KR101942862B1 - Creep Tester - Google Patents

Abstract

The present invention is a device for tensile creep or torsional creep test of concrete specimens, and has a characteristic that a plurality of experiments can be realized by one experiment. Specifically, the creep test machine according to the present invention includes a main shaft 102 coupled to a support 101, a coupling shaft 212 coupled to the main shaft, a load acting groove 213 formed on the other side, (Not shown).

Description

Creep Tester {Creep Tester}

The present invention is a device for tensile creep or torsional creep test of concrete specimens, and has a characteristic that a plurality of experiments can be realized by one experiment.

Patent Document 001 relates to a composite test apparatus for evaluating the characteristics of static and dynamic materials of concrete and a concrete test method using the same. More specifically, the present invention relates to a creep test, a strength test, an impact test, a general load- A general load tensile strength test, a rapid load tensile strength test, and a concrete strength test method using the same.

Patent Document 002 relates to a creep test machine in a concrete structure test, and relates to a self-weight load control creep test machine that performs a creep test by constantly applying a constant load without supplementing hydraulic pressure by external electrical or manual force. The precision load creep test machine using self-weight is to solve the inconvenience of using the hydraulic device and suggests the principle of the lever.

The creep test machine of Patent Document 003 is a high temperature furnace which receives the specimen and keeps the temperature constant; A lever arm to which a load cell is mounted and one end of the specimen is fixed to apply a load to the specimen; A tilt sensor for measuring the tilting of the lever arm; A specimen fixing part for fixing the other end of the specimen; A lifting unit for lifting and lowering the specimen fixing unit such that the lever arm is horizontal; A strain gauge for measuring a tensile length of the specimen; A temperature sensor for measuring a temperature inside the high temperature furnace; And a controller for alarming and reactivating when the temperature measured by the temperature sensor is sensed to be between the upper limit temperature and the lower limit temperature based on the set temperature when the power source is turned on after a power failure due to a power failure during the creep test, , The control unit is configured such that, when the measured temperature is higher than the upper limit temperature or lower than the lower limit temperature, the creep test is terminated at a room temperature setting of the temperature control apparatus and a state in which no load is applied to the specimen. Therefore, the creep test machine aims to secure the reliability of the experimental data by keeping the experimental environment of the temperature and the load, which are the main parameters of the specimen, constant.

Patent Document 004 is an invention relating to a creep displacement measuring apparatus, a specimen for measuring creep displacement, and a method for manufacturing a specimen. A creep displacement measuring apparatus includes a displacement detecting unit embedded in an object to detect a creep displacement of an object; And an elastic support coupled to the displacement sensing unit and elastically supporting the displacement sensing unit in a state of being embedded in the test body. A displacement detecting unit embedded in the test object to detect a creep displacement of the test specimen; And an elastic support coupled to the displacement sensing unit and elastically supporting the displacement sensing unit in a state of being embedded in the test body. In another embodiment, the displacement sensing unit may include a sensing unit sensing a creep displacement of the test sample. And a transfer unit electrically connected to the sensing unit to transfer a signal generated in the sensing unit.

KR 10-1670023 B1 (Registration date October 21, 2016) KR 10-2009-0003611 A (Published on January 12, 2009) KR 10-0958814 B1 (Registration date May 12, 2010) KR 10-2014-0037532 A (published on March 27, 2014)

The present invention is a device for tensile creep or torsion creep test of concrete specimens, and aims at implementing a plurality of experiments with one experiment.

A creep test machine according to the present invention comprises a main shaft 102 coupled to a support 101, a test shaft coupling part 212 coupled to the main shaft, a test piece coupling part 212 formed on one side, And a loading bar 210 for forming a load acting groove 213 in the loading bar 210.

The creep test apparatus according to the present invention is characterized in that the main shaft and the loading bar described above include a weight attaching belt 320 to which a plurality of weights 310 are coupled, And a first fixing pin 330 coupled to the first fixing pin 330 and the second fixing pin 330.

The creep test machine of the present invention is characterized in that the tensile creep test piece 400 having a uniform cross-sectional shape in the main shaft and the loading bar described above is fixed to one end of the tensile creep test piece and the other end is coupled to the test piece fastening portion of the loading bar And a second grip 420, one end of which is fixed to the other end of the tensile creep test piece, and the other end of which is coupled to the support.

The creep test machine of the present invention comprises a twist creep test piece 500 having a uniform cross-sectional shape in the main shaft and the loading bar described above, a first coupling part 510 for fixing one side of the twist creep test piece to the support, A second fastening part 520 for fixing the other end of the torsional creep specimen to the torsion link 530, and an interlocking link 540 for coupling the torsion link to the rod bar.

The creep test machine of the present invention is the creep test machine according to any one of the preceding inventions, characterized in that it comprises: a chamber (611) for receiving the creep test machine; a heat transfer device (612) housed in the chamber; A temperature sensor 614 and a humidity sensor 615 accommodated in the chamber.

The present invention is an invention for a concrete creep test machine, and it is advantageous to perform a creep test in a tensile direction or a twist direction of a specimen by a single experiment.

Since the creep test machine of the present invention uses a weight, it can continuously apply a constant load without a separate actuator, and various load conditions can be realized by weight weight control.

In the creep test machine of the present invention, since the main bush is mounted in the pivot hole of the loading bar, there is an effect that the static friction coefficient due to the extremely small movement of the loading bar is not affected.

The creep test machine of the present invention generates a stable axial torsional load by a torsion link interlocking with the loading bar and a rotating support attached to the torsion link.

The creep test machine of the present invention is equipped with a chamber, and various temperature and humidity environments are applied to the creep experiment by the chamber.

1 is a perspective view of a tensile creep test apparatus of the present invention.
FIG. 2 is a perspective view of a test specimen for the tensile creep test of the present invention. FIG.
3 is an exploded perspective view of a specimen for the tensile creep test of the present invention.
4 is a perspective view of the torsional creep test apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Example 1-1) The creep test machine of the present invention is a creep test machine comprising a main shaft 102 coupled to a support 101, a specimen coupling part 212 coupled to the main shaft, And a loading bar 210 for forming a load acting groove 213 on the other side.

Creep test is an experimental method to analyze the material deformation characteristics by applying a constant load for a long time. The present invention relates to an apparatus for creep testing of tensile or torsional load of concrete specimens. The test piece is attached to one side of the loading bar, and the weight is attached to the side of the loading bater. The central portion of the loading bar rotates in conjunction with the main shaft, and the main shaft is coupled to the support. The type of experiment can be selected according to the type of specimen on the side of the loading bar. In other words, tensile creep test can be performed by attaching tensile specimen, and twist creep test can be performed by mounting twist specimen. Weights are attached to the other side of the loading bar to give loads. Thus, the weighing device rotates the loading bar, and a load is applied to the opposite side of the loading bar with respect to the main shaft.

(Example 1-2) The creep test machine of the present invention is the creep test machine of Example 1-1, wherein a rotating hole 211 is formed in the loading bar 210, a main shaft is inserted into the rotating hole, And includes a main bush 220 between the holes.

Attach the weights and specimens to both sides of the loading bar. The loading bar rotates at a small angle over a long period of time. Therefore, the main shaft and the loading bar generate rotational resistance, and the rotational resistance can not obtain accurate test results. Therefore, the main bush is mounted between the main shaft and the pivot hole to reduce the rotational resistance. The main bush is fixed to the rotation hole and supports the main shaft. The inner diameter of the main bushing and the outer diameter of the main shaft are in contact with each other. The main bushes are made of Teflon, to reduce the coefficient of friction. Alternatively, a sliding or rolling bearing may be mounted in place of the main bush. When rolling bearings are used, they are preferably used as needle bearings.

(Example 1-3) The creep test machine of the present invention is the creep test machine according to Embodiment 1-1, wherein the support base includes a vertically formed support member.

The support of the creep test apparatus is fixed to the upper surface of the bed. Since the bed is formed of a heavy material, the center of gravity of the experimental apparatus is lowered. This has the purpose of preventing the center-of-gravity variation occurring during the experiment. Thus, the bed is formed of a metal or forms a structure in which concrete is filled in the metal. The upper surface of the bed is fixed to the support so as to form a plurality of engagement slots, and is formed so as to be mountable and detachable from the lower surface of the support. The bottom of the bed is equipped with an anti-vibration mount to block external vibration. The anti-vibration mount can adjust the height of each bed for horizontal control of the bed.

Example 1-4 The creep test machine of the present invention is the creep test machine of Example 1-1 wherein the support 101 comprises a first support 101a and a second support 101b, And a space S is formed between the two supports, and the main shaft is fixed between the first support and the second support.

The main shaft is combined with the weight of the loading bar, so there is a high risk of deformation. The main axis deformation causes serious experimental error, so it should be stable even under high load. When the main shaft is combined with one support, there is a high possibility of deformation due to the projecting beam structure. However, if two supports support both ends of the main shaft, the risk of deformation can be reduced. In addition, since the loading bar, the specimen, and the grip are positioned between the first and second supports, they are not subjected to external interference during the experiment. Therefore, it is preferable that the first and second supports are maintained at appropriate intervals.

(Example 2-1) A creep test machine of the present invention is a creep test machine according to Example 1-1, in which a plurality of weight weights 310 are coupled to each other, And a first fixing pin 330 coupled to the load acting groove 213.

Creep tests are performed under the same load for a long time. To this end, the loading bar is equipped with a weight. One weight or two or more weights. Weights Weights are used for one or more weights combination. The weight-weight coupling base is rod-shaped, and the weight is further fitted to the rod. And a first fixing pin is formed on the side of the weight coupling member to be engaged with the load acting groove. The load-acting grooves of the loading bar are slot-shaped, and the ends form a semicircular shape. The first fixing pin is brought into contact with the semicircle. The load acting groove radius is larger than the first fixing pin radius. This is to form the first fixing pin so as to be in contact with the loading bar.

(Example 2-2) In the creep test machine of the present invention, the first fixing pin bush 331 is coupled to the outer circumferential surface of the first fixing pin in Example 2-1.

During the creep test, creep specimens are subjected to a constant load over a long period of time. The creep specimen is deformed by the above load. The amount of deformation of the specimen affects the angle of the loading bar, which leads to a change in the initial installation angle of the loading bar and the weight attaching member. The first fixing pin is mounted on the first fixing pin for smooth sliding of the loading bar and the first fixing pin. This has the effect of reducing the coefficient of friction between the load acting groove and the first fixing pin. It is preferable that the first fixing pin bushing is made of Teflon material or an oilless bearing is used. Or equivalent objects and effects.

(Example 2-3) In Example 2-1, the creep testing machine of the present invention includes a weight support base 340 formed on the other side of the weight coupling and supported by a weight.

The weight support is attached to the other side of the weight attachment and is formed into a plate shape. Weight Weights A plurality of weights are seated on the side of the weights, and the weights weights prevent the weights from escaping.

(Example 2-4) In Example 2-3, the creep test machine of the present invention includes a support guide 350 having a groove formed therein for guiding the movement direction of the weight support.

Even if the angle of the loading bar changes during the creep test, the direction of the weights is vertical. However, the movement of the weight coupling unit is moved along the circular trajectory drawn by the first fixing pin about the main axis. The support guide contacts the weight support and guides the movement of the weight support. To this end, the support guide forms a groove in the block shape, and the groove guides the direction in which one side of the weight support is moved. The weights are placed in the direction of gravity, and the upper side is structured like a watch hanging on the loading bar. The watch structure can easily move to external vibration and wind force, which can not obtain precise experimental results. Therefore, in order to prevent movement against external influences, the support guide and the weight support stand form the coupling condition of the groove and the projection.

(Example 2-5) In Example 2-4, the creep test machine of the present invention is mounted on a bed, and a protective fence 360 is attached to a loading bar, a weight, and a weight accumulator.

The experimental apparatus is exposed to the outside. The introduction of unintended external obstacles causes an experimental error. In particular, external interference must be blocked during the loading bar and weighing experiment of the present invention. To do this, the bed is equipped with pans and the loading bar and weight are placed inside the pans. The fins form a door, which is used for mounting the weight during the preparation of the experiment.

(Example 3-1) In Example 1-1, the tensile creep test piece 400 of the creep test machine of the present invention had a uniform cross-sectional shape. One side of the first grip 410 is fixed to one end of the tensile creamped specimen and the other side is coupled to the specimen coupling part of the loading bar. One end of the second grip 420 is fixed to the other end of the tensile creep test piece, and the other end is coupled to the support.

For the tensile creep test of concrete specimens, tensile creep specimens are used and the cross section of the tensile creep specimen is uniform. Both ends of the tensile creep specimen form a wider end than the center side (experimental part), and the wide end is coupled to the first and second grips. The second grip is coupled to the support and the first grip is coupled to the loading bar. That is, the loading bar is pivoted by the weight and deformation of the tensile creep specimen, and the elongation of the tensile creep specimen leads to the change of the angle of the loading bar. That is, the uniform load of the weights imparts the tensile force to the tensile creep specimen for a long time, and it is possible to measure the displacement of the tensile creep specimen with time.

(Example 3-2) In Example 3-1, the first grip of the present invention forms a second fixing pin 411, and the second fixing pin is coupled to the specimen coupling portion.

 Rotation of the loading bar imparts tensile force to tensile creep specimens. During the test, the load acting on the tensile creep specimen must always act on the axial load of the specimen. However, as the angle of the loading bar increases, the tension load direction acting on the specimen varies depending on the angle of the loading bar. To overcome this, the first grip and the second grip have to be turned freely. For this rotation, the first grip and the specimen coupling allow sliding, and the second grip must be rotated. The second fixing pin engages the second fixing pin bushing 412 and is coupled to the specimen coupling groove. The outer diameter of the second fixing pin bush is formed to be smaller than the outer diameter of the groove of the specimen coupling portion, so that the second fixing pin bush and the specimen coupling groove always form point contact. By point contact, the tensile creep specimen can implement the axial loading conditions.

(Example 3-3) In Example 3-1, the creep test machine second grip of the present invention includes a third grip pin projecting to the support and being axially coupled to the third grip pin.

The second grip is engaged with the third fixing pin and the second drawing is rotated freely from the third fixing pin in order to implement the axial load condition of the tensile creep specimen. To this end, the third fixing pin fixed to the support mounts a third fixing pin bushing 422, and the third fixing pin bush is engaged with the second grip. The third fixing pin bush is freely rotated from the third fixing pin by the reduction of the coefficient of friction with the second grip.

(Example 3-4) In Example 3-1, a first load cell 430 is mounted on the second grip of the creep test machine of the present invention, and an extension 440 is mounted on the tensile creep specimen.

And the first load cell is fixed to the second grip to which the tensile creep sample is fixed. The load cell measures the load in real time and measures the load change with time. During the creep test, a tension meter is mounted on the middle of the tensile creep specimen to measure the elongation of the specimen. The extensometer measures the displacement in real time and measures the displacement of the specimen with time.

In another embodiment, the first load cell may be coupled to the first grip side. In another embodiment, the extensometer may be mounted to the first grip and the second grip. As another example, the angular value of the loading bar can be measured instead of the extensometer. A rotation angle measurement sensor can be used on the main axis for the measurement of the angle value, and a specific object is an LVDT. Alternatively, a scale may be formed on a support for fixing the bed, and a needle may be formed on the rotating loading bar to visually determine the angle change.

(Example 4-1) A creep test machine of the present invention is a creep test machine of Example 1-1, which comprises a twist creep test piece 500 having a uniform cross-sectional shape, a first fastening part 500 for fastening one side of the twist creep test piece to the support, A second coupling part 520 for fixing the other end of the torsion creeping specimen to the torsion link 530, and an interlocking link 540 for coupling the torsion link to the rod bar.

For the torsional creep test, one side of the torsional creep specimen is fixed to the support and the other side is fixed to the torsional link. The twist link rotation imparts a torsional load to the torsional creep specimen. The rotation of the torsion link is interlocked with the rotation of the loading bar. The combination of the loading bar and the torsional link uses an interlocking link. That is, the weighting rod is rotated, and the loading bar rotates the torsion link by the interlocking link. Rotation of the torsional link may cause twisting in the torsional creep specimen. The first and second fastening portions are coupled to both ends of the torsional creep specimen. The first and second fastening portions form insertion grooves having the same shape and size as those of the test piece, and both end surfaces of the test piece are fitted to the first and second fastening portions for fixing the torsional creep specimen of various shapes. The first fastening portion is fixed by a support and a fastener, and the second fastening portion is joined by a torsion link and a fastener. The rotation of the torsion link transfers the torsional load to the specimen through the second fastening portion.

(Example 4-2) In Example 4-1, a second load cell 550, one side of which is fixed to a support and the other side of which is coupled to the first fastening part.

The second load cell measures the torsion torque. To this end, the first fastening portion is engaged with the second load cell. This is to measure the twist amount of the specimen in real time according to the torsional torque.

(Embodiment 4-3) In Embodiment 4-2, a horizontal stand installed on the support and holding a bed plane and a horizontal plane, and a second load cell mounted on an upper end of the horizontal plane. And a specimen insertion port 132 through which the specimen is passed through the plane of the horizontal band and the extending support.

In order to improve the effect of the torsional creep test, it is preferable that the length of the fixing portion and the torsion portion of the torsional creep specimen are long. If the length of the torsional creep specimen is long, the specimen can not be installed between the narrow supports. To overcome this problem, a horizontal stand extending from the support stand is provided, and a specimen insertion hole is formed in the support stand. The specimen inlet penetrates the torsional creep specimen. The second load cell is mounted on the horizontal stand to fix one side of the elongated torsional creep specimen.

(Example 4-4) In Example 4-1, in the creep test machine of the present invention, two support rods are formed opposite to each other, and a main shaft, a loading bar, a torsional link, (560) for positioning the interlocking link, the second fastening portion and the twist creeping specimen, one side of which is coupled to one side of the torsion link, and the other side of which is axially coupled to the linkage support 141 of the second support .

In order for the axial torsional load to be fully transmitted to the torsional creep specimen, both sides of the torsional link must be supported axially. For this purpose, a hole-shaped linkage support is formed in the second support of the symmetrical supports. The rotatable supporter is coupled to the linkage support. Since the rotary support is mounted on the rear surface of the torsion link, the rotation of the loading bar is transmitted to the torsion link by the interlocking link, and both surfaces of the torsion link are fixed in the axial direction, so that a perfect torsional load can be imparted.

(Example 5-1) In any one of Examples 1-1 to 4-1, the creep test machine of the present invention includes a chamber 611 for receiving the creep test machine, a heat transfer device A heat generator 613 for circulating heated air or a coolant to the heat transfer device, a temperature sensor 614 and a humidity sensor 615 accommodated in the chamber.

As a test condition, the chamber is mounted to realize constant temperature and humidity conditions. A heat transfer device is formed inside the chamber, and the heat transfer device is preferably a pen coil. And the constitution of an equivalent object which generates the same purpose and effect as the pen coil is replaced. The heat transfer device is supplied with cool air or warm air from the outside, and the heat generating device supplies cold air or warm air. A temperature sensor and a humidity sensor are mounted inside the chamber.

(Example 5-2) In Example 5-1, the creep test machine of the present invention includes a controller 620 that receives the temperature sensor and the humidity sensor signal and operates the heat generator.

The controller controls the heat transfer device and the heat generating device to maintain the specified temperature inside the chamber. The controller receives the temperature sensor and the humidity sensor signal in the chamber and controls the operation of the heat generating device and the heat transfer device to continuously maintain the predetermined temperature and humidity environment.

(Example 5-3) In Example 5-1, the creep testing machine of the present invention includes a humidifying nozzle accommodated in the chamber and supplying moisture generated from an external humidifying device.

The inside of the chamber must implement various humidity environments. In order to realize a high humidity environment inside the chamber, the water vapor generated from the humidifier must be transferred into the chamber. In order to realize a low humidity environment inside the chamber, the cool air generated in the heat generating device is transferred to the heat transfer device inside the chamber. The water vapor is supplied to the humidifying nozzle, and the humidifying nozzle is operated by the humidifying control valve. The humidification control valve is operated by a humidification controller. The humidification controller controls the heat generating device and the heat transfer device.

101: support 101a: first support
101b: second support member 102: main shaft
120: Bed 131: Horizontal
132: specimen insertion hole 141:
210: Loading bar 211: Rotation hole,
212: specimen fastening part 213: load acting groove
220: main bush 310: weight weight
320: Weight weight coupling base 330: First fixing pin
331: first fixing pin bush 340: weight support base
350: Support guide 360: Fans
400: tensile creep test piece 410: first grip
411: second fixing pin 412: second fixing pin bush
420: second grip 421: third fixing pin
422: third fixing pin bush 430: first load cell
440: Extensometer 500: Torsion creep specimen
510: first fastening part 520: second fastening part
530: torsion link 540: interlock link
550: second load cell 560:
611: chamber 612: heat transfer device
613: heat generating device 614: temperature sensor
615: Humidity sensor 620: Controller

Claims (5)

In a creep test machine,
A main shaft 102 coupled to the support 101;
A test piece coupling portion 212 is formed on one side of the main shaft 102,
A loading bar 210 forming a load acting groove 213;
A weight attaching belt 320 to which a plurality of weights 310 are coupled;
A first fixing pin 330 formed at one side of the weight connecting rod 320 and coupled to the load acting groove 213;
The support 101 includes a first support 101a and a second support 101b and a space S is formed between the first support 101a and the second support 101b, (102) is fixed between a first support 101a and a second support 101b;
A weight support base 340 formed on the other side of the weight support base 320 and supporting a weight 310,
For guiding the movement direction of the weight support member 340,
A torsional creep specimen 500 having a uniform cross-sectional shape;
A first coupling part 510 for fixing one side of the torsional creeping specimen 500 to the support 101;
A second coupling part 520 for fixing the other side of the torsional creeping specimen 500 to the torsion link 530;
An interlocking link 540 coupling the torsion link 530 to the loading bar 210;
The main shaft, the loading bar, the torsion link, the interlocking link, the second coupling portion, and the torsion creep specimen 500 are positioned between the two first and second support rods formed opposite to each other, one side of which is coupled to the one torsion link, A rotary support 560 whose other end is axially coupled to the linkage support 141 of the second support;
A chamber 611 for receiving the creep test apparatus;
A heat transfer device 612 housed within the chamber 611;
A heat generating device 613 for circulating the heated air or the refrigerant to the heat transfer device 612;
A temperature sensor 614 and a humidity sensor 615 accommodated in the chamber 611;
A humidifying nozzle accommodated in the chamber and supplying moisture generated from an external humidifying device; Lt; / RTI >
delete The method according to claim 1,
A tensile creep test piece 400 having a uniform cross-sectional shape;
A first grip 410 having one end fixed to one end of the tensile creeping specimen 400 and the other end coupled to the specimen coupling part 212 of the loading bar 210;
And a second grip (420) having one end fixed to the other end of the tensile creep test specimen (400) and the other end coupled to the support stand (101).
delete delete

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