CN216594485U - Hoop for increasing opening displacement range of compact tensile test measurement notch - Google Patents
Hoop for increasing opening displacement range of compact tensile test measurement notch Download PDFInfo
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- CN216594485U CN216594485U CN202123127427.2U CN202123127427U CN216594485U CN 216594485 U CN216594485 U CN 216594485U CN 202123127427 U CN202123127427 U CN 202123127427U CN 216594485 U CN216594485 U CN 216594485U
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Abstract
The utility model discloses a hoop for increasing the expansion displacement range of a compact tensile test measurement gap, which is formed by connecting an upper connecting plate, an L-shaped connecting plate and a lower connecting plate to form a semi-enclosed frame, wherein one end of the upper connecting plate is connected with the top of the L-shaped connecting plate, the bottom edge of the L-shaped connecting plate is connected with the top edge of the lower connecting plate, so that the outer side of the joint of the bottom of the L-shaped connecting plate and the lower connecting plate forms a measurement gap, and the inner side forms a stepped notch. According to the utility model, two cuffs are respectively clamped on two sides of the notch position of the compact tensile test piece, so that the problem that in a fracture toughness test, after the COD extensometer reaches the measuring range, the opening displacement of the notch cannot be measured continuously or the opening displacement can only be obtained through fitting according to the relation between the chuck displacement and the opening displacement is solved, the accuracy of obtaining the opening displacement of the notch of the compact tensile test piece is improved in the experimental process and after the COD extensometer reaches the measuring range, and the method is suitable for popularization.
Description
Technical Field
The utility model relates to a hoop for measuring the notch displacement of a test piece in a fracture toughness test, in particular to a hoop for increasing the measurement range of the opening displacement of a notch in a compact tensile test.
Background
Fracture toughness characterizes the ability of a material to prevent crack propagation, and is a quantitative indicator for measuring the toughness of the material. Therefore, the determination of the fracture toughness of the material is of great known significance to engineering. The tests for obtaining the fracture toughness of the material generally comprise a compact tensile test and a three-point bending test, and in the straight-through notch compact tensile test, the opening displacement of a test piece under the action of load in the test process needs to be measured to obtain the fracture toughness of the material. However, the displacement range of the opening of the test piece of the COD extensometer equipped in the MTS testing machine is limited, and when the displacement of the opening of the test piece reaches the range of the COD extensometer, the displacement of the opening of the test piece cannot be obtained, so that the J integral of the second half section cannot be solved.
At present, in a compact tensile test, after COD reaches a measuring range, the method for continuously acquiring the opening displacement of the notch of the test piece is mainly characterized in that origin is used for fitting the opening displacement of the second half-section notch by using the relation between the opening displacement of the notch and the displacement of a chuck of the testing machine measured before the COD does not reach the measuring range, but because the relation between the opening displacement of the notch and the displacement of the chuck is different during loading and unloading, the slope of a straight line is different, and the relation between the opening displacement of the notch and the displacement of the chuck during each unloading is also different, therefore, the opening displacement of the notch obtained by adopting the fitting method cannot truly represent the opening displacement under different load changes in the test.
Therefore, the utility model of a cuff for increasing the measurement range of the opening displacement of the compact tensile test measurement gap is needed to be invented so as to measure the opening displacement of the test piece gap after the COD test piece reaches the measurement range.
Disclosure of Invention
The utility model provides a hoop for increasing the measurement range of the opening displacement of a notch in a compact tensile test, which can continuously measure the opening displacement of the notch of a test piece after a COD extensometer reaches the measurement range in the compact tensile test, thereby being beneficial to obtaining the fracture toughness of the test piece.
In order to achieve the purpose, the utility model adopts the following technical scheme:
increase the cuff that compact tensile test measured breach opened the displacement range, the cuff is connected by upper junction plate, L type connecting plate and lower connecting plate and constitutes half encirclement frame, L type connecting plate top is connected to upper junction plate one end, and L type connecting plate bottom edge is connected with lower connecting plate top edge, makes L type connecting plate bottom and lower connecting plate junction outside form and measures the breach, and the inboard cascaded notch that forms.
Furthermore, the middle part of the measuring gap is also provided with a sharp-angled bulge, and the bottom end of the sharp-angled bulge is parallel to the edge of the bottom of the lower connecting plate.
Further, the height of the inner side between the upper connecting plate and the lower connecting plate is set according to the height of the opening side of the compact tensile test piece notch.
Further, the top edge of the measuring notch is at the same level with the top edge of the lower connecting plate.
Further, the thickness of the lower connecting plate is set according to the opening size of the compact tensile test piece notch.
The cuff for increasing the opening displacement range of the compact tensile test measurement notch has the following advantages:
(1) through respectively clamping two sets of hoops on two sides of the compact tensile test piece notch, the top edge of the measurement notch on each hoop and the edge of the compact tensile test piece notch are kept on the same horizontal plane, the consistency of the measurement position of the COD extensometer and the original measurement position is realized, and the opening displacement of the compact tensile test piece notch can be truly reflected.
(2) Through the close fitting of cuff and compact tensile test piece, can prevent to press from both sides COD extension timing cuff not hard up, lead to the breach displacement that records inaccurate. The lower connecting plates with different thicknesses can be prepared to adapt to compact tensile test piece gaps with different opening degrees, and the opening displacement of the compact tensile test piece gap in the whole test process is obtained.
(3) The hoop is low in cost, simple and convenient to operate, and beneficial to increasing the displacement range of the COD test notch in the fracture toughness test.
Drawings
FIG. 1 is a schematic view of a ferrule of the present invention;
FIG. 2 is a schematic view of FIG. 1 in a test condition measuring the span of the opening displacement of the compact tensile specimen;
in the figure: 1. an upper connecting plate; 2. an L-shaped connecting plate; 3. a lower connecting plate; 4. a compact tensile test piece; 5. a COD extensometer; 6. measuring the gap; 7. the sharp corner is convex; 8. and a data acquisition unit.
Detailed Description
In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the following detailed description of the present invention is made with reference to the accompanying drawings and specific embodiments, and it should be noted that the specific embodiments are not intended to limit the scope of the claims of the present invention.
As shown in fig. 1, the hoop for increasing the expansion displacement range of the compact tensile test measurement notch provided by the embodiment is formed by connecting an upper connecting plate 1, an L-shaped connecting plate 2 and a lower connecting plate 3 to form a semi-enclosed frame, and preferably, the upper connecting plate 1, the L-shaped connecting plate 2 and the lower connecting plate 3 are all made of steel plates. The top of the L-shaped connecting plate 2 is connected with one end of the upper connecting plate 1, the bottom edge of the L-shaped connecting plate 2 is connected with the top edge of the lower connecting plate 3, a measuring notch 6 is formed at the outer side of the joint of the L-shaped connecting plate 2 and the lower connecting plate 3, the top edge of the measuring notch 6 and the top edge of the lower connecting plate 3 are at the same level, and the two hoops are clamped on the two sides of the notch of the compact tensile test piece 4 respectively.
The inner side of the joint of the bottom of the L-shaped connecting plate 2 and the lower connecting plate 3 forms a stepped notch which is used for matching the position of the notch of the compact tensile test piece 4. The height of the inner side between the upper connecting plate 1 and the lower connecting plate 3 is set according to the height of the opening side of the gap of the compact tensile test piece 4. The thickness of the lower connecting plate 3 is set according to the size of the opening of the gap of the compact tensile test piece 4.
The measuring gap 6 is a right-angle gap, the middle part of the right angle of the measuring gap 6 is also provided with a sharp-angled bulge 7, the bottom end of the sharp-angled bulge 7 is parallel to the edge of the bottom of the lower connecting plate 3, the effect of the sharp-angled bulge 7 lies in that the COD extensometer 5 is clamped between the measuring gaps 6 on the two hoops, the two sharp-angled bulges 7 can be respectively abutted against the two sides of the COD extensometer 5, and the non-slip of the COD extensometer 5 is ensured.
During the test, as shown in fig. 2, the surface of the compact tensile test piece 4 and the surface of the hoop are ensured to be free of impurities, the hoops which can be matched with the two sides of the notch of the compact tensile test piece 4 are selected, the two hoops are symmetrically clamped on the two sides of the notch of the compact tensile test piece 4 respectively, the measuring notches 6 of the two hoops are opposite respectively, the top edge of the measuring notch 6 arranged on the upper side of the notch of the compact tensile test piece 4 and the upper side edge of the notch of the compact tensile test piece 4 are on the same horizontal plane, the bottom edge of the measuring notch 6 arranged on the lower side of the notch of the compact tensile test piece 4 and the lower side edge of the notch of the compact tensile test piece 4 are on the same horizontal plane, the distance between the two measuring notches 6 is kept consistent with the distance of the opening displacement of the notch of the compact tensile test piece 4, the COD extensometer 5 is clamped between the measuring notches 6 on the two hoops, so that the two hoops and the compact tensile test piece 4 cannot be loosened, and the position measured by the COD extensometer 5 can be ensured to be unchanged, the COD extensometer 5 is connected to a data collector 8 by a data collection line.
The cuff for increasing the opening displacement range of the compact tensile test measurement notch has the working principle that: after the opening displacement of the notch of the compact tensile test piece 4 reaches the measuring range of the COD extensometer 5, a steel sheet with a certain thickness can be added on the surfaces of the measuring notches 6 on the two hoops, so that the opening displacement of the measuring notches 6 on the two hoops is reduced under the condition that the actual opening displacement of the notch of the compact tensile test piece 4 is not changed, the opening displacement of the notch 6 on the two hoops can be measured by the COD extensometer 5 within the measuring range, at the moment, the output data of the COD extensometer 5 is reset, then the load is continuously loaded and applied, the opening displacement of the notch of the compact tensile test piece 4 is obtained by the COD extensometer 5, finally, the data measured after being reset is superposed to the last value measured by the previous section of data through post-processing, and the obtained value is the actual opening displacement value of the test piece.
Claims (5)
1. The cuff for increasing the opening displacement range of the compact tensile test measurement gap is characterized in that the cuff is formed by connecting an upper connecting plate, an L-shaped connecting plate and a lower connecting plate to form a semi-enclosed frame, one end of the upper connecting plate is connected with the top of the L-shaped connecting plate, the bottom edge of the L-shaped connecting plate is connected with the top edge of the lower connecting plate, so that the outer side of the joint of the bottom of the L-shaped connecting plate and the lower connecting plate forms the measurement gap, and the inner side of the joint forms a stepped notch.
2. The ferrule as in claim 1, wherein the measuring gap is further provided with a pointed protrusion at the middle, the bottom end of the pointed protrusion being parallel to the bottom edge of the lower connecting plate.
3. The ferrule as in claim 1, wherein the inside height between the upper and lower connection plates is set according to the height of the open side of the compact tensile specimen notch.
4. The ferrule as in claim 1, wherein the measuring notch top edge is at the same level as the lower web top edge.
5. The cuff as in claim 1, wherein the thickness of the lower connecting plate is set according to the size of the opening of the compact tensile specimen notch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123127427.2U CN216594485U (en) | 2021-12-13 | 2021-12-13 | Hoop for increasing opening displacement range of compact tensile test measurement notch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202123127427.2U CN216594485U (en) | 2021-12-13 | 2021-12-13 | Hoop for increasing opening displacement range of compact tensile test measurement notch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216594485U true CN216594485U (en) | 2022-05-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202123127427.2U Active CN216594485U (en) | 2021-12-13 | 2021-12-13 | Hoop for increasing opening displacement range of compact tensile test measurement notch |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN216594485U (en) |
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2021
- 2021-12-13 CN CN202123127427.2U patent/CN216594485U/en active Active
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