Concrete tension test equipment
By adopting a TEC module annular heating structure and a layered insulation shell design in the concrete tension testing equipment, the problems of large temperature gradient differences and low thermal efficiency during thermal loading are solved, achieving a more efficient and safer testing environment.
Patent Information
- Application Number
- CN202521900968.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-04
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2035-09-04
AI Technical Summary
Existing concrete tension testing equipment suffers from problems such as large local temperature gradient differences, low thermal efficiency, and harsh working environment during thermal loading.
The ring heating structure composed of multiple TEC modules and the layered insulation shell design, combined with the dynamic sealing connection of metal bellows, achieve precise closed-loop temperature control and rapid cooling, forming a three-level thermal protection system.
It significantly reduces the axial temperature gradient of the thermal expansion rod, improves thermal efficiency, and enhances the safety and comfort of the testing environment.
Smart Images
Figure CN223611286U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to concrete detection technical field especially relates to a concrete tension test equipment. BACKGROUND
[0002] Concrete tension / tension stress strain full curve test is the test method that can reflect the tensile performance of concrete most, and the axial tension stress strain full curve of concrete can be divided into three parts: curve rising section, falling section and gentle part of falling section. The rising section of full curve and peak load can be completed on ordinary material testing machine, and the falling stage of full curve cannot be obtained completely due to the rigidity of testing machine and data acquisition.
[0003] There is a kind of concrete uniaxial tension stress strain full curve test method and testing device, and the test method is: the concrete test piece is pretreated, then is fixed in stress loading device, and starts tension test by thermal loading;The load, deformation displacement and damage change data of test piece are monitored in real time, and the deformation displacement data of test piece before and after peak load are collected by static acquisition and dynamic acquisition mode respectively;After test, the displacement data of test piece before and after damage are spliced with load data, and are processed, and complete stress strain full curve is drawn. Static and dynamic data acquisition mode are used before and after peak stress, which not only can ensure the accuracy and effectiveness of the collected data, but also can avoid the problems of too large data file and complex data processing process, and relatively accurate stress strain full curve can be drawn;
[0004] The above-mentioned disclosed technology realizes the application of thermodynamic principle in concrete tension test for the first time, but there are still some deficiencies in practical application, mainly as follows: it uses electric heating wire winding heating to drive thermal force to make rigid plate expand, the local heat flux density difference of electric heating wire leads to axial temperature gradient>15℃ / cm, and temperature fluctuation amplitude is ±25℃ under open-loop temperature control mode;Moreover, it does not set up heat preservation structure outside, and heat efficiency is only 38%, and 600℃ target temperature needs 210s time consumption;At the same time, it is not protected outside, so that the temperature of working space rises, and the working environment is poor, which is worth improving. UTILITY MODEL CONTENT
[0005] The utility model aims at solving the shortcomings in the prior art, and provides a concrete tension test equipment.
[0006] In order to achieve the above object, the utility model discloses the following technical scheme: a concrete tension test equipment, including lower rigid board, upper rigid board, test piece clamping device, measuring device, cold gas providing device and four groups of thermal expansion rods, the upper rigid board is fixedly connected on the lower rigid board upper wall through four groups of thermal expansion rods, the lower rigid board upper wall and be located between four groups of thermal expansion rods Fixedly connected with lower fixed seat, the lower wall of upper rigid board is connected with upper fixed seat through screw rod screw, the test piece clamping device is arranged between lower fixed seat and upper fixed seat, the thermal expansion rod outer wall of each group is all covered with heat preservation shell, the heat preservation shell inboard wall is provided with a plurality of annular heating structures, each group of annular heating structure is by a plurality of TEC module, the lower rigid board upper wall and be located between heat preservation shell and thermal expansion rod are provided with cage structure, the cage structure is by four groups with the lower rigid board upper wall fixed connection's support rod and a plurality of with support ring fixed connection's support ring, the support ring is covered outside thermal expansion rod, the fixed sleeve is fixedly connected with the inboard wall of support ring, the one end of fixed sleeve is slidably connected with sliding rod towards thermal expansion rod, the one end of sliding rod towards thermal expansion rod is provided with temperature detection structure for detecting the temperature of thermal expansion rod.
[0007] As a further description of the above technical solution:
[0008] The lower end of the heat preservation shell is fixedly connected with the lower rigid plate, and the heat preservation shell is composed of an inner shell, a heat insulation layer and an outer shell distributed in sequence from the inside to the outside.
[0009] As a further description of the above technical solution:
[0010] A plurality of annular heating structures are sequentially distributed along the axial direction of the heat preservation shell.
[0011] As a further description of the above technical solution:
[0012] The temperature detection structure comprises a mounting seat and a thermocouple, the mounting seat is fixedly connected to one end of the sliding rod towards the thermal expansion rod, and the thermocouple is fixedly connected to one end of the mounting seat away from the sliding rod.
[0013] As a further description of the above technical solution:
[0014] The inboard wall of the fixed sleeve is provided with a ceramic metal composite spring, and the sliding rod and the temperature detection structure are pressed against the outer wall of the thermal expansion rod by the ceramic metal composite spring.
[0015] As a further description of the above technical solution:
[0016] The outer wall of the heat preservation shell and close to the upper and lower ends are respectively fixedly connected with a group of pipe joints, and the two groups of pipe joints are connected with the cold gas providing device through the pipeline.
[0017] As a further description of the above technical solutions:
[0018] The upper end of the heat preservation shell is connected with the upper rigid plate through a metal bellows.
[0019] The utility model has the advantages of the following beneficial effects:
[0020] 1. Compared with the prior art, the concrete tension testing equipment adopts an annular heating structure composed of multiple TEC modules and cooperates with a layered heat preservation shell, reduces the axial temperature gradient of the thermal expansion rod through accurate closed-loop temperature control, solves the problem of local overheating caused by the winding of the heating wire, greatly shortens the heating time of the target temperature of 600 DEG C, and significantly improves the thermal efficiency.
[0021] 2. Compared with the prior art, the concrete tension testing equipment is designed by connecting a metal bellows and a three-layer composite heat preservation shell in a dynamic sealing manner, reduces the temperature rise of the working space, avoids the risk of high-temperature scalding, improves the thermal efficiency, and improves the safety of the test environment. BRIEF DESCRIPTION OF DRAWINGS
[0022] Figure 1 The utility model proposes a whole structure schematic diagram of a concrete tension testing equipment;
[0023] Figure 2 The utility model proposes a lower rigid plate, a heat preservation shell, a thermal expansion rod and a cage structure partial section schematic diagram of a concrete tension testing equipment;
[0024] Figure 3 The utility model proposes a cage structure and a thermal expansion rod of a concrete tension testing equipment;
[0025] Figure 4 The utility model proposes a concrete tension testing equipment; Figure 3 The utility model proposes a concrete tension testing equipment;
[0026] LEGEND:
[0027] 1. Lower rigid plate; 2. Upper rigid plate; 3. Lower fixed seat; 4. Upper fixed seat; 5. Screw rod; 6. Heat preservation shell; 601. Inner shell; 602. Heat insulation layer; 603. Outer shell; 7. Metal bellows; 8. Pipe joint; 9. Thermal expansion rod; 10. TEC module; 11. Support rod; 12. Support ring; 13. Fixed sleeve; 14. Sliding rod; 15. Mounting seat; 16. Thermocouple; 17. Ceramic metal composite spring; 18. Electronic micrometer; 19. Displacement sensor. DETAILED DESCRIPTION
[0028] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by the ordinary skilled in the art without creative labor belong to the protection scope of the utility model.
[0029] Referring to Figures 1 to 4 The utility model provides a kind of concrete tension test equipment: including lower rigid plate 1, upper rigid plate 2, test piece clamping device, measuring device, cold gas providing device and four groups of thermal expansion bar 9, upper rigid plate 2 is fixedly connected on the upper wall of lower rigid plate 1 by four groups of thermal expansion bar 9, lower fixed seat 3 is fixedly connected on the upper wall of lower rigid plate 1 and between four groups of thermal expansion bar 9, upper fixed seat 4 is screw-connected on the lower wall of upper rigid plate 2 by screw rod 5, test piece clamping device is arranged between lower fixed seat 3 and upper fixed seat 4, in the embodiment, the clamping and tension test process of concrete test piece are consistent with prior art, concrete test piece is clamped between upper fixed seat 4 and lower fixed seat 3 by test piece clamping device, and the side wall of concrete test piece and close to upper and lower sides are respectively provided with iron plate, measuring device includes displacement sensor 19 and electronic micrometer 18, and displacement sensor 19 and electronic micrometer 18 are all arranged between two groups of iron plates;
[0030] In order to realize the temperature field accurate control of thermal expansion bar 9, the outer wall of each thermal expansion bar 9 is sleeved with a heat preservation shell 6, the lower end of the heat preservation shell 6 is fixedly connected with the lower rigid plate 1, and the heat preservation shell 6 is composed of an inner shell 601, a heat insulation layer 602 and an outer shell 603 distributed in sequence from inside to outside.
[0031] Through the above structure, the inner shell 601 directly bears the high-temperature radiation of the thermal expansion bar 9, the heat insulation layer 602 reduces the axial heat conduction coefficient to 0.02 W / (m·K), and the outer shell 603 provides mechanical protection, forming a three-level thermal protection system, so that the temperature difference of the working section of the thermal expansion bar 9 is controlled within ±3℃, which not only avoids the risk of high-temperature scalding, but also improves the thermal efficiency from 38% to 72%, and completely improves the safety of the test environment.
[0032] In order to cool the thermal expansion bar 9 after tension test and eliminate the end cold bridge effect, one group of pipe joints 8 is fixedly connected to the outer wall of the heat preservation shell 6 and close to the upper and lower ends, and the two groups of pipe joints 8 are connected with the cold gas providing device through pipes.
[0033] The upper pipe joint 8 is used as the cold gas inlet, and the lower pipe joint 8 is used as the gas return port, forming a closed-loop forced convection cooling, which can reduce the temperature of the thermal expansion bar 9 after tension test.
[0034] In order to compensate for the sealing failure caused by the axial expansion of the thermal expansion rod 9, the upper end of the heat preservation shell 6 and the upper rigid plate 2 are connected by a metal bellows 7;
[0035] When the thermal expansion rod 9 is heated and elongated, the metal bellows 7 can be axially elongated by 8mm while maintaining an air tightness of 0.3MPa, preventing heat leakage and causing thermal field disturbance;
[0036] In order to establish an axially programmable temperature gradient, the inner wall of the heat preservation shell 6 is provided with a plurality of annular heating structures, each of which is composed of a plurality of TEC modules 10, and the plurality of annular heating structures are sequentially distributed along the axial direction of the heat preservation shell 6;
[0037] Each independently controlled TEC module 10 can be adjusted within a set temperature range, and the PID algorithm is used to realize a constant temperature accuracy of ±0.5℃ on the surface of the thermal expansion rod 9;
[0038] In order to overcome the temperature measurement error caused by the radial expansion of the thermal expansion rod 9, a cage structure is arranged on the upper wall of the lower rigid plate 1 and between the heat preservation shell 6 and the thermal expansion rod 9, the cage structure is composed of four groups of support rods 11 fixedly connected with the upper wall of the lower rigid plate 1 and a plurality of support rings 12 fixedly connected with the support rods 11, the support rings 12 are sleeved on the outside of the thermal expansion rod 9, the inner wall of the support ring 12 is fixedly connected with a fixing sleeve 13, one end of the fixing sleeve 13 facing the thermal expansion rod 9 is slidably connected with a sliding rod 14, one end of the sliding rod 14 facing the thermal expansion rod 9 is provided with a temperature detection structure for detecting the temperature of the thermal expansion rod 9, the temperature detection structure comprises a mounting seat 15 and a thermocouple 16, the mounting seat 15 is fixedly connected to one end of the sliding rod 14 facing the thermal expansion rod 9, and the thermocouple 16 is fixedly connected to one end of the mounting seat 15 away from the sliding rod 14;
[0039] When the diameter of the thermal expansion rod 9 increases by 0.4mm due to thermal expansion, the sliding rod 14 can smoothly retract along the fixing sleeve 13, ensuring that the thermocouple 16 on the mounting seat 15 always maintains a contact pressure of 5N±0.3N with the surface of the rod body;
[0040] In order to resist contact failure under the condition of rapid cooling and heating, the inner wall of the fixing sleeve 13 is provided with a ceramic metal composite spring 17, and the sliding rod 14 and the temperature detection structure are pressed against the outer wall of the thermal expansion rod 9 through the ceramic metal composite spring 17;
[0041] When the thermal expansion rod 9 experiences rapid cooling at a rate of 300℃ / min, the ceramic metal composite spring 17 can still maintain a constant pressure of 4.8-5.2N, so that the temperature measurement lag time of the thermocouple 16 is stable within 0.8s.
[0042] Working principle: the inner shell 601 directly bears the high temperature radiation of the thermal expansion rod 9, the heat insulation layer 602 reduces the axial heat conduction coefficient to 0.02 W / (m·K), and the outer shell 603 provides mechanical protection, forming a three-level thermal protection system, so that the temperature difference of the working section of the thermal expansion rod 9 is controlled within ±3℃, the outer wall of the heat preservation shell 6 is fixedly connected with a group of pipe joints 8 near the upper and lower ends, and the two groups of pipe joints 8 are connected with the cold gas providing device through pipelines; the upper pipe joint 8 is used as the cold gas inlet, and the lower pipe joint 8 is used as the gas return port, forming a closed loop forced convection cooling, which can reduce the temperature of the thermal expansion rod 9 after the tension test is completed; when the thermal expansion rod 9 is heated and elongated, the metal bellows 7 can be elongated by 8mm in the axial direction, while maintaining the air tightness of 0.3MPa, preventing the heat field disturbance caused by heat leakage; each independently controlled TEC module 10 can be adjusted within the set temperature range, and the PID algorithm is used to realize the constant temperature precision of ±0.5℃ of the surface of the thermal expansion rod 9; when the diameter of the thermal expansion rod 9 increases by 0.4mm due to thermal expansion, the sliding rod 14 can smoothly retract along the fixed sleeve 13, so as to ensure that the thermocouple 16 on the mounting seat 15 always maintains the contact pressure of 5N±0.3N with the surface of the rod body; when the thermal expansion rod 9 experiences rapid cooling at 300℃ / min, the ceramic metal composite spring 17 can still maintain a constant pressure of 4.8-5.2N, so that the temperature measurement lag time of the thermocouple 16 is stabilized within 0.8s.
[0043] Finally, it should be pointed out that: the above only preferred embodiments of the present application, and not for limiting the present application, although the foregoing detailed description of the present application, for the person skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement, within the spirit and principles of the present application, any modification, equivalent replacement, improvement, etc., should be included within the scope of the present application.
Claims
1. A concrete tension testing apparatus, characterized by: The utility model provides a kind of test device for testing the thermal expansion of test piece, including lower rigid plate (1), upper rigid plate (2), test piece clamping device, measuring device, cold gas providing device and four groups of thermal expansion rods (9), the upper rigid plate (2) is fixedly connected on the upper wall of lower rigid plate (1) by four groups of thermal expansion rods (9), the lower fixed base (3) is fixedly connected on the upper wall of lower rigid plate (1) and between four groups of thermal expansion rods (9), the upper fixed base (4) is screwedly connected on the lower wall of upper rigid plate (2) by screw rod (5), the test piece clamping device is arranged between lower fixed base (3) and upper fixed base (4), the thermal expansion rod (9) is provided with the heat preservation shell (6) on the outer wall of each group, and the inner side wall of heat preservation shell (6) is provided with multiple annular heating structures, each group of annular heating structure is composed of multiple TEC modules (10), the cage structure is arranged on the upper wall of lower rigid plate (1) and between heat preservation shell (6) and thermal expansion rod (9), the cage structure is composed of four groups of support rods (11) and multiple support rings (12) fixedly connected with support rod (11), the support ring (12) is sleeved on the outside of thermal expansion rod (9), the fixed sleeve (13) is fixedly connected on the inner side wall of support ring (12), the one end of fixed sleeve (13) towards thermal expansion rod (9) is slidably connected with sliding rod (14), and the temperature detection structure for detecting the temperature of thermal expansion rod (9) is arranged on the one end of sliding rod (14) towards thermal expansion rod (9).
2. A concrete tension testing apparatus as claimed in claim 1, wherein: The lower end of the heat preservation shell (6) is fixedly connected with the lower rigid plate (1), and the heat preservation shell (6) is composed of an inner shell (601), a heat insulation layer (602) and an outer shell (603) distributed in sequence from inside to outside.
3. A concrete tension testing apparatus as claimed in claim 2, wherein: The multiple annular heating structures are sequentially distributed along the axial direction of the heat preservation shell (6).
4. A concrete tension testing apparatus as claimed in claim 3, wherein: The temperature detection structure includes a mounting seat (15) and a thermocouple (16), the mounting seat (15) is fixedly connected to the one end of the sliding rod (14) towards the thermal expansion rod (9), and the thermocouple (16) is fixedly connected to the one end of the mounting seat (15) away from the sliding rod (14).
5. A concrete tension testing apparatus as claimed in claim 4, wherein: The inner side wall of the fixed sleeve (13) is provided with a ceramic metal composite spring (17), and the sliding rod (14) and the temperature detection structure are pressed against the outer wall of the thermal expansion rod (9) through the ceramic metal composite spring (17).
6. A concrete tension testing apparatus as claimed in claim 5, wherein: The outer wall of the heat preservation shell (6) and close to the upper and lower ends are respectively fixedly connected with a group of pipe joints (8), and the two groups of pipe joints (8) are connected with the cold gas providing device through pipelines.
7. A concrete tension testing apparatus as claimed in claim 6, wherein: The upper end of the heat preservation shell (6) and the upper rigid plate (2) are connected through a metal bellows (7).