KR20220098902A - Specimen Testing Apparatus Having Multi-Loading Modes - Google Patents

Abstract

The present invention relates to a specimen test apparatus having a complex load mode, which repeatedly applies various cyclic load types to specimens of various materials to rapidly test durability of the specimen. The present invention comprises: a load application unit (100) having an application unit (110) for applying a load from an upper side of the specimen (S); and a load movement unit (200) for reciprocating the application unit (110) in a longitudinal direction of the specimen.

Description

Specimen Testing Apparatus Having Multi-Loading Modes

The present invention relates to a fatigue testing apparatus having a complex load mode capable of rapidly testing the durability of a specimen by repeatedly applying various cyclic load types to specimens of various materials.

In general, fatigue tests used to measure the fatigue limit of various materials include repeated bending, repeated tensile compression, repeated twisting, and repeated impact tests.

There are many known test equipment that considers only one point or repeated test for a specific section of the existing test equipment, but the test equipment that evaluates the fatigue durability of the entire area of the test piece while moving is very insufficient.

In addition, since conventional fatigue testers were only able to apply simple load conditions such as bending fatigue or torsional fatigue, there was another problem in that it was impossible to provide a more realistic experimental state, which can be called the life of a fatigue test.

Therefore, it is possible to selectively apply dynamic and static loads to the test specimens, and the development of a tester with a complex load mode that can analyze both surface wear and cracks such as scratches and friction in one tester is difficult. it is necessary.

1. KR 10-1786736 (Registration date 2017.10.11; Bridge safety test device using modeled bridge specimen) 2. KR 10-1144939 (Registration date: May 2012; Load application device for testing mobile bridges) 3. KR 10-1190021 (Registration date 10.5 2012; Concrete creep test load holding system) 4. KR 10-1132002 (Registration date: March 23, 2012; Bending fatigue test jig) 5. KR 10-1680090 (Registration date: November 22, 2016; Method for evaluating contact fatigue test of composite structures) 6. KR 10-2099614 (Registration date: April 4, 2020; Method and apparatus for predicting fatigue life of composite blades for wind power generators)

The present invention has been devised to solve the above problems, and it is possible to perform a static load test such as a creep test and a repeated test of sliding contact (similar to scratch condition) or rolling contact. Vibration impact can be given to the test piece by changing the shape of the rod, the crack or delamination phenomenon of the test piece can be observed due to repeated loads, and the soundness of the entire test piece can be evaluated through the moving load. The purpose is to analyze the fatigue endurance limit of

The present invention is a specimen (S); The application unit 110 for applying a load from the upper side of the specimen (S) to the downward direction is coupled to the lower direction of the application unit 110, and a weight 140 for applying a load to the specimen (S). a load applying unit 100 provided with; and a load moving unit 200 provided at one side of the load applying unit 100 to reciprocate the applying unit 110 in the longitudinal direction of the specimen from the upper side of the specimen S.

The present invention further comprises a grip portion 300 for fixing both ends of the specimen (S), the specimen (S) may be characterized in that any one of plastic, fiber-reinforced composite, metal, and concrete.

When the specimen (S) of the present invention is made of a concrete material, the grip portion 300 includes a coupling plate 310 having an opening (311) formed in the approximately central portion so as to protrude toward the upper portion of the specimen (S); and, when the specimen (S) is made of a polymer or metal material, a grip 320 rotatably coupled to the coupling plate 310; may further include.

In the present invention, one side of the grip 320 may further include a stopper 330 for limiting the rotation angle of the grip 320 rotated according to the deflection of the specimen S.

The load applying unit 100 of the present invention includes a load support unit 130 coupled to the weight 140; and a fixed frame 120 coupled to one end of the applying unit 110 to be rotatable, and the other end being coupled to the load supporting unit 130 .

On one side of the applying unit 110 of the present invention, when the applying unit 110 reciprocates by driving the load moving unit 200, a rotation control unit so that the applying unit 110 can reciprocate without rotation. (111) may be characterized in that it is further provided.

The load transfer unit 200 of the present invention includes a driving unit 210 including a shaft 211; a power transmission unit 220 screwed to be movable in the longitudinal direction of the shaft 211 by rotation of the shaft 211; and a movement guide unit 230 for guiding the movement of the power transmission unit 220 .

The fixed frame 120 of the present invention further includes a slot 121 in the central portion, and one side of the power transmission unit 220 is inserted into the slot 121 so that the applying unit 110 can reciprocate. It may be characterized in that the power is transmitted to the load applying unit 100 side to make it possible.

In the present invention, a load may be applied to the entire exposed section of the specimen except for the specimen fixing portion. Thus, it is possible to measure the local resistance of the specimen as well as to evaluate the overall health of the specimen, and also to test the fatigue durability limit of the material in a shorter time than the conventional fatigue test.

The present invention can continuously move the fatigue load action point in a periodic or non-periodic manner. In this way, the actual load conditions in which the test material is used can be functionalized and reflected in the test conditions, so that it can have high realism. In addition, since the position and movement speed of the load action point can be adjusted, the effect of the load speed on the fatigue endurance of the specimen can be grasped.

Depending on the movement method of the load bar in contact with the specimen, the sliding contact mode test or the rolling contact mode test can be selectively performed. Thus, it is possible to simultaneously test the occurrence of surface cracks in the specimen from a microscopic point of view and the fatigue endurance limit of the test piece from a macroscopic point of view. Adhesive and abrasive wear environments are considered under sliding contact conditions, and fatigue wear environments are considered as rolling contact conditions.

The present invention can be installed outdoors. Through this, the effects of weathering degradation due to the natural environment and degradation under cyclic loading can be considered simultaneously.

In the present invention, it is possible to control the weight and period of the load transmitted to the specimen, so that the durability of materials or parts subjected to periodic or non-periodic loads can be tested, and the application unit provided in the load application unit performs non-rotational or rotational motion. By selectively enabling it, there is an advantage in that the fatigue of the specimen and various fracture processes of the surface or the coated surface can be tested.

The present invention can evaluate the fatigue properties of materials and members subjected to repeated contact loads, such as bearings, gears, rails, rotating wheels or hinges. In addition, it is possible to evaluate various fracture mechanisms such as substrate and coating surface by physical or chemical coating parameters such as raw material, thickness, hardness and surface roughness.

It is possible to evaluate material properties, lubricants, surface conditions, and the degree of influence of substances or reinforcing materials contained within the material. In addition, it is possible to trace and observe the entire process from crack generation, growth, and fracture on the surface or inside of the specimen.

1 is an overall conceptual view of a specimen testing apparatus according to the present invention;
2 is a partial conceptual view of a specimen testing apparatus according to the present invention;
3 is a conceptual diagram illustrating a load applying unit in the specimen testing apparatus according to the present invention;
4 is a conceptual view showing the coupling of the power transmission unit in the specimen testing apparatus according to the present invention;
5 is a conceptual view showing a grip part of the specimen testing apparatus according to the present invention;
6 is another conceptual view showing a grip part of the specimen testing apparatus according to the present invention;
7 is a conceptual diagram illustrating the movement of a load applying unit in the specimen testing apparatus according to the present invention;
8 is a conceptual view showing the movement of the grip part of the specimen testing apparatus according to the present invention;
9 is a conceptual diagram showing various applying parts of the specimen testing apparatus according to the present invention;

The specimen testing apparatus according to the present invention can be used indoors or outdoors, and in a state in which a constant vertical load is applied to the specimen by adjusting the weight of the weight 140 suspended from the load applying unit 100, the load moving unit 200 It is a test device that quickly evaluates the fatigue durability of a specimen in a complex load mode by periodically moving the load applying unit 100 left and right within the area of the exposed load test piece through a speed controller (not shown) of

Hereinafter, it will be described in detail with reference to the accompanying drawings.

The present invention includes a specimen (S), a load applying unit 100 for applying a load to the specimen (S), and a load moving unit 200 for reciprocating the load applying unit 100 .

1 is an overall conceptual diagram of a specimen testing apparatus according to the present invention. Referring to FIG. 1 , it can be seen that a total of four specimen testing apparatuses according to the present invention are set. This is merely exemplary, and the number may be selectable by the manufacturer or the user.

The load applying unit will be described with reference to FIGS. 2 and 3 . Through this, it is possible to know the load application method and the measurement methods such as displacement and strain of the specimen. The load applying unit 100 is provided with an applying unit 110 for applying a load downward by its own weight from the upper side of the specimen (S). A weight 140 for applying a load to the side of the specimen S by the load is provided in the lower direction of the applying unit 110 . The weight 140 may be directly or indirectly connected to the lower direction of the applying unit 110 . As shown in the drawings, it is not limited thereto only to show that they can be indirectly connected. The deflection of the specimen due to the weight can be measured in real time by using a contact displacement sensor or a non-contact displacement sensor for the vertical displacement of the applying unit 110 or the vertical displacement of the weight 140 . In addition, it is also possible to measure the strain of the specimen using a strain sensor (strain gauge).

Referring to FIG. 2 , it further includes a load support unit 130 coupled to the above-described weight 140 . The load support unit 130 and the weight 140 may be coupled through bolts and nuts. As shown, in addition to the structure, it may have various structures for the ease of replacement of the weight 140 . In addition, it is possible to match the target weight by using various weights as the weight 140 according to the target weight to be given.

Referring to FIG. 3 , the load applying unit 100 further includes a fixed frame 120 . One end of the fixed frame 120 is coupled to the applying unit 110 . It is preferable that a bearing or the like is interposed and coupled so that the applying unit 110 is rotatable. The other end of the fixed frame 120 is coupled to the load support unit 130 .

That is, as shown in FIG. 3 and the like, the applying unit 110 for applying a load in contact with the specimen, and a pair of fixed frames 120 that are coupled by interposing bearings at both ends of the applying unit 110, respectively, a pair of A load support unit 130 fixed to both ends of the fixed frame 120 is provided. Both ends of the load support unit 130 are coupled to both ends of the fixed frame 120 . It can be seen in FIG. 3 that the weight 140 is coupled to the center of the load support unit 130 .

As shown in FIGS. 2 to 4 , holes are perforated at both ends of the load support unit 130 . The guider 131 is inserted into the hole. When the load applying unit 100 moves up and down and left and right (movement), it prevents the load applying unit 100 from shaking due to the weight of the weight, and guides the stable vertical and horizontal movement (movement) of the load applying unit 100 . it is to do

Referring to FIG. 2 , a rotation control unit 111 is provided on one side of the applying unit 110 . The rotation control unit 111 is a configuration for controlling whether the application unit 100 is rotated or non-rotated sliding movement on the upper part of the specimen. That is, the application unit 110 is configured to apply a load to the specimen S while rotating, and to apply a load while sliding. The rotation control unit 111 may be coupled to the application unit 110 side by the motor M and the belt B connected to the shaft side of the motor M. In addition to the mechanical configuration such as the rotation control unit 111 shown in FIG. 2 , a configuration such as a stop pin may be inserted into the application unit 111 to control the rotation of the application unit 111 . Furthermore, the rotation control unit 111 will be able to select various mechanical elements by referring to the configuration for controlling whether the rotational movement or non-rotational sliding movement of the applying unit 110 .

The scratch test and static friction repeated test according to the non-rotational movement of the load applying unit 100 are possible, and the kinetic friction repeated test according to the rotational movement can be adjusted, so that the crack generation mechanism of the surface layer of the specimen can be analyzed. Furthermore, the effect of surface cracks and fractures on the entire specimen, for example, the propagation path of surface cracks or the notch effect according to surface cracks, can be analyzed, so that behavioral characteristics can be evaluated together.

The load moving unit 200 for the left and right reciprocating movement of the load applying unit 100 will be described with reference to FIGS. 2 to 4 .

The load moving unit 200 is provided on one side of the load applying unit 100 and configured to reciprocate the load moving unit 100 including the applying unit 110 in the longitudinal direction of the specimen.

The load moving unit 200 includes a driving unit 210 including a shaft 211, a power transmission unit 220 screwed to be movable in the longitudinal direction of the shaft 211 by rotation of the shaft 211, and power transmission. and a movement guide 230 for guiding the movement of the unit 220 .

Meanwhile, the load moving unit 200 may include a speed controller (not shown) capable of controlling the left and right moving speed of the above-described load applying unit 100 . Through this, the movement period can be adjusted.

The driving unit 210 may be a motor, and may be a mechanical element capable of transmitting other rotational force. The shaft 211 coupled to one side may be threaded. The thread formed on the shaft is engaged with the threaded transmission hole 221 provided on one side of the power transmission unit 220 . The power transmission unit 220 can reciprocate left and right by the screw thread formed in the transmission hole 221 by the forward/reverse rotation of the shaft 211 .

4 and the like, the fixed frame 120 has a slot 121 formed in the central portion thereof. When viewed from the side of the fixed frame 120, the power transmission unit 220 can be inserted by forming an open opening having a substantially diagonal shape, and the fixed frame 120 can naturally descend in the direction in which the specimen sags.

As shown in FIG. 4 , one side of the power transmitting unit 220 is inserted into the slot 121 to transmit power to the load applying unit 100 so that the applying unit 110 can reciprocate. That is, the rotational force of the driving unit 210 may be utilized as a power source capable of moving left and right of the power transmission unit 220 . As shown, the power transmission unit may be formed as an integrated body in a diagonally open substantially upward direction. On the other hand, it may be formed in a substantially hexahedral plate shape. When it becomes a pair of plate-shaped hexahedron, it may be inserted into both sides of a pair of fixed frames 120 .

Meanwhile, referring to FIG. 7 , deflection of the specimen occurs due to the weight of the weight 140 . At this time, there may be a case in which the power transmission unit 220 is inserted into the load applying unit 100 , in particular, the slot 121 of the fixed frame to prevent the deflection of the load applying unit 100 . In order to prevent this, as shown in FIG. 7 , only a portion of the power transmission unit 220 in the width direction can be inserted, so that when the load moving unit 200 moves up and down (moves from L0 to L1), it is fixed Interference caused by the frame 120 and the like is prevented.

The present invention can be tested on various specimens (S).

As the specimen (S) used in the specimen testing apparatus of the present invention, any one of plastics, fiber-reinforced composites, metals and concrete materials may be used. In addition, specimens made of various materials may be used.

It will be described with reference to FIG. 5 . Fig. 5(a) is a case of a concrete specimen, and Fig. 5(b) is a case of a polymer or metal.

Referring to FIGS. 5(a) and (b), when the specimen S is made of concrete, a block-type specimen such as a brick may be mainly used. In consideration of this, it has a shape that can be seated on the coupling plate 310 . That is, the grip portion 300 is a coupling plate 310 having an opening 311 formed on the approximately central portion so as to protrude toward the upper portion of the specimen S. The coupling plate 310 is a first coupling plate 310a and a second coupling plate 310b having a structure capable of fixing the upper side of the specimen seated on the first coupling plate 310a so as to support the lower portion of the sample. ) is made of A seating portion 312 may be provided on the first coupling plate 310a so that the specimen S can be seated and fixed thereto. The specimen S seated on the seating portion 312 may be firmly fixed by the second coupling plate 310b.

Meanwhile, when the specimen S is made of a polymer or metal material, a grip 320 rotatably coupled to the coupling plate 310 may be provided. The rotation shaft of the grip 320 is inserted and fixed in the seating hole 313 formed in the coupling plate, in particular, the first coupling plate 310a. As shown in FIGS. 8(a) and 8(b), the grip 320 was designed to be rotated smoothly at the same time as the specimen was deflected in the downward direction. Alternatively, a stopper 330 for fixing the separate grip 320 is provided so that the specimen can be fixed despite sagging downward. As shown in FIG. 2 , the stopper 330 is formed in the form of a pin, so that the grip is not rotated when it is inserted into one side of the grip 320 through left and right movement, and when the stopper 330 is removed from one side of the grip 320 , the grip is It was allowed to rotate naturally according to the deflection of the specimen.

Meanwhile, referring to FIG. 8(a) or (b), the strain measuring device 400 may be provided at the position of the specimen to be measured. The strain measuring device may be configured as a fixed or movable strain sensor.

As shown in FIG. 6 , the grip 320 has a structure suitable for fixing the specimen, and is configured to press the specimen on both upper and lower sides. One end of the rotation shaft 321 is inserted into the grip 320 , and the other end of the rotation shaft 321 is inserted into the seating hole 313 so that it can be freely rotated. Meanwhile, a fixing pin 322 is provided inside the grip 320 to firmly fix the specimen. When the specimen is firmly fixed by combining the upper grip with the lower grip, a separate fixing pin 322 and the like are provided to prevent the specimen from being separated due to sliding of the specimen.

Referring to FIG. 9 , the cross-section of the applying unit 110 of the load applying unit 100 may have a cross-sectional shape such as a circular (uniform load), an elliptical (irregular cyclic load), or a polygonal (cyclic load) shape. Through this, not only can a periodic load be applied to the side of the specimen, but also an irregular load can be applied, so that various specimen tests are possible. Through this, it is possible to simultaneously apply a high amplitude main cyclic loading and a minor low amplitude cyclic loading to the specimen at the same time, so that the fatigue life of the material or component can be applied more quickly and precisely. can be evaluated.

S specimen 100 load applied
200 Load moving part 300 Grip part

Claims (8)

specimen (S);
The application unit 110 for applying a load from the upper side to the lower side of the specimen (S) and a weight 140 for applying a load to the specimen (S) by being coupled to the lower direction of the application unit 110 . a load applying unit 100 provided with; and
A complex load mode comprising; a load moving unit 200 provided on one side of the load applying unit 100 to reciprocate the applying unit 110 in the longitudinal direction of the specimen from the upper side of the specimen (S) Specimen testing apparatus with
The method of claim 1,
It further comprises a grip portion 300 for fixing both ends of the specimen (S),
The specimen (S) is a specimen testing apparatus having a complex load mode, characterized in that any one of plastic, fiber-reinforced composite, metal, and concrete.
3. The method of claim 2,
When the specimen (S) is made of concrete,
The grip portion 300 includes a coupling plate 310 having an opening 311) formed on the central portion thereof so as to protrude toward the upper portion of the specimen S.
When the specimen (S) is a polymer or metal material,
Specimens testing apparatus having a complex load mode, characterized in that it further comprises a; grip 320 rotatably coupled to the coupling plate (310).
4. The method of claim 3,
Specimens having a complex load mode, characterized in that the grip 320 further includes a stopper 330 for limiting the rotation angle of the grip 320 rotated according to the deflection of the specimen S at one side of the grip 320 . test device.
The method of claim 1,
The load applying unit 100,
a load support unit 130 coupled to the weight 140; and
A specimen testing apparatus having a complex load mode, characterized in that it comprises a; one end is coupled to the application unit 110 is rotatably coupled, and the other end is a fixed frame (120) coupled to the load support unit (130).
6. The method of claim 5,
At one side of the applying unit 110, when the applying unit 110 is reciprocated by driving the load moving unit 200, a rotation control unit 111 so that the applying unit 110 can reciprocate without rotation. Specimen testing apparatus having a complex load mode, characterized in that it is further provided.
6. The method of claim 5,
The load moving unit 200,
a driving unit 210 including a shaft 211;
a power transmission unit 220 screwed to be movable in the longitudinal direction of the shaft 211 by rotation of the shaft 211; and
and a movement guide 230 for guiding the movement of the power transmission unit 220.
8. The method of claim 7,
The fixed frame 120 further includes a slot 121 in the central portion,
One side of the power transmitting unit 220 is inserted into the slot 121 to transmit power to the load applying unit 100 so that the applying unit 110 can reciprocate. Specimen testing apparatus with mode.

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