UHPC pull-out test device

Abstract

The utility model relates to a UHPC (Ultra High Performance Concrete) pull-out test device which effectively solves the problems that a pull-out device is not compact enough in structure, easy to eccentrically pull-out and concentrated in stress point. According to the technical scheme, the device comprises a lower half part and an upper half part, the lower half part comprises a thick-wall cylinder, the lower end of the inner wall of the cylinder is in a cone shape with the large end facing downwards, a plurality of axial plunger holes are evenly distributed in the circumference of the upper end face of the cylinder, an annular cavity is formed in the side wall of the cylinder, and the lower ends of all the plunger holes are communicated with the annular cavity; an oil pipe communicated with the annular cavity is arranged on the side wall of the cylinder; the upper half portion comprises a circular ring, the inner wall of the circular ring is in a cone shape with the large end facing upwards, and a plurality of axial plungers are fixed to the lower end face of the circular ring and inserted into plunger holes in the lower half portion in a one-to-one correspondence mode. According to the utility model, the axial size of the device is reduced, the structure is more compact, and the structural rigidity is stronger; eccentric inclined pulling can be avoided, and local damage of the sample caused by local stress or stress concentration is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of concrete performance detection, and specifically relates to a UHPC pull-out test device. BACKGROUND

[0002] UHPC is a kind of concrete material with super high strength, high toughness and high durability;When carrying out tensile test, the current pull-out test device generally adopts the mode that clamp fixture clamps the two ends of sample and then simultaneously applies tension;Such as the invention patent with application number CN202210356394.9, a clamping device for dog bone test block tensile strength detection is disclosed, the sample is set as dog bone shape with two ends swelling, then the two ends of sample are clamped by two sets of clamp fixtures, and tension loading is carried out.

[0003] The two sets of clamp fixtures of the above device are independent of each other, respectively want to pull out, the sample is located in the middle of the two sets of clamp fixtures, the axial dimension of the device is large, and the two sets of clamp fixtures need to be connected through the rack, the volume is large, and when loading large tension, due to the large axial length, the rigidity of the whole device is poor, and deformation is prone to occur;Moreover, the clamp fixture lacks effective positioning structure, the sample axis is prone to be not coincident with the tension direction, eccentric oblique tension is caused, and the test result is affected;In addition, the stress points of the clamp fixture and the sample are concentrated at the jaw, the stress position is concentrated, and the sample is prone to local damage. SUMMARY

[0004] The utility model provides a kind of UHPC pull-out test device, to solve the problem that pull-out device structure is not compact enough, is prone to eccentric oblique tension, and stress point is concentrated.

[0005] Its technical solution includes lower half and upper half, the lower half includes a thick-walled cylinder, the inner wall lower end of cylinder is the taper of large end downward, the upper end surface of cylinder is uniformly distributed with several axial plunger holes, the inner wall of cylinder is opened with an annular cavity, the lower end of all plunger holes is communicated with annular cavity, and the oil pipe that is communicated with annular cavity is mounted on the side wall of cylinder;The upper half includes a circular ring, the inner wall of circular ring is the taper of large end upward, and the lower end surface of circular ring is fixed with several axial plungers, and the plunger is inserted into the plunger hole of lower half one by one.

[0006] The upper half and the lower half are all divided into two parts that are left-right symmetrical, the left and right parts are connected by bolts, the annular cavity is composed of left arc cavity located in left part and right arc cavity located in right part, the two arc cavities are independent of each other, and each arc cavity is connected with an oil pipe.

[0007] The outer wall of the cylinder is provided with an axial first guide hole, the outer wall of the circular ring is provided with an axial second guide hole, a limiting screw rod is arranged between the first guide hole and the second guide hole, and a limiting nut is screwed on the screw rod.

[0008] The oil pipe is provided with a throttle valve.

[0009] The drawing test device is different from traditional drawing test devices in that the drawing force is applied to the two ends of the sample by the elongation of the upper half and the lower half, the axial dimension of the device is reduced, the structure is more compact, and the structural rigidity is stronger.

[0010] The plurality of plungers uniformly distributed in the circumference simultaneously apply pressure, so that the drawing force is uniformly distributed in the circumferential direction of the sample, the cone has an automatic centering function, the resultant force direction coincides with the sample axis, and eccentricity is avoided.

[0011] The sample end part is subjected to increased stress area through the conical surface contact, and local stress or stress concentration is avoided to cause local damage of the sample. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a front view of the utility model.

[0013] Figure 2 It is a top view of the utility model.

[0014] Figure 3 It is a perspective view of the utility model.

[0015] Figure 4 It is an explosion view of the utility model. DETAILED DESCRIPTION

[0016] In combination with the drawings, the utility model includes a lower half and an upper half, the lower half includes a thick-walled cylinder 1, the inner wall lower end of the cylinder 1 is a large-end-down cone, the upper end face of the cylinder 1 is circumferentially and uniformly provided with a plurality of axial plunger holes 2, an annular cavity 3 is opened in the side wall of the cylinder 1, the lower ends of all plunger holes 2 are in communication with the annular cavity 3, and the side wall of the cylinder 1 is provided with an oil pipe 4 in communication with the annular cavity 3; the upper half includes a circular ring 5, the inner wall of the circular ring 5 is a large-end-up cone, a plurality of axial plungers 6 are fixed to the lower end face of the circular ring 5, and the plungers 6 are one-to-one inserted into the plunger holes 2 of the lower half; oil is pumped or pressure is released into the annular cavity 3 through the oil pipe 4, the oil pressure acts on all plunger holes 2 through the annular cavity 3, so that the oil pressure in each plunger hole 2 is the same; under the action of the oil pressure, all plungers 6 can synchronously push the upper half to move upward or downward; the UHPC sample is made into a shape with a cone at each end and a columnar shape in the middle, the cones at the two ends are matched with the cones of the upper half and the lower half respectively, the upper half and the lower half are away from each other when pressure is added in the oil cavity, and the drawing force is applied to the sample through the conical surface.

[0017] The upper half and the lower half are each cut into two symmetrical parts, and the two parts are connected by bolts, the annular cavity 3 is composed of a left arc cavity 7 in the left part and a right arc cavity 8 in the right part, the two arc cavities are independent of each other, and each arc cavity is connected with an oil pipe 4; the device is cut into two parts so as to be buckled on the sample.

[0018] The outer wall of the cylinder 1 is provided with an axial first guide hole 9, the outer wall of the ring 5 is provided with an axial second guide hole 10, a limiting screw rod 11 is arranged between the first guide hole 9 and the second guide hole 10, a limiting nut 12 is screwed on the screw rod, the limiting nut 12 can limit the displacement of the plunger 6, and the upper half and the lower half are separated.

[0019] The oil pipe 4 is provided with a throttle valve 13, the speed of oil inflow can be limited, and the upper half is prevented from suddenly rushing when the sample is pulled off.

[0020] In use, the two parts are coaxially buckled on the sample, the two parts are connected by bolts, then oil is pumped into the annular cavity 3 through the oil pipe 4, all the plungers 6 are driven to move upwards, the conical end of the ring 5 and the conical end of the cylinder 1 are respectively matched with the conical ends of the upper end and the lower end of the sample, the sample is drawn, the drawing force of the sample is gradually increased with the gradual increase of the oil pressure, until the sample is broken, the oil pressure at the moment when the sample is broken is recorded, and the oil pressure is multiplied by the sum of the areas of the lower ends of all the plungers 6, so that the drawing force when the sample is pulled off is obtained.

[0021] After the test is completed, the bolts are removed, the device is separated, and the sample can be taken out.

[0022] The axial size of the device is reduced, the structure is more compact, and the structural rigidity is stronger; the direction of the drawing force resultant is coincident with the axis of the sample, eccentric oblique drawing is avoided; through the conical surface contact, the stress area of the end of the sample is increased, local stress or stress concentration is avoided, and local damage of the sample is avoided.

Claims

1. A UHPC pull-out test device comprising a lower half and an upper half, characterized in that, The lower half includes a thick-walled cylinder (1), the inner wall of which is downwardly tapered at the lower end, the upper end of the cylinder (1) is provided with a plurality of axial plunger holes (2) distributed uniformly in the circumference, an annular cavity (3) is formed in the side wall of the cylinder (1), the lower ends of all the plunger holes (2) are communicated with the annular cavity (3), and an oil pipe (4) is arranged on the side wall of the cylinder (1) and communicated with the annular cavity (3); the upper half includes a circular ring (5), the inner wall of which is upwardly tapered, and a plurality of axial plungers (6) are fixed to the lower end face of the circular ring (5), the plungers (6) are inserted into the plunger holes (2) of the lower half one by one.

2. The UHPC pull-out test device of claim 1, wherein, The upper half and the lower half are both cut into two parts which are symmetrical to each other, the two parts are connected by bolts, the annular cavity (3) is composed of a left arc-shaped cavity (7) in the left part and a right arc-shaped cavity (8) in the right part, the two arc-shaped cavities are independent of each other, and each arc-shaped cavity is connected with an oil pipe (4).

3. The UHPC pullout test device of claim 1, wherein, An axial first guide hole (9) is arranged on the outer wall of the cylinder (1), an axial second guide hole (10) is arranged on the outer wall of the circular ring (5), a limiting screw rod (11) is arranged between the first guide hole (9) and the second guide hole (10), and a limiting nut (12) is screwed on the screw rod.

4. The UHPC pullout test device of claim 1, wherein, A throttle valve (13) is arranged on the oil pipe (4).

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