ends of the four vertical steel plates 31.
The working principle of the experimental device is as follows:
after the small ball 1 is released from a certain height mark on the slide way 2 without initial speed, neglecting the energy caused by the friction force and air resistance of the slide way 2Loss of mass and effect of bead 1 size on drop height from equation V0 2The horizontal speed V at which the highly released bead 1 finally slides out of the horizontal section 23 can be obtained at 2gH0Wherein g is the acceleration of gravity, H is the release height of the bead 1, and the horizontal velocity V0Namely the horizontal initial speed of the projectile motion after the small ball 1 is separated from the slide way 2. And the horizontal distance between the horizontal section 23 and the cantilever test piece 7 is adjusted and determined so as to reduce the time for the small ball 1 to do projectile motion to the maximum extent. Because the time for the small ball 1 to do projectile motion is extremely short, and the falling heights of the small balls 1 released at different heights after colliding with the cantilever beam test piece 7 are close to each other, the collision positions of the small balls 1 released at different heights and the cantilever beam test piece 7 can be regarded as the same point, namely the collision point.
And in the collision process, the small ball 1 applies impulse with a certain magnitude to the cantilever test piece 7, and the impulse is marked as I. The small ball 1 obtains a horizontal initial velocity V of the projectile motion thereof after collision0Horizontal velocity V in opposite direction1Then the horizontal initial velocity of the small ball 1 is V1When the ball 1 lands on the copy paper 51, the ball moves to leave a mark on the copy paper 51. Measuring the horizontal distance x between the mark and the collision point by using a ruler, recording the horizontal displacement of the small ball 1 after colliding with the cantilever beam test piece 7 until the small ball rebounds to fall on the carbon paper 51 as s, recording the falling height as h, recording the elapsed time as t, and recording the diameter of the small ball 1 as d, then:
therefore, the temperature of the molten metal is controlled,
therefore, the impulse I is calculated by the following formula:
wherein m is the mass of the pellet 1.
When the small ball 1 impacts the cantilever beam test piece 7, the acceleration sensor 61 detects the acceleration of the cantilever beam test piece 7, transmits the acceleration to the dynamic signal acquisition instrument 63 through the charge amplifier 62 in a signal form, and the dynamic signal acquisition instrument 63 records and converts the acceleration into time-course data and establishes an acceleration time-course curve.
Calculating the damping ratio xi of the pervious concrete test piece by utilizing a free attenuation damping formula:
wherein, akAnd ak+1And the acceleration amplitude of any two left and right adjacent time interval periods on the established acceleration time interval curve is represented.
The above formulas and the derivation process of the corresponding formulas are all the prior art.
In the experimental process, the impulse with different sizes of the cantilever beam test piece 7 can be obtained by changing the mass and/or the release height of the small ball 1, so that the exciting forces with different sizes of the cantilever beam test piece 7 are realized, the size of the exciting force is controllable, the realization process of the exciting forces with different sizes is easy to operate, and the accuracy of the finally obtained damping ratio of the pervious concrete under different exciting forces is high.
Claims (8)
1. The utility model provides an experimental apparatus for be used for testing concrete damping ratio that permeates water which characterized in that: the device comprises an excitation unit, a test piece fixing unit and a data acquisition unit, wherein the excitation unit comprises a small ball, a slide way and a support, the slide way is installed on the support, the support is installed on a workbench surface, the slide way comprises an inclined section, an arc section and a horizontal section which are sequentially connected, the included angle between the inclined section and the horizontal plane is 45 degrees, the inclined section is marked with a plurality of height marks, the height marks correspond to different height positions respectively, the upper surface of the arc section is tangent to the upper surface of the inclined section and the upper surface of the horizontal section respectively, the test piece fixing unit is arranged in front of the horizontal section and used for fixing a cantilever beam test piece made of pervious concrete, the workbench surface is provided with carbon paper, the data acquisition unit comprises an acceleration sensor, Before an experiment, the cantilever beam test piece is fixed on the test piece fixing unit and is positioned right ahead of the horizontal section, the acceleration sensor is installed on the surface of one side of the cantilever beam test piece, which is far away from the horizontal section, and the acceleration sensor is electrically connected with the dynamic signal acquisition instrument through the charge amplifier.
2. The experimental device for testing the damping ratio of pervious concrete according to claim 1, wherein: the test piece fixing unit comprises a press machine, the press machine comprises an upper clamping plate and a lower clamping plate, the upper clamping plate and the lower clamping plate are used for clamping one end of the cantilever beam test piece up and down, and the other end of the cantilever beam test piece is located right ahead of the horizontal section.
3. The experimental device for testing the damping ratio of pervious concrete according to claim 2, wherein: the press machine is a WAY-2000 type electrohydraulic pressure tester.
4. The experimental device for testing the damping ratio of pervious concrete according to claim 1, wherein: the upper surfaces of the inclined section, the arc section and the horizontal section are respectively provided with a concave arc surface.
5. The experimental device for testing the damping ratio of pervious concrete according to claim 1, wherein: the cantilever beam test piece is characterized in that a first cement paste layer is coated on the local surface of one side, close to the horizontal section, of the cantilever beam test piece, and the first cement paste layer is opposite to the horizontal section.
6. The experimental device for testing the damping ratio of pervious concrete according to claim 1, wherein: the cantilever beam test piece is characterized in that a second cement clean slurry layer is coated on the local surface of one side, far away from the horizontal section, of the cantilever beam test piece, and the acceleration sensor is attached to the surface of the second cement clean slurry layer.
7. The experimental device for testing the damping ratio of pervious concrete according to claim 1, wherein: the support include the vertical steel sheet of polylith that sets up and the horizontal steel sheet that the level set up, the vertical steel sheet of polylith interval welding around the horizontal steel sheet on, the vertical steel sheet of polylith highly increase in proper order after preceding, the bottom of slide fix respectively the upper end of the vertical steel sheet of polylith.
8. The experimental device for testing the damping ratio of pervious concrete according to claim 1, wherein: the dynamic signal acquisition instrument is an INV3062VC type dynamic signal acquisition instrument.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921837968.4U CN211528096U (en) | 2019-10-29 | 2019-10-29 | Experimental device for be used for testing concrete damping ratio of permeating water |
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| CN201921837968.4U CN211528096U (en) | 2019-10-29 | 2019-10-29 | Experimental device for be used for testing concrete damping ratio of permeating water |
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