CN108225899B - Composite material sheet high-temperature tensile test fixture with self-centering function and method - Google Patents
Composite material sheet high-temperature tensile test fixture with self-centering function and method Download PDFInfo
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- CN108225899B CN108225899B CN201810001640.2A CN201810001640A CN108225899B CN 108225899 B CN108225899 B CN 108225899B CN 201810001640 A CN201810001640 A CN 201810001640A CN 108225899 B CN108225899 B CN 108225899B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/04—Chucks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/18—Performing tests at high or low temperatures
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0222—Temperature
- G01N2203/0226—High temperature; Heating means
Abstract
The invention relates to a composite material sheet high-temperature tensile test fixture with a self-centering function and a method thereof, wherein the composite material sheet high-temperature tensile test fixture comprises a hanging connector, a chuck, a connecting rod, a clamping ring, a supporting block and a protective frame; the upper and lower connecting rods are connected with the hanging joints through spherical hinge surfaces, and the two hanging joints are respectively fixed on the upper and lower beams of the testing machine; two supporting blocks are arranged on the front surface and the rear surface of each chuck in the thickness direction of the sample, and can be clamped through clamping rings. The test fixture is connected with the testing machine through the two spherical hinges, and automatic centering of the tensile test can be achieved. Simultaneously, the snap ring can automatic chucking sample under the action of gravity to realize automatically regulated and stabilize the clamp force in the sample temperature rise and fall thickness variation process. In addition, the protective frame is installed before the test is started, so that the upper chuck and the lower chuck can be accurately fixed by the clamp before the clamp is connected to the testing machine, and the thin sample is protected.
Description
Technical Field
The invention relates to a composite material sheet high-temperature tensile test fixture with a self-centering function and a method, belonging to the field of high-temperature tests of composite materials.
Background
The composite material has the advantages of high specific strength and specific stiffness, designable mechanical property and the like, and can be applied to aerospace aircrafts and hot end parts of engines to improve the performance of the engines and reduce the weight of the engines. Composite materials, such as ceramic matrix composites, are often used in high temperature applications to carry loads at high temperatures. Therefore, it is necessary to test the mechanical properties of the composite material at high temperature, and the high-temperature tensile test of the composite material is a necessary experimental means for testing the mechanical properties.
Referring to the high temperature tensile test standard ASTM C1359 for ceramic matrix composites, the contact portion between the fixture and the test specimen must be a flat uniform surface, not a point contact or a line contact, due to the brittleness of the ceramic matrix composite. Clamps can be broadly divided into two broad categories, active clamping interface and passive clamping interface. The clamps that actively grip the interface require mechanical, hydraulic or pneumatic force to grip the sample, and additional devices are required to provide pressure perpendicular to the sample surface, creating friction on the sample-to-clamp interface to grip the sample. The passive clamping interface is a direct mechanical connection for transmitting force to the test piece, such as a shoulder or a bore. For thin sheets, the holes can cause stress concentrations that can cause the sample to fail. In addition, if the holes are bored and fixed by pins, the pins are also easily deformed at high temperatures, resulting in inconvenience in handling.
Disclosure of Invention
The invention provides a composite material sheet high-temperature tensile test fixture with a self-centering function and a method thereof aiming at the defects of the problems, wherein the test fixture comprises a hanging joint 9, a connecting rod 8, a protective frame 7, an upper clamping ring 3, a lower clamping ring 6, an upper supporting block 2, a lower supporting block 5, a chuck 1 and a sample 4;
the hanging joint 9 comprises an upper hanging joint and a lower hanging joint, and the upper hanging joint and the lower hanging joint have the same structure; the hanging part of the upper hanging joint and the lower hanging joint is provided with a concave spherical surface 19, the radius of the spherical surface is determined according to the design load of the clamp, a cooling water nozzle 20 is arranged above the hanging part, and the hanging joint 9 is fixed on the testing machine;
the connecting rods 8 comprise upper connecting rods and lower connecting rods, and the upper connecting rods and the lower connecting rods have the same structure; one end 21 of the connecting rod is a convex spherical surface, the size of the convex spherical surface is the same as the radius of the concave spherical surface 19 of the hanging joint, and the connecting rod 8 and the hanging joint 9 form a spherical hinge connection through the concave spherical surface 19 and the convex spherical surface 21; the other end of the connecting rod is provided with an external thread 22, a pair of wrench operation planes 23 are arranged at positions close to the external thread, the length of the extension section 24 of the connecting rod is determined according to the size of the high-temperature furnace, and the convex spherical surface 21 is required to be ensured outside the high-temperature furnace;
the chuck 1 comprises an upper chuck and a lower chuck, the upper chuck and the lower chuck are identical in structure, an internal threaded hole 25 of the chuck 1 is in screwed connection with an external thread 22 of the connecting rod 8, and the chuck 1 and the connecting rod 8 are split, so that the chuck can be conveniently replaced according to different styles; a chuck positioning plane 11 is arranged right and right of an outer cylindrical surface of the chuck far away from the clamping end;
the upper supporting block 2 comprises an upper supporting block upper part 12 and an upper supporting block lower part 13, the upper supporting block upper part 12 is square, the left end surface and the right end surface are planes, and the left end surface and the right end surface of the upper supporting block lower part 13 are arc surfaces; the lower supporting block 5 comprises a lower supporting block upper part 14 and a lower supporting block lower part 15, the left end surface and the right end surface of the lower supporting block upper part 14 are arc surfaces, the lower supporting block lower part 15 is square, and the left end surface and the right end surface are planes; the upper supporting block 2 and the lower supporting block 5 respectively form an inverted T shape, the two inverted T shapes are in a group, the front surface and the rear surface of the sample 4 are respectively attached, and the left arc end face and the right arc end face are flush with the sample.
Under the loading state of a sample, the upper support block 2 and the lower support block 5 are placed in the chuck interior 16, the cross section shapes of the upper support block 2 and the lower support block 5 are mutually attached to the shape of the chuck interior 16, and the mutual positioning of the support blocks and the chuck is realized; along the thickness direction of the sample, the arc part 13 of the lower part of the upper supporting block is thickened, the square part 15 of the lower part of the lower supporting block is thickened, the thickening mode is gradually thickened from top to bottom according to a fixed angle (the included angle between the recommended sample binding surface of the upper supporting block and the supporting block is 3-6 degrees), and finally a wedge shape with a narrow top and a wide bottom is formed;
the upper snap ring 3 and the lower snap ring 6 are both in an inverted U shape, and the inner surfaces of the inner walls 17 and 18 of the upper snap ring and the lower snap ring are gradually thinned from top to bottom according to the same inclined angle as the lower part 13 of the upper supporting block and the lower part 15 of the lower supporting block; under the state of loading a sample, the inner walls 17 and 18 of the upper snap ring and the lower snap ring respectively press and fix the lower part 13 of the upper supporting block and the lower part 15 of the lower supporting block under the action of gravity; the upper hollow cylindrical parts 27 and 28 of the upper snap ring and the lower snap ring are mutually matched with the outer cylindrical surface 26 below the chuck, so that the mutual positioning of the snap ring and the chuck is realized, and the positioning of the sample in the front-back direction in the chuck is realized by means of the supporting block.
Upper and lower snap ring 3 and 6 can not only be through gravity self-holding sample 4, can also be according to test temperature automatic balance clamp force, and when the temperature of sample 4 and supporting shoe rose, the gross thickness of sample 4 and upper and lower supporting shoe 2 and 5 can increase, and upper and lower snap ring 3 and 6 can be supporting shoe rebound relatively, the automatic balance thickness direction clamp force.
The protective frame 7 is composed of a connecting rod 29, two cross rods 30 with the same structure and a K-shaped hand-screwed nut 31. And the assembled protective frame 7, the upper parts 10a of the protective frame positioning surfaces of the two cross rods and the lower parts 10b of the protective frame positioning surfaces are on the same plane.
The protective frame 7 is arranged on the chuck 1 before the test is started and when the sample is not loaded; the cross bar 30 can be inserted into the chuck 1 by unscrewing the K-hand nut 31, opening the half collar 32 and then locking the K-hand nut 31. The protection frame positioning surface 10 and the chuck positioning plane 11 are mutually matched and positioned, and the circumferential positioning of the upper chuck and the lower chuck is realized by means of the upper part 10a of the protection frame positioning surface and the lower part 10b of the protection frame positioning surface.
The upper and lower chucks 1 and the connecting rod 8 which is fixedly screwed with the chucks 1 form a whole through the installed protective frame 7, the sample 4, the upper and lower supporting blocks 2, 5 and the upper and lower clamping rings 3, 6 are installed under the state, then the whole clamp is installed in the concave spherical surface 19 inside the hanging joint 9 of the testing machine through the convex spherical surface 21 of the connecting rod 8, the beam of the testing machine is lifted, when the upper and lower concave spherical hinges just start to contact, the K-shaped hand is unscrewed from the nut 31, the semi-ring 32 is opened, and the protective frame 7 is taken down. The protective frame is installed on the clamp before the test begins, so that the sample can be protected, after the whole installation of the clamp is completed, the clamp can be integrally moved and installed on the testing machine through the protective frame, and the protective frame is detached again when the test begins, so that the installation accuracy can be guaranteed.
In the test process, even if the upper and lower hanging connectors 9 of the testing machine have deviation in direction and angle, so that the displacement and the force loading are not on the same vertical line, the existence of the spherical hinge surface of the connecting rod can also realize the self-centering of the upper and lower chucks in the test process, and the accuracy of the test result is ensured.
In the composite material high temperature tensile test, the test specimen is in a dumbbell shape and comprises two clamping sections 33, two transition sections 34 and an intermediate gauge length section 35. The left and right end faces of the transition section 34 are circular arc-shaped.
The specific installation method of the clamp comprises the following steps:
1) one of the two upper supporting blocks is arranged in the clamping groove of the upper clamping head, the clamping section of the sample is tightly attached to the upper supporting block, and the other one of the two upper supporting blocks is arranged in the clamping section of the compact sample.
2) The upper clamping ring is sleeved from the upper end of the upper chuck, and the upper supporting block is clamped under the action of gravity to position the sample in the upper chuck.
3) Firstly, the lower clamping ring is sleeved into a sample from the lower end of the sample and is temporarily fixed on the upper chuck, then the lower end of the sample is carefully placed into the lower chuck, the protective frame is arranged on the upper chuck and the lower chuck, and the upper chuck and the lower chuck are positioned.
4) The lower supporting block is arranged in the lower chuck clamping groove from two sides of the sample and is tightly attached to the lower clamping section of the sample, the lower clamping ring arranged before the lower supporting block is released from the position close to the upper chuck, the lower supporting block is clamped under the action of gravity, and the position of the sample in the lower chuck is positioned.
5) The cross beam of the testing machine is properly lowered, the integral upper clamp and the integral lower clamp which are fixed by the protective frame are arranged in the hanging joint of the testing machine, the convex spherical surface of the upper connecting rod is firstly arranged in the concave spherical surface of the upper hanging joint, the lower end of the lower connecting rod is arranged in the lower end of the lower hanging joint, and the cross beam of the testing machine is slowly raised, so that the lower end of the lower connecting rod and the concave spherical surface of the lower hanging joint just start to contact.
6) According to the test requirements, the circumferential positions of the upper clamp and the lower clamp are adjusted integrally, so that one surface of the sample is opposite to the observation lens.
7) And unscrewing K-shaped hand to screw the nut, opening the semi-ring of the cross rod of the protective frame, and taking down the protective frame 7. Ready to begin the test.
The material selected for all parts of the clamp except the sample 4 is high-temperature-resistant high-strength material, can be high-temperature alloy, can also be ceramic material and the like, so that the clamp can meet the high-temperature condition of the test.
The invention has the beneficial effects that:
the extension rod is connected with the testing machine through a spherical hinge, so that automatic centering of the upper clamp and the lower clamp in the process of tensile testing can be realized. The supporting block is additionally arranged in the sample thickness direction, so that the thin plate sample can be effectively prevented from buckling when the sample arc end face is loaded, and the clamping stability is ensured. Simultaneously, the snap ring can realize the effect of automatic chucking sample under the action of gravity to along with the temperature rise, sample and supporting shoe volume expansion, the snap ring can the automatically balanced clamp force. The chuck is connected with the extension rod through threads, so that the chuck can be conveniently replaced according to different sample specifications. In addition, the protective frame is temporarily installed before the test, so that the thin plate sample can be well protected from being damaged in the clamping process.
Drawings
FIG. 1 is a schematic view of a clip assembly.
Fig. 2 is a schematic view of a guard frame rail.
Fig. 3 is a schematic three-dimensional structure of the protective frame.
Fig. 4 and 5 are schematic views of the structure of the chuck.
Fig. 6 is a schematic view of a hanger joint structure.
Fig. 7 is a schematic view of a connecting rod structure.
Fig. 8 is a schematic structural view of the upper support block.
Fig. 9 is a schematic view of the lower support block structure.
Fig. 10, 11 and 12 are schematic diagrams of the upper snap ring structure.
Fig. 13, 14 and 15 are schematic structural diagrams of the upper snap ring.
FIG. 16 is a schematic view of a sample structure.
The numbers in the figures illustrate the following:
a chuck 1; an upper support block 2; an upper snap ring 3; sample 4; a lower support block 5; a lower snap ring 6;
a protective frame 7; a connecting rod 8; hanging a connector 9; a protective frame positioning surface 10; a protective frame positioning surface upper portion 10 a;
a lower part 10b of the positioning surface of the protective frame; a chuck positioning plane 11; an upper support block upper portion 12;
an upper support block lower portion 13; a lower support block upper portion 14; a lower support block lower portion 15; a collet interior 16;
an upper snap ring inner wall 17; a lower snap ring inner wall 18; a concave spherical surface 19; a cooling water nozzle 20; a convex spherical surface 21;
an external thread 22; a wrench operation plane 23; a rod extension section 24; an internally threaded hole 25; an outer cylindrical surface 26;
an upper snap ring hollow cylindrical portion 27; a lower snap ring hollow cylindrical portion 28; a connecting rod 29; a cross bar 30;
a K-hand nut 31; a half ring 32; a clamping section 33; a transition section 34; an intermediate gauge length section 35;
Detailed Description
The invention will be described in further detail with reference to a specific example in the accompanying drawings:
as shown in fig. 1: the utility model provides a anchor clamps for dull and stereotyped high temperature tensile test of combined material, includes that attach fitting 9, extension rod 8, protection frame 7, go up snap ring 3, lower snap ring 6, go up supporting block 2, lower supporting block 5, chuck 1 and sample 4 etc.. The hanging joint 9 is fixed on a testing machine, the connecting rod 8 and the hanging joint 9 form a spherical hinge through concave and convex spherical surfaces 19 and 21 to be connected, the chuck 1 is screwed with an external thread 22 of the connecting rod 8 through a chuck internal thread hole 25, the upper supporting block 2 and the lower supporting block 5 are respectively attached to the surface of the sample 4 and placed inside the chuck 1 and respectively clamped through the upper clamping ring 3 and the lower clamping ring 6, the protective frame 7 is installed on the chuck 1 before the test, the sample is not loaded, and the sample is taken down before the test.
In the composite high temperature tensile test, the shape of the test piece is shown in fig. 16. The coupon is dumbbell shaped and includes two clamping sections 33, a transition section 34 and an intermediate gauge length section 35. The transition section is arc-shaped. For composite samples, the thickness should generally be no less than 3mm, but tensile testing of ultra-thin samples with sample thicknesses ranging from 1mm to 3mm can be performed using the present fixture system. The cross section area of the gauge length section is not too small, and the width of the gauge length section is not less than 10mm according to the precision requirement of a related testing machine. The larger the width of the clamping section is, the larger the bearing area of the arc section is, the more effective the local compression condition can be improved, but the width of the clamping section is recommended to be between 20 and 25mm under the limitation of the size of a high-temperature furnace chamber. When the radius of the circular arc section is too small, the dangerous area of the sample is small, the position is concentrated, the sample is easy to break at the interface, and when the ratio of the radius of the circular arc to the width of the gauge length section is not less than 2.5, the size of the dangerous area gradually tends to be stable, namely the probability of obtaining the expected failure mode is greatly increased. When the length-to-width ratio of the gauge length is not less than 3, the gauge length can obtain uniform stress distribution. When the ratio of the length of the clamping section to the width of the gauge length section is not less than 2, the influence of the length of the clamping section on stress concentration tends to be stable. Therefore, it is recommended that the ratio of the radius of the circular arc to the width of the gauge length is 2.5 or more, and the ratio of the length-to-width ratio of the gauge length to the length of the clamping section to the width of the gauge length is 2.0 or more.
The upper supporting block 2 in fig. 8 and the lower supporting block 5 in fig. 9 are respectively provided with two blocks, one group of the two blocks is respectively attached to the front surface and the rear surface of the sample 4, and the left circular arc end face and the right circular arc end face are flush with the sample. The size of the arc surface of the lower part 13 of the upper support block and the upper part 14 of the lower support block is determined by the transition section 34 of the sample; the length and width of the square parts of the upper support block upper part 12 and the lower support block lower part 15 are respectively about 1mm larger than that of the surface of the clamping section 33 of the sample 4; the inclined surfaces of the thickened parts of the upper and lower supporting blocks 2 and 5 and the angle between the inclined surfaces and the sample binding surface are between 3 and 6 degrees.
Fig. 4 and 5 are schematic views of the structure of the chuck 1, wherein the interior 16 of the chuck conforms to the cross-sectional shapes of the upper support block 2 and the lower support block 5, and the cross-sectional dimensions thereof can be determined by the upper and lower support blocks 2 and 5; the internal thread hole 25 of the chuck is matched with the external thread 22 of the extension rod 8; the chuck 1 sets up chuck location plane 11 at the outer face of cylinder far away from the centre gripping section, and chuck location plane 11 is about 1mm apart from the surface of original face of cylinder.
The upper snap ring 3 in fig. 10, 11 and 12, together with the lower snap ring 6 in fig. 13, 14 and 15, has upper and lower snap ring inner walls 17, 18 respectively pressing and fixing the upper support block lower part 13 and the lower support block lower part 15, upper and lower snap ring upper hollow cylindrical parts 27, 28 fitting with the lower outer cylindrical surface 26 of the chuck, and the upper snap ring hollow cylindrical part 27 and the lower snap ring hollow cylindrical part 28 have different heights, so as to facilitate the upper and lower snap rings to be assembled.
Fig. 7 is a schematic structural view of the extension rod 8, in which the external thread 22 at one end of the extension rod is screwed into the internal thread hole 25 of the chuck, and a pair of wrench operation planes 23 are provided at positions close to the external thread, and the length of the extension section 24 of the extension rod is determined by the size of the high temperature furnace, so as to ensure that the convex spherical surface 21 at the other end of the extension rod is outside the high temperature furnace.
Fig. 6 is a schematic structural diagram of the hanging joint 9, a cooling water nozzle 20 is designed above the hanging joint, a spherical hinge structure is formed by a concave spherical surface 19 of the hanging joint 9 and a convex spherical surface 21 of the connecting rod, and the spherical radius is determined according to the design load of the clamp. Fig. 2 and 3 are schematic structural views of the protective frame 7, which is composed of a connecting rod 29, two cross rods 30 with identical structures and a K-shaped hand nut 31. Before the test is started, the test sample is arranged on the chuck 1 when not being loaded; the cross bar 30 can be inserted into the chuck 1 by unscrewing the K-hand nut 31, opening the half collar 32 and then locking the K-hand nut 31. The upper parts 10a and 10b of the positioning surfaces of the protection frames of the two cross rods 30 are matched with the chuck positioning plane 11, and the circumferential positioning of the upper chuck and the lower chuck can be realized by means of the upper parts 10a and 10b of the positioning surfaces of the protection frames.
The invention has not been described in detail and is within the skill of the art.
The above description is only a partial embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Claims (9)
1. The utility model provides a combined material sheet metal high temperature tensile test anchor clamps with from centering function which characterized in that: the test fixture comprises a hanging joint, a connecting rod, a protective frame, an upper clamping ring, a lower clamping ring, an upper supporting block, a lower supporting block, a chuck and a test sample;
the hanging joints comprise an upper hanging joint and a lower hanging joint, and the upper hanging joint and the lower hanging joint have the same structure; the hanging joint is fixed on the testing machine;
the connecting rods comprise upper connecting rods and lower connecting rods, and the upper connecting rods and the lower connecting rods have the same structure; one end of the connecting rod is a convex spherical surface, the size of the convex spherical surface is the same as the radius of the concave spherical surface of the hanging joint, and the connecting rod and the hanging joint are connected through a spherical hinge formed by the concave spherical surface and the convex spherical surface; the other end of the connecting rod is provided with an external thread, and a pair of wrench operation planes are arranged at the positions close to the external thread; the length of the extension section of the connecting rod is determined according to the size of the high-temperature furnace, and the convex spherical surface is required to be ensured to be outside the high-temperature furnace;
the clamping head comprises an upper clamping head and a lower clamping head, the upper clamping head and the lower clamping head are identical in structure, and an internal threaded hole of the clamping head is connected with an external thread of the connecting rod in a screwing mode; the chuck and the connecting rod are split, so that the chuck can be conveniently replaced according to different styles; a chuck positioning plane is arranged right and right of an outer cylindrical surface of the chuck far away from the clamping end;
the upper supporting block comprises an upper part and a lower part, the upper part of the upper supporting block is square, the left end surface and the right end surface of the upper part of the upper supporting block are planes, and the left end surface and the right end surface of the lower part of the upper supporting block are circular arc surfaces; the lower support block comprises a lower support block upper part and a lower support block lower part, the left end surface and the right end surface of the lower support block upper part are arc surfaces, the lower support block lower part is square, and the left end surface and the right end surface of the lower support block lower part are planes; the upper supporting block and the lower supporting block respectively form an inverted T shape, one group of the upper supporting block and the lower supporting block is attached to the front surface and the rear surface of the sample respectively, and the arc end surfaces of the upper supporting block and the lower supporting block are flush with the sample;
the inner surfaces of the inner walls of the upper snap ring and the lower snap ring are gradually thinned from top to bottom according to the same inclined plane angle with the lower part of the upper supporting block and the lower part of the lower supporting block;
the protective frame consists of a connecting rod, two cross rods with the same structure and a K-shaped hand-screwed nut; the upper parts of the positioning surfaces of the two cross rods and the lower parts of the positioning surfaces of the two cross rods are positioned on the same plane;
under the loading state of a sample, the upper supporting block and the lower supporting block are placed in the chuck, and the cross section shapes of the upper supporting block and the lower supporting block are mutually attached to the inner shape of the chuck, so that the mutual positioning of the supporting block and the chuck is realized; along the thickness direction of the sample, the circular arc part at the lower part of the upper supporting block is thickened, the square part at the lower part of the lower supporting block is thickened, the thickening mode is gradually thickened from top to bottom according to the angle of a fixed inclined plane, and finally a wedge shape with a narrow upper part and a wide lower part is formed; the angle of the inclined plane is 3-6 degrees.
2. The composite material sheet high-temperature tensile test fixture with self-centering function according to claim 1, characterized in that: under the state of loading a sample, the inner walls of the upper snap ring and the lower snap ring respectively press and fix the lower part of the upper supporting block and the lower part of the lower supporting block under the action of gravity; and the hollow cylindrical part at the upper part of the upper snap ring and the hollow cylindrical part at the upper part of the lower snap ring are mutually matched with the outer cylindrical surface below the chuck, so that the mutual positioning of the snap ring and the chuck is realized, and the positioning of the sample in the front-back direction in the chuck is realized by means of the upper support block and the lower support block.
3. The composite material sheet high-temperature tensile test fixture with self-centering function according to claim 1, characterized in that: upper and lower snap ring can not only pass through gravity self-holding sample, can also be according to test temperature automatic balance clamp force, and when the temperature of sample and supporting shoe risees, the gross thickness of sample and upper and lower supporting shoe can increase, and upper and lower snap ring can relative supporting shoe rebound, automatic balance thickness direction clamp force.
4. The composite material sheet high-temperature tensile test fixture with self-centering function according to claim 1, characterized in that: before the test is started, the protective frame is arranged on the chuck when the sample is not loaded; the K-type hand-screwed nut is unscrewed, the semi-ring is opened, the cross rod can be sleeved into the chuck, and then the K-type hand-screwed nut is locked; the protection frame positioning surface and the chuck positioning plane are mutually matched and positioned, and the circumferential positioning of the upper chuck and the lower chuck is realized by means of the upper part of the protection frame positioning surface and the lower part of the protection frame positioning surface.
5. The composite material sheet high-temperature tensile test fixture with self-centering function according to claim 1, characterized in that: the upper and lower chucks and the connecting rod which is fixedly connected with the chucks in a screwing way form a whole through a protective frame which is arranged in the upper and lower chucks, the upper and lower support blocks and the upper and lower clamping rings, then the whole clamp is arranged in a concave spherical surface which is arranged in a hanging joint of a testing machine through the convex spherical surface of the connecting rod, a crossbeam of the testing machine is lifted, when the upper and lower concave spherical hinges just start to contact, a K-shaped hand is unscrewed to screw a nut, a semi-ring is opened, and the protective frame is taken down; the protection frame is installed on anchor clamps before experimental the beginning, protects the sample, accomplishes the back at the whole installation of anchor clamps, through the protection frame with anchor clamps moving as a whole install the testing machine on, when experimental the beginning, tear it down again, can guarantee the accuracy nature of installation.
6. The composite material sheet high-temperature tensile test fixture with self-centering function according to claim 1, characterized in that: in the test process, even if the upper and lower hanger joints of the testing machine have deviations in position and angle, so that the displacement and the force loading are not on the same vertical line, the existence of the spherical hinge surface of the extension rod can also realize the self-centering of the upper and lower chucks in the test process, and the accuracy of the test result is ensured.
7. The composite material sheet high-temperature tensile test fixture with self-centering function according to claim 1, characterized in that: the sample is dumbbell-shaped and comprises two clamping sections, two transition sections and a middle gauge length section; the left and right end surfaces of the transition section are arc-shaped.
8. The composite material sheet high-temperature tensile test fixture with self-centering function according to claim 1, characterized in that: the material selected for all parts of the clamp except the sample is high temperature resistant and high strength material, including high temperature alloy and ceramic material.
9. The method for installing the composite material sheet high-temperature tensile test fixture with the self-centering function according to claim 1, is characterized by comprising the following steps of:
step 1: one of the two upper supporting blocks is arranged in the clamping groove of the upper chuck, the clamping section of the sample is tightly attached to the upper supporting block, and the other one of the two upper supporting blocks is arranged in the clamping section of the compacted sample;
step 2: the upper clamping ring is sleeved from the upper end of the upper chuck, the upper supporting block is clamped under the action of gravity, and the position of the sample in the upper chuck is positioned;
and step 3: firstly, sleeving a sample into a lower clamping ring from the lower end of the sample, temporarily fixing the sample on an upper chuck, then placing the lower end of the sample into the lower chuck, installing a protective frame on the upper chuck and the lower chuck, and positioning the upper chuck and the lower chuck;
and 4, step 4: the lower supporting block is arranged in a lower chuck clamping groove from two sides of the sample and is tightly attached to the lower clamping section of the sample, a lower clamping ring arranged before the lower supporting block is released from a position close to the upper chuck, the lower supporting block is clamped under the action of gravity, and the position of the sample in the lower chuck is positioned;
and 5: lowering the crossbeam of the testing machine, installing the integral upper clamp and the integral lower clamp which are fixed by the protective frame into a hanging joint arranged on the testing machine, firstly installing the convex spherical surface of the upper connecting rod into the concave spherical surface of the upper hanging joint, placing the lower end of the lower connecting rod into the lower end of the lower hanging joint, and slowly raising the crossbeam of the testing machine to ensure that the lower end of the lower connecting rod just begins to contact with the concave spherical surface and the convex spherical surface of the lower hanging joint;
step 6: adjusting the circumferential positions of the upper clamp and the lower clamp integrally to enable one surface of the sample to face the observation lens;
and 7: and unscrewing a K-shaped hand to screw the nut, opening the semi-ring of the cross rod of the protective frame, taking down the protective frame and preparing for starting the test.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810001640.2A CN108225899B (en) | 2018-01-02 | 2018-01-02 | Composite material sheet high-temperature tensile test fixture with self-centering function and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810001640.2A CN108225899B (en) | 2018-01-02 | 2018-01-02 | Composite material sheet high-temperature tensile test fixture with self-centering function and method |
Publications (2)
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| CN110044692A (en) * | 2019-05-22 | 2019-07-23 | 中国民航大学 | A kind of high temperature tension test fixture for fragile material flat test piece |
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| CN112326551B (en) * | 2020-11-13 | 2023-07-18 | 江苏省沙钢钢铁研究院有限公司 | Test method for performance of composite steel plate |
| CN112730090A (en) * | 2020-11-30 | 2021-04-30 | 中国原子能科学研究院 | Metal material high-temperature tensile elongation marking test device and method |
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| CN113984513B (en) * | 2021-10-27 | 2022-08-05 | 北京航空航天大学 | Near-far double-end aligning device |
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| CN2784910Y (en) * | 2005-04-27 | 2006-05-31 | 深圳市新三思材料检测有限公司 | High temperature creep endurance testing machine with protector |
| CN102323140B (en) * | 2011-08-11 | 2014-08-20 | 西北工业大学 | Sample and clamp for thin walled tube high temperature tensile test |
| JP6010733B2 (en) * | 2012-08-31 | 2016-10-19 | 東京瓦斯株式会社 | Plate-shaped specimen evaluation test unit and fixing jig used therefor |
| CN103674693A (en) * | 2013-12-08 | 2014-03-26 | 上海华龙测试仪器股份有限公司 | Clamping die for thin-plate high-temperature tensile test |
| CN205449688U (en) * | 2015-12-30 | 2016-08-10 | 北京汽车研究总院有限公司 | Hose testing experiment equipment |
| CN105651597A (en) * | 2016-04-01 | 2016-06-08 | 中国特种设备检测研究院 | Brittle material tensile test fixture |
| CN106092736A (en) * | 2016-08-01 | 2016-11-09 | 西北工业大学 | A kind of metal plate-like sample Temperature High Cycle Fatigue test fixture |
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