CN101738348A

CN101738348A - Drop hammer type shock test bench controlled by magnetic switch

Info

Publication number: CN101738348A
Application number: CN200910249071A
Authority: CN
Inventors: 丁一宁; 尤志国; 董帅; 陈相宇; 达布希拉图; 田贺; 王晓飞; 张发盛
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2009-12-31
Filing date: 2009-12-31
Publication date: 2010-06-16
Anticipated expiration: 2029-12-31
Also published as: CN101738348B

Abstract

The invention provides a drop hammer type shock test bench controlled by a magnetic switch, belongs to the technical field of civil engineering, and relates to a fiber concrete shock-resistance property test device. The device is characterized in that a shock rack is vertically welded to a bottom plate; a positioning cantilever is connected with the shock rack through a movable bolt, and the height is freely adjusted; the magnetic switch is connected with the positioning cantilever through a movable bolt, and the position is accurately adjusted. The free falling of the shock hammer is ensured, and the protecting device is clamped around four iron baffle plates on the bottom plate through square sleeves, thus the edge conditions of a test piece during shocking are same, and simultaneously the safety of the operators is ensured. The invention has the advantages of obvious enhancement of shock test accuracy, wide application, simple structure, easy operation, convenient carrying and enhancement of test safety.

Description

Drop hammer type shock test bench controlled by magnetic switch

Technical field

The invention belongs to technical field of civil engineering, relate to a kind of fiber concrete impact resistance test device, specially refer to drop hammer type shock test bench controlled by magnetic switch.

Background technology

Fiber concrete can improve mechanical properties of concrete and permanance, is widely used in building structure and the Tunnel Engineering, and development prospect is very optimistic.At present, the experimental provision that drops hammer that known fiber concrete shock resistance proving installation has the ACI544 council to recommend, China the similar of experimental provision and ACI544 council recommendation of dropping hammer.When using this device to test, need manually the steel ram hammer to be lifted specified altitude assignment and aimed at test specimen, loosen both hands then and make ram hammer fall concrete sample is impacted.The hammer location will inevitably produce deviation owing to liquidate manually, the height of ram hammer is constant in the time of can not guaranteeing to impact at every turn, can't guarantee that also the center of gravity trace when ram hammer falls at every turn passes the center of gravity of impacting ball, even initial velocity and initial acceleration can have influence on ram hammer and fall the time, thereby bring adverse influence can for the accuracy of test; Simultaneously,, cause ram hammer bounce-back back to fall test specimen is caused irregular impact for the second time, do not realize the consistance of each impact owing to do not have suitable protective device behind the ram hammer impact test piece.In addition, lack protective device and make ram hammer injure testing crew easily by a crashing object, exist can not support personnel's safety drawback.

The sample dimensions that experimental provision adopted of dropping hammer that the ACI544 council is recommended is that diameter is 150mm, and thickness is the patty test specimen of 63mm ± 3mm.Behind the new structure type long fibre that adds 50mm～65mm in the concrete, fiber is 150mm at diameter, thickness is to have certain orientation trend near the patty die trial limit wall of 63mm ± 3mm, forms " wall effect ", can't truly reflect the shock resistance of this kind fiber concrete material.

Summary of the invention

It is more accurate that the technical problem to be solved in the present invention provides a kind of impulse test that makes; the scope of application is more extensive; in light weight; be easy to carry; can protect operator safety; easy and simple to handle; the impact test apparatus that is particularly useful for domestic different building ground; thereby not only solved the initial height of drop that operation manually causes; initial velocity; the inconsistent problem of boundary condition when initial acceleration variation and each impulse test; solved center of gravity trace when ram hammer falls at every turn and can not pass a difficult problem of impacting the ball center of gravity, and solved the problem of " wall effect " that testing crew safety and long fibre exist in the concrete die trial.

Technical scheme of the present invention is:

Steel base plate 9 is fixed on the rigid foundation by expansion bolt, is provided with on the base plate 9 to impact frame 2, and this impacts frame 2 is made impact frame 2 and base plate 9 vertical welding by steel pipe.Vertical impact frame 2 is provided with the location cantilever 3 that a steel pipe is made.The left end of location cantilever 3 is to be placed in the steel annulus that impacts frame 2 outer wall of steel pipe, location cantilever 3 with impact frame 2 and be connected by movable bolt, and freely adjust highly along impact frame 2; The right-hand member of location cantilever 3 is a magnetic switch 1, magnetic switch 1 with locate cantilever 3 and be connected by movable bolt.By adjusting movable bolt, accurately adjust the position of magnetic switch 1, to guarantee the freely falling body of ram hammer 4.Hollow disk of steel of welding makes magnetic switch 1 adsorb ram hammer 4 easily below magnetic switch 1.In addition; above concrete sample 7; impact protection device 5 is set; protective device 5 is made of two parts up and down, and top is designed to " funnel " shape, and the lower part is designed to square sleeve 10; " funnel " and square sleeve 10 are to be made by steel plate; top " funnel " and lower part square sleeve 10 be by the steel pole welding, protective device 5 by lower part square sleeve 10 be stuck in four steel baffle plates 8 on the base plate around, the boundary condition when test specimen 7 is hit is identical.

Before carrying out impulse test, at first base plate 9 usefulness expansion bolts are fixed on the rigid foundation, adjust location cantilever 3 then to desired height, be fixed on the impact frame 2 that is connected with base plate 9 with movable bolt.Utilize plummet with magnetic switch 1 and impact ball 6 centerings, the center of gravity trace the when ram hammer 4 that makes magnetic switch 1 adsorb falls at every turn passes the center of gravity of impacting ball 6.And the square sleeve of protective device 5 by the lower part be stuck on four outer baffle plates 8 of concrete sample 7, promptly finished fixing to protective device 5.

When carrying out impulse test; open magnetic switch 1; ram hammer 4 is adsorbed on the magnetic switch 1 of location; close magnetic switch 1; absorption affinity disappears, and ram hammer 4 is done the movement of falling object under the effect of self gravitation, impacts the impact ball 6 that is placed on the test specimen end face; ram hammer 4 drops in the protective device 5 after finishing one-shot, whenever finishes one-shot and is a circulation.

When adopting fiber concrete, for the fiber of 30～50mm length, the employing diameter is 150mm, and thickness is the patty test specimen of 75mm; For the fiber of 50mm～65mm length, the employing diameter is 200mm, and thickness is the patty test specimen of 75mm.

Effect of the present invention and benefit are:

The present invention positions with the magnetic switch hammer that liquidates, and testing crew only need be controlled magnetic switch and can test, and has solved and has located inaccurate problem manually, guarantees that the initial falling speed perseverance of ram hammer is zero; Protective device makes the secondary pulse rule unanimity of ram hammer to test specimen.Magnetic switch and protective device have constant boundary condition when test specimen is hit, improved the accuracy of impulse test significantly.But protective device is protection test personnel's safety also.The present invention also has in light weight, is easy to carry; Need not any energy that orders about, environmental protection; Characteristics easy and simple to handle.And the scope of application is more extensive, is applicable to the research of the shock resistance of structural type long fibre concrete material when fibre length 30～65mm.In addition, in various places, especially the working-yard provides guarantee for carrying out high-quality impulse test easily.

Description of drawings

Accompanying drawing 1 is the structural representation of drop hammer type shock test bench controlled by magnetic switch.

Accompanying drawing 2 is A-A planimetric maps of drop hammer type shock test bench controlled by magnetic switch.

Among the figure: 1 magnetic switch; 2 impact frame; 3 location cantilevers; 4 ram hammers; 5 protective devices; 6 impact ball; 7 test specimens; 8 baffle plates; 9 base plates; 10 square sleeves.

Embodiment

Be described in detail concrete implementation step of the present invention below in conjunction with technical scheme and accompanying drawing.

Step 1. is fixed on the base plate 9 of the experimental provision mode by the expansion bolt anchoring on the rigid foundation.

Step 2. is regulated location cantilever 3 to desired height, and is fixed on the impact frame 2.

Step 3. is carried out accurate centering with magnetic switch 1 and impact ball 6, and is fixed on the cantilever 3 of location.

Step 4. is placed on test specimen 7 on the base plate 9 of smearing oil according to testing requirements, places flexible gasket between test specimen 7 and four baffle plates 8.

Step 5. is placed at the test specimen center and is impacted ball 6, and places protective device 5.

Step 6. is opened the knob of magnetic switch 1, makes it produce absorption affinity, and ram hammer 4 is adsorbed on it.

Step 7. is closed the knob of magnetic switch 1, and ram hammer 4 is done the movement of falling object under the self gravitation effect, impacts the impact ball that is placed on test specimen 7 centers.

Step 8. is whenever finished one-shot and is a circulation, continues then repeatedly test specimen to be impacted, and any three of four baffle plates 8 stop when contact in test specimen and test unit, at this moment test specimen destruction.

Claims

1. a drop hammer type shock test bench controlled by magnetic switch is made up of magnetic switch (1), impact frame (2), location cantilever (3), protective device (5), base plate (9) and square sleeve (10); It is characterized in that: steel base plate (9) is fixed on the rigid foundation by expansion bolt; Impact frame (2) and the vertical welding of base plate (9); Location cantilever (3) is connected by movable bolt with impact frame (2), and freely adjusts height along impacting frame (2); Magnetic switch (1) is connected by movable bolt with location cantilever (3); Protective device (5) is made of two parts up and down; top is designed to " funnel " shape; the lower part is designed to square sleeve (10); " funnel " and square sleeve (10) are to be made by steel plate; weld by steel pole with lower part square sleeve (10) on top " funnel "; protective device (5) by lower part square sleeve (10) be stuck in four steel baffle plates (8) on the base plate around, make the boundary condition of test specimen (7) when being hit identical.