A fracture test specimen mold with adjustable pre-formed notch position and depth

Abstract

This invention discloses a fracture test specimen mold with adjustable pre-formed notch position and depth. It includes a bottom template and a pair of long-side side templates and a pair of short-side side templates mounted on the bottom template. The bottom template has grooved slide rails on both sides. The long-side side templates are vertically fixed to the bottom template, and the short-side side templates have flanges at both ends. The long-side side templates are connected to the short-side side templates by fasteners. A pair of longitudinal support frames are installed inside the grooved slide rails on both sides of the bottom template. A transverse connecting frame is connected to the top of the pair of longitudinal support frames. A drive screw is connected to the middle of the transverse connecting frame via a nut. A sliding rod is connected to the bottom of the drive screw. The two ends of the sliding rod are embedded in the longitudinal grooves of the pair of longitudinal support frames and can slide up and down along the grooves under the drive of the drive screw. The sliding rod is fixedly connected to a cutting steel plate. This invention solves the problems of low efficiency and large dimensional deviations in traditional methods, enabling rapid, accurate, and flexible adjustment of the pre-formed notch position and depth, significantly improving specimen preparation efficiency and testing accuracy.

Description

Technical Field

[0001] This utility model belongs to the field of mold technology, specifically relating to a fracture test specimen mold with adjustable pre-formed notch position and depth. Background Technology

[0002] In the study of fracture mechanics properties of cement-based materials (such as concrete and cement mortar), pre-notched beam specimens are often used for fracture tests (such as three-point bending tests and antisymmetric four-point shear tests) to determine key fracture parameters of the material. To study the size effect of fracture parameters in different fracture modes (Type I, Type II, and Type I-II composite), it is necessary to repeatedly and precisely adjust the position (e.g., centered or offset) and depth (usually 0.2-0.5 times the specimen height) of the pre-notched beams on the specimen to ensure the accuracy, comparability, and repeatability of the test results. Currently, the main methods for preparing such notched beam specimens include: post-cutting (i.e., using a cutting machine to cut the specimen after casting and curing) and manual prefabrication (i.e., manually fixing a thin metal sheet in a specific position on the mold during casting, and removing it after the specimen hardens to form the notch). These existing methods have significant drawbacks: First, the post-cutting method requires specialized equipment and is inefficient, and it is easy to cause microcracks to propagate in the specimen, resulting in damage to the specimen before loading. Second, the post-cutting method is prone to irregular notch shapes and has poor control over the notch position, width and depth. Third, the manual prefabrication method requires replacing the metal sheet multiple times according to the size of the prefabrication gap, which is inefficient; Fourth, the prefabricated metal sheet is difficult to position accurately, which can easily lead to deviations in the position and depth of the notch or tilting of the notch. Summary of the Invention

[0003] To address the aforementioned problems, this utility model proposes a fracture test specimen mold with adjustable pre-formed notch position and depth. This specialized mold enables rapid, precise, and flexible adjustment of the pre-formed notch position and depth, thereby improving efficiency and accuracy.

[0004] The above objectives are achieved through the following technical solutions: This utility model discloses a fracture test specimen mold with adjustable pre-formed notch position and depth, comprising a bottom template and a pair of long-side side templates and a pair of short-side side templates mounted on the bottom template. The bottom template has grooved slide rails on both sides. The long-side side templates are vertically fixed to the bottom template. The short-side side templates have flange plates at both ends. The long-side side templates and short-side side templates are connected by fasteners. A pair of longitudinal support frames are installed inside the grooved slide rails on both sides of the bottom template. A transverse connecting frame is connected to the top of the pair of longitudinal support frames. A drive screw is connected to the middle of the transverse connecting frame by a nut. A sliding rod is connected to the bottom of the drive screw. The two ends of the sliding rod are embedded in the longitudinal grooves of the pair of longitudinal support frames and can slide up and down along the grooves under the drive of the drive screw. The sliding rod is fixedly connected to the slit steel plate.

[0005] Furthermore, the bottom of the pair of longitudinal support frames has a protrusion, and the support frame is embedded in the grooved slide rail of the bottom template through the protrusion and can slide in the grooved slide rail to adjust the position of the prefabricated notch.

[0006] Furthermore, a pair of longitudinal support frames have circular screw holes on their sides, and the shafts of a pair of positioning screws pass vertically through the screw holes respectively; each positioning screw is connected to a circular steel plate at one end near the long side template, the surface of the circular steel plate is covered with a rubber anti-slip pad, and the other end of the positioning screw has a nut.

[0007] Furthermore, a transverse support frame is provided between the pair of longitudinal support frames, and the transverse support frame has a transverse slot for the cut steel plate to pass through.

[0008] Furthermore, a horizontal positioning ruler is provided on the edge of the grooved slide rail.

[0009] Furthermore, the slit steel plate has a vertical positioning ruler on its side; the slit steel plate is fixed to the slide rod with screws.

[0010] Furthermore, the transverse connecting frame is fixed to the top of a pair of longitudinal support frames by screws.

[0011] Furthermore, the drive screw is hinged to the slide rod via a circular connector at the bottom, and the top of the drive screw has a rotating disk. By rotating the rotating disk, the position of the slide rod and the slit steel plate can be adjusted by moving the drive screw up and down.

[0012] The advantages of this utility model compared to the prior art are: 1. Significantly improved efficiency and flexibility: By sliding the longitudinal support frame to the desired scale position on the horizontal positioning ruler, the position of the pre-made notch can be flexibly adjusted (notch position adjustment), and the positioning screw can be tightened to fix the longitudinal support frame. Then, the cutting steel sheet can be pressed down to the predetermined scale position by adjusting the drive screw (notch depth adjustment). Users can quickly and continuously produce specimens with different notch positions and depths without changing the mold. It is particularly suitable for fracture test studies that require a large number of specimens with different parameters.

[0013] 2. Ensuring extremely high precision and consistency: Adjustment is achieved using positioning rulers with precise scales (horizontal and vertical), completely eliminating random errors caused by manual measurement and fixing. This ensures a high degree of consistency and repeatability in the notch position and depth of multiple specimens from the same batch, as well as specimens from different batches, thereby significantly improving the reliability and comparability of fracture test data.

[0014] 3. Simple operation and reduced costs: The mold has a simple structure, is intuitive and easy to operate, and requires minimal technical skills from operators. One mold can be used for multiple purposes, replacing the traditional solution of preparing multiple fixed molds, thus saving material costs, processing costs, and storage space.

[0015] 4. High practicality and broad application prospects: This mold can be directly adapted to the size of existing standard specimen molds, making it easy to promote. It can be widely used in the research of fracture mechanics properties of cement-based materials in universities, research institutes, quality testing centers, and other institutions, and has high practical value and market prospects. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is a schematic diagram showing the connection between the bottom template and a pair of long side templates of this utility model; Figure 3 This is a schematic diagram of the short side template of this utility model; Figure 4 This is a schematic diagram of the longitudinal support frame and the transverse support frame of this utility model; Figure 5 This is a schematic diagram of the positioning screw of this utility model; Figure 6 This is a schematic diagram of the transverse connecting frame of this utility model; Figure 7 This is a schematic diagram of the slide bar and drive screw of this utility model; Figure 8 This is a schematic diagram of the cutting steel sheet of this utility model; In the diagram: 1. Bottom template; 101. Groove slide rail; 102. Horizontal positioning ruler; 2. Long side template; 201. Fastener; 3. Short side template; 4. Longitudinal support frame; 401. Longitudinal groove; 402. Protrusion; 5. Positioning screw; 501. Positioning screw body; 502. Positioning screw nut; 503. Circular iron piece at the end of the positioning screw; 6. Transverse connecting frame; 601. Transverse slot; 7. Slide rod; 8. Cutting steel plate; 801. Vertical positioning ruler; 802. Cutting steel plate screw; 9. Transverse connecting frame; 901. Transverse connecting frame screw; 10. Drive screw; 1001. Drive screw body; 1002. Hinged connector; 1003. Rotary disk. Detailed Implementation

[0017] To further clarify the present invention, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Example 1: A fracture test specimen mold with adjustable pre-fabricated notch position and depth, see [link / reference] Figures 1 to 8 This includes: Bottom template 1: Bottom template 1 has grooved slide rails 101 on both sides. The bottom template is vertically fixed to a pair of long side templates 2. The long side templates 2 are connected to a pair of short side templates 3 by fasteners 201. The bottom template 1, long side templates 2, and short side templates 3 enclose the space for casting the specimen. After the specimen is cast, the templates can be removed for easy demolding, thereby reducing damage to the specimen during the demolding process.

[0019] A pair of longitudinal support frames (4): The bottom of the longitudinal support frame 4 has a protrusion 402, which is embedded in the grooved slide rail 101 of the bottom template 1. The position of the precast notch is precisely adjusted by sliding in the grooved slide rail and according to the horizontal positioning ruler at the edge of the grooved slide rail. It can produce a center notch beam specimen suitable for type I fracture test or an eccentric notch beam specimen suitable for type I-II composite fracture test.

[0020] A pair of positioning screws 5: The shaft 501 of the positioning screw 5 passes through a circular screw hole on the longitudinal support frame 4. A pair of circular steel plates 502 are provided at the ends of the positioning screws 5. The surface of the circular steel plates 502 is covered with rubber anti-slip pads to increase frictional resistance. The positioning screws 5 have nuts 503. Tightening the positioning screws can fix the position of the longitudinal support frame 4 to prevent displacement during specimen casting.

[0021] A transverse support frame 6 is vertically and fixedly connected to the longitudinal support frame 4. The transverse support frame 6 has a transverse slot 601. The cross-section of the transverse support frame 6 is trapezoidal, and the base area of ​​the transverse support frame 6 is increased to facilitate stable support.

[0022] A sliding rod 7: The two ends of the sliding rod 7 are embedded in the longitudinal grooves 401 of the longitudinal support frame 4, and can slide up and down along the grooves.

[0023] A slit steel plate 8: The slit steel plate 8 has a vertical positioning ruler 801 on its side for precise adjustment of the pre-cast notch size. The slit steel plate 8 is fixed to the slide rod 8 with screws 802. The slit steel plate 8 can be replaced if damaged. The slit steel plate 8 passes through the transverse slot 601 on the transverse support frame 6 to ensure that the slit steel plate can be inserted vertically into the specimen.

[0024] A transverse connecting frame 9: The transverse connecting frame 9 is fixed to the top of the longitudinal support frame 4 by screws 901. The transverse connecting frame 9 can be removed when installing or replacing the cutting steel sheet. A screw hole is opened in the middle of the transverse connecting frame 9.

[0025] A drive screw 10: The shaft 1001 of the drive screw 10 passes through a screw hole in the middle of the transverse connecting frame 9. The drive screw 10 is hinged to the slide bar 8 via a hinged connector 1002 at the bottom. A rotating disk 1003 is located at the top of the drive screw 10. The rotating disk 1003 is removable for easy installation of the drive screw. Rotating the rotating disk 1003 allows the drive screw to be adjusted up and down to adjust the position of the slide bar and the cutting plate according to the initial notch height ratio set in the test. A release agent is applied to the cutting steel sheet.

[0026] During specimen fabrication: Adjust the position of the precast notch according to the longitudinal support frame 4 in the test plan, and tighten the positioning screw 5 to fix the longitudinal support frame 4. Next, adjust the driving screw 10 by rotating the drive screw rotary disk 1003 according to the test plan, thereby adjusting the position of the slide rod 7 and the cutting steel plate 8. Pour cement-based material slurry into the space enclosed by the bottom template 1, the long side template 2 and the short side template (3). After the slurry has initially set, rotate the drive screw rotary disk 1003 to adjust the drive screw 10 upwards, thereby raising the cutting steel plate. Loosen the positioning screw 6 and pull the longitudinal support frame out of the groove slide rail of the bottom template 1. Remove the fasteners between the long side template 2 and the short side template 3, and disassemble the short side template 3. Complete the specimen demolding and curing.

Claims

1. A fracture test specimen mold with adjustable pre-formed notch position and depth, characterized in that: It includes a bottom template (1) and a pair of long side templates (2) and a pair of short side templates (3) mounted on the bottom template (1). The bottom template (1) has grooved slide rails (101) on both sides. The long side templates (2) are vertically fixed to the bottom template (1) and the short side templates (3) have flanges at both ends. The long side templates (2) and the short side templates (3) are connected by fasteners (201). The grooved slide rails (101) on both sides of the bottom template (1) are installed inside. A pair of longitudinal support frames (4) are provided, and a transverse connecting frame (9) is connected to the top of the pair of longitudinal support frames (4). A drive screw (10) is connected to the middle of the transverse connecting frame (9) by a nut. A slide rod (7) is connected to the bottom of the drive screw (10). The two ends of the slide rod (7) are embedded in the longitudinal grooves (401) of the pair of longitudinal support frames (4) and can slide up and down along the grooves under the drive of the drive screw (10). The slide rod (7) is fixedly connected to the slit steel plate (8).

2. The fracture test specimen mold with adjustable pre-formed notch position and depth according to claim 1, characterized in that: The bottom of the pair of longitudinal support frames (4) has a protrusion (402), and the support frame (4) is embedded in the groove slide rail (101) of the bottom template (1) through the protrusion (402) at the bottom and can slide in the groove slide rail to adjust the position of the prefabricated notch.

3. A fracture test specimen mold with adjustable pre-fabricated notch position and depth according to claim 1 or 2, characterized in that: A pair of longitudinal support frames (4) have circular screw holes on their sides, and the rods (501) of a pair of positioning screws (5) pass vertically through the screw holes respectively; each positioning screw (5) has a circular steel plate (502) connected to one end near the long side template (2), the surface of the circular steel plate (502) has a rubber anti-slip pad, and the other end of the positioning screw (5) has a nut (503).

4. A fracture test specimen mold with adjustable pre-fabricated notch position and depth according to claim 1 or 2, characterized in that: A transverse support frame (6) is also provided between the pair of longitudinal support frames (4), and the transverse support frame has a transverse slot (601) for the cut steel plate (8) to pass through.

5. A fracture test specimen mold with adjustable pre-fabricated notch position and depth according to claim 1 or 2, characterized in that: A horizontal positioning ruler (102) is provided on the edge of the groove slide rail (101).

6. A fracture test specimen mold with adjustable pre-formed notch position and depth according to claim 1 or 2, characterized in that: The slit steel plate (8) has a vertical positioning ruler (801) on its side; the slit steel plate (8) is fixed to the slide rod (7) with a cutting steel plate screw (802).

7. A fracture test specimen mold with adjustable pre-fabricated notch position and depth according to claim 1 or 2, characterized in that: The transverse connecting frame (9) is fixed to the top of a pair of longitudinal support frames (4) by transverse connecting frame screws (901).

8. A fracture test specimen mold with adjustable pre-formed notch position and depth according to claim 1 or 2, characterized in that: The drive screw (10) is hinged to the slide rod (7) through the circular connector (1002) at the bottom. The drive screw (10) has a rotating disk (1003) at the top. The position of the slide rod and the cutting steel plate can be adjusted by rotating the rotating disk (1003) up and down.

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