A measurement method suitable for deformation between wooden components of ancient buildings

Abstract

The present invention relates to a deformation measuring device for components and nodes in the wooden structure of an ancient building, and specifically to a measuring system suitable for deformation between wooden components of an ancient building, the measuring device comprising a sliding amount measuring device between bracket layers, a pressure-slip amount measuring device for column foot nodes, and a pressure-tenon-tenon-joint amount measuring device. The measuring system is mainly composed of three deformation variable measuring devices suitable for different positions, the deformation variable measuring devices comprising an inclination sensor, a small displacement sensor, and a small displacement combination sensor; the measurement data is mainly collected through a static strain gauge, and simultaneously input into a computer terminal for real-time recording, and the data of the corresponding sensors are integrated after being exported to calculate the required deformation amount at each position. The present invention forms a complete set of measurement systems suitable for horizontal and vertical relative deformation between wooden components of ancient buildings, which solves the problem of difficulty and inaccuracy in obtaining the relative deformation state between local components when studying the horizontal shear deformation of the structure.

Description

Technical Field

[0001] The invention relates to a deformation measuring device for main components and nodes in an ancient building wooden structure, in particular to a deformation measuring method suitable for wooden components of an ancient building. Background Art

[0002] Ancient wooden structures are one of the most important structural forms of historical buildings in my country, accounting for more than 70% of the country's historical buildings. In order to strengthen the protection of ancient wooden structures, my country has stipulated that cultural relics work should implement the principles of protection first, rescue first, reasonable use, and strengthened management. If the ancient wooden structure is located in an earthquake zone, the earthquake will cause varying degrees of damage to the ancient wooden structure. It can be seen that revealing the seismic mechanism of the ancient wooden structure is the basis for the reasonable repair and protection of many ancient wooden structures in areas with high earthquake intensity.

[0003] In order to obtain the disaster mechanism of ancient wooden buildings in earthquakes, the deformation of each component is often extracted through quasi-static tests. At present, the commonly used measurement methods often use potentiometer, resistance strain, capacitance, inductance, magnetic sensitivity, photoelectric and ultrasonic displacement sensors to obtain the absolute displacement of each component, or obtain the local strain at the connection node of each component by sticking strain gauges on the surface of the wood, and then obtain the stress state of the component based on the relationship between the node bending moment and the stress-strain of the wood.

[0004] When studying the horizontal shear (translational) deformation behavior of the wooden structure of ancient buildings, we should not only pay attention to the deformation of each structural layer (such as the bracket layer and the column frame layer), but also study the deformation of each main component and node (such as the inter-layer slip of the bracket, the mortise and tenon joints [the mortise and tenon joints are the relative slip between the mortise and tenon components], and the column foot node. For each structural layer, its horizontal and vertical absolute and relative displacement can be easily measured by traditional displacement meters, but for the deformation of local components and nodes of the structure, the traditional displacement measurement scheme is no longer applicable.

[0005] For brackets, their internal structure is complex and their components are arranged closely, which is not conducive to the arrangement of horizontal and vertical sensors. In addition, the connection method of bracket components is special, and it is not easy to obtain their deformation characteristics through mathematical models. At the same time, wood is an anisotropic biomass material, which is easily affected by the environment, various microorganisms and insect bites, and often suffers from diseases such as wood decay and cross-section weakening. The longer the existing time, the more serious the decay of the components. For example, the surface layer of about 3 cm of the wooden components of the Yingxian Wooden Pagoda is severely aged and the surface material is easy to peel off, while the internal late wood is as solid as new. Therefore, the deformation state obtained by sticking strain gauges on the surface of the wood, especially on the surface of diseased wooden structures, is inaccurate.

[0006] For the main nodes of the column frame layer of wooden structures, the mortise and tenon nodes [here specifically refers to the connection nodes between the column head and the upper components] and the column foot nodes, although their structures are relatively simple, they have large deformations and are the main deformation nodes under earthquakes. They will produce large relative rotation angles, which limits the layout of traditional sensors. For the column foot nodes, although their deformation characteristics can be roughly calculated through mathematical models, they are also based on ideal conditions. In fact, due to the material properties of wood (material properties are not strictly uniformly distributed), there are still large errors in the mathematical model, and there are also certain differences between the surface and internal properties of wood. Inputting the strain measured by the surface strain gauge into the mathematical model will further increase the error.

[0007] Under the action of horizontal earthquake force, beam components such as lintels, purpai fang, and plain fang in wooden structures almost maintain horizontal movement, while wooden columns show obvious swing characteristics: ① It is manifested at the node of the column foot, that is, the column bottom is repeatedly lifted on one side and pressed on the lower structure on the other side. When one side of the column bottom is lifted higher, there is almost only one point on the other side that is in contact with the lower structure, so that the entire structural weight above the column foot is almost entirely applied to this point, making it very easy for the wooden components to produce embedded compression deformation. Moreover, since the vertical (along the grain) compressive stiffness of the wooden column is very large, the deformation at this point will mainly be manifested on the structural components at the lower part, thereby causing greater damage to the lower components. This is also the main form of damage to the column frame layer of wooden structures; ② It is manifested at the mortise and tenon node, that is, in the relative rotation between the wooden column and the upper component, the upper component will also be repeatedly subjected to the concentrated reaction force from the edge of the column head mortise, which will also cause certain embedded compression damage.

[0008] At present, it is difficult to measure local structural deformations such as the slip between layers of brackets, the embedded pressure and relative slip of important nodes in the column frame layer through traditional displacement measurement methods. These local deformations are important factors affecting the overall performance of the structure. Therefore, there is an urgent need for a complete measurement system suitable for the deformation between wooden components of ancient buildings to achieve more accurate capture of the deformation behavior of ancient wooden structures. Summary of the invention

[0009] Aiming at the problem that the slippage between layers of brackets, the embedding pressure and relative slippage of important nodes of column frame layers are difficult to achieve through traditional displacement measurement means, the present invention provides a measurement method suitable for deformation between wooden components of ancient buildings.

[0010] The present invention is implemented by adopting the following technical scheme: a method for measuring deformation between wooden components of ancient buildings, comprising a device for measuring slippage between bracket layers, the device comprising an inclination sensor and a small displacement sensor, the small displacement sensor comprising a fixing unit and a deformation unit, the fixing unit further comprising a thin nail and a horn hook, the deformation unit further comprising a spring, a dovetail spring clip and a strain gauge; the inclination sensor is fixedly installed on the upper bracket component and the lower bracket component respectively, the small displacement sensor is symmetrically arranged between the upper bracket component and the lower bracket component, wherein the thin nail is fixed on the upper bracket component, the horn hook is fixed on the lower bracket component, the deformation unit is connected between the thin nail and the horn hook, after connection, the deformation unit is parallel to the bottom surface of the upper bracket component, and the strain gauge is arranged on the dovetail spring clip;

[0011] The measuring device comprises the following steps when measuring:

[0012] S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit;

[0013] S2: After the inclination sensor and the small displacement sensor are arranged, the initial state of the small displacement sensor is determined, that is, the arrangement height t of the deformation unit and the initial length l of the deformation unit are determined;

[0014] S3: Test the deformation unit and check whether the small displacement sensor works normally through the strain value output by the static strain gauge;

[0015] S4: After confirming that all sensors are correct, the measuring device enters the measuring state.

[0016] S5: If the bracket components of each layer slide and rotate relative to each other, the spatial position of the key points on each layer of the bracket components changes; at this moment, the strain gauge in the small displacement sensor on the same side as the rotation point outputs the strain value through the static strain gauge, and the length l1 of the deformation unit at this moment is deduced from the calibrated displacement-strain relationship, and the angle θ between the bracket components of each layer is deduced from the angle value output by the inclination sensor;

[0017] S6: The horizontal slip amount de between the upper and lower bracket components at this moment is obtained from the above data.

[0018] The above-mentioned method for measuring deformation between wooden components of ancient buildings also includes a column foot node embedding pressure-slippage measuring device, which includes an inclination sensor and a small displacement combination sensor; the small displacement combination sensor includes a fixed unit and two groups of deformation units, the fixed unit includes a thin nail and a horn hook, and the deformation unit includes a spring, a dovetail spring clip and a strain gauge; the inclination sensor is fixedly installed on the upper wooden component and the lower wooden component respectively, the thin nail in the small displacement combination sensor is vertically fixed on the lower wooden component, the horn hook is horizontally fixed on the upper wooden component, one end of one group of deformation units is hung with the horn hook, and the other end is hung on the top of the thin nail, the group of deformation units is a horizontal deformation unit, parallel to the lower wooden component, one end of another group of deformation units is hung with the horn hook, and the other end is hung at the junction of the thin nail and the lower wooden component, the group of deformation units is an inclined deformation unit, and the strain gauge is arranged on the dovetail spring clip;

[0019] The measuring device comprises the following steps when measuring:

[0020] S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit;

[0021] S2: After the inclination sensor and the small displacement combined sensor are arranged, the initial state of the small displacement combined sensor is determined, that is, the arrangement height t of the horizontal deformation unit and the initial length l of the horizontal deformation unit are determined;

[0022] S3: Test the deformation unit and check whether the small displacement combined sensor works normally through the strain value output by the static strain gauge;

[0023] S4: After confirming that all sensors are correct, the measuring device enters the measuring state;

[0024] S5: When the measured component undergoes relative rotation, sliding and embedded compression deformation, the spatial position of each key point of the measured component changes. When the small displacement combined sensor and the rotation point are on the same side, the length l1 of the horizontal deformation unit and the length l2 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. When the small displacement combined sensor and the rotation point are on the opposite side, the length l3 of the horizontal deformation unit and the length l4 of the inclined deformation unit are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. Finally, the angle θ between the upper wooden component and the lower wooden component is deduced through the angle value output by the inclination sensor.

[0025] S6: The horizontal slip and vertical pressure between the upper and lower wood members are obtained from the above data. When the small displacement combined sensor and the rotation point are on the same side, the horizontal slip Vertical pressure When the small displacement combined sensor and the rotation point are on the opposite side, the horizontal slip Vertical pressure D is the width of the contact surface between the upper wooden member and the lower wooden member.

[0026] The above-mentioned method for measuring deformation between wooden components of ancient buildings also includes a measuring device for the compression-tenon joint amount, which includes an inclination sensor and a small displacement combination sensor; the small displacement combination sensor includes a fixed unit and two groups of deformation units, the fixed unit includes a thin nail and a horn hook, and the deformation unit includes a spring, a dovetail spring clip and a strain gauge; the inclination sensor is fixedly installed on the upper wooden component and the lower wooden component respectively, the thin nail in the small displacement combination sensor is inverted and vertically fixed on the upper wooden component, the horn hook is horizontally fixed on the lower wooden component, one end of one group of deformation units is hung with the horn hook, and the other end is hung on the top of the thin nail, the group of deformation units is a horizontal deformation unit, parallel to the upper wooden component, one end of another group of deformation units is hung with the horn hook, and the other end is hung at the junction of the thin nail and the upper wooden component, the group of deformation units is an inclined deformation unit, and the strain gauge is arranged on the dovetail spring clip;

[0027] The measuring device comprises the following steps when measuring:

[0028] S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit;

[0029] S2: After the inclination sensor and the small displacement combined sensor are arranged, the initial state of the small displacement combined sensor is determined, that is, the arrangement height t of the horizontal deformation unit and the initial length l of the horizontal deformation unit are determined;

[0030] S3: Test the deformation unit and check whether the small displacement combined sensor works normally through the strain value output by the static strain gauge;

[0031] S4: After confirming that all sensors are correct, the measuring device enters the measuring state;

[0032] S5: At a certain moment, when the measured component undergoes relative rotation, tenon extraction and embedding and compression deformation, the spatial positions of the key points of the measured component change. When the small displacement combined sensor and the rotation point are on the same side, the strain value output by the static strain gauge is used to deduce the length l1 of the horizontal deformation unit and the length l2 of the inclined deformation unit at this moment from the calibrated displacement-strain relationship. When the small displacement combined sensor and the rotation point are on the opposite side, the strain value output by the static strain gauge is used to deduce the length l3 of the horizontal deformation unit and the length l4 of the inclined deformation unit at this moment from the calibrated displacement-strain relationship. Finally, the angle θ between the upper wooden component and the lower wooden component is deduced from the angle value output by the inclination sensor.

[0033] S6: The horizontal pulling amount and vertical pressing amount between the components at this moment are obtained from the above data. When the small displacement combined sensor and the rotation point are on the same side, the horizontal pulling amount Vertical pressure When the small displacement combined sensor and the rotation point are on the opposite side, the horizontal tenon pull Vertical pressure D' is the width of the contact surface between the lower wooden member and the upper wooden member.

[0034] The beneficial effects of the present invention are:

[0035] (1) Based on a variety of measurement devices for local deformation at different positions of ancient building wooden structures, a complete set of measurement systems and methods for deformation between ancient building wooden components has been formed, which solves the problem of difficulty and inaccuracy in obtaining the deformation state between local components when studying the horizontal shear (translational) deformation of structures in the past;

[0036] (2) Create favorable conditions for establishing a correct and scientific connection between the overall performance of the structure and local damage, and lay the foundation for related research on structural performance evaluation;

[0037] (3) The test results are accurate, the operability is strong, the precision is high, the process is simple and convenient, the cost is low, and the maintenance cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the structure of the device for measuring the slippage between bracket layers.

[0039] Figure 2 It is a structural schematic diagram of a small displacement sensor.

[0040] Figure 3 It is a cross-sectional diagram of the bracket interlayer slip measurement device and a schematic diagram of the interlayer relative slip.

[0041] Figure 4 Schematic diagram of interlayer relative slip calculation.

[0042] Figure 5 It is a structural schematic diagram of the column base node embedment-slip measurement device.

[0043] Figure 6 This is a schematic diagram of the structure of a small displacement combined sensor.

[0044] Figure 7 It is a cross-sectional diagram of the column base node pressure-slip measurement device and a schematic diagram of the relative slip pressure of the components.

[0045] Figure 8 Schematic diagram of the calculation of relative interlayer compression slip when the small displacement combined sensor and the rotation point are on the same side.

[0046] Fig. 9 Schematic diagram of the calculation of relative interlayer compression slip when the small displacement combined sensor and the rotation point are on opposite sides.

[0047] Fig.10 It is a structural schematic diagram of the device for measuring the compression and extraction amount of mortise and tenon joints.

[0048] Fig.11 It is a cross-sectional diagram of the device for measuring the compression and tenon-tenon joint joints and a schematic diagram of the compression and tenon-tenon joints of the components.

[0049] Fig.12 Schematic diagram of interlayer tenon-mortise and tenon compression calculation when the small displacement combined sensor and the rotation point are on the same side.

[0050] Fig.13 Schematic diagram of interlayer tenon-mortise and tenon pressure calculation when the small displacement combined sensor and the rotation point are on opposite sides.

[0051] In the figure: 1- tilt sensor, 2- small displacement sensor, 3- second layer of bracket, 4- first layer of bracket, 5- thin nail, 6- ram's horn hook, 7- spring, 8- dovetail spring clamp, 9- upper wooden component, 10- lower wooden component, 11- small displacement combination sensor. DETAILED DESCRIPTION

[0052] A method for measuring deformation between wooden components of ancient buildings, including a sliding measurement device between bracket layers, a column foot node pressure-slip measurement device, and a mortise and tenon node pressure-tenon measurement device. The measurement system is mainly composed of three deformation measurement devices suitable for different positions. The measurement data is mainly collected through static strain gauges and simultaneously input into a computer terminal for real-time recording. After export, the data of the corresponding sensors are integrated to calculate the required deformation at each position.

[0053] Embodiment 1: A device for measuring the slippage between bracket layers, such as Figure 1 As shown, the measured wooden component includes the second layer of brackets 3 and the first layer of brackets 4. The measuring device includes two inclination sensors 1 (one is arranged on each layer to measure the inclination angle of the component) and two small displacement sensors 2 (arranged symmetrically and must be along the direction of relative sliding between the bracket components). The structure of the small displacement sensor 2 is as follows Figure 2 As shown, it includes a fixing unit (thin nail 5, ram's horn hook 6), a deformation unit (spring 7, dovetail spring clip 8) and a strain gauge, wherein the specification of the spring 7 is determined according to the spacing between the thin nail 5 and the ram's horn hook 6 and the maximum deformation of the dovetail spring clip 8, while ensuring that the deformation unit is in a tensioned state, it can also ensure that the spring 7 and the dovetail spring clip 8 have sufficient expansion and contraction (according to the characteristics of the dovetail spring clip 8, accurate data cannot be measured if the opening is too large or closed); the thin nail 5 is fixed on the second layer 3 of the bracket, the ram's horn hook 6 is fixed on the first layer 4 of the bracket, the deformation unit is connected between the thin nail 5 and the ram's horn hook 6, and after connection, the deformation unit is parallel to the bottom surface of the second layer 3 of the bracket, and the strain gauge is arranged on the dovetail spring clip 8.

[0054] The measurement includes the following steps:

[0055] S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit;

[0056] S2: After the inclination sensor 1 and the small displacement sensor 2 are arranged, the initial state of the small displacement sensor 2 is determined, that is, the arrangement height t of the deformation unit and the initial length l of the deformation unit are determined; the inclination sensor is connected to the computer terminal via the USB serial port, the strain gauge is connected to the static strain gauge, and the static strain gauge is connected to the computer terminal via the USB serial port.

[0057] S3: Test the deformation unit to check whether the small displacement sensor 2 works normally through the strain value output by the static strain gauge;

[0058] S4: After confirming that all sensors are correct, the measuring device enters the measuring state.

[0059] S5: If the bracket components of each layer slide and rotate relative to each other, the spatial position of the key points on the bracket components of each layer changes (point a becomes point c, point d becomes point e); at this moment, the strain gauge outputs the strain value through the static strain gauge, and the length l1 of the deformation unit at this moment is deduced from the calibrated displacement-strain relationship, and the angle θ between the bracket second layer 3 and the bracket first layer 4 is deduced from the angle value output by the inclination sensor 1;

[0060] S6: From the above data, the horizontal slip amount de between the second-layer bracket 3 and the first-layer bracket 4 at this moment is obtained.

[0061] Measurement principle and calculation method:

[0062] Figure 3 The figure shows the front view, cross-sectional view, simplified cross-sectional view and inter-layer relative slip diagram based on the simplified view. The change in distance between the fine nail 5 and the horn hook 6 can be measured by the deformation unit, and the rotation angle of each layer of components can be measured by the inclination sensor 1. Usually, components will be accompanied by relative rotation during the relative slip process. Therefore, in order to obtain a more accurate horizontal slip amount (the slip amount along the component relative to the rotation point), the elongation on one side or the shortening on one side cannot be directly taken during the calculation. The influence of the relative rotation angle must be considered.

[0063] In order to ensure the accuracy of the measurement results, some specific requirements need to be added:

[0064] 1) There is no strict requirement for the embedding depth of the fine nail 5, as long as it is firm; the horn hook 6 needs to be embedded as deep as possible, and the closer the hook ring is to the surface of the first layer 4 of the bracket, the better.

[0065] 2) The exposed part of the thin nail 5 on the second layer 3 of the bracket and the exposed part of the horn hook 6 on the first layer 4 of the bracket should have great rigidity and should hardly deform during the expansion and contraction of the deformation unit, otherwise the measurement will be inaccurate; they need to be reinforced if necessary.

[0066] 3) In the initial state, the deformation unit must be parallel to the bottom surface of the second layer 3 of the bracket, and can be adjusted by the height of the spring 7 hanging on the thin nail 5; the spring 7 cannot slide on the thin nail 5 during the expansion and contraction of the deformation unit.

[0067] 4) The spacing between the fine nail 5 and the horn hook 6, the specifications of the spring 7 and the maximum deformation of the dovetail spring clamp 8 need to match each other. In the initial state, the dovetail spring clamp 8 needs to be adjusted to an open state, usually half of its maximum deformation. In the process of relative sliding of the components and driving the deformation unit to extend and retract, the dovetail spring clamp 8 must not be closed or opened too much, and the elongation of the spring 7 must not exceed its elastic range. This requires a rough measurement of the horizontal slip of the component in advance. For example, if the rough measurement shows that the slip is about 10mm, the maximum deformation of the deformation unit must exceed 20mm to ensure that there is enough deformation on both sides for extension and retraction.

[0068] 5) The deformation unit needs to be calibrated before use: Use a metal tensile test distance meter, and the step length is determined according to the design range of the deformation unit. It is required to be no less than 5 points. For example, if the design range is 20mm, the maximum step length should be 5mm.

[0069] 6) Before the formal measurement, the deformation unit needs to be pulled and the changes in the monitoring data need to be observed to ensure that the small displacement sensor 2 works normally.

[0070] When the first and second bracket layers 4 and 3 slide relative to each other and rotate relative to each other, the deformation units of the small displacement sensors 2 on both sides are in different working states. The horizontal slip amount will be calculated based on the small displacement sensor 2 on the side close to the rotation point. In order to see the geometric relationship in the calculation process more clearly, an analysis will be carried out through a relative slip diagram with an abnormal proportion.

[0071] like Figure 4 As shown, the initial points are a, b, d, and f. After the component rotates and slides relative to each other, the length of the deformation unit changes from ab to bc, which can be inferred by the data output by the static strain gauge (the length change of the deformation unit is inferred by the displacement-strain relationship calibrated in advance). Point a becomes point c, point d becomes point e, and ce=ad; θ is the angle between the second layer 3 of the bracket and the first layer 4 of the bracket after relative rotation, which can be measured by the inclination sensor 1; the lengths of ab and bf can be obtained by actual measurement, and because the deformation unit is parallel to the component at the beginning, the quadrilateral abfd is a rectangle, so it can be known that ad=bf, ab=df; de is the horizontal slip between the second layer 3 of the bracket and the first layer 4 of the bracket, that is, the final required value.

[0072] The process of solving the horizontal slip is as follows: set the height of the deformation unit to t, that is, ad = bf = ce = t, the initial length of the deformation unit to l, that is, ab = df = l, and the length of the deformation unit after deformation to l1, that is, bc = l1, then the vertical projection ce of ce y =tsinθ, the horizontal projection of ce x = tcosθ, vertical projection of bc bc y =ad-ce y =t-tsinθ, horizontal projection of bc get

[0073] At this point, the process of solving the horizontal slip amount through the small displacement sensor 2 on the side close to the rotation point is completed. Theoretically, when the upper and lower layer components are both rigid bodies, the calculation can also be performed through the small displacement sensor 2 on the side far away from the rotation point, but in actual situations, the bracket wood components are usually long strips of wooden components with low rigidity and complex connections between each other. Therefore, when reciprocating relative slip and rotation occur between the upper and lower layers, the small displacement sensor 2 on the side close to the rotation point should always be used to calculate the horizontal slip amount to obtain a more accurate measurement result.

[0074] Embodiment 2: A device for measuring the pressure-slippage of a column foot node, such as Figure 5 As shown, the measured wooden component includes an upper wooden component 9 (such as a wooden column) and a lower wooden component 10 (such as a plain beam under the column), and the measuring device includes two inclination sensors 1 (one is installed on each of the upper wooden component 9 and the lower wooden component 10, and is used to measure the inclination angle of the component), and two small displacement combination sensors 11 (along the direction of relative movement between the components, they can be arranged symmetrically, or only one can be arranged on a single side). The small displacement combination sensor 11 includes a fixing unit (a thin nail 5 and a horn hook 6) and two groups of deformation units (a spring 7 and a dovetail spring clip 8, one group being horizontal and the other group being inclined), wherein the specification of the spring 7 is determined according to the spacing between the thin nail 5 and the horn hook 6 and the maximum deformation of the dovetail spring clip 8, so as to ensure that the deformation unit is in a tensioned state while ensuring that the spring 7 and the dovetail spring clip 8 have sufficient expansion and contraction (accurate data cannot be measured if the dovetail spring clip is opened too wide or closed according to the characteristics of the dovetail spring clip); the thin nail 5 is vertically fixed on the lower wooden component 10, and the horn hook 6 is horizontally fixed on the upper wooden component 9; one end of the horizontal deformation unit is hung on the horn hook 6, and the other end is hung on the top of the thin nail 5; one end of the inclined deformation unit is hung on the horn hook 6, and the other end is hung on the junction of the thin nail 5 and the lower wooden component 10; and the strain gauge is arranged on the top surface of the dovetail spring clip 8.

[0075] The measurement includes the following steps:

[0076] S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit;

[0077] S2: After the inclination sensor 1 and the small displacement combination sensor 11 are arranged, the initial state of the small displacement combination sensor 11 is determined, that is, the arrangement height t of the horizontal deformation unit and the initial length l of the horizontal deformation unit are determined; the inclination sensor is connected to the computer terminal through the USB serial port, the strain gauge is connected to the static strain gauge, and the static strain gauge is connected to the computer terminal through the USB serial port;

[0078] S3: Test the deformation unit to check whether the small displacement combined sensor 11 works normally through the strain value output by the static strain gauge;

[0079] S4: After confirming that all sensors are correct, the measuring device enters the measuring state;

[0080] S5: When the measured component undergoes relative rotation, sliding and embedded compression deformation, the spatial position of each key point of the measured component changes. When the small displacement combined sensor 11 and the rotation point are on the same side, the length l1 of the horizontal deformation unit and the length l2 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. When the small displacement combined sensor 11 and the rotation point are on the opposite side, the length l3 of the horizontal deformation unit and the length l4 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. Finally, the angle θ between the upper wooden component 9 and the lower wooden component 10 is deduced through the angle value output by the inclination sensor 1.

[0081] S6: The horizontal slip and vertical pressure between the upper wood member 9 and the lower wood member 10 are obtained from the above data. When the small displacement combined sensor 11 and the rotation point are on the same side, the horizontal slip Vertical pressure When the small displacement combined sensor 11 is on the opposite side to the rotation point, the horizontal slip Vertical pressure D is the width of the contact surface between the upper wooden component 9 and the lower wooden component 10 . If the upper wooden component 9 is a wooden column, D is equal to the bottom diameter of the upper wooden component 9 .

[0082] Measurement principle and calculation method:

[0083] In order to ensure the accuracy of the measurement results, some specific requirements need to be added:

[0084] 1) There is no strict requirement for the embedding depth of the thin nail 5, as long as it is firm; the horn hook 6 needs to be embedded as deeply as possible, and the closer the hook ring is to the surface of the upper wooden member 9, the better.

[0085] 2) The exposed part of the thin nail 5 on the lower wooden component 10 and the exposed part of the horn hook 6 on the upper wooden component 9 should have great rigidity and should hardly deform during the expansion and contraction of the deformation unit, otherwise the measurement will be inaccurate; they need to be reinforced if necessary.

[0086] 3) In the initial state, the horizontal deformation unit must be parallel to the lower wooden component 10, and the height of the deformation unit hanging on the thin nail 5 can be adjusted by the spring 7. The inclined deformation unit connects the horn hook 6 and the junction of the thin nail 5 and the lower wooden component 10; the two sets of deformation units cannot slide on the thin nail 5 during the extension and retraction process.

[0087] 4) The spacing between the fine nail 5 and the horn hook 6, the specifications of the spring 7 and the maximum deformation of the dovetail spring clamp 8 need to match each other. In the initial state, the dovetail spring clamp 8 needs to be adjusted to an open state, usually half of its maximum deformation. In the process of relative movement of the components and driving the deformation unit to extend and retract, the dovetail spring clamp 8 must not be closed or opened too much, and the elongation of the spring 7 must not exceed its elastic range. This requires testing the relative movement of the components in advance, determining the range required for each deformation unit through the triangular geometric relationship, and using dovetail spring clamps 8 and springs 7 of appropriate specifications.

[0088] 5) The deformation unit needs to be calibrated before use: Use a metal tensile test distance meter, and the step length is determined according to the design range of the deformation unit. It is required to be no less than 5 points. For example, if the design range is 20mm, the maximum step length should be 5mm.

[0089] 6) Before formally measuring, the deformation unit needs to be pulled and the changes in monitoring data need to be observed to ensure that the small displacement combination sensor 11 works normally.

[0090] Figure 7 In the figure, there are the front view of the device, the simplified diagram, and the schematic diagram of relative sliding and compression of components based on the simplified diagram. The change in the side length of the triangle between the fine nail 5 and the horn hook 6 can be measured by the combined deformation unit, and the rotation angle of each component can be measured by the inclination sensor 1. For this type of node composed of vertical compression components and transverse compression components [the wooden column and the lower plain beam of the column are a typical example. The wooden column is compressed vertically along the grain, and the lower plain beam is compressed horizontally across the grain], due to the significant difference in the vertical and transverse compression properties of wood, the components will be accompanied by a certain degree of compression deformation during the relative rotation and sliding process, causing relatively serious damage to the components. Therefore, the sensors arranged at this type of node must be able to simultaneously measure the relative sliding and compression deformation between components.

[0091] When the components undergo reciprocating relative motion, the positions of the relative rotation points between the components will also change reciprocatingly. For the small displacement combination sensor 11 on one side, it will periodically face the situations where the rotation point is on the same side and the rotation point is on the opposite side. Since the upper wooden component 9 is more rigid than the lower wooden component 10 and can be approximately regarded as a rigid body, and the connection method between the components is simple, only the small displacement combination sensor 11 on one side can be used to infer the relative slip and embedment pressure under different situations through geometric relationships, that is, the required measurement results can be obtained by arranging the small displacement combination sensor 11 on only one side; of course, the small displacement combination sensor 11 can also be arranged symmetrically on both sides to facilitate comparison and verification of the calculation results on both sides to improve the final measurement accuracy.

[0092] In order to more clearly see the geometric relationship in the calculation process, the analysis will be carried out through a schematic diagram with non-normal scale;

[0093] (1) The following calculation is for the case where the small displacement combined sensor and the rotation point are on the same side.

[0094] like Figure 8 As shown, the initial points are a, b, d, and f. After the components rotate, slide, and embed, the lengths of the two groups of deformation units change from ab to bc and from af to cf, respectively, which can be inferred from the data output by the static strain gauge (the length change of the deformation unit is inferred from the displacement-strain relationship calibrated in advance). Point a becomes point c, point d becomes point e, and ce=ad; θ is the angle between the upper wooden component 9 and the lower wooden component 10 after relative rotation, which can be measured by the inclination sensor 1; the lengths of ab and bf can be obtained through actual measurement, and because the quadrilateral abfd is a rectangle, it can be known that ad=bf, ab=df; the horizontal projection of de is the horizontal slip between the upper wooden component 9 and the lower wooden component 10, and the vertical projection of de is the embedding deformation between the upper wooden component 9 and the lower wooden component 10, that is, the final required value.

[0095] The process of solving the horizontal slip and vertical embedding is as follows: the height of the horn hook 6 is set to t, that is, ad = bf = ce = t, the horizontal distance from the thin nail 5 to the horn hook 6 is l, that is, ab = df = l, and the lengths of the deformation unit after deformation are l1 and l2, that is, bc = l1, cf = l2, then the vertical projection ce of ce is y =tsinθ, the horizontal projection of ce x = tcosθ, vertical projection of bc Horizontal projection of bc Get the horizontal projection (slip) of de: The vertical projection (embedded) of de:

[0096] (2) The following calculates the situation where the small displacement combined sensor and the rotation point are on opposite sides.

[0097] like Fig. 9 As shown, the initial points are a, b, d, f, and g. After the components rotate, slide, and embed, the lengths of the two groups of deformation units change from ab to bc and from af to cf, respectively, which can be inferred from the data output by the static strain gauge (the length change of the deformation unit is inferred from the displacement-strain relationship calibrated in advance). Point a becomes point c, point d becomes point i, and point g becomes point h, ci=ad, hi=dg; θ is the angle between the upper wooden component 9 and the lower wooden component 10 after relative rotation, which can be measured by the inclination sensor 1; the lengths of ab and bf can be obtained through actual measurement, and because the quadrilateral abfd is a rectangle, it can be known that ad=bf, ab=df; the horizontal projection of gh is the horizontal slip between the upper wooden component 9 and the lower wooden component 10, and the vertical projection of gh is the embedding deformation between the upper wooden component 9 and the lower wooden component 10, that is, the final required value.

[0098] The process of solving the horizontal slip and vertical embedding is as follows: the bottom diameter of the upper wooden component 9 (taking the wooden column as an example) is set to D, that is, dg = hi = D, the height of the horn hook 6 is t, that is, ad = bf = ci = t, the horizontal distance from the thin nail 5 to the horn hook 6 is l, that is, ab = df = l, and the lengths of the deformation unit after deformation are bc = l3 and cf = l4, respectively. Then the vertical projection ci of ci is y =tsinθ, the horizontal projection ci of ci x =tcosθ, the vertical projection of hi y =Dcosθ, horizontal projection of hi x =Dsinθ, vertical projection of bc Horizontal projection of bc The horizontal projection (slip) of gh is: Vertical projection of gh (embedded):

[0099] Embodiment 3: A device for measuring the compression and extraction amount of a mortise and tenon joint, such as Fig.10As shown, the measured wood component includes an upper wood component 9 (such as a lintel) and a lower wood component 10 (such as a wooden column). The measuring device includes two inclination sensors 1 (one is installed on each of the upper wood component 9 and the lower wood component 10, for measuring the inclination angle of the component), and two small displacement combination sensors 11 (along the direction of relative movement between the components, they can be arranged symmetrically, or only one can be arranged on one side). The small displacement combination sensor 11 includes a fixing unit (a thin nail 5, a horn hook 6) and two groups of deformation units (a spring 7, a dovetail spring clip 8, one group horizontal and one group inclined). The thin nail 5 is inverted and fixed vertically on the upper wood component 9, and the horn hook 6 is fixed horizontally on the lower wood component 10. One end of the horizontal deformation unit is hung on the horn hook 6, and the other end is hung on the top of the thin nail 5. One end of the inclined deformation unit is hung on the horn hook 6, and the other end is hung on the junction of the thin nail 5 and the upper wood component 9. The strain gauge is set on the dovetail spring clip 8.

[0100] The measurement includes the following steps:

[0101] S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit;

[0102] S2: After the inclination sensor 1 and the small displacement combination sensor 11 are arranged, the initial state of the small displacement combination sensor 11 is determined, that is, the arrangement height t of the horizontal deformation unit and the initial length l of the horizontal deformation unit are determined; the inclination sensor 1 is connected to the computer terminal through the USB serial port, the strain gauge is connected to the static strain gauge, and the static strain gauge is connected to the computer terminal through the USB serial port;

[0103] S3: Test the deformation unit to check whether the small displacement combined sensor 11 works normally through the strain value output by the static strain gauge;

[0104] S4: After confirming that all sensors are correct, the measuring device enters the measuring state;

[0105] S5: At a certain moment, when the measured component undergoes relative rotation, mortise and tenon pulling (relative sliding) and embedded compression deformation, the spatial position of each key point of the measured component changes. When the small displacement combined sensor 11 and the rotation point are on the same side, the length l1 of the horizontal deformation unit and the length l2 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. When the small displacement combined sensor 11 and the rotation point are on the opposite side, the length l3 of the horizontal deformation unit and the length l4 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. Finally, the angle θ between the upper wooden component 9 and the lower wooden component 10 is deduced through the angle value output by the inclination sensor 1.

[0106] S6: The horizontal pulling amount and vertical pressing amount between the upper wood member 9 and the lower wood member 10 are obtained from the above data. When the small displacement combined sensor 11 and the rotation point are on the same side, the horizontal pulling amount Vertical pressure When the small displacement combined sensor 11 and the rotation point are on the opposite side, the horizontal tenon pull amount Vertical pressure D′ is the width of the contact surface between the lower wooden member 10 and the upper wooden member 9 . If the lower wooden member 10 is a wooden column, D′ is equal to the bottom diameter of the lower wooden member 10 .

[0107] Fig.11 The figure shows the front view, cross-section, simplified cross-section, and simplified diagram of the component mortise and tenon insertion and compression. The change in the side length of the triangle between the fine nail 5 and the horn hook 6 can be measured by the combined deformation unit, and the rotation angle of each component can be measured by the inclination sensor 1. In the mortise and tenon joint, the relative slip between the components can be regarded as mortise and tenon insertion.

[0108] When the components undergo reciprocating relative motion, the positions of the relative rotation points between the components will also change reciprocatingly. For the small displacement combination sensor 11 on one side, it will periodically face the situations where the rotation point is on the same side and the rotation point is on the opposite side. Since the lower wooden component 10 is more rigid than the upper wooden component 9 and can be approximately regarded as a rigid body, and the connection method between the components is simple, only the small displacement combination sensor 11 on one side can be used to calculate the relative tenon pull-out amount and embedding pressure under different situations through geometric relationships, that is, the required measurement results can be obtained by arranging the small displacement combination sensor 11 on only one side; of course, the small displacement combination sensor 11 can also be arranged symmetrically on both sides to facilitate comparison and verification of the calculation results on both sides to improve the final measurement accuracy.

[0109] In order to more clearly see the geometric relationship in the calculation process, the analysis will be carried out through a schematic diagram with non-normal scale;

[0110] (1) The following calculation is for the case where the small displacement combined sensor and the rotation point are on the same side.

[0111] like Fig.12As shown, the initial points are a, b, d, and f. After the relative rotation, tenon pulling (relative slip), and embedding and pressing of the components, the lengths of the two groups of deformation units change from ab to bc and from af to cf, respectively, which can be inferred from the data output by the static strain gauge (the length change of the deformation unit is inferred from the displacement-strain relationship calibrated in advance). Point a becomes point c, point d becomes point e, and ce=ad; θ is the angle between the upper wooden component 9 and the lower wooden component 10 after the relative rotation, which can be measured by the inclination sensor; the lengths of ab and bf can be obtained through actual measurement, and because the quadrilateral abfd is a rectangle, it can be known that ad=bf, ab=df; the horizontal projection of de is the amount of tenon pulling (relative slip) between the upper wooden component 9 and the lower wooden component 10, and the vertical projection of de is the amount of embedding and pressing deformation between the upper wooden component 9 and the lower wooden component 10, that is, the final required value.

[0112] The process of solving the horizontal mortise and tenon pull and vertical embedding is as follows: Assume that the height of the horn hook 6 is t, that is, ad = bf = ce = t, the horizontal distance from the thin nail 5 to the horn hook 6 is l, that is, ab = df = l, and the lengths of the deformation unit after deformation are l1 and l2, that is, bc = l1, cf = l2, then the vertical projection ce of ce is y =tsinθ, the horizontal projection of ce x = tcosθ, vertical projection of bc Horizontal projection of bc The horizontal projection of de (pulling the tenon): The vertical projection (embedded) of de:

[0113] (2) The following calculates the situation where the small displacement combined sensor and the rotation point are on opposite sides.

[0114] like Fig.13 As shown, the initial points are a, b, d, f, and g. After the relative rotation, tenon pulling (relative slip), and embedding and pressing of the components, the lengths of the two groups of deformation units change from ab to bc and from af to cf, respectively, which can be inferred from the data output by the static strain gauge (the length change of the deformation unit is inferred from the displacement-strain relationship calibrated in advance). Point a becomes point c, point d becomes point i, and point g becomes point h, ci=ad, hi=dg; θ is the angle between the upper wooden component 9 and the lower wooden component 10 after relative rotation, which can be measured by the inclination sensor; the lengths of ab and bf can be obtained through actual measurement, and because the quadrilateral abfd is a rectangle, it can be known that ad=bf, ab=df; the horizontal projection of gh is the amount of tenon pulling (relative slip) between the upper wooden component 9 and the lower wooden component 10, and the vertical projection of gh is the amount of embedding and pressing deformation between the upper wooden component 9 and the lower wooden component 10, that is, the final required value.

[0115] The process of solving the horizontal mortise and tenon pull and vertical embedding amount is as follows: Assume that the bottom diameter of the wood component 10 (taking the wood column as an example) is D′, that is, dg=hi=D′, the height of the horn hook 6 is t, that is, ad=bf=ci=t, the horizontal distance from the nail 5 to the horn hook 6 is l, that is, ab=df=l, the lengths of the deformation unit after deformation are bc=l3 and cf=l4, then the vertical projection ci of ci is y =tsinθ, the horizontal projection ci of ci x =tcosθ, the vertical projection of hi y =D′cosθ, the horizontal projection of hi x =D′sinθ, the vertical projection of bc Horizontal projection of bc The horizontal projection of gh (pulling tenon): Vertical projection of gh (embedded):

Claims

1. A method for measuring deformation between wooden components of ancient buildings, characterized by: The invention comprises a device for measuring the slippage between bracket layers, the device comprising an inclination sensor (1) and a small displacement sensor (2), the small displacement sensor (2) comprising a fixing unit and a deformation unit, the fixing unit further comprising a thin nail (5) and a horn hook (6), the deformation unit further comprising a spring (7), a dovetail spring clip (8) and a strain gauge; the inclination sensor (1) is fixedly installed on both the upper bracket component and the lower bracket component, the small displacement sensor (2) is symmetrically arranged between the upper bracket component and the lower bracket component, wherein the thin nail (5) is fixed on the upper bracket component, the horn hook (6) is fixed on the lower bracket component, the deformation unit is connected between the thin nail (5) and the horn hook (6), after the connection, the deformation unit is parallel to the bottom surface of the upper bracket component, and the strain gauge is arranged on the dovetail spring clip (8); The measuring device comprises the following steps when measuring: S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit; S2: After the inclination sensor (1) and the small displacement sensor (2) are arranged, the initial state of the small displacement sensor (2) is determined, that is, the arrangement height t of the deformation unit and the initial length l of the deformation unit are determined; S3: Test the deformation unit to check whether the small displacement sensor (2) works normally through the strain value output by the static strain gauge; S4: After confirming that all sensors are correct, the measuring device enters the measuring state; S5: If the bracket components of each layer slide and rotate relative to each other, the spatial position of the key points on the bracket components of each layer changes; at this moment, the strain gauge in the small displacement sensor (2) on the same side as the rotation point outputs the strain value through the static strain gauge, and the length l1 of the deformation unit at this moment is deduced from the calibrated displacement-strain relationship, and the angle θ between the bracket components of each layer is deduced from the angle value output by the inclination sensor (1); S6: The horizontal slip amount de between the upper and lower bracket components at this moment is obtained from the above data.

2. A method for measuring deformation between wooden components of ancient buildings according to claim 1, characterized in that: The invention also comprises a column foot node embedding pressure-slippage measurement device, which comprises an inclination sensor (1) and a small displacement combination sensor (11); the small displacement combination sensor (11) comprises a fixing unit and two groups of deformation units, the fixing unit further comprises a fine nail (5) and a horn hook (6), and each group of deformation units further comprises a spring (7), a dovetail spring clip (8) and a strain gauge; the inclination sensor (1) is fixedly installed on the upper wooden component (9) and the lower wooden component (10), and the small displacement combination sensor (11) is fixedly installed on the upper wooden component (9) and the lower wooden component (10). ) is vertically fixed on the lower wooden member (10), the horn hook (6) is horizontally fixed on the upper wooden member (9), one end of a group of deformation units is hung on the horn hook (6), and the other end is hung on the top of the thin nail (5), this group of deformation units is a horizontal deformation unit, parallel to the lower wooden member (10), another group of deformation units is hung on one end of the horn hook (6), and the other end is hung on the junction of the thin nail (5) and the lower wooden member (10), this group of deformation units is an inclined deformation unit, and the strain gauge is set on the dovetail spring clamp (8); The measuring device comprises the following steps when measuring: S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit; S2: after the inclination sensor (1) and the small displacement combined sensor (11) are arranged, the initial state of the small displacement combined sensor (11) is determined, that is, the arrangement height t of the horizontal deformation unit and the initial length l of the horizontal deformation unit are determined; S3: Testing the deformation unit to check whether the small displacement combined sensor (11) works normally by the strain value output by the static strain gauge; S4: After confirming that all sensors are correct, the measuring device enters the measuring state; S5: When the measured component undergoes relative rotation, sliding and embedded compression deformation, the spatial position of each key point of the measured component changes. When the small displacement combined sensor (11) and the rotation point are on the same side, the length l1 of the horizontal deformation unit and the length l2 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. When the small displacement combined sensor (11) and the rotation point are on the opposite side, the length l3 of the horizontal deformation unit and the length l4 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. Finally, the angle θ between the upper wooden component (9) and the lower wooden component (10) is deduced through the angle value output by the inclination sensor (1); S6: The relative slip and pressure between the upper wood member (9) and the lower wood member (10) at this moment are obtained from the above data. When the small displacement combined sensor (11) and the rotation point are on the same side, the relative slip Embedded pressure When the small displacement combined sensor (11) and the rotation point are on opposite sides, the relative slip Embedded pressure D is the width of the contact surface between the upper wood member (9) and the lower wood member (10).

3. A method for measuring deformation between wooden components of ancient buildings according to claim 2, characterized in that: The invention also comprises a device for measuring the amount of mortise and tenon joint compression and extraction, the device comprising an inclination sensor (1) and a small displacement combination sensor (11); the small displacement combination sensor (11) comprises a fixing unit and two groups of deformation units, the fixing unit further comprises a thin nail (5) and a horn hook (6), the deformation unit further comprises a spring (7), a dovetail spring clip (8) and a strain gauge; the inclination sensor (1) is fixedly installed on the upper wooden component (9) and the lower wooden component (10), the thin nail (5) in the small displacement combination sensor (11) is inverted, and the deformation unit (7) is inverted. The deformation unit is arranged to be vertically fixed on the upper wooden component (9), and the horn hook (6) is horizontally fixed on the lower wooden component (10). One end of a group of deformation units is hung on the horn hook (6), and the other end is hung on the top of the thin nail (5). The deformation unit is a horizontal deformation unit parallel to the upper wooden component (9). One end of another group of deformation units is hung on the horn hook (6), and the other end is hung on the junction of the thin nail (5) and the upper wooden component (9). The deformation unit is an inclined deformation unit, and the strain gauge is arranged on the dovetail spring clamp (8). The measuring device comprises the following steps when measuring: S1: Use the metal tensile test distance meter to calibrate the displacement-strain relationship of the deformation unit; S2: after the inclination sensor (1) and the small displacement combined sensor (11) are arranged, the initial state of the small displacement combined sensor (11) is determined, that is, the arrangement height t of the horizontal deformation unit and the initial length l of the horizontal deformation unit are determined; S3: Testing the deformation unit to check whether the small displacement combined sensor (11) works normally by the strain value output by the static strain gauge; S4: After confirming that all sensors are correct, the measuring device enters the measuring state; S5: At a certain moment, when the measured component undergoes relative rotation, tenon extraction and compression deformation, the spatial positions of the key points of the measured component change. When the small displacement combined sensor (11) and the rotation point are on the same side, the length l1 of the horizontal deformation unit and the length l2 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. When the small displacement combined sensor (11) and the rotation point are on the opposite side, the length l3 of the horizontal deformation unit and the length l4 of the inclined deformation unit at this moment are deduced from the calibrated displacement-strain relationship through the strain value output by the static strain gauge. Finally, the angle θ between the upper wooden component (9) and the lower wooden component (10) is deduced through the angle value output by the inclination sensor (1); S6: The pulling amount and the embedding amount between the upper wood member (9) and the lower wood member (10) are obtained from the above data. When the small displacement combined sensor (11) and the rotation point are on the same side, the pulling amount Embedded pressure When the small displacement combined sensor (11) and the rotation point are on opposite sides, the pulling amount Embedded pressure D' is the width of the contact surface between the lower wood member (10) and the upper wood member (9).

Images