Method for determining constitutive model of infilled wall considering stiffness contribution

Abstract

The application discloses a method for determining a filled wall constitutive model considering stiffness contribution, and relates to the field of finite element simulation, which comprises the following steps: establishing a five-section constitutive model of a diagonal bracing, determining the elastic modulus of the diagonal bracing, the tangent modulus of a strengthening section of the diagonal bracing, the corresponding secant modulus of the ultimate strain of the diagonal bracing, the ultimate strength of the diagonal bracing, the yield strength, the residual strength, the starting point strain corresponding to the ultimate strength of the diagonal bracing, and the end point strain corresponding to the ultimate strength of the diagonal bracing, correcting the ultimate strength of the diagonal bracing, the yield strength and the residual strength by using a strength reduction coefficient, and correcting the starting point strain corresponding to the ultimate strength of the diagonal bracing by using a starting point strain correction coefficient. The application can give material parameters of a simplified model corresponding to a wall body under the influence of different factors, and then accurately simulate the stiffness contribution of different wall bodies at different stages to the structure, so as to realize a structure modeling method considering the stiffness of the filled wall.

Description

Technical Field

[0001] This invention relates to the field of finite element simulation, and more particularly to a method for determining the constitutive model of an infill wall that considers stiffness contribution. Background Technology

[0002] Masonry infill walls are widely used in various structural forms due to their readily available and inexpensive materials, relatively simple construction process, and good thermal insulation, fire resistance, and durability. Current codes stipulate that seismic calculations should consider the impact of non-structural components such as infill walls on structural stiffness by reducing the fundamental period of the structure. Based on this idea, in structural design, infill walls are often treated as uniformly distributed line loads applied to the beams, and they provide some support and deformation coordination to the outer frame. This simplification ignores the stiffness contribution of the infill walls to the outer frame; therefore, considering the stiffness contribution of infill walls is of great significance for structural performance evaluation.

[0003] Masonry infill walls are composite materials composed of multiple materials. Their internal workings are relatively complex and their stress characteristics differ significantly from those of homogeneous walls. Therefore, extracting their stress characteristics and simplifying the wall into one or more abstract stress members is a reasonable approach. Among these, the diagonal brace model is widely used due to its reasonable stress calculation and simplicity. The diagonal brace model simplifies the wall into a diagonal brace with hinged ends, which is only subjected to compressive stress and cannot withstand tensile stress.

[0004] Currently, the parameters of diagonal braces, as an abstract representation of walls, are influenced by numerous factors related to the wall structure. Current methods primarily focus on adjusting the geometric properties of the braces to correct their axial stiffness, neglecting the determination of their material parameters. Masonry infill walls are multi-material composites composed of mortar and blocks, making their calculation and simulation challenging. Furthermore, the parameters of experimental specimens in model tests exhibit uncertainty due to construction quality and loading conditions, further complicating the systematic determination of diagonal brace parameters. Summary of the Invention

[0005] The main objective of this invention is to provide a method for determining the constitutive model of an infill wall that considers stiffness contribution, thereby solving the technical problem of difficulty in determining the parameters of a simplified model of an infill wall in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for determining the constitutive model of an infill wall considering stiffness contribution, the method comprising:

[0008] A five-segment constitutive model of diagonal bracing is established to reflect the stiffness degradation of infill walls. The five-segment constitutive model of diagonal bracing includes an elastic stage, a strengthening stage, a crack propagation stage, a plastic flow stage, and a failure stage.

[0009] Obtain the block's elastic modulus, block shear modulus, elastic modulus reduction factor, and shear modulus reduction factor; and based on the block's elastic modulus, block shear modulus, elastic modulus reduction factor, and shear modulus reduction factor, obtain the diagonal brace's elastic modulus.

[0010] Based on the elastic modulus of the diagonal brace, the tangent modulus of the reinforced section of the diagonal brace and the secant modulus corresponding to the ultimate strain of the diagonal brace are obtained.

[0011] Obtain the viscous force damage coefficient and friction correction coefficient of the infill wall under ultimate load, and obtain the ultimate strength of the diagonal brace based on the viscous force damage coefficient and friction correction coefficient.

[0012] Based on the ultimate strength of the diagonal brace, the yield strength and residual strength are obtained;

[0013] Obtain the strain ductility coefficient, and based on the strain ductility coefficient, the ultimate strength of the diagonal brace, the yield strength, and the residual strength, obtain the starting strain and the ending strain corresponding to the ultimate strength of the diagonal brace.

[0014] Obtain the strength reduction factor, and correct the ultimate strength, yield strength, and residual strength of the diagonal brace based on the strength reduction factor;

[0015] Obtain the starting strain correction coefficient, and correct the starting strain corresponding to the ultimate strength of the diagonal brace based on the starting strain correction coefficient.

[0016] Optionally, in the above method for determining the constitutive model of the infill wall considering stiffness contribution, the step of obtaining the block elastic modulus, block shear modulus, elastic modulus reduction factor, and shear modulus reduction factor, and obtaining the diagonal brace elastic modulus based on the block elastic modulus, block shear modulus, elastic modulus reduction factor, and shear modulus reduction factor, includes:

[0017] The shear modulus of the wall is obtained based on the shear modulus of the masonry block and the shear modulus reduction factor.

[0018] The elastic modulus of the wall is obtained based on the elastic modulus of the block and the elastic modulus reduction factor.

[0019] The bending stiffness and shear stiffness of the wall are obtained based on the wall shear modulus, the wall elastic modulus, the height, cross-sectional area and moment of inertia of the infill wall.

[0020] Based on the bending stiffness and shear stiffness of the wall, the lateral stiffness of the infill wall is obtained;

[0021] The elastic modulus of the diagonal brace is obtained based on the lateral stiffness of the infill wall.

[0022] Optionally, in the above method for determining the constitutive model of the infill wall considering stiffness contribution, the step of obtaining the viscous force damage coefficient and friction correction coefficient of the infill wall under ultimate load, and obtaining the ultimate strength of the diagonal brace based on the viscous force damage coefficient and friction correction coefficient, includes:

[0023] Obtain the tangential bond strength and viscous force damage coefficient of the mortar;

[0024] The mortar joint bond strength is obtained based on the tangential bond strength and the viscous force damage coefficient.

[0025] The friction coefficient of mortar, the tangential bond strength of mortar, the bending capacity of the frame beam, and the normal average contact stress between the wall and the frame are obtained to obtain the friction force of the mortar joint.

[0026] The ultimate load of the wall is obtained based on the joint adhesion and joint friction.

[0027] The ultimate strength of the diagonal brace is obtained based on the ultimate load of the wall.

[0028] Optionally, in the above method for determining the constitutive model of the infill wall considering stiffness contribution, obtaining the strain ductility coefficient includes:

[0029] Obtain the thickness and aspect ratio of the infill wall;

[0030] The strain ductility coefficient is determined based on the thickness and aspect ratio of the infill wall.

[0031] Optionally, in the above method for determining the constitutive model of the infill wall considering stiffness contribution, obtaining the starting strain corresponding to the ultimate strength of the brace and the ending strain corresponding to the ultimate strength of the brace based on the strain ductility coefficient, the ultimate strength of the brace, the yield strength, and the residual strength includes:

[0032] The strain ductility coefficient is defined as the ratio of the initial strain corresponding to the ultimate strength of the brace to the final strain corresponding to the ultimate strength of the brace.

[0033] Determine the starting strain corresponding to the ultimate strength of the diagonal brace based on its elastic modulus, ultimate strength, yield strength, and residual strength.

[0034] The endpoint strain corresponding to the ultimate strength of the diagonal brace is determined based on the starting strain and strain ductility coefficient corresponding to the ultimate strength of the diagonal brace.

[0035] Optionally, in the above method for determining the constitutive model of the infill wall considering stiffness contribution, the step of obtaining the strength reduction factor and correcting the ultimate strength, yield strength, and residual strength of the diagonal brace based on the strength reduction factor includes:

[0036] The relationship between yield strength and opening ratio is fitted using a quadratic function to determine the yield strength reduction factor of the diagonal brace, and the yield strength is corrected based on the yield strength reduction factor of the diagonal brace.

[0037] The relationship between the ultimate strength of the diagonal brace and the opening ratio is fitted using an exponential function to determine the ultimate strength reduction factor of the diagonal brace, and the ultimate strength of the diagonal brace is corrected based on the ultimate strength reduction factor of the diagonal brace.

[0038] By fitting the relationship between residual strength and opening ratio using a linear function, the residual strength reduction factor is determined, and the residual strength is corrected based on the residual strength reduction factor.

[0039] Optionally, in the above method for determining the constitutive model of the infill wall considering stiffness contribution, the step of obtaining the initiation strain correction coefficient and correcting the initiation strain corresponding to the ultimate strength of the diagonal brace according to the initiation strain correction coefficient includes:

[0040] The starting strain correction factor is defined as the ratio of the starting strain of the diagonal brace of the wall without horizontal eccentricity at the opening to the starting strain of the diagonal brace of the wall with horizontal eccentricity at the opening.

[0041] The initial strain correction coefficient is determined using the fitting formula;

[0042] Based on the aforementioned starting strain correction coefficient, the starting strain corresponding to the ultimate strength of the diagonal brace is corrected.

[0043] The above-described one or more technical solutions provided by this invention can have the following advantages or at least achieve the following technical effects:

[0044] This invention proposes a method for determining the constitutive model of an infill wall considering stiffness contribution. This method involves establishing a five-segment constitutive model of the diagonal brace to reflect the stiffness degradation of the infill wall; obtaining the elastic modulus, shear modulus, elastic modulus reduction factor, and shear modulus reduction factor of the masonry blocks; obtaining the elastic modulus of the diagonal brace based on these parameters; obtaining the tangential modulus of the reinforced segment and the secant modulus corresponding to the ultimate strain of the diagonal brace based on the elastic modulus of the diagonal brace; obtaining the viscous force damage coefficient and friction correction factor of the infill wall under ultimate load; and obtaining the ultimate strength of the diagonal brace based on these parameters. The ultimate strength of the diagonal brace is used to obtain the yield strength and residual strength; the strain ductility coefficient is obtained, and based on the strain ductility coefficient, the ultimate strength of the diagonal brace, the yield strength, and the residual strength, the starting strain and the ending strain corresponding to the ultimate strength of the diagonal brace are obtained; the strength reduction coefficient is obtained, and the ultimate strength, yield strength, and residual strength of the diagonal brace are corrected based on the strength reduction coefficient; the starting strain correction coefficient is obtained, and the starting strain corresponding to the ultimate strength of the diagonal brace is corrected based on the starting strain correction coefficient. This method can provide the material parameters of the simplified model corresponding to the wall under different influencing factors, and thus accurately simulate the contribution of different walls to the stiffness of the structure at different stages, thereby realizing a structural modeling method that considers the stiffness of the infill wall. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A flowchart illustrating the first embodiment of the method for determining the constitutive model of an infill wall considering stiffness contribution according to the present invention;

[0047] Figure 2 A five-segment constitutive model of diagonal bracing to reflect the stiffness degradation of infill walls;

[0048] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0050] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0051] In this invention, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element. Furthermore, the meaning of "and / or" throughout the text includes three parallel options; for example, "A and / or B" includes option A, option B, or options where both A and B are satisfied.

[0052] In this invention, unless otherwise explicitly specified and limited, the terms "connection" and "fixed" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements.

[0053] In this invention, if there are descriptions involving "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0054] In this invention, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" can be used interchangeably.

[0055] For those skilled in the art, the specific meanings of the above terms in this invention can be understood according to the specific circumstances. Furthermore, the technical solutions of the various embodiments can be combined with each other; however, this is based on the premise that those skilled in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0056] Example 1

[0057] Reference Figures 1 to 2 This paper presents a first embodiment of the method for determining the constitutive model of an infill wall that considers stiffness contribution.

[0058] The method includes:

[0059] Step S100: Establish a five-segment constitutive model of the diagonal brace to reflect the stiffness degradation of the infill wall, wherein the five-segment constitutive model of the diagonal brace includes an elastic stage, a strengthening stage, a crack propagation stage, a plastic flow stage, and a failure stage;

[0060] Step S200: Obtain the block elastic modulus, block shear modulus, elastic modulus reduction coefficient, and shear modulus reduction coefficient; and obtain the diagonal brace elastic modulus based on the block elastic modulus, block shear modulus, elastic modulus reduction coefficient, and shear modulus reduction coefficient.

[0061] Step S300: Based on the elastic modulus of the diagonal brace, obtain the tangent modulus of the reinforced section of the diagonal brace and the secant modulus corresponding to the ultimate strain of the diagonal brace;

[0062] Step S400: Obtain the viscous force damage coefficient and friction force correction coefficient of the infill wall under the ultimate load, and obtain the ultimate strength of the diagonal brace based on the viscous force damage coefficient and friction force correction coefficient.

[0063] Step S500: Obtain the yield strength and residual strength based on the ultimate strength of the diagonal brace;

[0064] Step S600: Obtain the strain ductility coefficient. Based on the strain ductility coefficient, the ultimate strength of the diagonal brace, the yield strength, and the residual strength, obtain the starting strain corresponding to the ultimate strength of the diagonal brace and the ending strain corresponding to the ultimate strength of the diagonal brace.

[0065] Step S700: Obtain the strength reduction factor, and correct the ultimate strength, yield strength, and residual strength of the diagonal brace according to the strength reduction factor;

[0066] Step S800: Obtain the starting strain correction coefficient, and correct the starting strain corresponding to the ultimate strength of the diagonal brace according to the starting strain correction coefficient.

[0067] This invention proposes a method for determining the constitutive model of an infill wall considering stiffness contribution. This method involves establishing a five-segment constitutive model of the diagonal brace to reflect the stiffness degradation of the infill wall; obtaining the elastic modulus, shear modulus, elastic modulus reduction factor, and shear modulus reduction factor of the masonry blocks; obtaining the elastic modulus of the diagonal brace based on these parameters; obtaining the tangential modulus of the reinforced segment and the secant modulus corresponding to the ultimate strain of the diagonal brace based on the elastic modulus of the diagonal brace; obtaining the viscous force damage coefficient and friction correction factor of the infill wall under ultimate load; and obtaining the ultimate strength of the diagonal brace based on these parameters. The ultimate strength of the diagonal brace is used to obtain the yield strength and residual strength; the strain ductility coefficient is obtained, and based on the strain ductility coefficient, the ultimate strength of the diagonal brace, the yield strength, and the residual strength, the starting strain and the ending strain corresponding to the ultimate strength of the diagonal brace are obtained; the strength reduction coefficient is obtained, and the ultimate strength, yield strength, and residual strength of the diagonal brace are corrected based on the strength reduction coefficient; the starting strain correction coefficient is obtained, and the starting strain corresponding to the ultimate strength of the diagonal brace is corrected based on the starting strain correction coefficient. This method can provide the material parameters of the simplified model corresponding to the wall under different influencing factors, and thus accurately simulate the contribution of different walls to the stiffness of the structure at different stages, thereby realizing a structural modeling method that considers the stiffness of the infill wall.

[0068] Further, the step of obtaining the block's elastic modulus, block shear modulus, elastic modulus reduction factor, and shear modulus reduction factor, and obtaining the diagonal brace's elastic modulus based on the block's elastic modulus, block shear modulus, elastic modulus reduction factor, and shear modulus reduction factor, includes:

[0069] The shear modulus of the wall is obtained based on the shear modulus of the masonry block and the shear modulus reduction factor.

[0070] Specifically, G w =α G G b ;

[0071] In the formula, G w Let α be the shear modulus of the wall. G G is the shear modulus reduction factor. b This is the shear modulus of the wall.

[0072] The elastic modulus of the wall is obtained based on the elastic modulus of the block and the elastic modulus reduction factor.

[0073] Concrete, E m =α E E b ,

[0074] In the formula, E m Let α be the elastic modulus of the wall. E E is the shear elastic reduction coefficient.b This refers to the elastic modulus of the block.

[0075] In one example, the elastic modulus reduction factor and the shear modulus reduction factor were obtained by parameter estimation using simulated data, with the elastic modulus reduction factor being 0.876 and the elastic modulus reduction factor being 0.421.

[0076] The bending stiffness and shear stiffness of the wall are obtained based on the wall shear modulus, the wall elastic modulus, the height, cross-sectional area and moment of inertia of the infill wall.

[0077] Specifically,

[0078]

[0079]

[0080]

[0081] In the formula, K fl K sh For the flexural stiffness and shear strength of the wall; E m G w h represents the elastic modulus and shear modulus of the wall. w A w I w Let be the height, cross-sectional area, and moment of inertia of the infill wall.

[0082] Based on the bending stiffness and shear stiffness of the wall, the lateral stiffness of the infill wall is obtained;

[0083] The elastic modulus of the diagonal brace is obtained based on the lateral stiffness of the infill wall.

[0084] Specifically, based on the correspondence between the infill wall and the diagonal braces in the simplified model, the relationship between the axial stiffness of the diagonal braces and the lateral stiffness of the infill wall can be expressed as:

[0085]

[0086] The elastic modulus of the diagonal brace is obtained by using the lateral stiffness of the infill wall:

[0087]

[0088] In the formula, K w θ represents the lateral stiffness of the wall; A represents the cross-sectional area of ​​the diagonal brace; and θ represents the angle between the diagonal brace and the horizontal direction.

[0089] The cross-sectional area of ​​the diagonal brace is obtained by multiplying the wall thickness by the width of the diagonal brace. The calculation method for the width of the diagonal brace is as follows:

[0090] a = 0.175(λh) col ) -0.4 rinf ;

[0091]

[0092] In the formula, h col I col Here are the height and moment of inertia of the frame column; t inf h inf E represents the thickness and height of the infill wall. fe E m These are the elastic modulus of concrete and the elastic modulus of masonry, respectively.

[0093] Further, obtaining the viscous force damage coefficient and friction correction coefficient of the infill wall under ultimate load, and obtaining the ultimate strength of the diagonal brace based on the viscous force damage coefficient and friction correction coefficient, includes:

[0094] Obtain the tangential bond strength and viscous force damage coefficient of the mortar;

[0095] The mortar joint bond strength is obtained based on the tangential bond strength and the viscous force damage coefficient.

[0096] The friction coefficient of mortar, the tangential bond strength of mortar, the bending capacity of the frame beam, and the normal average contact stress between the wall and the frame are obtained to obtain the friction force of the mortar joint.

[0097] The ultimate load of the wall is obtained based on the joint adhesion and joint friction.

[0098] The ultimate strength of the diagonal brace is obtained based on the ultimate load of the wall.

[0099] Specifically, once the infill wall enters the plastic phase, the mortar contact surface is damaged, and the frictional behavior ends its dormant state. The ultimate load of the wall can be assessed by considering the mortar joint adhesion and frictional force.

[0100] F lim =F coh +F fri =cA w +μσ b tα b B,

[0101] In the formula, F coh F fri The bonding force and friction force provided by the mortar joint; c is the average shear bond stress of the mortar joint, μ is the coefficient of friction of the mortar, σ b The average normal contact stress between the frame and the wall is given by α, where t is the wall thickness and α is the stress between the frame and the wall. b This is the contact length coefficient, the ratio of the contact length between the infill wall and the frame to the wall width.

[0102] Due to the large load, the mortar joint has entered the damage development stage, and the mortar joint adhesion can be expressed as:

[0103] cA w =α c c0A w ,

[0104] In the formula, α c c is the viscous force damage coefficient when the wall is under ultimate load; c0 is the tangential bond strength of the mortar.

[0105] The bearing capacity provided by friction is affected by the vertical load on the wall. The vertical load on the wall is related to the bending capacity of the beam and the ratio of the stiffness of the frame to the wall. The calculation method is as follows:

[0106]

[0107] In the formula, α f The friction correction coefficient of the mortar joints when the wall is under ultimate load; P w M represents the tangential bond strength of the mortar. b0 σ represents the bending capacity of the frame beam. b0 The normal average contact stress of the wall and frame is determined according to the compressive strength of the masonry.

[0108] In one example, the viscous force damage coefficient and the friction force correction coefficient were obtained by parameter estimation using simulated data, with the viscous force damage coefficient being 0.522 and the friction force correction coefficient being 0.317.

[0109] In one example, the relationship between the elastic modulus of the diagonal brace and the secant modulus corresponding to the tangential modulus of the reinforced section and the ultimate strain is obtained by fitting simulated data.

[0110] E t =0.4435E y ;

[0111] E s =0.0047E y ;

[0112] In the formula, E y E represents the elastic modulus of the diagonal brace. t E represents the tangent modulus of the diagonal brace reinforcement segment. s This is the secant modulus corresponding to the ultimate strain of the diagonal brace.

[0113] In one example, the relationship between the ultimate strength, yield strength, and residual strength of the brace was obtained by fitting simulated data.

[0114] f y =0.563f m ;

[0115] fr =0.540f m ;

[0116] In the formula, f m f represents the ultimate strength of the diagonal brace. y f is the yield strength of the diagonal brace; r This represents the residual strength of the diagonal brace.

[0117] Further, obtaining the strain ductility coefficient includes:

[0118] Obtain the thickness and aspect ratio of the infill wall;

[0119] The strain ductility coefficient is determined based on the thickness and aspect ratio of the infill wall.

[0120] Specifically, the calculation method for the strain ductility coefficient of the infill wall under different influencing factors is as follows:

[0121]

[0122] In the formula, B / H is the width-to-height ratio of the wall; t w This refers to the wall thickness.

[0123] Further, the step of obtaining the starting strain and ending strain corresponding to the ultimate strength of the brace based on the strain ductility coefficient, the ultimate strength of the brace, the yield strength, and the residual strength includes:

[0124] The strain ductility coefficient is defined as the ratio of the initial strain corresponding to the ultimate strength of the brace to the final strain corresponding to the ultimate strength of the brace.

[0125] Determine the starting strain corresponding to the ultimate strength of the diagonal brace based on its elastic modulus, ultimate strength, yield strength, and residual strength.

[0126] The endpoint strain corresponding to the ultimate strength of the diagonal brace is determined based on the starting strain and strain ductility coefficient corresponding to the ultimate strength of the diagonal brace.

[0127] Specifically, the relationship between the ultimate strength of the diagonal brace and the initial and final strains is established:

[0128]

[0129]

[0130] In the formula, α s ε1 is the strain ductility coefficient of the diagonal brace, which reflects the plastic deformation capacity of the diagonal brace without significant reduction in bearing capacity after reaching its ultimate strength; ε2 is the strain at the starting point corresponding to the ultimate strength of the diagonal brace; ε3 is the strain at the ending point corresponding to the ultimate strength of the diagonal brace.

[0131] Further, obtaining the strength reduction factor, and correcting the ultimate strength, yield strength, and residual strength of the diagonal brace based on the strength reduction factor, includes:

[0132] The relationship between yield strength and opening ratio is fitted using a quadratic function to determine the yield strength reduction factor of the diagonal brace, and the yield strength is corrected based on the yield strength reduction factor of the diagonal brace.

[0133] The relationship between the ultimate strength of the diagonal brace and the opening ratio is fitted using an exponential function to determine the ultimate strength reduction factor of the diagonal brace, and the ultimate strength of the diagonal brace is corrected based on the ultimate strength reduction factor of the diagonal brace.

[0134] By fitting the relationship between residual strength and opening ratio using a linear function, the residual strength reduction factor is determined, and the residual strength is corrected based on the residual strength reduction factor.

[0135] Specifically, to account for the impact of the opening ratio on parameters such as the yield strength of the bracing model, a strength reduction factor is used to account for the strength degradation caused by the opening in the wall. The calculation method for the strength reduction factor is as follows:

[0136]

[0137] In the formula, α f f is the strength reduction factor for the diagonal brace; w,h For the corresponding strength index of the wall with openings; f w,c This refers to the corresponding strength index for walls without openings.

[0138] Since the impact of the opening ratio on the various parameters of the diagonal brace varies, quadratic, exponential, and linear functions are used to fit the relationship between yield strength, ultimate strength, residual strength, and opening ratio to determine the yield strength reduction factor α. fy Ultimate strength reduction factor α fm With residual strength reduction factor α fr The determination is as follows:

[0139] α fy =-0.008097φ 2 +-0.009770φ+0.9981;

[0140] α fm =1.2988e -0.01823φ -0.3101

[0141] α fr = -0.01272φ + 0.9698,

[0142] In the formula, α fy α fm α frφ represents the yield strength reduction factor, ultimate strength reduction factor, and residual strength reduction factor of the diagonal brace, and φ is the wall opening ratio.

[0143] Further, the step of obtaining the starting strain correction coefficient and correcting the starting strain corresponding to the ultimate strength of the diagonal brace based on the starting strain correction coefficient includes:

[0144] The starting strain correction factor is defined as the ratio of the starting strain of the diagonal brace of the wall without horizontal eccentricity at the opening to the starting strain of the diagonal brace of the wall with horizontal eccentricity at the opening.

[0145] The initial strain correction coefficient is determined using the fitting formula;

[0146] Based on the aforementioned starting strain correction coefficient, the starting strain corresponding to the ultimate strength of the diagonal brace is corrected.

[0147] Specifically, to account for the influence of horizontal eccentricity of the opening on parameters such as the initial strain of the bracing model, an initial strain correction factor is used to account for the change in the deformation capacity of the wall caused by the horizontal eccentricity of the opening. The relationship between the initial strain correction factor and the eccentricity distance for fitting door and window openings is as follows:

[0148]

[0149]

[0150] In the formula, α ε S is the strain correction factor at the starting point of the diagonal brace; S / B is the ratio of the eccentricity distance of the opening to the width of the wall.

[0151] It should be noted that the sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above embodiments are only optional embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made under the inventive concept of the present invention using the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are all included within the patent protection scope of the present invention.

Claims

1. A method for determining the constitutive model of an infill wall considering stiffness contribution, characterized in that, The method includes: A five-segment constitutive model of diagonal bracing is established to reflect the stiffness degradation of infill walls. The five-segment constitutive model of diagonal bracing includes an elastic stage, a strengthening stage, a crack propagation stage, a plastic flow stage, and a failure stage. Obtaining the block's elastic modulus, block shear modulus, elastic modulus reduction factor, and shear modulus reduction factor, and then obtaining the diagonal brace's elastic modulus based on these parameters, includes: obtaining the wall's shear modulus based on the block's shear modulus and shear modulus reduction factor; obtaining the wall's elastic modulus based on the block's elastic modulus and elastic modulus reduction factor; obtaining the wall's bending stiffness and shear stiffness based on the wall's shear modulus, wall's elastic modulus, infill wall's height, cross-sectional area, and moment of inertia; obtaining the infill wall's lateral stiffness based on the wall's bending stiffness and shear stiffness; and obtaining the diagonal brace's elastic modulus based on the infill wall's lateral stiffness. Based on the elastic modulus of the diagonal brace, the tangent modulus of the reinforced section of the diagonal brace and the secant modulus corresponding to the ultimate strain of the diagonal brace are obtained. The process involves obtaining the viscous force damage coefficient and friction correction coefficient of the infill wall under ultimate load, and then determining the ultimate strength of the diagonal brace based on these coefficients. This includes: obtaining the tangential bond strength and viscous force damage coefficient of the mortar; obtaining the mortar joint bond strength based on the tangential bond strength and viscous force damage coefficient; obtaining the mortar friction coefficient, mortar tangential bond strength, the bending capacity of the frame beam, and the normal average contact stress between the wall and the frame to obtain the mortar joint friction force; obtaining the ultimate load of the wall based on the mortar joint bond strength and mortar joint friction force; and obtaining the ultimate strength of the diagonal brace based on the ultimate load of the wall. Based on the ultimate strength of the diagonal brace, the yield strength and residual strength are obtained; Obtain the strain ductility coefficient, and based on the strain ductility coefficient, the ultimate strength of the brace, the yield strength, and the residual strength, obtain the starting strain and the ending strain corresponding to the ultimate strength of the brace. Obtain the strength reduction factor, and correct the ultimate strength, yield strength, and residual strength of the diagonal brace based on the strength reduction factor; Obtain the starting strain correction coefficient, and correct the starting strain corresponding to the ultimate strength of the diagonal brace based on the starting strain correction coefficient.

2. The method for determining the constitutive model of an infill wall considering stiffness contribution as described in claim 1, characterized in that, The process of obtaining the strain ductility coefficient includes: Obtain the thickness and aspect ratio of the infill wall; The strain ductility coefficient is determined based on the thickness and aspect ratio of the infill wall.

3. The method for determining the constitutive model of an infill wall considering stiffness contribution as described in claim 2, characterized in that, The process of obtaining the starting strain and ending strain corresponding to the ultimate strength of the diagonal brace based on the strain ductility coefficient, ultimate strength of the diagonal brace, yield strength, and residual strength includes: The strain ductility coefficient is defined as the ratio of the initial strain corresponding to the ultimate strength of the diagonal brace to the final strain corresponding to the ultimate strength of the diagonal brace. Determine the starting strain corresponding to the ultimate strength of the diagonal brace based on its elastic modulus, ultimate strength, yield strength, and residual strength. The endpoint strain corresponding to the ultimate strength of the diagonal brace is determined based on the starting strain and strain ductility coefficient corresponding to the ultimate strength of the diagonal brace.

4. The method for determining the constitutive model of an infill wall considering stiffness contribution as described in claim 1, characterized in that, The process of obtaining the strength reduction factor and correcting the ultimate strength, yield strength, and residual strength of the diagonal brace based on the strength reduction factor includes: The relationship between yield strength and opening ratio is fitted using a quadratic function to determine the yield strength reduction factor of the diagonal brace, and the yield strength is corrected based on the yield strength reduction factor of the diagonal brace. The relationship between the ultimate strength of the diagonal brace and the opening ratio is fitted using an exponential function to determine the ultimate strength reduction factor of the diagonal brace, and the ultimate strength of the diagonal brace is corrected based on the ultimate strength reduction factor of the diagonal brace. By fitting the relationship between residual strength and opening ratio using a linear function, the residual strength reduction factor is determined, and the residual strength is corrected based on the residual strength reduction factor.

5. The method for determining the constitutive model of an infill wall considering stiffness contribution as described in claim 1, characterized in that, The step of obtaining the starting strain correction coefficient and correcting the starting strain corresponding to the ultimate strength of the diagonal brace based on the starting strain correction coefficient includes: The starting strain correction factor is defined as the ratio of the starting strain of the diagonal brace of the wall without horizontal eccentricity at the opening to the starting strain of the diagonal brace of the wall with horizontal eccentricity at the opening. The initial strain correction coefficient is determined using the fitting formula; Based on the aforementioned starting strain correction coefficient, the starting strain corresponding to the ultimate strength of the diagonal brace is corrected.

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