An experimental device for simulating low-cycle repeated load of a wood beam-column mortise and tenon joint
By designing a test device to simulate the mortise and tenon joint of wooden beams and columns, and by using a combination of a clamping device and a loading device, the problem of pull-out caused by the deviation of the force direction of the wooden beam from the normal was solved, thus achieving the stability and accuracy of the test and enabling precise monitoring of the rotation and loading cycle of the wooden beam.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTHEAST UNIV
- Filing Date
- 2022-11-23
- Publication Date
- 2026-05-19
AI Technical Summary
In existing low-cycle repeated loading tests of mortise and tenon joints of wooden beams and columns, deviation of the force direction of the wooden beam from the normal direction can easily lead to the premature pull-out of the wooden beam, affecting the accuracy of the test.
A test device was designed to simulate low-cycle repeated loading of mortise and tenon joints of wooden beams and columns. By coordinating the clamping device and the loading device, the load direction of the wooden beam is kept along the normal direction of the wooden beam when it is loaded, so as to avoid pull-out force. The upper and lower slide rails in the clamping device and the rotating shaft hinge in the loading device are connected to ensure the stability of the load direction.
It effectively avoids premature pull-out of the mortise and tenon joints, ensuring the accuracy and stability of the test, and can accurately monitor the rotation of the wooden beam and the loading cycle, providing stable loading conditions.
Smart Images
Figure CN115717975B_ABST
Abstract
Description
field
[0001] This disclosure belongs to the field of civil engineering technology, specifically relating to a test device for simulating low-cycle repeated loading of mortise and tenon joints in wooden beams and columns. background
[0002] In ancient wooden structures, load-bearing components are connected using mortise and tenon joints. These joints exhibit significant semi-rigid characteristics, possessing not only excellent load-bearing capacity but also allowing for a certain degree of deformation to dissipate energy when subjected to dynamic responses such as wind vibration or seismic loads. However, over the long course of history, the properties of the wood in ancient wooden buildings generally degrade, and the mortise and tenon joints are weakened by natural and human factors, posing a significant threat to the overall performance of the wooden structure. Therefore, research on the mechanical properties of mortise and tenon joints in wooden beams and columns, and precise understanding of their failure modes, hysteresis curves, and energy dissipation capabilities, is of paramount importance for the protection and reinforcement of ancient wooden structures.
[0003] Low-cycle repeated loading is an effective and conventional method for studying the mechanical properties of mortise and tenon joints in timber beams and columns. In existing experimental studies, the loading direction of the timber beam is often kept perpendicular. This loading method generates pull-out force when the timber beam rotates, causing the timber beam to be pulled out prematurely. Therefore, a test device for simulating low-cycle repeated loading of mortise and tenon joints in timber beams and columns is proposed. Summary of the Invention
[0004] The purpose of this disclosure is to provide a test device for simulating low-cycle repeated loading of mortise and tenon joints of wooden beams and columns, which overcomes the common problem that the force direction of wooden beams deviates from the normal direction, which easily leads to the premature pull-out of the wooden beams.
[0005] The purpose of this disclosure can be achieved through the following methods:
[0006] A test device for simulating low-cycle repeated loading of a mortise and tenon joint in a wooden beam-column configuration includes a loading platform, a wooden beam, and a wooden column. The loading platform includes a reaction frame, with fixed frames fixedly connected to both ends of the reaction frame. Support plates are fixedly connected to the lower ends of the two fixed frames, and column base positioning components are fixedly connected to the upper ends of the support plates. A jack is fixedly connected to the lower end of the reaction frame, directly above the column base positioning components. The wooden column is installed between the column base positioning components and the jack. A reaction support platform is fixedly connected to the upper end of the support plate, located to one side of the column base positioning components. One end of the wooden beam is connected to the wooden column via a tenon and a mortise. A clamping device is installed on the outer surface of the wooden beam, and a loading device is installed between the clamping device and the reaction support platform.
[0007] Preferably, the lower end of the wooden column is installed inside the column base positioning component, and the upper end of the wooden column is fitted with the output end of the jack.
[0008] Preferably, the column base positioning component is a component consisting of a bottom steel plate and four surrounding steel plates, wherein the lower end face of the wooden column is in contact with the upper end face of the bottom steel plate of the column base positioning component and the outer surface is in contact with the four surrounding steel plates.
[0009] Preferably, the clamping device includes an upper clamping steel plate and a lower clamping steel plate. The lower end face of the upper clamping steel plate engages with an upper slide rail, and the upper end face of the lower clamping steel plate engages with a lower slide rail. The lower end face of the upper slide rail is in contact with the upper end face of the wooden beam, and the upper end face of the lower slide rail is in contact with the lower end face of the wooden beam. The upper clamping steel plate and the lower clamping steel plate are connected by a tie rod.
[0010] Preferably, the lengths of the upper and lower slide rails are both greater than the lengths of the upper and lower clamping steel plates plus twice the sum of the tenon length of the wooden beam and the height of the wooden beam.
[0011] Preferably, the loading device includes a screw, with a fixed plate fixedly connected to the lower end of the screw. Two sets of fixed plates are provided. The screw is fixedly connected to the reaction bearing platform through the two sets of fixed plates and nuts. An electric nut is threaded onto the outer surface of the screw. A rotating shaft hinge is provided at the upper end of the screw. A connection port adapted to the rotating shaft hinge is provided on the lower end face of the lower clamping steel plate. The lower clamping steel plate is hinged to the rotating shaft hinge through the connection port using a pin.
[0012] Preferably, the test device further includes a rotation angle value device, which includes a wooden beam rotation angle value dial and a tenon and mortise rotation angle value dial. The wooden beam rotation angle value dial is installed at the midpoint of one side of the upper hoop steel plate, and the tenon and mortise rotation angle value dial is installed parallel to the rotating plane at the height of the cross-section of the tenon and mortise joint of the wooden column.
[0013] Preferably, the test device further includes a control console, which is electrically connected to the wooden beam angle value dial, the tenon and mortise angle value dial, and the electric nut.
[0014] The beneficial effects of this disclosure are:
[0015] This test device for simulating low-cycle repeated loading of mortise and tenon joints in wooden beams and columns, through the upper and lower sliding rails in the clamping device and the connection port that cooperates with the rotating shaft hinge in the loading device, can keep the load direction along the normal direction of the wooden beam after it rotates under load, thus preventing pull-out force and avoiding premature pull-out of the mortise and tenon joints during the test. Attached Figure Description
[0016] To more clearly illustrate the embodiments of this disclosure or the existing solutions, the accompanying drawings used in the embodiments or existing descriptions will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this disclosure;
[0018] Figure 2 This is a front view of an embodiment of this disclosure;
[0019] Figure 3 This is a top view of a mortise and tenon joint according to an embodiment of this disclosure;
[0020] Figure 4 This is a front view of the mortise and tenon joint according to an embodiment of this disclosure;
[0021] Figure 5 This is a schematic diagram of a wooden beam and column according to an embodiment of this disclosure;
[0022] Figure 6 This is a schematic diagram of the loading platform structure according to an embodiment of this disclosure;
[0023] Figure 7 This is a schematic diagram of the clamping device structure according to an embodiment of the present disclosure;
[0024] Figure 8 This is a schematic diagram of the loading device structure according to an embodiment of the present disclosure;
[0025] Figure 9 This is a schematic diagram of the connection between the lower clamping steel plate and the loading device in an embodiment of this disclosure;
[0026] Figure 10 This is a schematic diagram of the connection between the loading device and the reaction support platform according to an embodiment of this disclosure.
[0027] In the diagram: 1. Loading platform; 101. Column base positioning component; 102. Reaction bearing platform; 103. Jack; 104. Reaction frame; 2. Clamping device; 201. Upper slide rail; 202. Lower slide rail; 203. Upper clamping steel plate; 204. Lower clamping steel plate; 205. Tie rod; 206. Connection port; 3. Loading device; 301. Electric nut; 302. Screw; 303. Fixing plate; 304. Rotating shaft hinge; 4. Angle value device; 401. Wooden beam angle value dial; 402. Mortise and tenon angle value dial; 5. Control console; 6. Wooden beam; 7. Wooden column. Detailed Implementation
[0028] The solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this disclosure.
[0029] like Figure 1-10 As shown, a test device for simulating low-cycle repeated loading of a mortise and tenon joint of a wooden beam and column includes a loading platform 1, a wooden beam 6, and a wooden column 7. The loading platform 1 includes a reaction frame 104, with fixed frames fixedly connected to both ends of the reaction frame 104. A support plate is fixedly connected to the lower end face of the two fixed frames, and a column base positioning component 101 is fixedly connected to the upper end face of the support plate. A jack 103 is fixedly connected to the lower end face of the reaction frame 104 and directly above the column base positioning component 101. The wooden column 7 is installed between the column base positioning component 101 and the jack 103. A reaction support platform 102 is fixedly connected to the upper end face of the support plate and to one side of the column base positioning component 101. One end of the wooden beam 6 is connected to the wooden column 7 by a tenon. A clamping device 2 is installed on the outer surface of the wooden beam 6, and a loading device 3 is installed between the clamping device 2 and the reaction support platform 102.
[0030] After the mortise and tenon joints of the wooden beam and column are made, the wooden column 7 is placed in the column foot positioning component 101 of the loading platform 1. The top of the wooden column 7 is subjected to vertical load by the jack 103 fixed to the lower end face of the reaction frame 104 of the loading platform 1. The clamping device 2 and the loading device 3 are adjusted and installed according to the actual size of the mortise and tenon joints of the wooden beam and column and the position of the loading point.
[0031] The lower end of the wooden column 7 is installed inside the column base positioning component 101, and the upper end of the wooden column 7 is in contact with the output end of the jack 103. The column base positioning component 101 is a component composed of a bottom steel plate and four surrounding steel plates. The lower end face of the wooden column 7 is in contact with the upper end face of the bottom steel plate of the column base positioning component 101, and the outer surface is in contact with the four surrounding steel plates.
[0032] The clamping device 2 includes an upper clamping steel plate 203 and a lower clamping steel plate 204. The lower end face of the upper clamping steel plate 203 engages with the upper slide rail 201, and the upper end face of the lower clamping steel plate 204 engages with the lower slide rail 202. The lower end face of the upper slide rail 201 is in contact with the upper end face of the wooden beam 6, and the upper end face of the lower slide rail 202 is in contact with the lower end face of the wooden beam 6. The upper clamping steel plate 203 and the lower clamping steel plate 204 are connected by a tie rod 205.
[0033] The lengths of the upper slide rail 201 and the lower slide rail 202 are both greater than the lengths of the upper clamping steel plate 203 and the lower clamping steel plate 204 plus twice the sum of the tenon length and the height of the wooden beam 6, so that the lengths of the upper slide rail 201 and the lower slide rail 202 are sufficient to prevent the upper clamping steel plate 203 and the lower clamping steel plate 204 from coming off when the wooden beam 6 rotates.
[0034] The loading device 3 includes a screw 302, with a fixed plate 303 fixedly connected to the lower end of the screw 302. Two sets of fixed plates 303 are provided. The screw 302 is fixedly connected to the reaction support 102 through the two sets of fixed plates 303 and nuts. An electric nut 301 is threadedly connected to the outer surface of the screw 302. A rotating shaft hinge 304 is provided at the upper end of the screw 302. A connection port 206 adapted to the rotating shaft hinge 304 is provided on the lower end face of the lower clamping steel plate 204. The lower clamping steel plate 204 is hinged to the rotating shaft hinge 304 through the connection port 206 using a pin.
[0035] The clamping device 2 can rotate around the pivot hinge 304. The vertically downward load applied by the loading device 3 at the pivot hinge 304 is decomposed into a force in the normal direction of the wooden beam 6 and a force in the tangential direction of the wooden beam 6. At the same time, the wooden beam 6 clamped by the upper slide rail 201 and the lower slide rail 202 can slide relative to the upper clamping steel plate 203 and the lower clamping steel plate 204 to a large extent, reducing the tangential pull-out force generated by the decomposition, thereby ensuring that only the normal direction load is generated on the wooden beam 6.
[0036] The experimental setup also includes an angle-calculating device 4, which comprises a wooden beam angle-calculating dial 401 and a tenon-and-mortise angle-calculating dial 402. The wooden beam angle-calculating dial 401 is installed at the midpoint of one side of the upper hoop steel plate 203, and the tenon-and-mortise angle-calculating dial 402 is installed parallel to the rotating plane at the variable cross-section height of the tenon-and-mortise joint of the wooden column 7. Both the wooden beam angle-calculating dial 401 and the tenon-and-mortise angle-calculating dial 402 here use Hall effect GT-C type angle sensors.
[0037] The test apparatus also includes a control console 5, which is electrically connected to the wooden beam angle numerical dial 401, the tenon and mortise angle numerical dial 402 and the electric nut 301.
[0038] Real-time monitoring of the rotation angle and correction of the loading rate are key to maintaining a stable cycle. During the test, as the wooden beam 6 rotates, it usually causes the pre-set fixed loading rate to become disordered in the loading cycle. However, by simultaneously collecting the rotation angle data at the loading clamping point of the wooden beam 6 and the mortise and tenon joint of the wooden column 7, it is sufficient to accurately determine the absolute rotation of the wooden beam 6 in the coordinate space. The control console 5 calculates and corrects the absolute rotation of the wooden beam, which yields a stable loading cycle control signal. The control signal is then transmitted to the electric nut 301 to achieve automatic correction of the loading rate during the loading process of the wooden beam.
[0039] The experimental steps are as follows:
[0040] First, fabricate the mortise and tenon joints between the wooden beams and columns. Based on the actual dimensions of the mortise and tenon joints and the location of the loading point, adjust the distance between the loading platform 1 and the loading device 3. The loading point is located at the midpoint of the wooden beam. Referencing actual structural examples in the Jiangnan region, the tenon extends outwards from the outer surface of the column by approximately half the column diameter. The tenon thickness is approximately 1 / 4 of the column diameter. Using a 1:1.76 scaled-down tenon with a shoulder-type tenon as an example, see attached... Figure 5 As shown;
[0041] Next, the wooden column 7 with the mortise and tenon joint of the wooden beam and column is placed in the column foot positioning component 101 of the loading platform 1. The top of the wooden column 7 is subjected to vertical load by the jack 103 fixed to the lower end face of the reaction frame 104 of the loading platform 1. The wooden beam rotation angle value dial 401 is installed at the loading clamp of the wooden beam 6, and the mortise and tenon rotation angle value dial 402 is installed at the mortise and tenon joint of the wooden column 7.
[0042] Then, the upper slide rail 201 and the lower slide rail 202 are clamped on the wooden beam 6, and the positions of the upper clamping steel plate 203 and the lower clamping steel plate 204 are adjusted so that the upper slide rail 201 and the lower slide rail 202 will not come off during loading. The tie rod 205 is tightened, and the normal load of the wooden beam 6 is applied by the loading device. The loading device 3 and the clamping device 2 are connected by the pivot hinge 304 and the connection port 206.
[0043] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0044] The foregoing has shown and described the basic principles, main features, and advantages of this disclosure. Those skilled in the art should understand that this disclosure is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this disclosure. Various changes and modifications can be made to this disclosure without departing from its spirit and scope, and all such changes and modifications fall within the scope of this disclosure as claimed.
Claims
1. A test apparatus for simulating low-cycle repeated loading of mortise and tenon joints in wooden beams and columns, comprising a loading platform (1), a wooden beam (6), and a wooden column (7), characterized in that, The loading platform (1) includes a reaction frame (104), with fixed frames fixedly connected to both ends of the reaction frame (104), and a support plate fixedly connected to the lower end face of the two fixed frames. A column base positioning component (101) is fixedly connected to the upper end face of the support plate. A jack (103) is fixedly connected to the lower end face of the reaction frame (104) and directly above the column base positioning component (101). The wooden column (7) is installed between the column base positioning component (101) and the jack (103). A reaction support platform (102) is fixedly connected to the upper end face of the support plate and to one side of the column base positioning component (101). One end of the wooden beam (6) is connected to the wooden column (7) by a tenon. A clamping device (2) is installed on the outer surface of the wooden beam (6). A loading device (3) is installed between the clamping device (2) and the reaction support platform (102). The clamping device (2) includes an upper clamping steel plate (203) and a lower clamping steel plate (204). The lower end face of the upper clamping steel plate (203) engages with the upper slide rail (201), and the upper end face of the lower clamping steel plate (204) engages with the lower slide rail (202). The lower end face of the upper slide rail (201) is in contact with the upper end face of the wooden beam (6), and the upper end face of the lower slide rail (202) is in contact with the lower end face of the wooden beam (6). The upper clamping steel plate (203) and the lower clamping steel plate (204) are connected by a tie rod (205). The loading device (3) includes a screw (302), and a fixed plate (303) is fixedly connected to the lower end of the screw (302). Two sets of fixed plates (303) are provided. The screw (302) is fixedly connected to the reaction support (102) through the two sets of fixed plates (303) and nuts. An electric nut (301) is threaded on the outer surface of the screw (302). A rotating shaft hinge (304) is provided at the upper end of the screw (302). A connection port (206) adapted to the rotating shaft hinge (304) is provided on the lower end face of the lower clamping steel plate (204). The lower clamping steel plate (204) is hinged to the rotating shaft hinge (304) through the connection port (206) using a pin.
2. The experimental apparatus for simulating low-cycle repeated loading of mortise and tenon joints in wooden beams and columns according to claim 1, characterized in that, The lower end of the wooden column (7) is installed inside the column base positioning component (101), and the upper end of the wooden column (7) is attached to the output end of the jack (103).
3. The experimental apparatus for simulating low-cycle repeated loading of mortise and tenon joints in wooden beams and columns according to claim 1, characterized in that, The column base positioning component (101) is a component consisting of a bottom steel plate and four surrounding steel plates. The lower end face of the wooden column (7) is in contact with the upper end face of the bottom steel plate of the column base positioning component (101) and the outer surface is in contact with the four surrounding steel plates.
4. The experimental apparatus for simulating low-cycle repeated loading of mortise and tenon joints in wooden beams and columns according to claim 1, characterized in that, The lengths of the upper slide rail (201) and the lower slide rail (202) are both greater than the lengths of the upper clamping steel plate (203) and the lower clamping steel plate (204) plus twice the tenon length of the wooden beam (6) and the height of the wooden beam (6).
5. The experimental apparatus for simulating low-cycle repeated loading of mortise and tenon joints in timber beams and columns according to claim 1, characterized in that, The test device also includes a rotation value device (4), which includes a wooden beam rotation value dial (401) and a tenon and mortise rotation value dial (402). The wooden beam rotation value dial (401) is installed at the midpoint of one side of the upper hoop steel plate (203), and the tenon and mortise rotation value dial (402) is installed parallel to the rotating plane at the height of the cross section of the tenon and mortise joint of the wooden column (7).
6. The experimental apparatus for simulating low-cycle repeated loading of mortise and tenon joints in timber beams and columns according to claim 1, characterized in that, The test device also includes a control console (5), which is electrically connected to the wooden beam angle numerical dial (401), the tenon and mortise angle numerical dial (402), and the electric nut (301).