JPH0245800Y2 - - Google Patents

Description

[Detailed explanation of the invention] 3-1 Purpose of the invention The invention relates to a jig for processing a specimen platen, and in particular removes residual stress due to welding before introducing a fatigue notch into a crack opening displacement (COD) specimen. The present invention relates to a jig for performing platen processing for the purpose.

3-1-1 Industrial Application Fields Recently, in the design of large structures made by welding, such as ships, offshore structures, or tanks, in order to increase safety against brittle fracture,
Crack opening displacement based on fracture mechanics
The concept of opening displacement (hereinafter referred to as COD) is beginning to be used. Therefore, it has become necessary to conduct numerous COD tests in order to develop materials and evaluate the brittleness of new products. Additionally, as structures become larger, the size of COD test specimens that require full thickness is also increasing.

Generally, in COD test pieces, it has become common practice to introduce fatigue notches as notches in order to imitate defects caused by fatigue, which are often experienced in failure accidents of actual structures, and it has become common practice to introduce fatigue notches as notches. is often introduced into welds where toughness is generally considered to be poor. However, residual stress exists in the weld, and therefore fatigue notches often cannot be uniformly introduced. Therefore, in order to eliminate the residual stress caused by welding and insert fatigue notches uniformly and evenly, the
Platen processing is performed to give compressive plastic strain of about 0.3 to 1%. The present invention is utilized for such platen processing. The shape of the COD test piece is shown in Figure 3 A and B, where B: plate thickness, W:
The board width (=2B). An enlarged view of the notch portion is shown in FIG. 4, and the tip of the mechanical notch 2 is a fatigue notch 4. FIG. 5 shows a conceptual diagram of platen processing, in which the COD test piece 6 is given compressive plastic strain by an upper chip 8 and a lower chip 10 from above and below.

3-1-2 Prior Art Conventional platen processing will be explained with reference to FIG. That is, using a compression tester or a universal tester, place the lower chip 10 on the crosshead 12, place the COD test piece 6 on top of it, place the upper chip 8 on top of it, and test the column 14, the testing machine frame 16, Platen processing was performed via the load cell 18 and compression member 20. The diameter of the chips 8 and 10 is usually 1/2 of the board thickness.

The conventional platen processing described above has the following problems.

(A) The axes of the upper and lower chips 8 and 10 for platen processing do not match, which is dangerous.

(B) If the thickness of the test piece 6 is 100 mm, the size of the test piece 6 is 100 mm x 200 mm x 1000 mm, and its weight is 160 kg. Such a heavy object with a diameter of 50
It is extremely difficult, dangerous and time consuming to set the platen on a platen with a thickness of 1/2 mm (1/2 of a plate thickness of 100 mm).

(C) Steel plate 22 is attached to the steel plate after welding as shown in Figure 7.
Angular deformation often occurs in the steel plate 22, and the test piece 6 taken from such a steel plate 22 naturally has angular deformation as shown in FIG. For this reason, it is more difficult to align the axes of the upper and lower chips 8, 10, and if platen processing is performed without alignment, an uneven load is applied to the platen, which often results in scattering or destruction of the platen. The compressive load reaches 120 tons for a plate thickness of 100 mm, and uneven loads are extremely dangerous.

3-1-3 Problems to be Solved by the Invention The present invention solves the problems of the prior art described above, and allows the axes of the upper and lower chips 8 and 10 to coincide and to stably set the test specimen 6 that has weight or angular deformation. The purpose of this invention is to provide a platen processing jig that can be used to process a platen.

3-2 Structure of the invention 3-2-1 Means for solving problems The gist of the invention is as follows. That is, in a test piece platen processing jig that applies local compressive plastic strain to a crack opening displacement (COD) test piece through the upper and lower chips, the lower chip attached to the processing bed on the crosshead and the lower chip The upper tip is held movably up and down by a holding member coaxially with the tip, and an elastic member is attached to the processing bed and holds the test piece near both longitudinal ends thereof. This is a unique test piece platen processing jig.

The details of the present invention will be explained with reference to the embodiments illustrated in FIGS. 1A, B, and C. A lower chip 10 is attached to the processing bed 24. Further, the upper tip 8 is held movably up and down by an L-shaped holding member 28 guided by a guide 26 so that its center axis coincides with that of the lower tip 10. Processing bed 24
Two elastic members 30 are attached to the top and hold the COD test piece 6 near both ends in the longitudinal direction. If the height of the elastic member 30 is set several mm higher than the height of the lower chip 10, even the test piece 6 with angular deformation can be stably set. The material of the elastic member 30 is preferably urethane rubber in terms of durability and ease of use.

In addition, in order to set the processing amount to a specified value, it is also necessary to take out the test piece 6 during platen processing, measure the thickness, and then reprocess it. For this reason, it is necessary to repeat the cycle of setting the test piece → platen processing → taking out → thickness measurement. At this time, in order to match the platen processing position, a jig that can set the test piece 6 at the same position as in the previous processing was installed on the processing bed. 24
It is desirable to install it on top.

3-2-2 Operation Next, the operation of the platen processing jig of the present invention having the above-mentioned configuration will be explained. The jig of the present invention is set in a compression testing machine, the upper tip 8 is raised by the holding member 28, and the test piece 6 is placed on the elastic member 30.
If you set it above the upper tip 8 and lower it, the second
Even the test piece 6 having angular deformation as shown in Figures A and B can be stably set. The crosshead 12 is raised to start compression processing, a load is applied to the test piece 6 by the upper tip 8, the elastic member 30 is deformed, and it is not until the test piece 6 comes into contact with the lower tip 10 that the upper and lower tips are applied to the test piece 6. Compression processing according to steps 8 and 10 is performed. Since the upper chip 8 was held by the holding member 28 so as to be coaxial with the lower chip 10, the test piece 6 could always be compressed coaxially.

3-3 Effects of the invention This invention consists of a lower tip attached to the processing bed,
Since it is composed of an upper tip that is held movably up and down by a holding member so as to be coaxial with the lower tip, and an elastic member that holds the test piece, the following effects can be achieved.

(b) It became possible to easily and safely set and process test specimens that were heavy or deformed, and it was possible to prevent the platen from scattering or breaking.

(b) Since the upper and lower chips can always be compressed on the same axis, uniform plastic strain can be applied to the test piece.

(c) Since it is easy to adjust the axes of the upper and lower chips and to set the test piece, the test piece setting time was reduced to about 1/3, and work efficiency was significantly improved.

[Brief explanation of the drawing]

Figures 1A, B, and C all show a platen processing jig according to an embodiment of the present invention, and Figures 2A and 2B are a plan view, a front view, and a side view, respectively. 3A and 3B show the COD test piece, and the top view, side view, and FIG.
Enlarged cross-sectional view showing the notch part of the COD test piece, No. 5
The figure is a perspective view showing the concept of platen processing, Fig. 6 is a front view showing conventional platen processing, Fig. 7 is a perspective view showing a steel plate with angular deformation, and Fig. 8 shows a test piece with angular deformation. FIG. 6... COD test piece, 8... Upper chip, 10...
... lower tip, 12 ... crosshead, 24 ... bed for processing, 26 ... guide, 28 ... holding member, 30 ... elastic member.

Claims (1)

[Scope of utility model registration request] In a specimen platen processing jig that applies local compressive plastic strain to a crack opening displacement (COD) test specimen through upper and lower chips, the lower chip is attached to a processing bed on a crosshead; The upper tip is coaxially held by a holding member such that it can be raised and lowered, and an elastic member is attached to the processing bed and holds the test piece near both longitudinal ends thereof. Jig for processing specimen platen.