Hexagonal segment model test system

Abstract

The invention provides a hexagonal segment model test system, and belongs to the technical field of tunnel engineering model tests. The system comprises a test base, a model duct piece and a loading and monitoring assembly, a fixed support column group and a counter-force support column group are arranged above the test base, the fixed support column group is used for fixing the model duct piece, and the counter-force support column group is used for providing counter-force support; the loading and monitoring assembly is composed of a movable supporting column set, a multi-stage loading module and a monitoring control module, the movable supporting column set moves in the radial direction of the model segment to be matched with loading, the multi-stage loading module is used for achieving loading of different loads, and the monitoring control module is used for monitoring data and controlling the loading process. The problems that an existing hexagonal duct piece model test system is single in loading mode, poor in reaction frame supporting column fixity, disturbed in load transmission precision, difficult to simulate the multi-factor synergistic effect, incomplete in monitoring control and the like are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel engineering model tests, and particularly to a hexagonal segment model test system. Background Art

[0002] In the field of tunnel engineering construction, hexagonal segments are widely used in tunnel lining structures due to their good spatial adaptability and mechanical properties. Accurately determining the mechanical properties of hexagonal segments is crucial for ensuring the long-term stability and safe operation of tunnels. Therefore, a reliable model test system is essential. However, there are many problems that cannot be ignored in the existing hexagonal segment model test technologies.

[0003] For example, under actual working conditions, the loads borne by hexagonal segments are complex and diverse, including circumferentially distributed earth pressure, water pressure, as well as concentrated forces and bending moments generated by changes in geological conditions, construction disturbances, etc. However, the loading function of the existing test systems is limited, and it is difficult to simultaneously simulate the combined action of multiple loads. Even if multiple loads can be applied, it is difficult to guarantee the loading accuracy. For example, when simulating circumferential uniform loads, the uniformity of the load distribution cannot meet the actual requirements, resulting in the test results being unable to accurately reflect the mechanical behavior of the segments in the real environment.

[0004] Secondly, the structural design of the test device is not reasonable enough, and the stability of the reaction support system is insufficient. During the loading process, the reaction frame struts are prone to displacement and deformation, affecting the loading effect and test accuracy. Moreover, the mutual interference between components during the loading process is serious. For example, when the struts move, they will generate friction with the loading auxiliary components, interfering with the load transfer path, making the actual force on the segments inconsistent with the expected loading, and increasing the test error.

[0005] In addition, the limitations of the monitoring means are also relatively prominent. During the test process, the monitoring of key data such as the deformation, stress and strain distribution of the segments is not comprehensive and real-time enough. Most existing systems can only arrange sensors at limited positions, making it difficult to obtain the overall mechanical response of the segments, which makes the evaluation of the segment performance one-sided and unable to detect potential safety hazards in a timely manner.

[0006] Therefore, the existing test systems have a single loading method and are difficult to simultaneously apply circumferential uniform loads and orthogonal concentrated forces, resulting in the inability to simulate the soil-water pressure coupling effect in actual working conditions. The fixing property of the reaction frame struts is poor, and it cannot adapt to the different requirements of integral ring loading and joint loading. During the loading process, the movement of the struts is prone to friction with the hoop welding wires, affecting the load transfer accuracy and causing great interference. At the same time, the existing test systems lack effective simulation means for the combined action of multiple factors such as tunnel burial depth, water head height, and lateral pressure coefficient. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a hexagonal segment model test system, which solves the problems of single loading method, poor fixity of the reaction frame struts, interference with the load transfer accuracy, difficulty in simulating the synergistic action of multiple factors, and imperfect monitoring and control in the existing hexagonal segment model test system.

[0008] To achieve the above object, the present invention provides the following solution:

[0009] A hexagonal segment model test system, comprising a test base, a model segment, and a loading and monitoring assembly. Above the test base, there are respectively provided a fixed strut group and a reaction strut group. The fixed strut group is used to fix the model segment, and the reaction strut group is used to provide reaction support. The loading and monitoring assembly is composed of a moving strut group, a multi-stage loading module, and a monitoring and control module. The moving strut group moves along the radial direction of the model segment to cooperate with the loading. The multi-stage loading module is used to achieve the loading of different loads, and the monitoring and control module is used to monitor data and control the loading process.

[0010] Preferably, the fixed strut group includes a main anchoring strut and a segment positioning strut group. The main anchoring strut and the segment positioning strut group are respectively welded above the test base, and the main anchoring strut is connected to an external anchor pull-out tester.

[0011] Preferably, the segment positioning strut group includes a first segment positioning strut and a second segment positioning strut. The first segment positioning strut and the second segment positioning strut are used to stabilize the model segment, and the first segment positioning strut and the second segment positioning strut are respectively arranged at an angle of 45° with the main anchoring strut.

[0012] Preferably, the moving strut group includes a first radial loading strut and a second radial loading strut. Both the first radial loading strut and the second radial loading strut are slidably connected to the surface of the test base, and a reaction strut group is provided on one side of both the first radial loading strut and the second radial loading strut.

[0013] Preferably, the reaction strut group includes a first orthogonal reaction strut and a second orthogonal reaction strut. The first orthogonal reaction strut is perpendicular to the adjacent first radial loading strut, and the second orthogonal reaction strut is perpendicular to the adjacent second radial loading strut. Both the first orthogonal reaction strut and the second orthogonal reaction strut are fixedly connected above the test base.

[0014] Preferably, the multi-stage loading module includes a circumferentially uniformly distributed loading unit and a concentrated force loading unit. The circumferentially uniformly distributed loading unit consists of an anchor pull tester and hoop wires. Guide grooves adapted to the diameter of the hoop wires are provided on the contact surfaces of the first segment positioning strut, the second segment positioning strut, the first radial loading strut, and the second radial loading strut with the model segment; the starting end of the hoop wire is fixed on the main anchoring strut, sequentially passes through the guide grooves of the first segment positioning strut, the second radial loading strut, the first radial loading strut, and the first orthogonal reaction strut, and the end is connected to the anchor of the anchor pull tester to form a closed-loop loading path for applying circumferentially uniformly distributed loads.

[0015] The concentrated force loading unit consists of two groups of hydraulic jacks, which are respectively arranged between the first orthogonal reaction strut and the first radial loading strut, and between the second orthogonal reaction strut and the second radial loading strut for applying concentrated forces.

[0016] Preferably, the loading modes of the hydraulic jacks include a full-ring loading mode and a joint loading mode; in the full-ring loading mode, the hydraulic jacks are fixed on the caisson bases of the first orthogonal reaction strut and the second orthogonal reaction strut to push the first radial loading strut and the second radial loading strut to apply orthogonal concentrated forces to the model segment; in the joint loading mode, the hydraulic jacks are alternately installed between the main anchoring strut and the first segment positioning strut, or between the second segment positioning strut and the first orthogonal reaction strut, and cooperate with the welded steel frame to achieve equivalent loading of positive and negative bending moments at the joints.

[0017] Preferably, the welded steel frame is provided with constraint grooves matching the ends of the model segment joints to reverse the loading direction of the bending moment of the model segment joints by changing the jacking direction of the hydraulic jacks.

[0018] Preferably, the monitoring and control module includes a displacement sensor array and a strain gauge grid. The displacement sensor array is used to monitor the displacement changes of the model segment during the loading process in real time, covering the full-ring displacement field of the model segment during full-ring loading, and is arranged directionally on the lower side of the positive bending moment area and the upper side of the negative bending moment area during joint loading; the strain gauge grid is used to measure the strain of the model segment when it is stressed, and is arranged on the inner and outer wall surfaces of the model segment during full-ring loading, and is symmetrically distributed along both sides of the joints of the model segment during joint loading.

[0019] Preferably, the monitoring and control module further includes a loading regulation unit, which consists of a preloading mechanism and a graded loading mechanism. In the stage of the preloading mechanism, 5% - 10% of the design load is applied to the system to eliminate the gaps generated during the assembly of each structure in the system; in the stage of the graded loading mechanism, after each level of load is applied, data acquisition is carried out when the displacement change rate of the model segment < 0.01 mm / min.

[0020] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0021] (1) Through the circumferentially uniformly distributed loading unit and the concentrated force loading unit of the multi-stage loading module of the present invention, circumferentially uniformly distributed loads and orthogonal concentrated forces can be applied synchronously to simulate the soil-water pressure coupling effect under actual working conditions. The hoop wire is used in cooperation with the anchor pull tester to apply circumferentially uniformly distributed loads, and the hydraulic jacks apply concentrated forces in different position combinations, with high loading accuracy, providing accurate data support for studying the mechanical properties of hexagonal segments.

[0022] (2) The fixed support group, the reaction support group and the movable support group provided by the present invention cooperate with each other, and different loading modes of the hydraulic jacks enable the test system to well adapt to the different requirements of full-ring loading and joint loading. When performing full-ring loading, the movable support is pushed to apply orthogonal concentrated forces, and when performing joint loading, positive and negative bending moment equivalent loading is achieved in cooperation with the welded steel frame to comprehensively test the stress performance of different parts of the segment.

[0023] (3) The displacement sensor array and strain gauge grid in the monitoring and control module provided by the present invention are reasonably arranged during full-ring and joint loading to comprehensively and accurately monitor the displacement and strain of the segment. The preloading mechanism of the loading control unit eliminates the assembly gap, and the hierarchical loading mechanism collects data based on the displacement change rate, ensuring the accuracy and reliability of the test data and improving the test quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is the structural top view of a hexagonal segment model test system of the present invention;

[0026] Figure 2 It is the overall structural schematic diagram provided in Embodiment 1 of the present invention.

[0027] Description of the reference numerals:

[0028] 1, main anchoring support; 2, first segment positioning support; 3, second segment positioning support; 4, first orthogonal reaction support; 5, second orthogonal reaction support; 6, first radial loading support; 7, second radial loading support; 8, model segment; 9, hoop wire; 10, hydraulic jack; 11, test base; 12, welded steel frame. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] To make the above objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0031] Embodiment 1

[0032] As Figure 1 and Figure 2 shown, the present invention provides a hexagonal segment model test system, including a test base 11, a model segment 8, and a loading and monitoring component. Above the test base 11, a fixed support column group and a reaction support column group are respectively provided. The fixed support column group is used to fix the model segment 8, and the reaction support column group is used to provide reaction support. The loading and monitoring component is composed of a moving support column group, a multi-stage loading module, and a monitoring and control module. The moving support column group moves radially along the model segment 8 to cooperate with the loading. The multi-stage loading module is used to achieve the loading of different loads, and the monitoring and control module is used to monitor data and control the loading process.

[0033] Among them, the fixed support column group includes a main anchoring support column 1 and a segment positioning support column group. The main anchoring support column 1 and the segment positioning support column group are respectively welded above the test base 11, and the main anchoring support column 1 is connected to an external anchor pull-out tester. The segment positioning support column group includes a first segment positioning support column 2 and a second segment positioning support column 3. The first segment positioning support column 2 and the second segment positioning support column 3 are used to stabilize the model segment 8, and the first segment positioning support column 2 and the second segment positioning support column 3 are respectively arranged at an angle of 45° with the main anchoring support column 1.

[0034] The moving support column group includes a first radial loading support column 6 and a second radial loading support column 7. Both the first radial loading support column 6 and the second radial loading support column 7 are slidably connected to the surface of the test base 11, and a reaction support column group is provided on one side of both the second radial loading support column 7 and the second radial loading support column 7.

[0035] The reaction support column group includes a first orthogonal reaction support column 4 and a second orthogonal reaction support column 5. The first orthogonal reaction support column 4 is perpendicular to the adjacent first radial loading support column 6, and the second orthogonal reaction support column 5 is perpendicular to the adjacent second radial loading support column 7. Both the first orthogonal reaction support column 4 and the second orthogonal reaction support column 5 are fixedly connected above the test base 11.

[0036] The multi-stage loading module includes a circumferentially uniformly distributed loading unit and a concentrated force loading unit. The circumferentially uniformly distributed loading unit consists of an anchor pull-out tester and a hoop wire 9. The anchor pull-out tester is an existing device and is not shown in the drawings. Those skilled in the art are aware of the specific structure of this device. The contact surfaces of the first segment positioning strut 2, the second segment positioning strut 3, the first radial loading strut 6, and the second radial loading strut 7 with the model segment 8 are all provided with guide grooves adapted to the diameter of the hoop wire 9. The starting end of the hoop wire 9 is fixed on the main anchoring strut 1, passes through the guide grooves of the first segment positioning strut 2, the second radial loading strut 7, the first radial loading strut 6, and the first orthogonal reaction strut 4 in sequence, and the end is connected to the anchor of the anchor pull-out tester to form a closed-loop loading path for applying circumferentially uniformly distributed loads.

[0037] The concentrated force loading unit consists of two groups of hydraulic jacks 10, which are respectively arranged between the first orthogonal reaction strut 4 and the first radial loading strut 6, and between the second orthogonal reaction strut 5 and the second radial loading strut 7, for applying concentrated forces.

[0038] The loading modes of the hydraulic jack 10 include a full-ring loading mode and a joint loading mode. In the full-ring loading mode, the hydraulic jack 10 is fixed on the bearing bases of the first orthogonal reaction strut 4 and the second orthogonal reaction strut 5, and pushes the first radial loading strut 6 and the second radial loading strut 7 to apply orthogonal concentrated forces to the model segment 8. In the joint loading mode, the hydraulic jack 10 is alternately installed between the main anchoring strut 1 and the first segment positioning strut 2, or between the second segment positioning strut 3 and the first orthogonal reaction strut 4, and cooperates with the welded steel frame 12 to achieve equivalent loading of positive and negative bending moments at the joints. The welded steel frame 12 is provided with constraint grooves matching the joint ends of the model segment 8 to reverse the loading direction of the bending moment of the model segment 8 by changing the pushing direction of the hydraulic jack 10.

[0039] The monitoring and control module includes a displacement sensor array and a strain gauge grid. The displacement sensor array and the strain gauge grid are not shown in the drawings. Since their positions will change during full-ring loading and joint loading, their installation methods are as follows: The displacement sensor array is used to monitor the displacement changes of the model segment 8 during the loading process in real time, covering the full-ring displacement field of the model segment 8 during full-ring loading, and arranged directionally on the lower side of the positive bending moment area and the upper side of the negative bending moment area during joint loading. The strain gauge grid is used to measure the strain of the model segment 8 when it is stressed, arranged on the inner and outer wall surfaces of the model segment 8 during full-ring loading, and symmetrically distributed along both sides of the joint of the model segment 8 during joint loading.

[0040] The module further includes a loading control unit, which is composed of a preloading mechanism and a hierarchical loading mechanism. In the stage of the preloading mechanism, a 5% - 10% design load is applied to the system to eliminate the gaps generated during the assembly of each structure in the system. In the stage of the hierarchical loading mechanism, after each load is applied, data is collected when the displacement change rate of the model segment 8 < 0.01 mm / min.

[0041] In this embodiment, the working principle of the system is as follows: First, prepare the test base 11, and weld and fix the main anchoring pillar 1, the first segment positioning pillar 2, the second segment positioning pillar 3, the first orthogonal reaction force pillar 4, and the second orthogonal reaction force pillar 5 above the test base 11. The main anchoring pillar 1 is connected to an external anchor puller. The first segment positioning pillar 2 and the second segment positioning pillar 3 are respectively arranged at an angle of 45° with the main anchoring pillar 1 to stabilize the model segment 8. Then, slide the first radial loading pillar 6 and the second radial loading pillar 7 on the surface of the test base 11 so that they can move radially along the model segment 8. Hydraulic jacks 10 are respectively installed between the first radial loading pillar 6 and the first orthogonal reaction force pillar 4, and between the second radial loading pillar 7 and the second orthogonal reaction force pillar 5 to form two pairs of orthogonal concentrated force loading structures.

[0042] Second, select a 20-ton anchor puller, two 20-ton manual split hydraulic jacks 10 and hoop welding wires 9. Fix the starting end of the hoop welding wire 9 on the main anchoring pillar 1, and sequentially pass through the guiding grooves of the first segment positioning pillar 2, the second radial loading pillar 7, the first radial loading pillar 6, and the first orthogonal reaction force pillar 4, and connect the end to the anchor of the anchor puller to form a closed-loop loading path for applying circumferential uniform loads. The two groups of hydraulic jacks 10 are respectively arranged between the first orthogonal reaction force pillar 4 and the first radial loading pillar 6, and between the second orthogonal reaction force pillar 5 and the second radial loading pillar 7 for applying concentrated forces.

[0043] Third, install a displacement sensor array and a strain gauge grid on the model segment 8. During the integral ring loading, the displacement sensors cover the full-ring displacement field of the model segment 8, and the strain gauge grid is arranged on the inner and outer wall surfaces of the model segment 8. During the joint loading, the displacement sensors are arranged directionally on the lower side of the positive moment area and the upper side of the negative moment area, and the strain gauges are symmetrically distributed along both sides of the joint of the model segment 8. At the same time, set the loading control unit. In the stage of the preloading mechanism, a 5% - 10% design load is applied to the system to eliminate the gaps generated during the assembly of each structure in the system. In the stage of the hierarchical loading mechanism, after each load is applied, continuously monitor the displacement change of the model segment 8, and data is collected when the displacement change rate < 0.01 mm / min.

[0044] Finally, when performing full-ring loading, the hydraulic jack 10 is fixed on the caisson bases of the first orthogonal reaction strut 4 and the second orthogonal reaction strut 5. Start the hydraulic jack 10 to push the first radial loading strut 6 and the second radial loading strut 7, and apply orthogonal concentrated forces to the model segment 8. Meanwhile, start the anchor pull-out meter and apply circumferential uniform loads through the hoop welding wire 9. During this process, use the displacement sensor array and strain gauge grid to monitor the displacement and strain data of the model segment 8 in real time, and collect data according to the settings of the loading control unit.

[0045] When performing joint loading, the hydraulic jack 10 is alternately installed between the main anchoring strut 1 and the first segment positioning strut 2, or between the second segment positioning strut 3 and the first orthogonal reaction strut 4, and cooperate with the welded steel frame 12 with constraint grooves matching the joint ends of the model segment 8 for loading. By changing the pushing direction of the hydraulic jack 10, the reversal of the bending moment loading direction of the model segment 8 joint is realized, simulating the equivalent loading conditions of positive and negative joint bending moments, and synchronously monitoring and collecting displacement and strain data.

[0046] Through the above content, the test system provided by this embodiment can effectively simulate the complex stress conditions of the hexagonal segment in the actual project, providing reliable data support for studying its mechanical properties.

[0047] Therefore, by adopting the above-mentioned hexagonal segment model test system, problems such as single loading method, poor fixity of the reaction frame struts, interference with the load transfer accuracy, difficulty in simulating the cooperative action of multiple factors, and imperfect monitoring and control in the existing hexagonal segment model test system are solved.

[0048] In this article, specific examples are used to elaborate on the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation mode and application scope. To sum up, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A hexagonal segment model test system, characterized in that It includes a test base, model segments, and a loading and monitoring assembly. Above the test base, there are respectively a fixed support pillar group and a reaction support pillar group. The fixed support pillar group is used to fix the model segments, and the reaction support pillar group is used to provide reaction support. The loading and monitoring assembly consists of a moving support pillar group, a multi-stage loading module, and a monitoring and control module. The moving support pillar group moves along the radial direction of the model segments to cooperate with the loading. The multi-stage loading module is used to achieve the loading of different loads, and the monitoring and control module is used to monitor data and control the loading process.

2. The hexagonal segment model test system according to claim 1, characterized in that, The fixed support pillar group includes a main anchoring support pillar and a segment positioning support pillar group. The main anchoring support pillar and the segment positioning support pillar group are respectively welded above the test base, and the main anchoring support pillar is connected to an external anchor pullout tester.

3. The hexagonal segment model test system according to claim 2, wherein The segment positioning support pillar group includes a first segment positioning support pillar and a second segment positioning support pillar. The first segment positioning support pillar and the second segment positioning support pillar are used to stabilize the model segments, and the first segment positioning support pillar and the second segment positioning support pillar are respectively arranged at an angle of 45° with the main anchoring support pillar.

4. A hexagonal segment model test system according to claim 3, characterized in that The moving support pillar group includes a first radial loading support pillar and a second radial loading support pillar. Both the first radial loading support pillar and the second radial loading support pillar are slidably connected to the surface of the test base, and on one side of both the second radial loading support pillar and the second radial loading support pillar, there is the reaction support pillar group.

5. The hexagonal segment model test system according to claim 4, characterized in that, The reaction support pillar group includes a first orthogonal reaction support pillar and a second orthogonal reaction support pillar. The first orthogonal reaction support pillar is perpendicular to the adjacent first radial loading support pillar, and the second orthogonal reaction support pillar is perpendicular to the adjacent second radial loading support pillar. Both the first orthogonal reaction support pillar and the second orthogonal reaction support pillar are fixedly connected above the test base.

6. The hexagonal segment model test system according to claim 5, wherein, The multi-stage loading module includes a circumferentially uniformly distributed loading unit and a concentrated force loading unit. The circumferentially uniformly distributed loading unit consists of an anchor pullout tester and a hoop wire. On the contact surfaces of the first segment positioning support pillar, the second segment positioning support pillar, the first radial loading support pillar, and the second radial loading support pillar with the model segments, there are respectively provided guiding grooves adapted to the diameter of the hoop wire. The starting end of the hoop wire is fixed on the main anchoring support pillar, passes through the guiding grooves of the first segment positioning support pillar, the second radial loading support pillar, the first radial loading support pillar, and the first orthogonal reaction support pillar in sequence, and the end is connected to the anchor of the anchor pullout tester to form a closed-loop loading path for applying circumferentially uniformly distributed loads. The concentrated force loading unit consists of two groups of hydraulic jacks, which are respectively arranged between the first orthogonal reaction support pillar and the first radial loading support pillar, and between the second orthogonal reaction support pillar and the second radial loading support pillar, for applying concentrated forces.

7. A hexagonal segment model test system according to claim 6, characterized in that, The loading modes of the hydraulic jack include the integral ring loading mode and the joint loading mode; in the integral ring loading mode, the hydraulic jack is fixed on the bearing base of the first orthogonal reaction strut and the second orthogonal reaction strut, and pushes the first radial loading strut and the second radial loading strut to apply orthogonal concentrated forces to the model segment; in the joint loading mode, the hydraulic jacks are alternately installed between the main anchoring strut and the first segment positioning strut, or between the second segment positioning strut and the first orthogonal reaction strut, and cooperate with the welded steel frame to achieve equivalent loading of the positive and negative bending moments of the joint.

8. The hexagonal segment model test system according to claim 7, wherein, The welded steel frame is provided with a constraint groove matching the end of the model segment joint, so as to reverse the loading direction of the bending moment of the model segment joint by changing the pushing direction of the hydraulic jack.

9. The hexagonal segment model test system according to claim 1, wherein, The monitoring and control module includes a displacement sensor array and a strain gauge grid. The displacement sensor array is used to monitor the displacement change of the model segment during the loading process in real time, covering the full-ring displacement field of the model segment during integral ring loading, and arranged directionally on the lower side of the positive bending moment area and the upper side of the negative bending moment area during joint loading; the strain gauge grid is used to measure the strain of the model segment when it is stressed, arranged on the inner and outer wall surfaces of the model segment during integral ring loading, and symmetrically distributed along both sides of the joint of the model segment during joint loading.

10. The hexagonal segment model test system according to claim 9, characterized in that, The monitoring and control module also includes a loading regulation unit, which is composed of a preloading mechanism and a graded loading mechanism. In the stage of the preloading mechanism, 5% - 10% of the design load is applied to the system to eliminate the gaps generated during the assembly of each structure in the system; in the stage of the graded loading mechanism, after each stage of load is applied, data collection is carried out when the displacement change rate of the model segment < 0.01 mm / min.

Images