JP2022046066A - Tensile testing method for shape steel and tensile testing device for shape steel - Google Patents

Abstract

To provide a tensile testing method of shape steel which can measure extension of a testing piece easily.SOLUTION: A tensile testing method of shape steel according to one embodiment of the present invention comprises: a first step of preparing a testing piece of the shape steel and a camera; a second step of giving marks to two spots apart in a tension direction of the testing piece; a third step of pulling and breaking the testing piece while imaging the marks at the two spots with the camera; a fourth step of measuring a distance between the marks at the two spots when the testing piece is broken on the basis of an image or video imaged with the camera in the third step; and a fifth step of measuring extension of the testing piece on the basis of the distance between the marks at the two spots in a standard state of the testing piece before pulling the testing piece in the third step, and the distance between the marks at the two spots measured in the fourth step.SELECTED DRAWING: Figure 14

Description

The present invention relates to a structural steel tensile test method and a structural steel tensile test apparatus.

Conventionally, for example, a tensile test method for a shaped steel as proposed in Patent Document 1 has been known.

In Patent Document 1, a pair of load-balanced assemblies grip both ends of a structural steel test piece, and a human or a machine separates the pair of load-balanced assemblies from each other to break the test pieces. Pull the test piece until it reaches the end.

Japanese Unexamined Patent Publication No. 2014-235164

Here, in general, in the conventional tensile test method for shaped steel as in Patent Document 1, two marks are marked on the test piece, which are separated from each other in the pulling direction, and the test piece is not pulled. The elongation of the test piece is measured based on the distance between the two marks in the reference state of the test piece and the distance between the two marks in the state where the pieces of the test piece that have been pulled and broken are butted against each other. However, such a method has a problem that it takes time and effort to measure the elongation of the test piece.

Therefore, an object of the present invention is to provide a tensile test method for shaped steel and a tensile test device for shaped steel, which can easily measure the elongation of a test piece.

In order to solve the above problems, the structural steel tensile test method according to the embodiment of the present invention comprises the first step of preparing the structural steel test piece and the camera, and the test piece in the tensile direction. The second step of marking two separated places, the third step of pulling and breaking the test piece while taking an image of the two marks with the camera, and the third step of taking an image with the camera in the third step. The fourth step of measuring the distance between the two marks when the test piece is broken and the reference state of the test piece before pulling the test piece in the third step based on the image or video. The present invention is characterized by comprising a fifth step of measuring the elongation of the test piece based on the distance between the two marks in the above two places and the distance between the two marks measured in the fourth step. And.

According to the above configuration, it is possible to measure the distance between two marks when the test piece is broken, based on the image or video image taken by the camera. Then, the elongation of the test piece is increased based on the distance between the two marks in the reference state of the test piece before the test piece is pulled and the distance between the two marks when the test piece is broken. Can be measured.

According to the present invention, it is possible to provide a tensile test method for a shaped steel and a tensile test device for the shaped steel, which can easily measure the elongation of the test piece.

It is a schematic diagram which shows the tensile test apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the arrangement relation of the test piece, the lighting apparatus, and two cameras in the tensile test apparatus which concerns on one Embodiment of this invention. It is a perspective view of the reference test piece and the test piece used in the tensile test apparatus which concerns on one Embodiment of this invention, (A) is the figure which shows the reference test piece, (B) is the figure which shows the test piece. It is a schematic diagram which shows the state which the reference test piece in the state held by the tension device is image | image | photographed with the camera in the tensile test apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows how the tensile test apparatus which concerns on one Embodiment of this invention determines the correlation between the distance between three reference marks, and the pixel of an image or a moving image. It is a schematic diagram which shows the mode that the marking of the test piece is read by the auxiliary camera in the tensile test apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the state of measuring the thickness of three places of a test piece by the tensile test apparatus which concerns on one Embodiment of this invention, (A) is the thickness of one end side in the length direction of a test piece. (B) is a diagram measuring the central thickness of the test piece in the length direction, (C) is a diagram measuring the thickness of the other end side of the test piece in the length direction. Is. It is a schematic diagram which shows the mode that the test piece is installed in the tensile device by the robot in the tensile test apparatus which concerns on one Embodiment of this invention. FIG. 6 is a schematic view showing a state in which a test piece is pulled by the tensile device and broken in the tensile test device according to the embodiment of the present invention, and is a diagram showing a state in which (A) starts pulling the test piece, (B). Is a diagram when the test piece is broken, and (C) is a diagram after the test piece is broken. It is a schematic diagram which shows the stress-strain curve generated in the test piece when the test piece is pulled by the tensile test apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the mode that the piece of the test piece is removed from the tension device by the robot in the tensile test apparatus which concerns on one Embodiment of this invention, and (A) is removing the fragment of a test piece from the lower gripping mechanism. FIG. 3B is a diagram in which a piece of a test piece is removed from the upper gripping mechanism, and FIG. 3C is a diagram after removing a piece of a test piece from the upper and lower gripping mechanisms. It is a schematic diagram which shows the appearance that the work of removing a piece of a test piece from the upper gripping mechanism by a robot is assisted by the impact device in the tensile test apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows schematic operation of the impact device of the tensile test apparatus which concerns on one Embodiment of this invention, (A) is the figure which shows the initial state before injecting air into a cylinder, (B) is a cylinder. It is a figure when the piston moves to the tip side after injecting air into a cylinder, and (C) is a figure when a piston returns to a proximal end side after injecting air into a cylinder. It is a flowchart which shows the tensile test method which concerns on one Embodiment of this invention.

Hereinafter, the tensile test apparatus according to the embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the present embodiment. Further, in the following, the same or corresponding elements are designated by the same reference numerals throughout all the figures, and the overlapping description thereof will be omitted.

(Tensile test device 10)
FIG. 1 is a schematic view showing a tensile test apparatus according to this embodiment. The tensile test apparatus 10 according to the present embodiment is used to perform a tensile test on the test piece T of the shaped steel and measure the elongation of the test piece T. As shown in FIG. 1, the tensile test device 10 captures an image of the tensile device 20 for pulling and breaking the test piece T and the marks La and Lb (see FIG. 2) attached to the test piece T at two places. The two cameras 11a and 11b shown by the broken line in FIG. 1 are provided.

(Tension device 20)
As shown in FIG. 1, the tensioning device 20 includes a base 21, an upper gripping mechanism 30 (first gripping mechanism) for gripping one end of the test piece T in the length direction, and the length of the test piece T. A lower gripping mechanism 40 (second gripping mechanism) for gripping the other end in the direction, and four columns 22a to 22d erected on the base 21 to support the upper and lower gripping mechanisms 30 and 40. And have. Further, the tensioning device 20 further includes a control device 60 for controlling the operation of the upper and lower gripping mechanisms 30 and 40.

(Robot 70)
As shown in FIG. 1, the tensile test device 10 further includes a robot 70 for transporting the test piece T. The robot 70 is arranged adjacent to the tensioning device 20. The robot 70 is a so-called vertical articulated robot having six joint axes. That is, the robot 70 has a base 71 and its base end connected to the base 71, and is provided at the robot arm 72 including six joint axes and the tip of the robot arm 72 to hold the test piece T. It is a known structure having the robot hand 73 of the above.

(Camera 11a, 11b)
FIG. 2 is a schematic view showing the arrangement relationship of a test piece, a lighting device, and two cameras in the tensile test device according to the present embodiment. In addition, in FIG. 2, the drawing of the tensioning device 20 and the like is omitted in order to avoid the complexity of appearance. As shown in FIG. 2, the camera 11a is provided to take an image of the mark La located on the upper side of the test piece T while the test piece T is held by the tensioning device 20. On the other hand, the camera 11b is provided to take an image of the mark Lb located below the test piece T in a state where the test piece T is gripped by the tensioning device 20. It is preferable that the cameras 11a and 11b use products having the same model number. The cameras 11a and 11b are connected to the control device 60, respectively.

The tensile test device 10 further includes lighting devices 13a and 13b that illuminate the test piece T held by the tensile device 20 with light in order to sharpen the image or video image captured by the cameras 11a and 11b.

The cameras 11a and 11b are respectively arranged in front of the test piece T so that the optical axis extends in the horizontal plane. The cameras 11a and 11b are arranged at a distance D ₁ (for example, about 300 mm) from the test piece T in the horizontal direction, respectively. Further, the cameras 11a and 11b are arranged at a distance D ₂ (for example, about 200 mm) from each other in the vertical direction.

The lighting device 13a is arranged slightly on the test piece T side of the camera 11a and above the camera 11a, and is mainly arranged so as to illuminate the mark La of the test piece T and its surroundings. On the other hand, the lighting device 13b is arranged slightly below the camera 11b on the test piece T side of the camera 11b, and is arranged so as to mainly illuminate the mark Lb of the test piece T and its surroundings.

(Reference test piece BT, test piece T)
3A and 3B are perspective views of a reference test piece and a test piece used in the tensile test apparatus according to the present embodiment, where FIG. 3A is a diagram showing a reference test piece and FIG. 3B is a diagram showing a test piece.

As shown in FIG. 3A, the reference test piece BT has a rectangular parallelepiped shape. In other words, the reference test piece BT has a plate shape having a uniform width in the length direction. A reference stamped BS showing a test piece number for traceability is engraved on one end surface of the reference test piece BT in the length direction.

Of the side surfaces on one side in the width direction of the reference test piece BT, the portion on one side in the length direction is provided with linear reference marks BLa to BLc extending in the thickness direction of the reference test piece BT. The reference marks BLa to BLc are arranged in parallel with each other at equal intervals in the length direction of the reference test piece BT. That is, the reference marks BLa to BLc are separated from each other in the direction corresponding to the pulling direction of the test piece T.

Of the side surfaces on one side in the width direction of the reference test piece BT, the other side portion in the length direction is provided with linear reference marks BLd to BLf extending in the thickness direction of the reference test piece BT. The reference marks BLd to BLf are arranged in parallel with each other at equal intervals in the length direction of the reference test piece BT. That is, the reference marks BLd to BLf are separated from each other in the direction corresponding to the pulling direction of the test piece T.

It is preferable that the distance between the reference marks BLa and BLb, the distance between the reference marks BLb and BLc, the distance between the reference marks BLd and BLe, and the distance between the reference marks BLe and BLf are equal to each other. Further, in consideration of pulling the test piece T upward and measuring the elongation of the test piece T as described later, one end surface of the reference test piece BT (in other words, the reference of the reference test piece BT). The distance from the end face on the side closer to the mark BLa) to the reference mark BLa is from the other end face of the reference test piece BT (in other words, the end face of the reference test piece BT on the side closer to the reference mark BLf) to the reference mark BLf. It is preferably shorter than the distance to.

The reference marks BLa to BLf may be attached to the reference test piece BT after the surface of the reference test piece BT is subjected to the surface treatment ST. At this time, for example, the base treatment may be white, and the reference marks BLa to BLf may be black, respectively.

The reference test piece BT may be molded from, for example, a material such as stainless steel having heat resistance and corrosion resistance, or may be molded from the same material as the test piece T by the same manufacturing method. The method for producing the test piece T will be described later.

As shown in FIG. 3B, the test piece T has a plate shape and is provided at one end of a parallel portion Ta having a uniform width in the length direction and a parallel portion Ta in the length direction. It has a grip portion Tb having a width larger than that of the grip portion Tb, and a grip portion Tc provided at the other end in the length direction of the parallel portion Ta and having the same shape as the grip portion Tb. An engraved S indicating a test piece number for traceability is engraved on the end face of the grip portion Tb (in other words, the end face on one side of the test piece T).

Of the side surfaces on one side in the width direction of the parallel portion Ta, the portion on the grip portion Tb side is provided with a linear mark La extending in the thickness direction of the test piece T. Further, of the side surface on one side in the width direction of the parallel portion Ta, the portion on the grip portion Tc side is provided with a linear mark Lb extending in the thickness direction of the test piece T. That is, the marks La and Lb are separated in the pulling direction.

As with the reference marks BLa and BLb, the marks La and Lb may be attached to the test piece T after the surface of the test piece T is subjected to the surface treatment ST, respectively. At this time, for example, the base treatment may be white and the marks La and Lb may be black, respectively.

Although it depends on the size and shape of the test piece T, the distance between the marks La and Lb in the reference state of the test piece T before pulling the test piece T is, for example, 180 mm or more and 220 mm or less. Further, when the test piece T breaks, for example, the distance between the marks La and Lb is 320 mm or less. The maximum distance between the marks La and Lb when the test piece T breaks is defined by, for example, the distances D ₁ and D ₂ (see FIG. 2) and the imaging ranges Ra and Rb (see FIG. 4) described later. ..

The test piece T is manufactured by manufacturing a shaped steel (for example, H-shaped steel, I-shaped steel, channel steel, flat steel, etc.) from one molten steel, for example, based on the Japanese Industrial Standards (JIS) or ship grade. It may be formed by cutting out from shaped steel.

FIG. 4 is a schematic view showing a state in which a reference test piece held by the tensile device is imaged by a camera in the tensile test device according to the present embodiment. Here, the detailed structure of the upper and lower gripping mechanisms 30 and 40 will be described with reference to FIG.

As shown in FIG. 4, the upper gripping mechanism 30 includes a pair of upper sliding portions 31a and 31b and a pair of upper sliding portions 36a arranged inside the pair of upper sliding portions 31a and 31b. , 36b and.

The pair of upper sliding portions 31a and 31b are plane-symmetrical with respect to the vertical planes along the central axis C of the upper gripping mechanism 30 and the lower gripping mechanism 40 extending in the vertical direction. The pair of upper slidable portions 31a and 31b each have a lower surface 32 and a slidable surface 33 extending upward from the inner end edge of the lower surface 32. The slidable surface 33 is inclined so as to spread outward in the width direction of the upper gripping mechanism 30 from the lower surface 32 toward the upper side.

The pair of upper sliding portions 36a and 36b, like the pair of upper sliding portions 31a and 31b, are plane-symmetrical with respect to the vertical plane along the central axis C. The pair of upper sliding portions 36a and 36b have a lower surface 37, a sliding surface 38 extending upward from the outer edge of the lower surface 37, and a gripping surface 39 extending upward from the inner edge of the lower surface 37, respectively. Have. The sliding surface 38 is inclined so as to spread outward in the width direction of the upper gripping mechanism 30 at an angle corresponding to the sliding surface 33 from the lower surface 32 toward the upper side. The grip surface 39 is parallel to the vertical plane along the central axis C. The gripping surface 39 is provided with a contact member 51 that comes into contact with the gripping portion Tb of the test piece T.

The pair of upper sliding portions 36a and 36b maintain a state of being plane-symmetrical with respect to the vertical plane along the central axis C, and the sliding surface 38 of the upper sliding portion 36a is the upper sliding portion 31a. It slides on the slidable surface 33, and similarly, the sliding surface 38 of the upper sliding portion 36b slides on the slidable surface 33 of the upper slidable portion 31b. At this time, since the sliding surface 33 of each of the pair of upper sliding portions 31a and 31b and the sliding surface 38 of each of the pair of upper sliding portions 36a and 36b are inclined as described above, the pair. As the upper sliding portions 36a and 36b slide upward, the distance between the gripping surfaces 39 of the pair of upper sliding portions 36a and 36b increases.

The lower gripping mechanism 40 has a structure in which the upper gripping mechanism 30 is turned upside down, and has a pair of lower sliding portions 41a and 41b corresponding to the pair of upper sliding portions 31a and 31b described above and a pair of upper sliding portions 41a and 41b described above. It has a pair of lower sliding portions 46a and 46b corresponding to the sliding portions 36a and 36b. The pair of under-sliding portions 41a and 41b each have an upper surface 42 and a slidable surface 43, respectively. Further, the pair of lower sliding portions 46a and 46b each have an upper surface 47, a sliding surface 48 and a gripping surface 49, respectively. A contact member 52 that abuts on the grip portion Tc of the test piece T is provided on the grip surface 49 of each of the pair of lower sliding portions 46a and 46b.

The pair of lower sliding portions 46a and 46b are plane-symmetrical with respect to the vertical plane along the central axis C, and the pair of upper sliding portions 36a and 36b are vertically inverted while being slid. The sliding surface 48 of the moving portion 46a slides on the sliding surface 43 of the lower sliding portion 41a, and the sliding surface 48 of the lower sliding portion 46b is the sliding surface 43 of the lower sliding portion 41b. Slide on.

In the upper gripping mechanism 30, by sliding the pair of upper sliding portions 36a and 36b with respect to the pair of upper sliding portions 31a and 31b, the gripping surfaces 39 of the pair of upper sliding portions 36a and 36b respectively. You can adjust the interval between. Further, in the lower gripping mechanism 40, the pair of lower sliding portions 46a and 46b are slid with respect to the pair of lower sliding portions 41a and 41b while maintaining the state of being turned upside down with the upper gripping mechanism 30. The distance between the gripping surfaces 49 of each of the pair of lower sliding portions 46a and 46b can be adjusted. As a result, the distance between the gripping surfaces 39 of the pair of upper sliding portions 36a and 36b and the distance between the gripping surfaces 49 of each of the pair of lower sliding portions 46a and 46b are always the same.

As described above, the distance between the gripping surfaces 39 of the pair of upper sliding portions 36a and 36b and the distance between the gripping surfaces 49 of the pair of lower sliding portions 46a and 46b can be adjusted, so that the upper and lower grips can be gripped. As shown in FIG. 4, the mechanisms 30 and 40 can appropriately grip the reference test piece BT (same as above) according to the thickness of the reference test piece BT (and the test piece T).

(Determining the correlation between the reference marks BLa to BLf and the pixel P)
Here, based on FIGS. 4 and 5, using the tensile test apparatus 10, the distance between the reference marks BLa and BLb, the distance between the reference marks BLb and BLc, and the pixels of the image or video imaged by the camera 11a. The correlation with P is determined, and the correlation between the distance between the reference marks BLd and BLe and the distance between the reference marks BLe and BLf and the pixel P of the image or video imaged by the camera 11b is determined. An example of the embodiment will be described. FIG. 5 is a schematic view showing how the tensile test apparatus according to the present embodiment determines the correlation between the distance between the three reference marks and the pixels of the image or video.

First, the distance between the reference marks BLa and BLb, the distance between the reference marks BLb and BLc, the distance between the reference marks BLd and BLe, and the distance between the reference marks BLe and BLf attached to the reference test piece BT are measured in advance. Keep it.

Next, as shown in FIG. 4, the grip portion BTb of the reference test piece BT is gripped by the upper grip mechanism 30 so that the reference marks BLa to BLf appear in front of the tensioning device 20, and the grip portion of the reference test piece BT is gripped. The BTc is gripped by the lower gripping mechanism 40.

Further, the imaging range Ra is adjusted so that the reference markers BLa to BLc are located within the imaging range Ra by the camera 11a shown by the broken line in FIG. 4, and the reference markers BLa to BLc are imaged by the camera 11a. Similarly, the imaging range Rb is adjusted so that the reference marks BLd to BLf are located within the image pickup range Rb by the camera 11b shown by the broken line in the figure, and the reference marks BLd to BLf are imaged by the camera 11b.

Here, as described above, it is preferable that the cameras 11a and 11b are products having the same model number. Further, for example, it is preferable that the pixels P of the image or video imaged by the cameras 11a and 11b and the sizes of the imaging ranges Ra and Rb are the same as each other. Not limited to the above cases, the cameras 11a and 11b may be products having different model numbers. Further, the pixels P of the image or video imaged by the cameras 11a and 11b, and the sizes of the imaging ranges Ra and Rb may be different from each other.

Further, as described above, since the distance from one end surface of the reference test piece BT to the reference mark BLa is shorter than the distance from the other end surface of the reference test piece BT to the reference mark BLf, the reference test piece BT The distance from one end surface to the upper end side of the imaging range Ra is preferably shorter than the distance from the other end surface of the reference test piece BT to the lower end side of the imaging range Rb.

The image pickup range Ra by the camera 11a adjusted at this time has the same position and size as the image pickup range Ra by the camera 11a when imaging the mark La of the test piece T, which will be described later with reference to FIG. In other words, the distance in the optical axis direction of the camera 11a from the camera 11a to the mark La is the same as the distance in the optical axis direction of the camera 11a from the camera 11a to the reference mark BLa. Since the same applies to the image pickup range Rb by the camera 11b, the description thereof will not be repeated here.

Then, as shown in FIG. 5, the distance between the reference marks BLa and BLb measured in advance, the distance between the reference marks BLb and BLc, and the image or video captured by the camera 11a are used. The correlation between the distance and the distance between the reference marks BLb and BLc and the pixel P of the image or the video is determined. Similarly, the distance between the reference marks BLd and BLe and the distance between the reference marks BLe and BLf measured in advance, and the distance between the reference marks BLd and BLe and the reference mark BLe based on the image or video captured by the camera 11b. , The correlation between the distance between BLf and the image or the pixel P of the video is determined.

(An example of an embodiment for measuring the elongation of the test piece T)
An example of an embodiment in which the elongation of the test piece T is measured by using the tensile test device 10 will be described with reference to FIGS. 1 and 6 to 13.

First, as shown in FIG. 1, a plurality of test pieces T are prepared on a table 14 arranged side by side on the robot 70. Here, for example, the tensile test device 10 may be configured to be able to measure the elongation of up to 50 test pieces T at a time. In such a case, for example, 50 test pieces T are two stacked in the thickness direction so that each marking S can be imaged by the sub camera 12 (see FIGS. 1 and 6) described later. It may be arranged adjacently on the table 14.

FIG. 6 is a schematic view showing a state in which the marking of the test piece is read by the auxiliary camera in the tensile test apparatus according to the present embodiment.

Next, as shown in FIG. 6, the test piece number indicated on the marking S of the test piece T is read by the sub camera 12. The test piece number read by the sub camera 12 is transmitted to the control device 60.

FIG. 7 is a schematic view showing a state in which the thickness of the test piece is measured at three points by the tensile test apparatus according to the present embodiment, and FIG. 7A is a schematic view showing that the thickness of the test piece is measured at one end side in the length direction of the test piece. The figure measuring the thickness, (B) is the figure measuring the central thickness in the length direction of the test piece, and (C) is measuring the thickness on the other end side in the length direction of the test piece. It is a figure.

Further, as shown in FIG. 7, the robot hand 73 holds the grip portion Tb of the test piece T, the posture of the robot arm 72 is changed, and the test piece T is placed up to the cross-section measuring device 15 juxtaposed with the robot 70. Transport.

The cross-section measuring device 15 has optical sensors 16a and 16b arranged so as to face each other in the vertical direction. By inserting the test piece T between the optical sensors 16a and 16b, the robot 70 reduces the thickness of the three parts of the test piece T between the marks La and Lb in the length direction of the test piece T. Measure. Further, the robot 70 changes the direction of the test piece T and inserts the test piece T between the optical sensors 16a and 16b, so that the mark La, among the test pieces T, in the length direction of the test piece T. Measure the width of the part between Lb at three points.

If there is no abnormality in the thickness or width of the test piece T measured as described above, the test piece T is conveyed to the tensioning device 20 by the robot 70. On the other hand, if there is an abnormality in the thickness or width of the test piece T (for example, based on the fact that the thickness or width of the three parts of the test piece T varies more than the permissible value, the control device 60 determines that the abnormality is present. If), the test piece T is transported to a predetermined place other than the tensioning device 20 and no further processing is performed (that is, the test piece T determined to be abnormal is excluded from the elongation measurement target).

FIG. 8 is a schematic view showing a state in which a test piece is installed in a tensile device by a robot in the tensile test device according to the present embodiment.

Then, as shown in FIG. 8, the test piece T is installed in the tensioning device 20 by the robot 70. The robot 70 is connected to the control device 60, and adjusts the height position of the test piece T with respect to the tensioning device 20 based on the test piece number of the test piece T stored in the control device 60.

For example, as shown in FIG. 8, the end faces of the test piece T on the grip portion Tb side are at the same height as the upper surfaces of the pair of upper sliding portions 36a and 36b, and the end faces of the test piece T on the grip portion Tc side are paired. When the test piece T is gripped by the upper and lower gripping mechanisms 30 and 40 so as to be at the same height as the lower surfaces of the lower sliding portions 46a and 46b, a pair of upper sliding portions 31a and 31b are slid. The height positions of the portions 36a and 36b, the height positions of the pair of lower sliding portions 46a and 46b with respect to the pair of lower sliding portions 41a and 41b, and the height positions where the robot 70 should convey the test piece T are determined. It depends on the thickness of the test piece T. Further, the control device 60 can derive the thickness of the test piece T based on the test piece number of the test piece T.

As described above, the robot 70 reaches the height position where the test piece T should be gripped by the upper and lower gripping mechanisms 30 and 40 based on the test piece number of the test piece T stored in the control device 60. It is possible to accurately convey the test piece T and appropriately deliver the test piece T to the upper and lower gripping mechanisms 30 and 40.

9A and 9B are schematic views showing a state in which the test piece is pulled by the tensile device and broken in the tensile test apparatus according to the present embodiment, and FIG. 9A is a diagram showing a state in which the test piece is started to be pulled, (B). ) Is the figure when the test piece is broken, and (C) is the figure after the test piece is broken. Further, FIG. 10 is a schematic diagram showing a stress-strain curve generated in the test piece when the test piece is being pulled by the tensile test apparatus according to the present embodiment.

Next, as shown in FIGS. 9A to 9C, the test piece T is pulled and broken by the pulling device 20 while the mark La is imaged by the camera 11a and the mark Lb is imaged by the camera 11b. .. As shown in FIGS. 9A to 9C, in the present embodiment, the upper gripping mechanism 30 (in other words, a pair of upper sliding portions 31a and 31b and a pair of upper sliding portions 36a and 36b). However, it is possible to move up and down with respect to the columns 22a to 22d by the elevating mechanism provided on the columns 22a to 22d (see FIG. 1). On the other hand, the lower gripping mechanism 40 (in other words, the pair of lower sliding portions 41a and 41b and the pair of lower sliding portions 46a and 46b) is fixed to the columns 22a to 22d, and is similar to the upper gripping mechanism 30. It does not move up and down with respect to the columns 22a to 22d.

Here, as shown in FIG. 1, the tensile test device 10 further includes distance sensors 18a and 18b fixed to a frame 19 erected on the mounting surface. The distance sensor 18a is provided to measure the distance to the reflector 17a attached to the upper gripping mechanism 30, and the distance sensor 18b is to measure the distance to the reflector 17b attached to the lower gripping mechanism 40. It is provided in. That is, it is possible to measure the height positions of the upper and lower gripping mechanisms 30 and 40 by the distance sensors 18a and 18b. The distance sensors 18a and 18b are connected to the control device 60, respectively. The control device 60 can control the ascending / descending operation of the upper gripping mechanism 30 based on the measured values by the distance sensors 18a and 18b.

Further, as shown in FIG. 1, the tensile test device 10 further includes a stress measuring device 80 for measuring the stress generated in the test piece T when the test piece T is pulled by the tensile device 20. The stress measuring device 80 includes a load meter (not shown) for measuring the tensile load applied to the test piece T, a tensile load indicator 82 for displaying the magnitude of the tensile load, and a value measured by the stress measuring device 80. It has a monitor 84 for displaying the stress-strain curve (see FIG. 10) of the test piece T obtained based on the above.

The stress measuring device 80 is connected to the control device 60. Then, in the stress-strain curve shown in FIG. 10, the control device 60 is the upper gripping mechanism from the time point S when the stress becomes smaller than the maximum value MV by a predetermined value V in the region after the stress exceeds the maximum value MV. Slow down the ascent rate of 30. In other words, the control device 60 moves the upper gripping mechanism 30 in the length direction of the test piece T so that the relative speeds of the upper and lower gripping mechanisms 30 and 40 slow down from the time point S.

In addition to the image or video of FIG. 9B captured by the cameras 11a and 11b, the control device 60 includes the distance between the reference marks BLa and BLb, the distance between the reference marks BLb and BLc, and the image captured by the camera 11a. Alternatively, the test piece is based on the correlation with the pixel P of the video, the distance between the reference marks BLd and BLe, and the distance between the reference marks BLe and BLf and the pixel P of the image or video captured by the camera 11b. The distance between the marks La and Lb when T is broken is measured.

The distance between the marks La and Lb in the reference state of the test piece T before the test piece T is pulled may be measured based on the image or video of FIG. 9A captured by the cameras 11a and 11b. Alternatively, it may be measured in advance when marking La and Lb on the test piece T.

Then, the control device 60 measures the distance between the marks La and Lb in the reference state of the test piece T before pulling the test piece T, and the mark measured based on the image or video of FIG. 9B and the correlation. The elongation of the test piece T is measured based on the distance between La and Lb.

FIG. 11 is a schematic view showing a state in which a test piece fragment is removed from the tensile device by a robot in the tensile test apparatus according to the present embodiment, and FIG. 11A is a schematic view showing the state in which the test piece fragment is removed from the lower gripping mechanism. (B) is a diagram in which a piece of a test piece is removed from the upper gripping mechanism, and (C) is a diagram after removing a piece of a test piece from the upper and lower gripping mechanisms.

As shown in FIG. 11A, after the test piece T was broken, the piece T ₁ of the test piece T was gripped by the upper gripping mechanism 30, and the piece T ₂ of the test piece T was gripped by the lower gripping mechanism 40. It becomes a state. Then, as shown in the figure, the fragment T ₂ gripped by the lower gripping mechanism 40 is gripped by the robot hand 73, and the fragment T ₂ is released from the lower gripping mechanism 40, whereby the robot hand 73 is gripped from the lower gripping mechanism 40. Hand over the fragment T ₂ to. In this way, the robot 70 can remove the fragment T ₂ from the lower gripping mechanism 40.

As described above, the height position of the pair of lower sliding portions 46a and 46b with respect to the pair of lower sliding portions 41a and 41b depends on the thickness of the test piece T, and the control device 60 is tested. The thickness of the test piece T can be derived based on the test piece number of the piece T. Therefore, the control device 60 can derive the distance in the height direction between the upper surface 42 of each of the pair of lower sliding portions 41a and 41b and the upper surface 47 of each of the pair of lower sliding portions 46a and 46b. Further, the control device 60 can derive the height position of the lower gripping mechanism 40 based on the measured values by the distance sensors 18a and 18b.

Based on the information derived as described above, the control device 60 can move the robot hand 73 to an appropriate height position and reliably deliver the fragment T ₂ from the lower gripping mechanism 40 to the robot hand 73. ..

As shown in FIG. 11B, after removing the fragment T ₂ from the lower gripping mechanism 40, the fragment T ₁ gripped by the upper gripping mechanism 30 is gripped by the robot hand 73, and the fragment T ₁ is gripped from the upper gripping mechanism 30. By releasing the above, the fragment T1 is handed _over from the upper gripping mechanism 30 to the robot hand 73. In this way, the robot ₇₀ can remove the fragment T1 from the upper gripping mechanism 30 to bring it into the state shown in FIG. 11 (C).

The details of the mode in which the control device 60 moves the robot hand 73 to an appropriate height position and reliably delivers the fragment T1 from the _upper gripping mechanism 30 to the robot hand 73 can be found in the robot from the lower gripping mechanism 40 described above. Since it is the same as the mode in which the fragment T ₂ is surely delivered to the hand 73, the description thereof will not be repeated here.

(Impact device 90)
FIG. 12 is a schematic view showing a state in which the tensile test device according to the present embodiment assists the work of removing a piece of a test piece from the upper gripping mechanism by a robot by an impact device. 13A and 13B are cross-sectional views schematically showing the operation of the impact device, where FIG. 13A shows an initial state before injecting air into the cylinder, and FIG. 13B shows an initial state before injecting air into the cylinder. It is a figure when the piston moves to the tip side, and (C) is a figure when the piston returns to the base end side after injecting air into the cylinder.

As shown in FIGS. 12 and 13, an impact device 90 is attached in the vicinity of the lower surface 37 on the back surface of the upper sliding portion 36a. The impact device 90 includes a cylinder 91 and a piston 96 that can reciprocate in the cylinder 91.

An injection hole 92a for injecting air into the cylinder 91 is provided at the base end of the cylinder 91. Further, on the side surface of the cylinder 91, a discharge hole 92b for discharging the air injected into the cylinder 91 to the outside is provided. Further, the tip of the cylinder 91 is provided with a through hole 92c for the tip of the shaft portion 97 of the piston 96 to penetrate.

A proximal spring member 93a is provided coaxially with the cylinder 91 on the proximal side of the internal space of the cylinder 91. The base end of the base end spring member 93a is fixed to the base end surface of the internal space of the cylinder 91. On the other hand, on the tip end side of the internal space of the cylinder 91, the tip spring member 93b is provided coaxially with the cylinder 91 and the proximal end spring member 93a. The base end of the tip spring member 93b is fixed to the tip surface of the internal space of the cylinder 91.

The piston 96 has a shaft portion 97 coaxial with the cylinder 91. As described above, the tip portion of the shaft portion 97 penetrates the through hole 92c of the piston 96. The piston 96 further has a proximal flange 98a provided at the proximal end of the shaft portion 97 and a central flange 98b provided at the center of the shaft portion 97. Further, the piston 96 further has a positioning portion 99 that protrudes from the proximal end flange 98a on the side opposite to the shaft portion 97 and is inserted into the proximal end spring member 93a. By inserting the positioning portion 99 into the proximal spring member 93a, the piston 96 can reciprocate in the cylinder 91 in the axial direction while being positioned in a plane orthogonal to the axial direction of the piston 96.

The operation of the impact device 90 will be described in detail with reference to FIGS. 13 (A) to 13 (C).

As shown in FIG. 13A, the proximal flange 98a of the piston 96 is located closer to the proximal end side of the discharge hole 92b of the cylinder 91 in the initial state before injecting air into the cylinder 91. At this time, the urging force of the proximal end spring member 93a to urge the proximal end flange 98a toward the distal end side (hereinafter, simply referred to as "the urging force of the proximal end spring member 93a") and the distal end spring member 93b are the shaft portion 97 and The urging force for urging the proximal end flange 98a to the proximal end side via the central flange 98b (hereinafter, simply referred to as “the urging force by the tip spring member 93b”) is in a balanced state.

Next, as shown by the white arrow in FIG. 13B, air is injected into the cylinder 91 from the injection hole 92a. Immediately after injecting air in this way, as shown by the black arrow in the figure, the urging force by the proximal end spring member 93a and the air existing on the proximal end side of the proximal end flange 98a in the internal space of the cylinder 91. The resultant force with the pressure that urges the base end flange 98a toward the tip side (hereinafter, simply referred to as "pressure due to air on the base end side") is based on the urging force by the tip spring member 93b and the internal space of the cylinder 91. Since the air existing on the tip side of the end flange 98a is larger than the resultant force with the pressure that urges the base end flange 98a to the base end side (hereinafter, simply referred to as "pressure due to the air on the tip side"), the base The end flange 98a (in other words, the piston 96) moves toward the tip side.

After a certain period of time has passed by injecting air into the cylinder 91 from the injection hole 92a, the proximal flange 98a is located closer to the tip side than the discharge hole 92b, as shown in FIG. 13B. As a result, as shown by the white arrow in the figure, the air on the base end side is discharged from the discharge hole 92b, and the base end flange 98a is separated from the base end spring member 93a. The resultant force between the force and the pressure due to the air on the base end side becomes smaller. On the other hand, since the proximal flange 98a moves to the distal end side and the volume on the distal end side is smaller than that on the proximal end flange 98a in the internal space of the cylinder 91, the pressure due to the air on the distal end side increases. As described above, as shown by the black arrow in FIG. 13B, the resultant force of the urging force of the proximal spring member 93a and the pressure of the air on the proximal end side is the urging force of the distal end spring member 93b. Since it is smaller than the resultant force with the pressure due to the air on the tip side, the base end flange 98a (in other words, the piston 96) is pushed back to the base end side.

Then, when a certain period of time has elapsed from the state of FIG. 13 (B), as shown in FIG. 13 (C), the proximal flange 98a is pushed back to the proximal side, and the proximal flange 98a is more than the discharge hole 92b. It will be located on the base end side. As a result, as shown by the white arrow in the figure, the air on the tip side is discharged from the discharge hole 92b, and the central flange 98b is separated from the tip spring member 93b. The resultant force with the pressure due to the air becomes smaller. On the other hand, since the proximal flange 98a moves to the proximal side and the volume on the proximal end side is smaller than that on the proximal end flange 98a in the internal space of the cylinder 91, the pressure due to the air on the distal end side increases. Further, since the proximal end flange 98a abuts on the proximal end spring member 93a, the urging force of the proximal end spring member 93a also increases. As described above, as shown by the black arrow in FIG. 13C, the resultant force of the urging force by the proximal end spring member 93a and the pressure due to the air on the proximal end side is the urging force by the distal end spring member 93b. Since the force becomes larger than the resultant force with the pressure due to the air on the tip side, the base end flange 98a (in other words, the piston 96) is pushed back to the tip side.

As the piston 96 repeatedly reciprocates as described above, the tip portion of the piston 96 repeatedly hits the upper sliding portion 36a. As a result, the impact device 90 can repeatedly apply an impact to the fragment T ₁ of the test piece T via the upper sliding portion 36a. A similar impact device 90 may be attached to each of the upper sliding portion 36b and the pair of lower sliding portions 46a and 46b. The effect of providing the impact device 90 will be described later.

(effect)
The tensile test apparatus 10 according to the present embodiment can measure the distance between the marks La and Lb when the test piece T is broken, based on the image or the image of FIG. 9B captured by the cameras 11a and 11b. can. Then, based on the distance between the marks La and Lb in the reference state of the test piece T before pulling the test piece T and the distance between the marks La and Lb when the test piece T breaks, the test piece T Elongation can be measured. As a result, for example, as in the conventional case, the distance between the marks La and Lb in the reference state of the test piece T, and the marks La in the state where the fragments T ₁ and T ₂ of the test piece T that have been pulled and broken are butted against each other. Based on the distance between Lb, it is possible to easily measure the elongation of the test piece T as compared with the case of measuring the elongation of the test piece T.

Further, in the present embodiment, the marks La and Lb are linear extending in the thickness direction of the test piece T, respectively, and in the reference state of the test piece T, the distance between the marks La and Lb is the length of the test piece T. In the vertical direction, it is 180 mm or more and 220 mm or less, and when the test piece T is pulled in the length direction of the test piece T to break and the test piece T breaks, the distance between the marks La and Lb is 320 mm or less. Therefore, the distance between the marks La and Lb when the test piece T is broken can be accurately measured based on the image or the image of FIG. 9B captured by the cameras 11a and 11b. This improves the measurement accuracy of the elongation of the test piece T.

Further, in the present embodiment, since one camera 11a and 11b are provided for each of the marks La and Lb, the distance between the marks La and Lb when the test piece T breaks is measured more accurately. Can be done. As a result, the measurement accuracy of the elongation of the test piece T is further improved.

Then, in the present embodiment, in addition to the image or video of FIG. 9B captured by the cameras 11a and 11b, the distance between the reference marks BLa and BLb, the distance between the reference marks BLb and BLc, and the image captured by the camera 11a. Based on the correlation between the image or video pixel P and the distance between the reference markers BLd and BLe and the distance between the reference markers BLe and BLf and the pixel P of the image or video captured by the camera 11b. Since the distance between the marks La and Lb when the test piece T is broken is measured, the distance between the marks La and Lb when the test piece T is broken can be measured more accurately. As a result, the measurement accuracy of the elongation of the test piece T is further improved.

Further, in the present embodiment, the distance in the optical axis direction of the camera 11a from the camera 11a to the mark La is the same as the distance in the optical axis direction of the camera 11a from the camera 11a to the reference mark BLa. The distance between the marks La and Lb when the test piece T is broken can be measured more accurately. Similarly, since the distance in the optical axis direction of the camera 11b from the camera 11b to the mark Lb and the distance in the optical axis direction of the camera 11b from the camera 11b to the reference mark BLb are the same, the test piece T is used. The distance between the marks La and Lb at the time of breakage can be measured more accurately. As described above, the measurement accuracy of the elongation of the test piece T is further improved.

Further, in the present embodiment, the surface of the test piece T is subjected to the surface treatment ST, and the test pieces T are marked with the marks La and Lb. Therefore, the image of FIG. 9B captured by the cameras 11a and 11b or It becomes easy to distinguish the landmarks La and Lb based on the image. Thereby, the distance between the marks La and Lb when the test piece T is broken can be measured more accurately. As a result, the measurement accuracy of the elongation of the test piece T is further improved. Since the same applies to the reference marks BLa to BLf of the reference test piece BT, the description thereof will not be repeated here.

Further, since the tensile test device 10 according to the present embodiment further includes a robot 70 for transporting the test piece T, the test piece T can be easily installed in the tensile device 20 by the robot 70. Further, the fragments T ₁ and T ₂ of the test piece T that have been pulled and broken can be easily removed from the tensioning device 20 by the robot 70.

The tensile test device 10 according to the present embodiment further includes a stress measuring device 80, and the stress is predetermined to be higher than the maximum value MV in the stress-strain curve of the test piece T obtained based on the measured value by the stress measuring device 80. Since the ascending speed of the upper gripping mechanism 30 is slowed down from the time point S when the value V becomes smaller, the speeds of the marks La and Lb when the test piece T breaks can be slowed down. This makes it easier to discriminate the marks La and Lb based on the image or video of FIG. 9B captured by the cameras 11a and 11b, so that the distance between the marks La and Lb when the test piece T is broken is further increased. It can be measured accurately. As a result, the measurement accuracy of the elongation of the test piece T is further improved.

Further, the tensile test device 10 according to the present embodiment further includes an impact device 90 that applies an impact to the fragments T ₁ and T ₂ of the test piece T via the upper and lower gripping mechanisms 30 and 40. Here, the tensioning device 20 needs to pull the test piece T with a relatively large force in order to break the test piece T. At this time, the upper and lower parts of the test piece T are not displaced from the gripping position by the upper gripping mechanism 30 and the gripping portion Tc of the test piece T is not displaced from the gripping position by the lower gripping mechanism 40. The gripping mechanisms 30 and 40 need to grip the gripping portions Tb and Tc of the test piece T with a relatively large force.

As described above, the fragment T ₁ of the test piece T after being pulled and broken may be released from the grip by the upper gripping mechanism 30 and then stick to the abutting member 50 of the upper gripping mechanism 30. be. Therefore, for example, when the robot 70 removes the fragment T ₁ from the upper grip mechanism 30, after releasing the grip of the fragment T ₁ by the upper grip mechanism 30 (or after releasing the grip of the fragment T ₁ by the upper grip mechanism 30). ), The fragment T ₁ attached to the contact member 50 of the upper gripping mechanism 30 is grasped by the robot hand 73, the fragment T ₁ is shaken, and the impact device 90 repeats the fragment T ₁ via the upper gripping mechanism 30. By applying _an impact, the fragment T1 can be peeled off from the abutting member 50 of the upper gripping mechanism 30.

(Example of tensile test method for shaped steel)
Finally, an example of a tensile test method for shaped steel will be described with reference to FIG. Here, an example of a tensile test method performed using the above-mentioned tensile test device 10 will be described.

First, step S1 (first step) for preparing the test piece T, the reference test piece BT, the cameras 11a and 11b, the tensioning device 20, the robot 70, and the stress measuring device 80 is performed. At this time, for example, 50 test pieces T and 1 reference test piece BT may be prepared. Further, for example, a sub camera 12, lighting devices 13a, 13b, a table 14, a cross-sectional measuring device 15, distance sensors 18a, 18b, a control device 60, an impact device 90, and the like may be further prepared.

Next, step S2 (sixth step) of attaching the reference marks BLa to BLf to the reference test piece BT is performed. The reference marks BLa to BLf may be attached to the reference test piece BT after the surface of the reference test piece BT is subjected to the surface treatment ST.

Further, step S3 (7th step) of measuring the distance between the reference marks BLa and BLb, the distance between the reference marks BLb and BLc, the distance between the reference marks BLd and BLe, and the distance between the reference marks BLe and BLf is performed. ..

Next, in a state where the reference test piece BT is gripped by the tensioning device 20, the reference marks BLa to BLc are imaged by the camera 11a, and the reference marks BLd to BLf are imaged by the camera 11b in step S4 (8th step). ..

Further, the correlation between the distance between the reference marks BLa and BLb measured in step S3 and the distance between the reference marks BLb and BLc and the pixel P of the image or video image captured by the camera 11a in step S4 is determined. Further, a step of determining the correlation between the distance between the reference marks BLd and BLe measured in step S3 and the distance between the reference marks BLe and BLf and the pixel P of the image or video image captured by the camera 11b in step S4. 5 (9th step) is performed.

Next, step S6 is performed in which the marks La and Lb are attached to two places of the test piece T that are separated from each other in the pulling direction (second step). The marks La and Lb may be attached to the test piece T after the surface of the test piece T is subjected to the surface treatment ST.

Further, step S7 (third step) is performed in which the mark La is imaged by the camera 11a and the test piece T is pulled by the tensioning device 20 to break while the mark Lb is imaged by the camera 11b. At this time, the test piece T may be installed in the tensioning device 20 by the robot 70. Further, before performing step S7, the marking S of the test piece T may be imaged by the sub camera 12. Further, before performing step S7, the thickness and the width of the three points of the test piece T are measured by the cross-section measuring device 15, and if an abnormality is confirmed in the test piece T based on the measured values, the said. The test piece T may be transported to a predetermined place other than the tensioning device 20 so that the test piece T is not subjected to the subsequent processing.

Next, step S8 (fourth step) is performed to measure the distance between the marks La and Lb when the test piece T is broken, based on the images or videos captured by the cameras 11a and 11b in step S7. At this time, even if the distance between the marks La and Lb when the test piece T is broken is measured based on the correlation determined in step S5 in addition to the images or videos captured by the cameras 11a and 11b in step S7. good. Further, in the stress-strain curve of the test piece T, the ascending speed of the upper gripping mechanism 30 is increased from the time point S when the stress becomes smaller than the maximum value MV by a predetermined value V in the region after the stress exceeds the maximum value MV. It may be slowed down (in other words, the relative speeds of the upper and lower gripping mechanisms 30 and 40 may be slowed down).

Finally, step S9 (fifth step) of measuring the elongation of the test piece T based on the distance between the marks La and Lb in the reference state of the test piece T and the distance between the marks La and Lb measured in step S8. I do. The distance between the marks La and Lb in the reference state of the test piece T may be measured based on the image or video of FIG. 9A captured by the cameras 11a and 11b, or the test piece T may be measured. It may be measured in advance when the marks La and Lb are attached. Further, after performing this step S8, the robot 70 may remove the fragment T ₂ of the test piece T from the lower gripping mechanism 40 and remove the fragment T ₁ of the test piece T from the upper gripping mechanism 30. Further, the work of removing the fragments T ₁ and T ₂ by the robot 70 in this way may be assisted by the impact device 90.

By performing the above steps S1 to S9, the elongation of the test piece T can be easily measured. For example, 50 test pieces T are prepared in step S1, and marks La and Lb are attached to each of the 50 test pieces T in step S6. It is possible to efficiently measure the elongation of 50 test pieces T by repeating only steps S7 to S9.

Further, for example, before measuring the elongation of 50 test pieces T (in other words, when the first steps S1 to S6 are performed), after measuring the elongation of 25 test pieces T, and 50 pieces. After all the elongation of the test piece T is measured, the reference mark BLa is imaged by the camera 11a, and the reference mark BLb is imaged by the camera 11b in step S4, and between the reference marks BLa and BLb measured in step S3. Of the distance, the distance between the reference marks BLb and BLc, the distance between the reference marks BLd and BLe, the distance between the reference marks BLe and BLf, and the pixel P of the image or video captured by the cameras 11a and 11b in step S4. Step S5 may be performed to determine the correlation. Thereby, the distance between the marks La and Lb when the test piece T is broken can be measured more accurately. As a result, the measurement accuracy of the elongation of the test piece T is further improved.

(Modification example)
From the above description, many improvements and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description should be construed as an example only and is provided for the purpose of teaching those skilled in the art the best aspects of carrying out the present invention. The details of its structure and / or function can be substantially changed without departing from the spirit of the present invention.

In the above embodiment, a case where the mark La is imaged by the camera 11a and the mark Lb is imaged by the camera 11b has been described (in other words, a case where one camera is provided for each of the two marks will be described. did). However, the present invention is not limited to this case, and the landmarks La and Lb may be imaged by one camera 11a.

In the above embodiment, the case where the lower gripping mechanism 40 is fixed and the upper gripping mechanism 30 is raised to pull and break the test piece T has been described. However, the present invention is not limited to this case, and the upper gripping mechanism 30 may be raised and the lower gripping mechanism 40 may be lowered to pull the test piece T to break it, or the upper gripping mechanism 30 may be broken. Is fixed and the lower gripping mechanism 40 is lowered, so that the test piece T may be pulled and broken.

In the above embodiment, the height positions of the upper and lower gripping mechanisms 30 and 40 are measured by the distance sensors 18a and 18b (and the reflectors 17a and 17b), and the ascending speed of the upper gripping mechanism 30 is measured based on the measured values. The case of controlling is described. However, the present invention is not limited to this case, and for example, when the test piece T is being pulled, the speeds of the landmarks La and Lb are derived from the images or videos captured by the cameras 11a and 11b, and based on the derived speeds. , The ascending speed of the upper gripping mechanism 30 may be controlled. Alternatively, in order to improve the accuracy, the ascending speed of the upper gripping mechanism 30 may be controlled based on both the front stage and the rear stage.

In the above embodiment, the case where the marks La and Lb are linear extending in the thickness direction of the test piece T and the reference marks BLa to BLf are linear extending in the thickness direction of the reference test piece BT has been described. However, the present invention is not limited to this case, and for example, even if the marks La and Lb are linear extending in the width direction of the test piece T and the reference marks BLa to BLf are linear extending in the width direction of the reference test piece BT. good.

In the above embodiment, a case where six reference marks BLa to BLf are attached to the reference test piece BT and the reference marks BLa to BLf are imaged by the cameras 11a and 11b has been described. However, the present invention is not limited to this case, and the reference test piece BT may be provided with at least two reference marks, and each of the at least two reference marks may be imaged by one camera. Alternatively, the at least two reference marks may be imaged by at least one camera.

(summary)
In order to solve the above problems, the structural steel tensile test method according to the embodiment of the present invention comprises the first step of preparing the structural steel test piece and the camera, and the test piece in the tensile direction. The second step of marking two separated places, the third step of pulling and breaking the test piece while taking an image of the two marks with the camera, and the third step of taking an image with the camera in the third step. The fourth step of measuring the distance between the two marks when the test piece is broken and the reference state of the test piece before pulling the test piece in the third step based on the image or video. The present invention is characterized by comprising a fifth step of measuring the elongation of the test piece based on the distance between the two marks in the above two places and the distance between the two marks measured in the fourth step. And.

According to the above configuration, it is possible to measure the distance between two marks when the test piece is broken, based on the image or video image taken by the camera. Then, the elongation of the test piece is increased based on the distance between the two marks in the reference state of the test piece before the test piece is pulled and the distance between the two marks when the test piece is broken. Can be measured. As a result, it becomes possible to easily measure the elongation of the test piece.

The two marks are linear extending in the thickness direction or the width direction of the test piece, respectively, and in the third step, the test piece is pulled in the length direction of the test piece to be broken, and the test piece is broken. In the reference state of the test piece, the distance between the two marks is 180 mm or more and 220 mm or less in the length direction of the test piece, and when the test piece breaks, the distance between the two marks is between the two marks. The distance may be 320 mm or less.

According to the above configuration, the distance between the two marks when the test piece is broken can be accurately measured based on the image or video image captured by the camera. This improves the measurement accuracy of the elongation of the test piece.

In the first step, one camera may be provided for each of the two landmarks.

According to the above configuration, the distance between the two marks when the test piece is broken can be measured more accurately, so that the measurement accuracy of the elongation of the test piece is further improved.

In the first step, a reference test piece of the shaped steel is further prepared separately from the test piece, and before performing the third to fifth steps, reference marks are placed in at least two places of the reference test piece. The sixth step, the seventh step of measuring the distance between the at least two reference marks before the third to the fifth steps, and the third to the fifth steps. In addition, between the 8th step of capturing the image of the at least 2 reference marks by the camera and the at least 2 reference marks measured in the 7th step before performing the 3rd to 5th steps. And the ninth step of determining the correlation between the distance between the at least two reference marks and the image or the pixel of the video based on the image or video captured by the camera in the eighth step. And, in the fourth step, in addition to the image or video captured by the camera in the third step, when the test piece is broken based on the correlation determined in the ninth step. The distance between the two landmarks may be measured.

According to the above configuration, the distance between the two marks when the test piece is broken can be measured more accurately, so that the measurement accuracy of the elongation of the test piece is further improved.

In the third step, the distance from the camera to the mark in the optical axis direction of the camera, and in the seventh step, the distance from the camera to the reference mark in the optical axis direction of the camera. It may be the same.

According to the above configuration, the distance between the two marks when the test piece is broken can be measured more accurately, so that the measurement accuracy of the elongation of the test piece is further improved.

In the second step, the surface of the test piece may be subjected to a base treatment, and then the test piece may be marked at the two locations.

According to the above configuration, the distance between the two marks when the test piece is broken can be measured more accurately, so that the measurement accuracy of the elongation of the test piece is further improved.

In the first step, a tensioning device for pulling and breaking the test piece is further prepared in the third step, and the tensioning device includes a first gripping mechanism for gripping one end of the test piece. It has a second gripping mechanism for gripping the other end of the test piece and a control device for controlling the operation of the first and second gripping mechanisms, and in the third step, the first And even if the test piece is pulled and broken by moving at least one of the first and second gripping mechanisms in the pulling direction while the test piece is gripped by the second gripping mechanism. good.

According to the above configuration, the test piece can be easily pulled and broken.

In the first step, a robot for transporting the test piece may be further prepared, and in the third step, the test piece may be installed in the tension device by the robot.

According to the above configuration, the test piece can be easily installed in the tensioning device by the robot.

In the first step, a stress measuring device for measuring the stress generated in the test piece when the test piece is being pulled by the tension device is further prepared, and in the third step, the control device is said to be the same. In the stress strain curve of the test piece obtained based on the value measured by the stress measuring device, the stress becomes smaller than the maximum value by a predetermined value in the region after the stress exceeds the maximum value. At least one of the first and second gripping mechanisms may be moved in the pulling direction so that the relative speeds of the first and the second gripping mechanism become slower.

According to the above configuration, it becomes easier to distinguish between the two marks based on the image or video captured by the camera, so that the distance between the two marks when the test piece breaks should be measured more accurately. Can be done. As a result, the measurement accuracy of the elongation of the test piece is further improved.

In the first step, in order to remove the fragments of the test piece attached to the first and second gripping mechanisms from the first and second gripping mechanisms after performing the third step, the first step is performed. Further, an impact device for applying an impact to the fragment of the test piece via the first and the second gripping mechanism may be further prepared.

According to the above configuration, when a piece of a test piece that has been pulled and broken is attached to a tensioning device, the piece of the test piece can be easily peeled off from the pulling device.

In order to solve the above-mentioned problems, a tensile test apparatus for performing a tensile test method for any of the above-mentioned shaped steels, and at least the camera for imaging the two marks in the third step. It is characterized by being prepared.

According to the above configuration, it is possible to easily measure the elongation of the test piece.

10 Tensile test device 11a, 11b Camera 20 Tensile device 30 Upper gripping mechanism (first gripping mechanism)
31a, 31b Pair of upper sliding parts 36a, 36b Pair of upper sliding parts 40 Lower gripping mechanism (second gripping mechanism)
41a, 41b Pair of under-sliding parts 46a, 46b Pair of under-sliding parts 60 Control device 70 Robot 80 Stress measuring device 90 Impact device T Test piece T ₁ , T ₂ Fragment La, Lb Marker BT Reference test piece BLa ~ BLf reference mark P pixel

Claims (11)

It is a tensile test method for shaped steel.
The first step of preparing the structural steel test piece and the camera,
Of the test pieces, the second step of marking two places separated in the pulling direction, and
The third step of pulling and breaking the test piece while imaging the two marks with the camera,
Based on the image or video imaged by the camera in the third step, the fourth step of measuring the distance between the two marks when the test piece is broken, and the fourth step.
Based on the distance between the two marks in the reference state of the test piece before pulling the test piece in the third step and the distance between the two marks measured in the fourth step. The fifth step of measuring the elongation of the test piece and
A method for conducting a tensile test on a shaped steel. The two marks are linear extending in the thickness direction or the width direction of the test piece, respectively.
In the third step, the test piece is pulled in the length direction of the test piece to break it.
In the reference state of the test piece, the distance between the two marks is 180 mm or more and 220 mm or less in the length direction of the test piece.
The tensile test method for shaped steel according to claim 1, wherein when the test piece breaks, the distance between the two marks is 320 mm or less. The tensile test method for shaped steel according to claim 1 or 2, wherein in the first step, one camera is provided for each of the two marks. In the first step, a reference test piece of the shaped steel is further prepared separately from the test piece.
Before performing the third to fifth steps, the sixth step of marking at least two reference marks on the reference test piece and the sixth step.
Before performing the third to fifth steps, the seventh step of measuring the distance between the at least two reference marks and the seventh step.
Before performing the third to fifth steps, the eighth step in which the at least two reference marks are imaged by the camera, and
Based on the distance between the at least two reference marks measured in the seventh step and the image or video captured by the camera in the eighth step before performing the third to fifth steps. Further comprising a ninth step of determining the correlation between the distance between the at least two reference marks and the image or the pixel of the video.
In the fourth step, in addition to the image or video captured by the camera in the third step, the two marks when the test piece is broken based on the correlation determined in the ninth step. The tensile test method for shaped steel according to any one of claims 1 to 3, wherein the distance between the sections is measured. In the third step, the distance from the camera to the mark in the optical axis direction of the camera, and in the seventh step, the distance from the camera to the reference mark in the optical axis direction of the camera. The tensile test method for shaped steel according to claim 4, which is the same. The tensile test method for shaped steel according to any one of claims 1 to 5, wherein in the second step, the surface of the test piece is subjected to a base treatment, and then the test piece is marked at the two locations. .. In the first step, a pulling device for pulling and breaking the test piece in the third step is further prepared.
The tensioning device is
A first gripping mechanism for gripping one end of the test piece,
A second gripping mechanism for gripping the other end of the test piece,
It has a control device for controlling the operation of the first and second gripping mechanisms, and has.
In the third step, the test piece is gripped by the first and second gripping mechanisms, and at least one of the first and second gripping mechanisms is moved in the pulling direction. The tensile test method for a shaped steel according to any one of claims 1 to 6, wherein the test piece is pulled to break. In the first step, a robot for transporting the test piece is further prepared.
The tensile test method for shaped steel according to claim 7, wherein in the third step, the test piece is installed in the tensile device by the robot. In the first step, a stress measuring device for measuring the stress generated in the test piece when the test piece is being pulled by the tensioning device is further prepared.
In the third step, the control device has the stress from the maximum value in the region after the stress exceeds the maximum value in the stress-strain curve of the test piece obtained based on the measured value by the stress measuring device. At least one of the first and second gripping mechanisms is moved in the pulling direction so that the relative speeds of the first and second gripping mechanisms become slower from the time when the value becomes smaller by a predetermined value. Item 7. The method for tensile test of shaped steel according to Item 7 or 8. In the first step, in order to remove the fragments of the test piece attached to the first and second gripping mechanisms from the first and second gripping mechanisms after performing the third step, the first step. The tensile test method for shaped steel according to any one of claims 7 to 9, further preparing an impact device for applying an impact to the fragment of the test piece via the first grip mechanism and the second gripping mechanism. A tensile test apparatus for performing the tensile test method for shaped steel according to any one of claims 1 to 10.
A tensile test apparatus comprising at least the camera for imaging the two landmarks in the third step.

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