Carbon fiber prepreg lap shear test piece curing clamp capable of regulating and controlling contact surface pressure

Abstract

The invention relates to a carbon fiber prepreg lap shear test piece curing clamp capable of regulating and controlling the pressure of a contact surface, which is characterized by comprising a U-shaped clamp main body, a first clamping seat, a second clamping seat, a third clamping seat, a first clamping assembly and a second clamping assembly, the upper end of the first clamping base and the upper end of the third clamping base are each connected with a first clamping assembly, the left side and the right side of the upper end of the second clamping base are each provided with an L-shaped plate connected with the second clamping base into a whole, and the L-shaped plate, located on the right side, of the second clamping base is connected with a first clamping assembly. The second clamping assembly is arranged at the upper end of the second clamping base and located on the L-shaped plate on the left side. By adopting the structure, the contact pressure of the lap joint interface can be adjusted, so that the pressure of the lap joint surface of the test piece in the lap shear test is equal to the contact pressure of the lap joint interface in the real manufacturing process of a product, and a lap shear strength result tested in the lap shear test is more accurate.

Description

Technical Field

[0001] The invention relates to the technical field of composite material curing fixtures, in particular to a curing fixture required for making a lap shearing fixture using small-tow carbon fiber prepreg yarns. Background Art

[0002] Carbon fiber composites are very popular building materials today. Carbon fiber composites have good mechanical properties, including high specific strength, high tensile strength and delayed local buckling. In addition, good corrosion resistance and durability are excellent properties of carbon fiber composites. Carbon fiber is often used as a structural member or for local reinforcement in civil engineering. Common forms of carbon fiber include carbon fiber cloth, carbon fiber plate, carbon fiber rod, carbon fiber prepreg yarn, etc.

[0003] The interlaminar shear strength of carbon fiber prepreg yarn needs to be measured by lap shear test. The lap shear test is a mechanical test, which is usually used to test the interlaminar shear strength and the bonding strength of materials. It is widely used in composite materials. The lap shear test usually uses two (100±0.25)x(25±0.25)mm 2 The rectangular specimen has an overlap length of 12.5±0.25mm. Since small-tow carbon fiber prepreg yarns are usually slender and narrow strips, it is difficult to make them into the specimen size required in the lap shear test. Therefore, small-tow prepreg yarns have difficulty in specimen preparation in the lap shear test. In addition, in the actual product manufacturing process, the lap interface is not only subject to the bonding force of the resin, but also often accompanied by a certain pressure. The existing lap shear test curing fixture cannot adjust the contact pressure of the lap interface, so the lap shear strength results tested in the lap shear test have certain errors. In summary, in order to solve the above problems, it is particularly important to design a carbon fiber prepreg lap shear specimen curing fixture that can adjust the contact surface pressure. Summary of the invention

[0004] The present invention designs a carbon fiber prepreg lap shear specimen curing fixture with adjustable contact surface pressure to solve the problem of difficulty in sample preparation of small-tow carbon fiber prepreg in lap shear test. The present invention can adjust the carbon fiber prepreg to the required size through the fixture after it is wound to the required thickness. In addition, the present invention also realizes adjustable lap interface contact pressure, so that the lap shear strength is closer to the actual situation.

[0005] In order to solve the above-mentioned technical problems, the present invention provides a carbon fiber prepreg yarn shear specimen curing fixture with adjustable contact surface pressure, characterized in that it includes a U-shaped fixture body, a first clamping seat, a second clamping seat, a third clamping seat, a first clamping assembly and a second clamping assembly, the lower end of the second clamping seat is fixed in the U-shaped fixture body, the first clamping seat and the third clamping seat are respectively arranged on the left and right sides of the second clamping seat, the lower ends of the first clamping seat and the third clamping seat are connected to the U-shaped fixture body through a left and right translation mechanism, the upper ends of the first clamping seat and the third clamping seat are each connected to a first clamping assembly, the left and right sides of the upper end of the second clamping seat are each provided with an L-shaped plate connected thereto, the lower end of the L-shaped plate on the left side of the second clamping seat is flush with the upper end of the L-shaped plate on the right side, the L-shaped plate on the right side of the second clamping seat is connected to a first clamping assembly, and the second clamping assembly is arranged on the upper end of the second clamping seat and the L-shaped plate on the left side.

[0006] Further: the upper ends of the first clamping seat and the third clamping seat are both provided with a first clamping groove, and a second clamping groove is formed between the L-shaped plate located on the right side of the second clamping seat and the right side wall of the second clamping seat, the first clamping assembly is composed of a first rotating rod, a first spiral rod and a first clamping block, one end of the first spiral rod is provided with a first connecting head for connecting the first rotating rod, a first through hole is provided on the first connecting head for the first rotating rod to pass through, the first rotating rod passes through the first connecting head along the first through hole and is movably connected to the first connecting head, one end of the first rotating rod is detachably connected to a limiting nut, the upper ends of the first clamping seat and the third clamping seat and the first connecting head located at The L-shaped plate on the right side of the second clamping seat is provided with a first threaded through hole matching the first screw rod, the first screw rods on the first clamping seat and the third clamping seat extend into the first clamping groove along the first threaded through hole and are connected to the first clamping block, the first screw rod on the L-shaped plate on the right side of the second clamping seat passes through the first threaded through hole and extends into the second clamping groove and is connected to the first clamping block, the first clamping block is movably connected to the first screw rod and its end face on the side away from the first screw rod is set to a wavy curved surface, the bottom surface in the first clamping groove and the right end face of the second clamping seat facing the first clamping block are set to clamping surfaces matching the wavy curved surface.

[0007] Furthermore: a first sliding groove for the first pulley to slide up and down is opened on the side wall of the first clamping groove, the upper end of the first sliding groove is open, and the first clamping block is connected to the first sliding groove through the first pulley.

[0008] Furthermore: the left and right translation mechanism includes a main screw, a rotating joint and a main rotating rod. The main screw is horizontally rotated and connected between the two side walls of the U-shaped clamp body through the rotating joints at both ends. One end of the main screw is connected to the main rotating rod through a rotating joint. A second through hole is opened on the second clamping seat relative to the position of the main screw. The main screw passes through the second clamping seat along the second through hole and is movably connected with the second clamping seat. A third through hole is opened on the first clamping seat and the third clamping seat relative to the position of the main screw. A connecting block is respectively arranged on the left and right sides of the first clamping seat and the third clamping seat relative to the position of the third through hole. A second threaded through hole is opened on the connecting block relative to the position of the main screw, and the connecting block is connected to the main screw through the second threaded through hole.

[0009] Furthermore: a scale structure is horizontally arranged on the inner wall of the U-shaped clamp body below the main screw, and scale indicator blocks are arranged at the bottom of the first clamping seat and the third clamping seat.

[0010] Furthermore: a horizontal slide rail is also provided on the inner wall of the U-shaped clamp body, and the first clamping seat and the third clamping seat are connected to the horizontal slide rail via an I-shaped sliding block provided on the back.

[0011] Furthermore: the second clamping assembly is composed of a contact surface pressure adjustment assembly and a first clamping assembly, wherein the first clamping assembly is installed on an L-shaped plate located on the left side of the second clamping seat, the L-shaped plate is provided with a first threaded through hole matching the first spiral rod, the middle position of the second clamping seat is provided with a third clamping groove, the contact surface pressure adjustment assembly includes a second rotary rod, a second spiral rod, a second clamping pressure block and a micro gravity / pressure sensor, the second rotary rod is movably connected to the upper end of the second spiral rod through a second connecting head, and the top of the second clamping seat is provided with a second threaded through hole matching the first spiral rod. A third threaded through hole matching the second screw rod is provided, the lower end of the second screw rod extends into the third clamping groove along the third threaded through hole and is movably connected to the second clamping block, a groove for placing a micro gravity / pressure sensor is provided at the bottom of the third clamping groove, the micro gravity / pressure sensor is placed in the groove, the second clamping block contacts the micro gravity / pressure sensor in the groove under the cooperation of the second screw rod and the third threaded through hole, the left end face of the second clamping block is also set to a wavy surface, and the second clamping block is clamped by cooperating with the first clamping block on its left side.

[0012] Furthermore: horizontally arranged sliding grooves are provided on the L-shaped plates on the left and right sides of the second clamping seat, and the first clamping block arranged on the second clamping seat is connected to the sliding groove through the second pulley, wherein the sliding groove located on the right L-shaped plate is the second sliding groove, and the sliding groove located on the left L-shaped plate is the third sliding groove, the right end of the second sliding groove is open, and the left end of the third sliding groove is open.

[0013] Furthermore: a fourth vertically arranged slide groove is also provided in the third clamping groove, the second clamping block is connected to the fourth slide groove through a third pulley, and the upper end of the fourth slide groove is open.

[0014] Furthermore: the front end of the groove at the bottom of the third clamping groove is open, and the micro gravity / pressure sensor placed in the groove is sent out from the front end of the groove by a pushing mechanism. The pushing mechanism is composed of a third screw rod, a knob, a sensor groove push block and a fixing nut. A fourth threaded through hole connected to the groove is provided on the back of the second clamping seat, and the fourth threaded through hole matches the third screw rod. The knob is installed at one end of the third screw rod, and the other end of the third screw rod extends into the groove along the fourth threaded through hole and is connected to the sensor groove push block. The sensor groove push block is detachably mounted on the third screw rod through fixing nuts at both ends.

[0015] After adopting the above structure, the beneficial effects of the present invention are as follows:

[0016] 1. The present invention provides a scale structure in the U-shaped clamp body, and accurately controls the translation of the first clamping seat and the third clamping seat through the scale structure, so that the carbon fiber prepreg yarn can be adjusted to the required size through the clamp after being wound to the required thickness.

[0017] 2. The present invention provides a micro gravity / pressure sensor in the groove of the second clamping seat, through which the adjustable contact pressure of the overlapping interface is realized, making the overlapping shear strength closer to the actual situation.

[0018] 3. The clamping interface of the first clamping assembly and the second clamping assembly in the present invention is a wavy curved surface, the purpose of which is to increase the friction and bite force to prevent the prepreg yarn from slipping off the clamping part when the tension is high during the straightening process of the prepreg yarn. This structure increases the practical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0020] Figure 1 It is a three-dimensional structural diagram of the present invention.

[0021] Figure 2 It is the main structural diagram of the present invention.

[0022] Figure 3 It is the structural diagram of the left and right translation mechanism.

[0023] Figure 4 This is a structural diagram of the first clamping assembly.

[0024] Figure 5This is the connection structure diagram of the sensor groove push block.

[0025] Figure 6 It is a structural diagram of the second clamping seat.

[0026] In the figure: 1 is the U-shaped clamp body, 2 is the first clamping seat, 3 is the second clamping seat, 4 is the third clamping seat, 5 is the L-shaped plate, 6 is the first rotating rod, 7 is the first spiral rod, 8 is the first clamping block, 9 is the limiting nut, 10 is the first slide groove, 11 is the main screw rod, 12 is the rotary joint, 13 is the main rotating rod, 14 is the connecting block, 15 is the scale structure, 16 is the scale indicating block, 17 is the horizontal slide rail, 18 is the I-shaped slider, 19 is the second rotating rod, 20 is the second spiral rod, 21 is the second clamping block, 22 is the groove, 23 is the second slide groove, 24 is the third slide groove, 25 is the fourth slide groove, 26 is the third spiral rod, 27 is the knob, 28 is the sensor groove push block, and 29 is the fixing nut. DETAILED DESCRIPTION

[0027] like Figure 1 and Figure 2The carbon fiber prepreg lap shear specimen curing fixture shown in the figure has adjustable contact surface pressure, comprising a U-shaped fixture body 1, a first clamping seat 2, a second clamping seat 3, a third clamping seat 4, a first clamping assembly and a second clamping assembly, the lower end of the second clamping seat is fixed in the U-shaped fixture body, the first clamping seat and the third clamping seat are respectively arranged on the left and right sides of the second clamping seat, the lower ends of the first clamping seat and the third clamping seat are connected to the U-shaped fixture body through a left and right translation mechanism, the upper ends of the first clamping seat and the third clamping seat are each connected to a first clamping assembly, the left and right sides of the upper end of the second clamping seat are each provided with an L-shaped plate 5 connected thereto, the lower end of the L-shaped plate on the left side of the second clamping seat is flush with the upper end of the L-shaped plate on the right side, the L-shaped plate on the right side of the second clamping seat is connected to a first clamping assembly, and the second clamping assembly is arranged on the upper end of the second clamping seat and on the L-shaped plate on the left side. The present invention has a total of four clamping parts for clamping prepreg yarns, wherein the first clamping assembly on the first clamping seat and the first clamping assembly on the right side of the second clamping seat are a group for clamping a piece of prepreg yarn, the first clamping assembly on the left side of the second clamping assembly on the second clamping seat and the first clamping assembly on the third clamping seat are a group for clamping another piece of prepreg yarn, the first clamping assembly on the first clamping seat and the first clamping assembly on the second clamping seat are movable clamping parts, and the second clamping assembly and the first clamping assembly on the second clamping seat are arranged on the upper and lower sides, on the one hand, it can ensure that the lap area of ​​the prepreg yarn is the value specified by the specification; on the other hand, one piece of prepreg yarn is placed on the left and lower side, and the other piece is placed on the right and upper side. Compared with parallel placement, this placement method can prevent the prepreg yarn from being pulled out of the clamping part by tension during the straightening process to a certain extent; the present invention solves the problem of difficulty in sample preparation of small-tow carbon fiber prepreg yarn in the lap shear test by adopting the above structure.

[0028] like Figure 4The upper ends of the first clamping seat and the third clamping seat shown are both provided with a first clamping groove, and a second clamping groove is formed between the L-shaped plate located on the right side of the second clamping seat and the right side wall of the second clamping seat. The first clamping assembly is composed of a first rotating rod 6, a first spiral rod 7 and a first clamping block 8. One end of the first spiral rod is provided with a first connecting head for connecting the first rotating rod, and a first through hole is provided on the first connecting head for the first rotating rod to pass through. The first rotating rod passes through the first connecting head along the first through hole and is movably connected to the first connecting head. One end of the first rotating rod is detachably connected to a limiting nut 9. The upper ends of the first clamping seat and the third clamping seat and the first connecting head located at The L-shaped plate on the right side of the second clamping seat is provided with a first threaded through hole matching the first screw rod, the first screw rods on the first clamping seat and the third clamping seat extend into the first clamping groove along the first threaded through hole and are connected to the first clamping block, the first screw rod on the L-shaped plate on the right side of the second clamping seat extends into the second clamping groove through the first threaded through hole and is connected to the first clamping block, the first clamping block is movably connected to the first screw rod and the end face of the side away from the first screw rod is set as a wavy curved surface, the bottom surface in the first clamping groove and the right end face of the second clamping seat facing the first clamping block are both set as clamping surfaces matching the wavy curved surface. The present invention controls the lifting and lowering of the first screw rod by rotating the first rotary rod to give the first clamping block a certain clamping pressure; and the first rotary rod can slide along the first through hole to avoid too small a spacing and prevent the first rotary rod from colliding with other structures.

[0029] like Figure 4 The side wall of the first clamping groove is provided with a first slide groove 10 for the first pulley to slide up and down, the upper end of the first slide groove is open, and the first clamping block is connected to the first slide groove through the first pulley. The present invention adopts this structure to prevent the first clamping block from detaching from the clamping seat and to enable it to move up and down along the first slide groove.

[0030] like Figure 1 , Figure 2 , Figure 3 and Figure 4The left-right translation mechanism shown includes a main screw 11, a rotary joint 12 and a main rotating rod 13. The main screw is horizontally rotatably connected between the two side walls of the U-shaped clamp body through the rotary joints at both ends. One end of the main screw is connected to the main rotating rod through the rotary joint. A second through hole is provided on the second clamping seat relative to the position of the main screw. The main screw passes through the second clamping seat along the second through hole and is movably connected with the second clamping seat. A third through hole is provided on the first clamping seat and the third clamping seat relative to the position of the main screw. A connecting block 14 is respectively provided on the left and right sides of the first clamping seat and the third clamping seat relative to the position of the third through hole. A second threaded through hole is provided on the connecting block relative to the position of the main screw, and the connecting block is connected to the main screw through the second threaded through hole. A scale structure 15 is horizontally provided on the inner wall of the U-shaped clamp body below the main screw, and a scale indicator block 16 is provided at the bottom of the first clamping seat and the third clamping seat. The left and right threads on the main screw are opposite. When the main screw rotates, the first clamping seat and the third clamping seat move in opposite directions to achieve the purpose of tightening the prepreg yarn. At the same time, the scale indicator blocks at the bottom of the first clamping seat and the third clamping seat are used in conjunction with the scale structure to ensure that the test piece reaches the length specified in the specification. By adopting this structure, the carbon fiber prepreg yarn can be adjusted to the required size through the clamp after being wound to the required thickness, thereby increasing practical performance.

[0031] like Figure 3 and Figure 4 The inner wall of the U-shaped clamp body is provided with a horizontal slide rail 17, and the first clamping seat and the third clamping seat are connected to the horizontal slide rail through an I-shaped slide block 18 provided on the back. The I-shaped slide block is connected to the horizontal slide rail to ensure that the first clamping seat and the third clamping seat do not rotate during the left and right movement, and only perform left and right translation movement.

[0032] like Figure 2 and Figure 6The second clamping assembly shown is composed of a contact surface pressure adjustment assembly and a first clamping assembly, wherein the first clamping assembly is installed on an L-shaped plate located on the left side of the second clamping seat, the L-shaped plate is provided with a first threaded through hole matching the first screw rod, the middle position of the second clamping seat is provided with a third clamping groove, the contact surface pressure adjustment assembly includes a second rotary rod 19, a second screw rod 20, a second clamping pressure block 21 and a micro gravity / pressure sensor, the second rotary rod is movably connected to the upper end of the second screw rod through a second connector, and the top of the second clamping seat is provided with a There is a third threaded through hole matching the second screw rod, the lower end of the second screw rod extends into the third clamping groove along the third threaded through hole and is movably connected to the second clamping block, and a groove 22 for placing a micro gravity / pressure sensor is opened at the bottom of the third clamping groove. The micro gravity / pressure sensor is placed in the groove, and the second clamping block contacts the micro gravity / pressure sensor in the groove under the cooperation of the second screw rod and the third threaded through hole. The left end face of the second clamping block is also set to a wavy surface, and the second clamping block is clamped by cooperating with the first clamping block on its left side.

[0033] like Figure 2 and Figure 6 The L-shaped plates on the left and right sides of the second clamping seat are shown to be provided with horizontally arranged sliding grooves, and the first clamping pressure block arranged on the second clamping seat is connected to the sliding groove through the second pulley, wherein the sliding groove located on the right L-shaped plate is the second sliding groove 23, and the sliding groove located on the left L-shaped plate is the third sliding groove 24, the right end of the second sliding groove is open, and the left end of the third sliding groove is open, and the third clamping groove is also provided with a vertically arranged fourth sliding groove 25, the second clamping pressure block is connected to the fourth sliding groove through the third pulley, and the upper end of the fourth sliding groove is open.

[0034] like Figure 2 , Figure 5 and Figure 6The front end of the groove at the bottom of the third clamping groove shown is open, and the micro gravity / pressure sensor placed in the groove is sent out from the front end of the groove by a pushing mechanism. The pushing mechanism is composed of a third screw rod 26, a knob 27, a sensor groove push block 28 and a fixing nut 29. The back of the second clamping seat is provided with a fourth threaded through hole connected to the groove, and the fourth threaded through hole matches the third screw rod. The knob is installed at one end of the third screw rod, and the other end of the third screw rod extends into the groove along the fourth threaded through hole and is connected to the sensor groove push block. The sensor groove push block is detachably mounted on the third screw rod through the fixing nuts at both ends. The third clamping groove on the second clamping seat is used as the prepreg overlap part. The groove inside is used to place the micro gravity / pressure sensor. When the second rotary rod rotates to move the second screw downward, pressure can be applied. The contact pressure of the overlap interface can be controlled according to the value displayed by the sensor. When the required pressure is reached, the sensor groove push block in the groove can be pushed outward by rotating the knob on the rear side to form a complete plane below the overlap interface, so as to achieve uniform pressure on the overlap interface and prevent damage to the micro gravity / pressure sensor during the curing process. Since the overlap area specified in the specification is small, it is usually (12.5±0.25)x(25±0.25)mm 2 Therefore, a micro gravity / pressure sensor with a diameter of ≤1 cm is used here. The groove is designed based on a micro gravity / pressure sensor with a diameter of 1 cm and a thickness of 8 mm. The size of this groove can be adjusted according to the size of the sensor. The present invention uses the above structure to achieve the effect of adjustable lap interface contact pressure, making the lap shear strength closer to the actual situation.

[0035] The use steps of the present invention are specifically as follows:

[0036] 1) Use a winding machine to wind the prepreg yarn into a sheet of a certain thickness, and cut two pieces for use;

[0037] 2) Move the clamping parts on the left and right sides to a size slightly smaller than that specified in the specification (100±0.25mm), clamp one of the prepreg yarn sheets on the first clamping assembly on the first clamping seat and the first clamping assembly on the right side of the second clamping seat, and clamp the other sheet on the first clamping assembly on the left side of the second clamping assembly on the second clamping seat and the first clamping assembly on the third clamping seat;

[0038] 3) Rotate the main screw to move the first and third clamping seats on the left and right sides outward to tighten the prepreg yarn sheet, and make the length reach 100±0.25mm according to the scale indicator blocks under the first and third clamping seats;

[0039] 4) Place the micro gravity / pressure sensor in the groove, rotate the second rotary rod above the second clamping seat to increase the pressure of the overlapping interface, and according to the reading on the display of the micro gravity / pressure sensor, make the pressure reach the required value, and stop rotating and pressurizing; at this time, rotate the knob to push out the micro gravity / pressure sensor by pushing out the sensor groove push block, and the sensor groove push block in the groove will fill the groove area, so that the pressure of the overlapping part remains unchanged and the pressure value is uniform;

[0040] 5) The prepreg yarn sheet clamped by the clamp is solidified. After solidification, the rotary rods are rotated to unload the force to remove the clamp, and the wavy clamping part is cut off with a cutting machine to obtain the test piece required for the lap shear test.

[0041] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A carbon fiber prepreg shear specimen curing fixture capable of adjusting contact surface pressure, characterized in that: The invention comprises a U-shaped clamp body (1), a first clamping seat (2), a second clamping seat (3), a third clamping seat (4), a first clamping assembly and a second clamping assembly, wherein the lower end of the second clamping seat is fixed in the U-shaped clamp body, the first clamping seat and the third clamping seat are respectively arranged on the left and right sides of the second clamping seat, the lower ends of the first clamping seat and the third clamping seat are connected to the U-shaped clamp body through a left-right translation mechanism, the upper ends of the first clamping seat and the third clamping seat are respectively connected to a first clamping assembly, the left and right sides of the upper end of the second clamping seat are respectively arranged with an L-shaped plate (5) connected thereto, the lower end of the L-shaped plate on the left side of the second clamping seat is flush with the upper end of the L-shaped plate on the right side, the L-shaped plate on the right side of the second clamping seat is connected with a first clamping assembly, and the second clamping assembly is arranged on the upper end of the second clamping seat and the L-shaped plate on the left side.

2. A carbon fiber prepreg lap shear specimen curing fixture capable of adjusting contact surface pressure according to claim 1, characterized in that: The upper ends of the first clamping seat and the third clamping seat are both provided with a first clamping groove, and a second clamping groove is formed between the L-shaped plate located on the right side of the second clamping seat and the right side wall of the second clamping seat. The first clamping assembly is composed of a first rotating rod (6), a first spiral rod (7) and a first clamping pressure block (8). One end of the first spiral rod is provided with a first connecting head for connecting the first rotating rod, and a first through hole is provided on the first connecting head for the first rotating rod to pass through. The first rotating rod passes through the first connecting head along the first through hole and is movably connected to the first connecting head. One end of the first rotating rod is detachably connected to a limiting nut (9). The upper ends of the first clamping seat and the third clamping seat The first clamping block is connected to the L-shaped plate on the right side of the second clamping seat, and the first clamping block is connected to the first clamping block through the first threaded through hole. The first clamping block is movably connected to the first screw rod and the end face of the side away from the first screw rod is set to a wavy curved surface. The bottom surface in the first clamping groove and the right end face of the second clamping seat facing the first clamping block are set to clamping surfaces matching the wavy curved surface.

3. A carbon fiber prepreg lap shear specimen curing fixture capable of adjusting contact surface pressure according to claim 2, characterized in that: A first slide groove (10) for the first pulley to slide up and down is provided on the side wall of the first clamping groove, the upper end of the first slide groove is open, and the first clamping pressure block is connected to the first slide groove through the first pulley.

4. The carbon fiber prepreg lap shear specimen curing fixture with adjustable contact surface pressure according to claim 1, characterized in that: The left-right translation mechanism comprises a main screw (11), a rotary joint (12) and a main rotating rod (13); the main screw is horizontally rotatably connected between the two side walls of the U-shaped clamp body through the rotary joints at both ends; one end of the main screw is connected to the main rotating rod through the rotary joint; a second through hole is provided on the second clamping seat relative to the position of the main screw; the main screw passes through the second clamping seat along the second through hole and is movably connected thereto; a third through hole is provided on the first clamping seat and the third clamping seat relative to the position of the main screw; a connecting block (14) is respectively provided on the left and right sides of the first clamping seat and the third clamping seat relative to the position of the third through hole; a second threaded through hole is provided on the connecting block relative to the position of the main screw; the connecting block is connected to the main screw through the second threaded through hole.

5. A carbon fiber prepreg lap shear specimen curing fixture capable of adjusting contact surface pressure according to claim 4, characterized in that: A scale structure (15) is horizontally arranged on the inner wall of the U-shaped clamp body below the main screw, and scale indicating blocks (16) are arranged at the bottom of the first clamping seat and the third clamping seat.

6. The carbon fiber prepreg lap shear specimen curing fixture with adjustable contact surface pressure according to claim 1, characterized in that: A horizontal slide rail (17) is also provided on the inner wall of the U-shaped clamp body, and the first clamping seat and the third clamping seat are connected to the horizontal slide rail via an I-shaped slide block (18) provided on the back.

7. The carbon fiber prepreg lap shear specimen curing fixture capable of adjusting contact surface pressure according to claim 1, characterized in that: The second clamping assembly is composed of a contact surface pressure adjustment assembly and a first clamping assembly, wherein the first clamping assembly is installed on an L-shaped plate located on the left side of the second clamping seat, the L-shaped plate is provided with a first threaded through hole matching the first screw rod, the middle position of the second clamping seat is provided with a third clamping groove, the contact surface pressure adjustment assembly includes a second rotary rod (19), a second screw rod (20), a second clamping pressure block (21) and a micro gravity / pressure sensor, the second rotary rod is movably connected to the upper end of the second screw rod through a second connector, and the top of the second clamping seat A third threaded through hole matching the second screw rod is provided, the lower end of the second screw rod extends into the third clamping groove along the third threaded through hole and is movably connected to the second clamping block, a groove (22) for placing a micro gravity / pressure sensor is provided at the bottom of the third clamping groove, the micro gravity / pressure sensor is placed in the groove, the second clamping block contacts the micro gravity / pressure sensor in the groove under the cooperation of the second screw rod and the third threaded through hole, the left end face of the second clamping block is also set as a wavy curved surface, and the second clamping block is clamped by cooperating with the first clamping block on its left side.

8. A carbon fiber prepreg lap shear specimen curing fixture capable of adjusting contact surface pressure according to any one of claims 2 or 7, characterized in that: The L-shaped plates on the left and right sides of the second clamping seat are provided with horizontally arranged sliding grooves, and the first clamping pressure block arranged on the second clamping seat is connected to the sliding groove through the second pulley, wherein the sliding groove located on the right L-shaped plate is the second sliding groove (23), and the sliding groove located on the left L-shaped plate is the third sliding groove (24), the right end of the second sliding groove is open, and the left end of the third sliding groove is open.

9. The carbon fiber prepreg lap shear specimen curing fixture capable of adjusting contact surface pressure according to claim 7, characterized in that: A fourth sliding groove (25) is vertically arranged in the third clamping groove, and the second clamping pressure block is connected to the fourth sliding groove through the third pulley, and the upper end of the fourth sliding groove is open.

10. The carbon fiber prepreg lap shear specimen curing fixture capable of adjusting contact surface pressure according to claim 7, characterized in that: The front end of the groove at the bottom of the third clamping groove is open, and the micro gravity / pressure sensor placed in the groove is sent out from the front end of the groove by a pushing mechanism. The pushing mechanism is composed of a third screw rod (26), a knob (27), a sensor groove push block (28) and a fixing nut (29). The back of the second clamping seat is provided with a fourth threaded through hole connected to the groove, and the fourth threaded through hole matches the third screw rod. The knob is installed at one end of the third screw rod, and the other end of the third screw rod extends into the groove along the fourth threaded through hole and is connected to the sensor groove push block. The sensor groove push block is detachably installed on the third screw rod through the fixing nuts at both ends.

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