A simplified modeling and optimization design method for modular building transverse connection nodes

Abstract

The present application belongs to the technical field of modular building, and particularly relates to a simplified modeling and optimized design method of a transverse connecting node of a modular building. The method comprises the following steps: step 1, obtaining parameters of a test specimen, modeling by using a layered shell unit, obtaining key calculation data, and constructing a constitutive relationship of a double-node unit; step 2, establishing an elastoplastic finite element model of a high-rise modular shear wall structure; step 3, performing elastoplastic analysis on the model, recording structural responses, and calculating damage parameters; and step 4, judging whether to adjust component design parameters according to a damage parameter limit value. The present application constructs a constitutive of a double-node unit of bending / shearing behavior by using layered shell simulation data, establishes a damage evaluation model under multiple levels of earthquakes, and optimizes the reinforcement ratio and the width of the post-pouring section based on the degree of damage overrun, thereby forming a closed loop of “constitutive modeling → structural analysis → damage evaluation → parameter optimization”, and providing a design platform with adjustable and controllable disaster resistance performance for high-rise modular buildings.

Description

Technical Field

[0001] This invention belongs to the field of modular building technology, specifically relating to a simplified modeling and optimized design method for lateral connection nodes in modular buildings. Background Technology

[0002] Currently, the construction industry faces several challenges, including labor shortages due to an aging population and significant environmental pollution from traditional construction sites. Modular construction, on the other hand, integrates a large number of prefabricated modules that can be pre-assembled off-site, alleviating labor and pollution issues. Furthermore, due to the increasing density of urban development, modular construction is also being increasingly applied to high-rise buildings.

[0003] In recent years, the seismic performance of high-rise modular buildings has received increasing attention, and research on its seismic performance mainly relies on numerical simulation. Simulation of the connections between modules is a key focus in numerical simulations of modular buildings. The simplest approach is to treat the modular structure as a cast-in-place structure; however, the joints between modules in modular buildings are prone to semi-rigidity, leading to significant simulation errors. The generalized modulus reduction method is a relatively convenient way to consider the connections between modules, but it cannot obtain the stress-strain state at these connections. Using spring elements to simulate the stress-strain state at the connections between modules is more direct; the parameters of the connecting springs can be defined through simple calculations using joint data obtained from previous experiments. Summary of the Invention

[0004] This invention discloses a simplified modeling and optimization design method for lateral connection nodes in modular buildings. By constructing a constitutive model of a two-node unit with bending / shear behavior using layered shell simulation data, a damage assessment model under multi-level earthquakes is established. Based on the degree of damage exceeding the limit, the reinforcement ratio and the width of the post-cast section are optimized, forming a closed loop of "constitutive modeling → structural analysis → damage assessment → parameter optimization", providing a design platform with adjustable disaster resistance performance for high-rise modular buildings.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A simplified modeling and optimized design method for lateral connection nodes in modular buildings includes the following steps:

[0007] Step 1. Obtain the parameters of the test specimen, use the layered shell element of the finite element software OpenSees to model it, obtain key calculation data, and construct the constitutive relation of the two-node element;

[0008] Step 2. Establish an elastic-plastic finite element model of the high-rise modular shear wall structure;

[0009] Step 3. Perform elastoplastic analysis on the model, record the structural response, and calculate the damage parameters;

[0010] Step 4. Determine whether to adjust the component design parameters based on the damage parameter limits.

[0011] Preferably, in step 1: by obtaining the load-mid-span deflection curve and load-slip curve, as well as the component deformation data, through simulated bending and shear tests of the transverse connection node, the constitutive relationship of the axial spring and shear spring of the post-cast section is established. The specific steps are as follows:

[0012] Step 1.1: Obtaining component information: including (1) Bending specimen information: width of post-cast section, reinforcement ratio, total length of slab, thickness of slab, and connection height of post-cast section; (2) Shear specimen information: reinforcement ratio of specimen, specimen thickness, and specimen width;

[0013] Step 1.2: Shell element modeling to obtain deformation data of the post-cast section: Use OpenSees software for modeling, use layered shell elements to model standard bending and shear members, simulate the bending test of the floor slab connection node to obtain the load-deflection curve of the bending member and the compression deformation of the upper part and the tensile deformation of the lower part of the post-cast section, simulate the load slip curve of the shear member of the floor slab connection node, and extract the feature points of the two curves, namely the yield point, the hardening point and the failure point;

[0014] Step 1.3: Bending Mechanical Equilibrium Analysis of the Member: Simplify the original shell element bending model by dividing the shell element bending slab model into two rigid body rectangles in the middle, and perform simplified force analysis on one part. The lower left corner of the left rigid body rectangle is subjected to support reaction force, the experimental loading force is applied at 2 / 3 of the rigid body length from the upper left corner, the upper right corner of the rectangle is subjected to horizontal compressive force F1, and the lower right corner of the rectangle is subjected to horizontal tensile force F2. Establish the simplified mechanical equilibrium equations under the bending test state of the member, and analyze the force situation in the compression and tension zones of the post-cast section:

[0015] ;

[0016] ;

[0017] ;

[0018] ;

[0019] ;

[0020] ;

[0021] In the above formula, y 挠度 L1 is the deflection in the direction of force at the middle of the shell element bending model, where L is the length of the rectangular rigid body, L2 is the width of the rectangular rigid body, and L1 = 2 / 3L.

[0022] Substitute the yield point, hardening point, and failure point parameters from the simulated load-deflection curves into the simplified mechanical equilibrium equations for calculating F1 and F2 under bending test conditions:

[0023] and ;

[0024] The compressive force F1 and tensile force F2 of the corresponding two-node element are calculated. Combined with the deformation data of the post-cast section, the trilinear hysteretic constitutive relation of the two-node axis is fitted to simulate the bending behavior under seismic action.

[0025] Step 1.4: Shear Mechanics Equilibrium Analysis of the Component: The mechanical model of the shell element shear component is simplified to three rigid rectangles. The middle rigid rectangle is connected to the left and right rigid rectangles respectively. The middle rigid rectangle is subjected to four shear forces, which come from the shear forces between the bottom of the middle rigid rectangle and the two side rigid rectangles, and the shear forces between the top of the two side rigid rectangles and the middle rigid rectangle. A simplified mechanical formula F=P / 4 is established under the shear test state of the component, where P is the load applied in the shear test, and F is the load of the shear constitutive relationship at the characteristic point of the load-slip curve to be calculated. The yield point, hardening point, and failure point parameters of the load-slip curve obtained from the simulation are substituted into the simplified mechanical formula F=P / 4 under the shear test state of the component to calculate the shear force F at the characteristic point. The slip at the characteristic point of the constitutive relationship is equal to the slip amount of the characteristic point of the load-slip curve obtained from the simulation, and the magnitude of the load is the same as F, thus obtaining the constitutive curve in the shear direction of the two nodes.

[0026] Step 1.5: Constituent Construction: The horizontal connection nodes of the modular building are simulated using dual-node elements. Hysteretic materials are used to define the mechanical properties of the dual-node elements on the local x-axis and local y-axis, that is, the bending and shearing capacity of the floor connection nodes.

[0027] Preferably, step 2 includes the following specific steps:

[0028] Step 2.1: Shear wall element: The shear wall is simulated using displacement-based beam-column elements, whose sections are defined by concrete02 and steel02 fibers, and rigid arms are constructed using elastic beam-column elements with an elastic modulus magnified by 1000 times to simulate the length of the shear wall section and connect it to the coupling beam.

[0029] Step 2.2: Coupling Beam Element: The coupling beam is simulated using the same displacement-based beam-column element as the shear wall;

[0030] Step 2.3: Two-Node Unit: The twoNodeLink unit is used to simulate the mechanical properties of the floor slab joints. This unit is used to connect the corners of adjacent modules.

[0031] Step 2.4: Based on the following formula:

[0032] Bending capacity is calculated based on the connection length of the module, using the following formula:

[0033] ;

[0034] Shear capacity is calculated based on the shear area of ​​the module, using the following formula:

[0035] ;

[0036] The data of the standard specimen of the two-node element constitutive model established in step 1.5 are converted.

[0037] Preferably, step 3 includes the following specific steps:

[0038] Step 3.1: Select seismic waves: Select four earthquake intensities: frequent earthquakes, design earthquakes, rare earthquakes, and extremely rare earthquakes; perform elastoplastic time history analysis on the model;

[0039] Step 3.2 Record structural response data: Record the displacement of each point in the structure to calculate the inter-story drift angle; record the relative displacement of the two-node element on the x-axis and y-axis in the local coordinate system to obtain the compression deformation, tensile deformation and shear slip of the two-node element, so as to calculate the bending damage parameter and shear damage parameter.

[0040] Step 3.3: Calculate the bending damage parameters and shear damage parameters according to the formulas respectively;

[0041] Formula for calculating shear damage parameters: , where δ s δ represents the maximum relative slip in time history analysis. u It is the limit slip at the point of specimen failure obtained from testing or simulation;

[0042] Formula for calculating bending damage parameters: , where θ s θ represents the maximum bending deflection in the time history analysis. u It is the ultimate bending deflection at failure of the specimen, obtained from testing or simulation; according to the formula in step 1.3: ,according to Calculate .

[0043] Preferably, step 4 includes the following specific steps:

[0044] Step 4.1: Check whether the component meets the seismic resistance requirements under all four seismic intensity conditions, specifically:

[0045] Under frequent earthquakes, D s and D bIt should not exceed 0.08; under the design earthquake, D s and D b It should not exceed 0.3; under rare earthquakes, D s and D b It should not exceed 0.6; in extremely rare earthquakes, D s and D b It should not exceed 0.8;

[0046] Step 4.2: If the shear or bending damage parameters exceed the limit, the basic parameters of the component, namely the reinforcement ratio and the width of the post-cast section, should be adjusted. The adjustment formula is as follows:

[0047] ;

[0048] ;

[0049] These are the adjustment coefficients for shear damage parameters and bending damage parameters, respectively.

[0050] The above formula yields the modified values ​​for the new reinforcement ratio and the width of the post-cast section connection, at which point the basic information of the component changes.

[0051] Step 4.3: Starting from step 1.2 again, model the specimen based on the layered shell → obtain key point data → derive the axial / shear spring force through the mechanical equilibrium equation → construct the hysteretic constitutive model for the two-node element → establish the overall structural model (including the two-node connection) → perform elastoplastic analysis → calculate damage parameters → determine whether the seismic requirements are met.

[0052] Step 4.4: If the requirements are met, output the suggested component parameters.

[0053] The beneficial effects of the simplified modeling and optimized design method for lateral connection nodes in modular buildings of this invention are as follows:

[0054] 1. Compared with the generalized modulus reduction method, the present invention uses dual-node elements to better output the deformation and stress of the connecting nodes.

[0055] 2. This invention ingeniously decouples the deformation of the connection node into bending and shearing, and further decouples the bending of the connection node into tension at one end and compression at the other end, and calculates the mechanical constitutive model of the connection node through mechanical analysis.

[0056] 3. This invention derives formulas by fitting damage parameters, reinforcement ratio of connection nodes, and width of post-cast sections, enabling iterative design based on damage results after elastoplastic analysis, thus achieving optimized structural design. Attached Figure Description

[0057] Figure 1: Flowchart of the method of the present invention.

[0058] Figure 2 : Shell element load-deflection curve and shell element load-slip curve.

[0059] Figure 3 Simplified stress analysis diagram of a bending member.

[0060] Figure 4 Simplified stress analysis diagram of a shear member.

[0061] Figure 5 Flowchart for establishing an elastoplastic analysis model.

[0062] Figure 6 : Constitutive relations of the axial spring and shear spring in Example 6. Detailed Implementation

[0063] The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0064] The following embodiments can be understood as illustrating a part of the structure or method of the present invention individually, or as combining the embodiments to explain the broader structure or method of the present invention.

[0065] Example 1:

[0066] A simplified modeling and optimized design method for lateral connection nodes in modular buildings, such as... Figure 1 As shown, it includes the following steps:

[0067] Step 1. Obtain the parameters of the test specimen, use the layered shell element of the finite element software OpenSees to model it, obtain key calculation data, and construct the constitutive relation of the two-node element;

[0068] Step 2. Establish an elastic-plastic finite element model of the high-rise modular shear wall structure;

[0069] Step 3. Perform elastoplastic analysis on the model, record the structural response, and calculate the damage parameters;

[0070] Step 4. Determine whether to adjust the component design parameters based on the damage parameter limits.

[0071] Example 2:

[0072] Based on Example 1, this example discloses:

[0073] like Figure 2As shown, in step 1: by simulating the bending and shear resistance tests of the transverse connection nodes, the load-mid-span deflection curves and load-slip curves, as well as the component deformation data, are obtained, and the constitutive relationship between the axial spring and shear spring of the post-cast section is established. The specific steps are as follows:

[0074] Step 1.1: Obtaining component information: including (1) Bending specimen information: width of post-cast section, reinforcement ratio, total length of slab, thickness of slab, and connection height of post-cast section; (2) Shear specimen information: reinforcement ratio of specimen, specimen thickness, and specimen width;

[0075] For the flexural specimens, the total length of the slab is 2000mm, the thickness is 120mm, and the connection height of the post-cast section is generally 400mm. For the shear specimens, the main information needed is the reinforcement ratio; the thickness is the same as the actual slab, 400mm, and the overall width is 640mm. To facilitate the measurement of shear slip at the concrete connection interface in the shear displacement direction, the two side components are offset from the middle component by 100mm along the height direction, with a cross-sectional dimension of 120mm × 400mm.

[0076] Step 1.2: Shell element modeling to obtain deformation data of the post-cast section: Use OpenSees software for modeling, use layered shell elements to model standard bending and shear members, simulate the bending test of the floor slab connection node to obtain the load-deflection curve of the bending member and the compression deformation of the upper part and the tensile deformation of the lower part of the post-cast section, simulate the load slip curve of the shear member of the floor slab connection node, and extract the feature points of the two curves, namely the yield point, the hardening point and the failure point;

[0077] Step 1.3: Bending mechanical equilibrium analysis of the component: such as Figure 3 As shown, the original shell element bending model is simplified by dividing the shell element bending floor slab model into two rigid body rectangles, and a simplified force analysis is performed on one part. The lower left corner of the left rigid body rectangle is subjected to support reaction force, the experimental loading force is applied at 2 / 3 of the rigid body length from the upper left corner, the upper right corner of the rectangle is subjected to horizontal compressive force F1, and the lower right corner of the rectangle is subjected to horizontal tensile force F2. According to... Figure 3 A simplified mechanical equilibrium equation is established under bending test conditions of the component, and the stress conditions in the compression and tension zones of the post-cast section are analyzed:

[0078] ;

[0079] ;

[0080] ;

[0081] ;

[0082] ;

[0083] ;

[0084] In the above formula, y 挠度 L is the deflection in the direction of force at the middle of the shell element bending model, L is the length of the rectangular rigid body, L2 is the width of the rectangular rigid body, and L1 = 2 / 3L.

[0085] Substitute the yield point, hardening point, and failure point parameters from the simulated load-deflection curves into the simplified mechanical equilibrium equations for calculating F1 and F2 under bending test conditions:

[0086] and ;

[0087] The compressive force F1 and tensile force F2 of the corresponding two-node element are calculated. Combined with the deformation data of the post-cast section, the trilinear hysteretic constitutive relation of the two-node axis is fitted to simulate the bending behavior under seismic action.

[0088] Step 1.4: Shear equilibrium analysis of the component: such as Figure 4 As shown, the mechanical model of the shell element shear member is simplified into three rigid rectangles. The middle rigid rectangle is connected to the left and right rigid rectangles respectively. The middle rigid rectangle is subjected to four shear forces, which come from the shear forces at the bottom of the middle rigid rectangle and the two side rigid rectangles, and the shear forces at the top of the two side rigid rectangles and the middle rigid rectangle. A simplified mechanical formula for the member under shear test conditions is established: F=P / 4, where P is the load applied in the shear test, and F is the load of the shear constitutive relationship at the characteristic point of the load-slip curve to be calculated. The yield point, hardening point, and failure point parameters of the simulated load-slip curve are substituted into the simplified mechanical formula F=P / 4 under the member under shear test conditions to calculate the shear force F at the characteristic point. The slip at the constitutive relationship characteristic point is equal to the slip amount of the characteristic point of the simulated load-slip curve, and the magnitude of the load is the same as F, thus obtaining the constitutive curve in the shear direction of the two nodes.

[0089] Step 1.5: Constituent Construction: The lateral connection nodes of the modular building are simulated using two-node elements (elementtwoNodeLink). The mechanical properties of the two-node elements along the local x-axis and local y-axis are defined using uniaxial material hysteretic, which represents the bending and shearing capacity of the floor connection nodes.

[0090] Example 3:

[0091] Based on Example 1, this example discloses:

[0092] like Figure 5 As shown, step 2 includes the following specific steps:

[0093] Step 2.1: Shear wall element: The shear wall is simulated using displacement-based beam-column elements, whose sections are defined by concrete02 and steel02 fibers, and rigid arms are constructed using elastic beam-column elements with an elastic modulus magnified by 1000 times to simulate the length of the shear wall section and connect it to the coupling beam.

[0094] Step 2.2: Coupling Beam Element: The coupling beam is simulated using the same displacement-based beam-column element as the shear wall;

[0095] Step 2.3: Two-Node Unit: The twoNodeLink unit is used to simulate the mechanical properties of the floor slab joints. This unit is used to connect the corners of adjacent modules.

[0096] Step 2.4: Based on the following formula:

[0097] Bending capacity is calculated based on the connection length of the module, using the following formula:

[0098] ;

[0099] Shear capacity is calculated based on the shear area of ​​the module, using the following formula:

[0100] ;

[0101] The data of the standard specimen of the two-node element constitutive model established in step 1.5 are converted.

[0102] Example 4:

[0103] Based on Example 1, this example discloses:

[0104] Step 3 includes the following specific steps:

[0105] Step 3.1: Select seismic waves: Select four earthquake intensities: frequent earthquakes, design earthquakes, rare earthquakes, and extremely rare earthquakes; perform elastoplastic time history analysis on the model;

[0106] Step 3.2 Record structural response data: Record the displacement of each point in the structure to calculate the inter-story drift angle; record the relative displacement of the two-node element on the x-axis and y-axis in the local coordinate system to obtain the compression deformation, tensile deformation and shear slip of the two-node element, so as to calculate the bending damage parameter and shear damage parameter.

[0107] Step 3.3: Calculate the bending damage parameters and shear damage parameters according to the formulas respectively;

[0108] Formula for calculating shear damage parameters: , where δ sδ represents the maximum relative slip in time history analysis. u It is the limit slip at the point of specimen failure obtained from testing or simulation;

[0109] Formula for calculating bending damage parameters: , where θ s θ represents the maximum bending deflection in the time history analysis. u It is the ultimate bending deflection at failure of the specimen, obtained from testing or simulation; according to the formula in step 1.3: ,according to Calculate .

[0110] Example 5:

[0111] Based on Example 1, this example discloses:

[0112] Step 4 includes the following specific steps:

[0113] Step 4.1: Check whether the component meets the seismic resistance requirements under all four seismic intensity conditions, specifically:

[0114] Under frequent earthquakes, D s and D b It should not exceed 0.08; under the design earthquake, D s and D b It should not exceed 0.3; under rare earthquakes, D s and D b It should not exceed 0.6; in extremely rare earthquakes, D s and D b It should not exceed 0.8;

[0115] Step 4.2: If the shear or bending damage parameters exceed the limits, the basic parameters of the component, namely the reinforcement ratio and the width of the post-cast section, should be adjusted. The adjustment formula is as follows: The adjusted parameters will also change under different earthquake intensities. This is because under frequent earthquakes, we want the structure to maintain an elastic working state. At this time, the adjustment coefficient is larger because it can significantly increase the stiffness and strength of the structure to maintain an elastic working state. Under design earthquakes, rare earthquakes, and extremely rare earthquakes, the structure is difficult to maintain elasticity and dissipates huge seismic energy more through plastic deformation. Significantly increasing the reinforcement ratio and the width of the post-cast section connection may reduce the ductility of the structure, and the adjustment coefficient should be more conservative. Therefore, different adjustment parameters should be used for different earthquake intensities.

[0116] ;

[0117] ;

[0118] These are the adjustment coefficients for shear damage parameters and bending damage parameters, respectively.

[0119] As shown in the table below:

[0120]

[0121] The above formula yields the modified values ​​for the new reinforcement ratio and the width of the post-cast section connection, at which point the basic information of the component changes.

[0122] Step 4.3: Starting from step 1.2 again, model the specimen based on the layered shell → obtain key point data → derive the axial / shear spring force through the mechanical equilibrium equation → construct the hysteretic constitutive model for the two-node element → establish the overall structural model (including the two-node connection) → perform elastoplastic analysis → calculate damage parameters → determine whether the seismic requirements are met.

[0123] Step 4.4: If the requirements are met, output the suggested component parameters.

[0124] Example 6:

[0125] Based on the above embodiments, this embodiment provides a specific application example:

[0126] S1: Basic building information: This building has a seismic fortification intensity of 8 degrees, a basic design seismic acceleration of 0.2g, a seismic group of Group 3, a structural damping ratio of 0.05, a site category of Class II, a site characteristic period of 0.45s, and a seismic fortification category of Class C.

[0127] S2: For flexural specimens, the required information includes the width of the post-cast section, reinforcement ratio, total slab length of 2000mm, thickness of 120mm, and a post-cast section connection height typically taken as 400mm. For shear specimens, the required information mainly includes the reinforcement ratio; the thickness is the same as the actual slab, 400mm, and the overall width is 640mm. To facilitate the measurement of shear slip at the concrete connection interface in the shear slip direction, the two side components are offset from the middle component by 100mm along the height direction, with a cross-sectional dimension of 120mm × 400mm.

[0128] S3: Establish a shell element model to obtain the load-deflection curve and load-slip curve, as shown below. Figure 2 As shown. Simultaneously, the compression and tension of the post-cast section of the bending member are obtained.

[0129] S4: Define the constitutive relations of the two-node element in the local x-direction and local y-direction, as follows: Figure 6 As shown.

[0130] S5: Establishing the Elastoplastic Analysis Model: Shear Wall Elements: Shear walls are simulated using displacement-based beam-column elements. Their sections are defined by concrete02 and steel02 fibers. Rigid arms are constructed using elastic beam-column elements with a modulus of elasticity magnified 1000 times to simulate the length of the shear wall section and connect to the coupling beams. Coupling Beam Elements: Coupling beams are simulated using the same displacement-based beam-column elements as the shear walls. Two-Node Elements: TwoNodeLink elements are used to simulate the mechanical properties at floor slab joints, connecting the corners of adjacent modules. Since the two-node element constitutive model established in S4 uses data from standard specimens, it should be converted in the model.

[0131] S6: Perform elastoplastic analysis: Select earthquake waves: Select earthquake intensities of 4 magnitudes: frequent earthquake (PGA=0.07g), design earthquake (0.2g), rare earthquake (0.4g), and extremely rare earthquake (0.6g); Perform elastoplastic time history analysis on this model.

[0132] S7: Output Results: Record the displacement of each point in the structure to calculate the inter-story drift angle. Record the relative displacement of the two-node element along the x and y axes in the local coordinate system to obtain the compressive deformation, tensile deformation, and shear slip of the two-node element, in order to calculate the bending damage parameters and shear damage parameters. See the table below:

[0133]

[0134] S8: Analyze the results: and All are greater than the limit. The design results do not meet the design requirements, and adjustments need to be made to the reinforcement ratio of the components and the connection width of the post-cast sections.

[0135] S9: Perform over-limit adjustment: as shown in the table below:

[0136]

[0137] The adjusted reinforcement ratio and the width of the post-cast section should both be the maximum values ​​in the table. Based on the calculation results and the actual project conditions, the reinforcement ratio is taken as 1.23%, and the width of the post-cast section is taken as 1200mm.

[0138] S10: Repeat steps S1-S8 above.

[0139] S11: Output the adjusted results, as shown in the table below:

[0140]

[0141] It can be seen that, and All are less than the limit. The design results are reasonable. The adjusted component parameters are a reinforcement ratio of 1.23% and a post-cast section width of 1200mm.

[0142] Note: When the calculated reinforcement ratio exceeds 2.5%, or the width of the post-cast section exceeds 1800mm and still does not meet the limit value of the damage parameter requirements, the design of the vertical lateral force resisting members of the structure should be checked for rationality.

[0143] Working principle of the invention:

[0144] 1. The design method proposed in this invention adjusts the reinforcement ratio and post-cast section connection width of the connection nodes between modular building modules to ensure that they meet customized damage parameter limits under various seismic intensities. The damage parameter limits for the connection nodes can be set considering multiple factors, making it more consistent with the performance-based seismic engineering design philosophy than current seismic design codes.

[0145] 2. This invention decouples the deformation of the connection node under earthquake conditions into bending deformation and shear deformation, constructs the constitutive relationship between the shear capacity and bending capacity of the connection node, and uses a two-node element that can define mechanical properties in multiple directions to simulate the seismic performance of the connection node.

[0146] 3. Current design methods mostly modify the constitutive models of concrete and steel reinforcement materials using the generalized modulus reduction method to simulate the impact of joint damage on the structure. However, this method cannot accurately obtain the stress and deformation of the joints, and the computational burden of using solid elements for modeling is too high. To address the distortions of existing modulus reduction methods and the inefficiency of solid elements, a dual-node element approach is adopted to directly output joint deformation data. The experimental data is then converted using mechanical equilibrium equations to construct the constitutive model, achieving accurate and efficient simulation.

[0147] 4. This invention proposes an iterative design based on dynamic elastic-plastic analysis, which has a simple calculation method and achieves structural optimization design through iterative design.

Claims

1. A method of simplified modeling and optimized design of a modular building cross-connection node, characterized in that, It comprises the following steps: Step 1. Obtain the parameters of the test component, use the layered shell element of the finite element software OpenSees to model, obtain the key calculation data, and build the constitutive relation of the double-node element; the specific steps are: Step 1.1: Component information acquisition: including (1) bending-resistant component information: post-cast section width, reinforcement ratio, slab total length, slab thickness, post-cast section connection height; (2) shear-resistant component information: component reinforcement ratio, component thickness, component width; Step 1.2: Shell element obtains post-cast section deformation data: use OpenSees software for modeling, use layered shell element to model standard bending-resistant and shear-resistant components, simulate the bending-resistant test of the floor connection joint to obtain the bending-resistant component load-deflection curve and the compression deformation of the upper part and the tensile deformation of the lower part of the post-cast section, simulate the shear-resistant component load-slippage curve of the floor connection joint shear-resistant test, and extract the characteristic points of the two curves, namely the yield point, the strengthening point and the failure point; Step 1.3: Analysis of bending mechanics balance of components: simplify the original bending shell element model, divide the bending shell element floor slab model into two rigid rectangles from the middle, and simplify the stress analysis of a part; the left part of the rigid rectangle is subjected to the support reaction at the lower left corner, is subjected to the test load at a distance of 2 / 3 of the length of the rigid body from the left upper corner of the rigid body, is subjected to a horizontal pressure F1 at the right upper corner of the rectangular rigid body, and is subjected to a horizontal tension F2 at the right lower corner of the rectangular rigid body; the simplified mechanical equilibrium equation under the bending test state of the component is established, and the stress conditions of the compression zone and the tension zone of the post-cast section are analyzed: ； ； ； ； ； ； In the above formula, y 挠度 is the deflection of the force direction of the middle part of the bending model of the shell unit, L is the length of the rectangular rigid body, L2 is the width of the rectangular rigid body, and L1=2 / 3L. Substitute the yield point, strengthening point and failure point parameters of the simulated load-deflection curve into the simplified mechanical equilibrium equation under the bending test state to calculate the formula of F1 and F2: and ; Calculate the corresponding compression force F1 and tensile force F2 of the double-node element, combine the post-cast section deformation data, and fit the three-linear hysteretic constitutive relation of the double-node axial direction to simulate the bending behavior under seismic action; Step 1.4: Analysis of the mechanical equilibrium of the shear component: the mechanical model of the shell element shear component is simplified into three rigid rectangulars, the middle rigid rectangular is connected with the left and right rigid rectangulars, the middle rigid rectangular is subjected to four shear forces, which are derived from the shear forces between the bottom of the middle rigid rectangular and the two side rigid rectangulars and the shear forces between the top of the two side rigid rectangulars and the middle rigid rectangular; the simplified mechanical formula under the state of the shear test of the component is established , P2 is the loading load of the shear test, F V is the load to be calculated at the shear constitutive relationship of the characteristic point of the load-slip curve; the yield point, the strengthening point and the failure point parameters of the simulated load-slip curve are substituted into the simplified mechanical formula under the state of the shear test of the component , the shear force F V of the characteristic point is calculated; the slip of the characteristic point of the constitutive relationship is equal to the slip amount of the characteristic of the simulated load-slip curve, the size of the load is the same as F V , and the constitutive curve in the shear direction of the double-node is obtained; Step 1.5: Constitutive relation construction: the modular building transverse connection joint is simulated using a double-node element, and the hysteretic material is used to define the mechanical properties of the local x-axis and local y-axis of the double-node element, that is, the bending and shear capacity of the floor connection joint; Step 2. Establish an elastoplastic finite element model of a high-rise modular shear wall structure; Step 3. Perform elastoplastic analysis on the model, record the structure response, and calculate the damage parameter; Step 4. Determine whether to adjust the component design parameters according to the damage parameter limit value.

2. The method of simplified modeling and optimized design of a modular building cross-connection node according to claim 1, characterized in that, The step 2 comprises the following specific steps: Step 2.1: Shear wall element: the shear wall is simulated by a displacement-based beam-column element, the cross section of which is defined by concrete fibers concrete02 and steel fibers steel02, and an elastic beam-column element with an elastic modulus amplified by 1000 times is used to construct a rigid arm to simulate the length of the shear wall cross section and connect with the coupling beam; Step 2.2: Coupling beam element: the coupling beam is simulated by the same displacement-based beam-column element as the shear wall; Step 2.3: Double-node element: the twoNodeLink element is used to simulate the mechanical properties of the floor joint, and the corner parts of adjacent modules are connected using this element; Step 2.4: According to the following formula: The bending capacity is converted according to the length of the module, and the conversion formula is: ； The shear capacity is converted according to the shear area of the module, and the conversion formula is: ； The data of the standard component of the double-node unit constitutive established in step 1.5 is converted.

3. The method of simplified modeling and optimized design of a modular building cross-connection node according to claim 1, characterized in that, The step 3 comprises the following specific steps: Step 3.1, selecting seismic waves: selecting 4-level earthquake intensity: frequently occurring earthquake, earthquake prevention, rare earthquake, extremely rare earthquake; performing elastic-plastic time history analysis on the model; Step 3.2, recording structure response data: recording the displacement of each point of the structure to calculate the interlayer displacement angle; recording the relative displacement of the x-axis and y-axis of the double-node unit in the local coordinate system to obtain the compression deformation, tensile deformation and shear slip of the double-node unit, and to calculate the bending damage parameter and the shear damage parameter; Step 3.3, calculating the bending damage parameter and the shear damage parameter according to the formula respectively: Shear damage parameter calculation formula: where δ s is the maximum relative slip in the time history analysis, δ u is the ultimate slip at failure of the member from the test or simulation. Formula for calculating bending damage parameters: , where θ s θ represents the maximum bending deflection in the time history analysis. u It is the ultimate bending deflection at component failure, obtained through testing or simulation; according to the formula in step 1.3: ,according to Calculate .

4. The method of simplified modeling and optimized design of a modular building cross-connection node according to claim 3, characterized in that, The step 4 comprises the following specific steps: Step 4.1: check whether the component meets the seismic requirements under the four earthquake intensities, specifically: Under frequent earthquake, D s and D b not more than 0.08; under fortification earthquake, D s and D b not more than 0.3; Under rare earthquake, D s and D b not more than 0.6; under very rare earthquake, D s and D b not more than 0.8; Step 4.2: if the shear or bending damage parameter exceeds the limit value, adjust the basic parameters of the component, i.e. the reinforcement ratio and the width of the post-cast section, and the adjustment formula is as follows: ； ； are respectively a shear damage parameter adjustment coefficient, a bending damage parameter adjustment coefficient; Through the above formula, the modified value of the new reinforcement ratio and the post-cast section connection width is obtained, and the basic information of the component is changed at this time; Step 4.3 judges whether the seismic requirements are met; Step 4.4: when the requirements are met, output the component parameters.

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