Method for constructing a geopolymer coating bond slip constitutive model

Abstract

The present application provides a kind of construction method of geopolymer coating bond-slip constitutive model, it is related to concrete bond-slip constitutive research technical field, the present application carries out center pull test to geopolymer coating steel reinforced concrete test piece, obtains loading end slip, free end slip and bond stress data;Calculate relative slip and average bond stress, analyze relative slip and average bond stress, obtain the relationship between relative slip length and average bond stress, the relationship between relative slip length and average bond stress is corrected by geopolymer influence coefficient;Bond stress data are analyzed, and the relationship between relative anchoring position and relative bond stress is obtained;According to the relationship between the corrected relative slip length and average bond stress, and the relationship between relative anchoring position and relative bond stress, the bond-slip constitutive relationship of geopolymer coating is constructed, and the bond-slip constitutive relationship of geopolymer coating is corrected based on complex network entropy flow logic.

Description

Technical Field

[0001] This invention relates to the field of concrete bond-slip constitutive research technology, specifically a method for constructing a geopolymer coating bond-slip constitutive model. Background Technology

[0002] In existing bond-slip constitutive studies, global or local bond curve fitting is typically used to establish material interface relationships. However, these methods often treat the anchorage section as a global continuum, ignoring potential local differences along the anchorage length (such as coating thickness fluctuations, local peeling, manufacturing defects, or sensor point noise). This leads to deviations or physically intuitive distributions in the resulting constitutive relationships when faced with local anomalies or non-uniform interface conditions. More importantly, simple global fitting lacks an effective "correction" mechanism to specifically correct those local anomalies, rather than using global parameters to mask local problems, thus affecting the reliability of engineering designs and the model's extrapolation ability. To address this, this application proposes discretizing the bond anchorage length into network nodes and using the node bond stress and relative position slip as network flow-edge weights to detect and correct local anomaly distributions in a structured manner, thereby overcoming this shortcoming of traditional methods.

[0003] To address the shortcomings of traditional methods, two key capabilities are needed: first, to construct constraint indices based on discrete nodes that reflect the characteristics of "distribution and sequence"; and second, to adjust the model sparsly with minimal cost after discovering distribution anomalies, so that the constitutive relation is restored to a state that satisfies physical rationality, rather than changing global parameters on a large scale.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a method for constructing a constitutive model of adhesive slip of a geopolymer coating, so as to solve the problems mentioned in the background art.

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

[0007] A method for constructing a constitutive model of bond slip in a geopolymer coating, comprising the following steps:

[0008] Step 1: Conduct a center pull-out test on the concrete specimens of the polymer-coated steel reinforcement to obtain the center pull-out test data, which includes the slip at the loaded end, the slip at the free end, and the bond stress data.

[0009] Step 2: Calculate the relative slip based on the slip at the loaded end and the slip at the free end, obtain the average bond stress based on the bond stress data, analyze the relative slip and the average bond stress to obtain the relationship between the relative slip length and the average bond stress, and correct the relationship between the relative slip length and the average bond stress using the geopolymer influence coefficient;

[0010] Step 3: Analyze the bond stress data to obtain the relationship between relative anchorage position and relative bond stress; based on the corrected relationship between relative slip length and average bond stress, and the relationship between relative anchorage position and relative bond stress, construct the bond-slip constitutive relationship of the geopolymer coating;

[0011] Step 4: Divide the bond anchorage length of the reinforcing bar into M equally spaced network nodes, determine the area under the jurisdiction of each network node, calculate the relative position slip based on the slip at the loaded end and the slip at the free end, and regard the relative position slip of each node as the node flow and the bond stress as the node edge weight to construct entropy change order constraint;

[0012] Step 5: Identify anomalous nodes based on the entropy change characteristics of network nodes. Based on the minimum modification recovery model, apply sparsification adjustment only to the region under the jurisdiction of the anomalous node to restore the entropy change order constraint of the constitutive relation at the minimum cost, and derive the recovered geopolymer coating bond-slip constitutive relation.

[0013] Furthermore, the logic for obtaining the center pull-out test data is as follows:

[0014] 1.1 Prepare concrete specimens of polymer-coated steel bars. The two ends of the steel bars that pass through the specimen are designated as the free end and the loaded end, respectively. The section of the steel bars that extends into the specimen and is bonded to the concrete is designated as the bonded section, and the section of the steel bars that extends into the specimen and is not bonded to the concrete is designated as the unbonded section. Several strain gauges are placed in the bonded section of the steel bars.

[0015] 1.2 Place the specimen on the steel pier at the bottom of the reaction frame, with the loading end of the reinforcing bar extending downwards out of the reaction frame and fixed at the lower clamp of the universal tensile testing machine. The top of the reaction frame is fixed at the upper clamp of the universal tensile testing machine by clamping screws. Install displacement gauge No. 1 at the free end of the reinforcing bar, install displacement gauge No. 2 on the upper surface of the specimen, and install displacement gauges No. 3 and No. 4 on the upper surface of the specimen extending out of the steel pier.

[0016] 1.3 Start the universal tensile and compressive testing machine, pull the loading end of the steel bar downward at a loading rate of 1 mm / min, and obtain the strain data measured by the strain gauges and the displacement data measured by each displacement gauge in real time until the specimen fails.

[0017] 1.4 Analyze strain and displacement data to obtain real-time data on loaded end slip, free end slip, and bond stress.

[0018] Furthermore, the formula for calculating the slip at the free end is as follows:

[0019] ;

[0020] in, For free end sliding, Derive the displacement for displacement gauge No. 1. The derived displacement of displacement gauge No. 2;

[0021] The formula for calculating the slip at the loading end is:

[0022] ;

[0023] in, For loading end sliding, This refers to the unbonded length of the reinforcing steel, i.e., the length of the unbonded section. It refers to the bond anchorage length of the reinforcing steel, which is the length of the bonded section. , The derived displacements are for displacement gauges No. 3 and No. 4, respectively.

[0024] The strain data includes the strain magnitude and the distance from the strain point to the loading end; the strain data is analyzed according to elasticity theory and internal force balance relationship to obtain bond stress data, which includes bond stress and the distance from the strain point to the loading end, and the strain point is the strain gauge installation point of the steel bar bonded section.

[0025] Furthermore, the relative slip and the average bond stress at the same moment were calculated. The relative slip and average bond stress from multiple center pull-out tests were input into linear fitting software to obtain the relationship between the relative slip length and the average bond stress. The fitting result is expressed as follows:

[0026] ;

[0027] ;

[0028] in, For relative slip Average bond stress at time For relative slip, , , , These are undetermined coefficients, fitted using specific experimental data;

[0029] The relationship between slip length and average bond stress is corrected using the geopolymer influence coefficient, and is expressed as follows:

[0030] ;

[0031] in, For the corrected relative slip Corrected mean bond stress at that time This is relative slip;

[0032] Furthermore, the geopolymer influence coefficient is:

[0033] ;

[0034] in, The geopolymer influence coefficient, The aspect ratio of the geopolymer coating, The number of geopolymer coating layers. , The correction coefficients were obtained by fitting the center pull-out test data using the least squares method.

[0035] Furthermore, the formula for calculating the relative anchorage position is:

[0036] ;

[0037] in, For relative anchoring positions, The distance from the strain point to the loading end;

[0038] The formula for calculating relative bond stress is:

[0039] ;

[0040] in, The average bond stress is represented as At that time, relative anchoring position Relative bond stress at the location, The average bond stress is shown to be At that time, relative anchoring position Bond stress at the location;

[0041] Calculate the relative anchorage position and relative bond stress at each strain point. Input the relative anchorage position and relative bond stress at the relative anchorage position into image fitting software to obtain the relative anchorage position-relative bond stress curve. Simplify the relative anchorage position-relative bond stress curve by applying a broken line function to obtain the simplified relative anchorage position-relative bond stress curve, representing the relative anchorage position-relative bond stress as multiple segments. piecewise functions of the form ,in, , is the fitting constant.

[0042] Furthermore, the constitutive relation of the bond-slip of the geopolymer coating is as follows:

[0043] ;

[0044] in, For relative slip The relative anchoring position is The bonding stress at that time.

[0045] Furthermore, the bond anchorage length of the reinforcing bars is divided into M equal-length bond anchorage segments, with the center of each bond anchorage segment serving as a network node; the area governed by each network node is... , For the first The distance from each network node to the loading end. For indexes of network nodes;

[0046] The relative slip at specimen failure is obtained, and the bond stress and relative position slip of each network node are obtained based on the relative slip at failure and the constitutive relationship of the geopolymer coating bond slip.

[0047] The formula for calculating relative position slip is:

[0048] ;

[0049] in, Under the relative slip condition at failure, the first The relative positions of the nodes slide. This refers to the free end slip under relative slip at the time of failure. This refers to the loading end slippage under relative slippage at the time of failure;

[0050] The entropy-change order constraint is constructed as follows:

[0051] ;

[0052] ;

[0053] ;

[0054] ;

[0055] in, To represent the orderliness of entropy change, Under the relative slip condition at failure, the first Bond stress at each node, The entropy of the bond stress distribution. To preset the entropy of bond stress distribution, To represent the threshold of entropy change orderliness, These are the weight parameters.

[0056] Furthermore, determine whether the entropy change order constraint is satisfied when the failure occurs. If it is satisfied, it is considered that there are no abnormal network nodes, and the constitutive relationship of the geopolymer coating adhesion slip described in step 3 is directly derived.

[0057] If the entropy change order constraint is not satisfied, then the entropy change characteristic is calculated using the following formula:

[0058] ;

[0059] in, For the first The entropy change characteristics of each node; according to Sort the network nodes in descending order, and then... One network node is identified as an abnormal network node. To Round up;

[0060] Generate anomaly nodes that satisfy the entropy-change ordering constraint to adjust the initial population. Each individual in the anomaly node-adjusted initial population is represented as... , The first in the initial population Individual, Represents the first in the initial population Individual, the first The amount of bond stress adjustment for each abnormal network node, in order to Using a genetic algorithm to optimize the initial population with the goal of minimizing the population size, the optimal individual is obtained. The optimal individual is represented as... , For the optimal individual, For the first Optimal bond stress adjustment for anomalous network nodes This is an index for abnormal network nodes. This represents the total number of abnormal network nodes.

[0061] Furthermore, the specific adjustment principle is to maintain the bond-slip constitutive relationship of the geopolymer coating in non-abnormal network nodes and their respective jurisdictions, in accordance with... The adjustment size is used to adjust the adhesion-slip constitutive relation of the geopolymer coating for each abnormal network node and its jurisdiction.

[0062] Compared with the prior art, the beneficial effects of the present invention are:

[0063] This invention effectively identifies local anomalous nodes by discretizing the bonded anchorage length using a network and introducing entropy-varying order constraints, thus avoiding the masking of local defects by global fitting methods. Furthermore, it employs a minimum modification recovery model, implementing sparsification adjustments only in anomalous node regions and combining this with genetic algorithm optimization to restore the physical rationality of the constitutive relation at minimal cost. This method not only ensures the authenticity and continuity of experimental data in non-anomalous regions but also improves the model's sensitivity and correction ability to local anomalies, thereby enhancing the accuracy, stability, and engineering applicability of the constitutive relation. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the overall method flow of the present invention.

[0065] Figure 2 This is a distribution diagram of the displacement gauge sensors;

[0066] In the diagram: 1, displacement gauge No. 1; 2, displacement gauge No. 2; 3, displacement gauge No. 3; 4, displacement gauge No. 4. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0068] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0069] Example:

[0070] Please see Figure 1 The present invention provides a technical solution:

[0071] A method for constructing a constitutive model of bond slip in a geopolymer coating, comprising the following steps:

[0072] Step 1: Conduct a center pull-out test on the concrete specimens of the polymer-coated steel reinforcement to obtain the center pull-out test data, which includes the slip at the loaded end, the slip at the free end, and the bond stress data.

[0073] The logic for obtaining the center pull-out test data is as follows:

[0074] 1.1 Prepare concrete specimens of polymer-coated steel bars. The two ends of the steel bars that pass through the specimen are designated as the free end and the loaded end, respectively. The section of the steel bars that extends into the specimen and is bonded to the concrete is designated as the bonded section, and the section of the steel bars that extends into the specimen and is not bonded to the concrete is designated as the unbonded section. Several strain gauges are placed in the bonded section of the steel bars.

[0075] The preparation method is as follows: First, sodium silicate, sodium hydroxide, and purified water are mixed in a certain proportion to obtain sodium silicate solution and sodium hydroxide solution. After standing for 24 hours, they are mixed to obtain an alkaline activator. The solution is placed in a sealed glass container for later use. Then, graphene and silicon dioxide are added to the alkaline activator one after the other and dispersed in an ultrasonic disperser at 480W for 20 minutes to ensure that the nanomaterials are uniformly dispersed in the solution. At this time, the solution is transparent blackish-gray. Then, latex powder is slowly added to the mixed solution and stirred with a glass rod until the powder is evenly distributed. The solution is poured into a mixture of metakaolin, cement, and slag solid powders in a certain proportion, and stirred continuously. Then, an adhesive and an organosilicon defoamer are added in sequence and stirred evenly. Finally, styrene-acrylic emulsion is added and stirred slowly to obtain a metakaolin-based polymer coating.

[0076] 1.2 Place the specimen on the steel pier at the bottom of the reaction frame, with the loading end of the reinforcing bar extending downwards out of the reaction frame and fixed at the lower clamp of the universal tensile testing machine. The top of the reaction frame is fixed at the upper clamp of the universal tensile testing machine by clamping screws. Install displacement gauge 1 at the free end of the reinforcing bar, install displacement gauge 2 on the upper surface of the specimen, and install displacement gauge 3 and displacement gauge 4 on the steel pier extending out of the upper surface of the specimen.

[0077] Please see Figure 2 , Figure 2 This is a distribution diagram of the displacement gauge sensors;

[0078] 1.3 Start the universal tensile and compressive testing machine, pull the loading end of the steel bar downward at a loading rate of 1 mm / min, and obtain the strain data measured by the strain gauges and the displacement data measured by each displacement gauge in real time until the specimen fails.

[0079] 1.4 Analyze strain and displacement data to obtain real-time data on loaded end slip, free end slip, and bond stress.

[0080] Furthermore, the formula for calculating the slip at the free end is as follows:

[0081] ;

[0082] in, For free end sliding, Derive the displacement for displacement gauge No. 1. The derived displacement of displacement gauge No. 2;

[0083] The formula for calculating the slip at the loading end is:

[0084] ;

[0085] in, For loading end sliding, This refers to the unbonded length of the reinforcing steel, i.e., the length of the unbonded section. It refers to the bond anchorage length of the reinforcing steel, which is the length of the bonded section. , The derived displacements are for displacement gauges No. 3 and No. 4, respectively.

[0086] The strain data includes the strain magnitude and the distance from the strain point to the loading end; the strain data is analyzed according to elasticity theory and internal force balance relationship to obtain bond stress data, which includes bond stress and the distance from the strain point to the loading end, and the strain point is the strain gauge installation point of the steel bar bonded section.

[0087] Before the specimen failed due to bond stress, the stress and strain of the polymer-coated steel reinforcement were in the elastic stage (according to the relative relationship of forces, the elastic force and bond stress of the steel reinforcement are equal), therefore... , The elastic modulus of the reinforcing steel bar. At the strain point, the elastic force of the reinforcing steel. The strain value at the strain point. This represents the bond stress at the strain point.

[0088] Step 2: Calculate the relative slip based on the slip at the loaded end and the slip at the free end, obtain the average bond stress based on the bond stress data, analyze the relative slip and the average bond stress to obtain the relationship between the relative slip length and the average bond stress, and correct the relationship between the relative slip length and the average bond stress using the geopolymer influence coefficient;

[0089] Furthermore, the relative slip and the average bond stress at the same moment were calculated. The relative slip and average bond stress from multiple center pull-out tests were input into linear fitting software to obtain the relationship between the relative slip length and the average bond stress. The fitting result is expressed as follows:

[0090] ;

[0091] ;

[0092] in, For relative slip Average bond stress at time For relative slip, , , , These are undetermined coefficients, fitted using specific experimental data;

[0093] In this embodiment, the specific fitting result is as follows:

[0094] ;

[0095] The number of coating layers directly affects the interface complexity and mechanical transfer path between the steel reinforcement and concrete. When the coating is a single layer, the mechanical action between the steel reinforcement and concrete is mainly transmitted through a single interface. However, under multi-layer coating conditions, interlayer slip, energy dissipation, and additional weakening effects occur between the interfaces, resulting in the overall bond strength not being a simple linear additive relationship, but rather exhibiting a "layer number effect." Therefore, introducing the number of layers as a correction parameter can accurately reflect the attenuation or enhancement effect of the coating layer structure on bond-slip behavior.

[0096] The aspect ratio (i.e., the ratio of coating thickness to rebar diameter) reflects the relative thickness of the coating on the rebar surface. When the aspect ratio is small, the coating only serves as a surface modification, with limited impact on bond performance. As the aspect ratio increases, the contribution of the coating thickness relative to the rebar diameter becomes more significant, enhancing the isolation effect between the rebar and concrete, reducing interfacial friction, and potentially improving durability and delaying slip failure to a certain extent. Since this effect is significantly nonlinear, introducing the aspect ratio as a correction parameter allows for a systematic quantification of the difference in the effect of coating thickness on rebars of different diameters, thus enabling the model to have cross-size applicability.

[0097] The number of layers and aspect ratio of geopolymer coatings are the most important parameters reflecting their interfacial properties. The number of layers determines the complexity of the coating interface; multi-layer structures are prone to forming weakening zones and slip surfaces between interfaces, resulting in a stress transfer mechanism different from that of single-layer coatings. The aspect ratio reflects the relative scale of the coating thickness to the diameter of the reinforcing steel, directly affecting the effective exertion of mechanical interlocking force and interfacial friction. Therefore, selecting the number of layers and aspect ratio as correction factors can capture the main effects of geopolymer coatings on adhesion performance at the geometric scale and structural level.

[0098] Geopolymer coatings, after hardening, exhibit high density and chemical activity. On the one hand, they can enhance the durability and corrosion resistance of the reinforcing steel surface; however, the isolation layer they form can also affect the direct contact between the reinforcing steel and concrete. When the coating is thick, it weakens interfacial friction and mechanical interlocking, reducing bond stress. When the coating is too thin or the number of layers is insufficient, the coating is prone to localized failure under load, leading to stress concentration and bond degradation. Therefore, the effect of geopolymer coatings on bond stress can both enhance durability and delay bond failure, and may also introduce a stress-weakening effect, requiring quantitative correction for accurate reflection.

[0099] By introducing influence coefficients based on the number of layers and aspect ratio into the constitutive model, the effect of geopolymer coatings on bond stress can be quantitatively corrected. After correction, the model maintains high consistency and prediction accuracy under different coating thicknesses, number of layers, and rebar diameters. Especially in complex cases such as thick coatings and multi-layer coatings, the model avoids stress calculation biases and significantly improves its ability to describe bond-slip relationships. The corrected model not only enhances the reliability of geopolymer-coated rebar design but also provides a more solid theoretical foundation for its widespread application in high-durability engineering.

[0100] The relationship between slip length and average bond stress is corrected using the geopolymer influence coefficient, and is expressed as follows:

[0101] ;

[0102] in, For the corrected relative slip Corrected mean bond stress at that time This is relative slip;

[0103] Furthermore, the geopolymer influence coefficient is:

[0104] ;

[0105] in, The geopolymer influence coefficient, The aspect ratio of the geopolymer coating, The number of geopolymer coating layers. , The correction coefficients were obtained by fitting the center pull-out test data using the least squares method.

[0106] The center pull-out test data were analyzed using the least squares method to obtain correction coefficients. Existing techniques were employed to normalize the relative slip-mean bond stress data of specimens with different coating thicknesses and number of layers. First, a basic bond curve was obtained by fitting data from the uncoated or baseline group. Then, the logarithm of the ratio of the measured bond stress of each group to the baseline curve was taken, and a linear regression equation was constructed using the logarithm of the aspect ratio and the number of layers as independent variables. The regression coefficients were then solved using the least squares method to obtain the parameters in the influence coefficients. This method ensures that the sum of squared residuals for each parameter is minimized across the entire sample, and the fitting effect can be verified through residual distribution and the coefficient of determination, thus yielding a stable and generalizable expression for the influence coefficients.

[0107] Finally, the correction coefficients for the geopolymer materials and coatings are obtained. , .

[0108] The coefficient of variation (0.140) and variance (0.976) are less than 1, indicating that the calculation formula obtained from statistical regression has a good fit and can be used as a formula for calculating the bond anchorage strength between polymer-coated steel bars and concrete. Verification showed that the calculation results of this formula agree well with the experimental results and can effectively correct the relationship between bond stress and relative slip.

[0109] In this embodiment, The specific fitting results are as follows:

[0110] .

[0111] Step 3: Analyze the bond stress data to obtain the relationship between relative anchorage position and relative bond stress; based on the corrected relationship between relative slip length and average bond stress, and the relationship between relative anchorage position and relative bond stress, construct the bond-slip constitutive relationship of the geopolymer coating;

[0112] Furthermore, the formula for calculating the relative anchorage position is:

[0113] ;

[0114] in, For relative anchoring positions, The distance from the strain point to the loading end;

[0115] The formula for calculating relative bond stress is:

[0116] ;

[0117] in, The average bond stress is represented as At that time, relative anchoring position Relative bond stress at the location, The average bond stress is represented as At that time, relative anchoring position Bond stress at the location;

[0118] Calculate the relative anchorage position and relative bond stress at each strain point. Input the relative anchorage position and relative bond stress at the relative anchorage position into image fitting software to obtain the relative anchorage position-relative bond stress curve. Simplify the relative anchorage position-relative bond stress curve by applying a broken line function to obtain the simplified relative anchorage position-relative bond stress curve, representing the relative anchorage position-relative bond stress as multiple segments. piecewise functions of the form ,in, , is the fitting constant.

[0119] The relative anchorage position-relative bond stress curve is simplified by a polygonal line. Specifically, the endpoints and extreme points of the relative anchorage position-relative bond stress curve are extracted, and the endpoints and extreme points are connected sequentially according to the direction of the independent variable coordinate axis to obtain the simplified relative anchorage position-relative bond stress curve.

[0120] In this embodiment, the fitting result of the relative anchorage position-relative bond stress relationship is as follows:

[0121] ;

[0122] Furthermore, the constitutive relation of the bond-slip of the geopolymer coating is as follows:

[0123] ;

[0124] in, For relative slip The relative anchoring position is The bonding stress at that time.

[0125] Step 4: Divide the bond anchorage length of the reinforcing bar into M equally spaced network nodes, determine the area under the jurisdiction of each network node, calculate the relative position slip based on the slip at the loaded end and the slip at the free end, and regard the relative position slip of each node as the node flow and the bond stress as the node edge weight to construct entropy change order constraint;

[0126] The bond anchorage length of the reinforcing bars is divided into M equal-length bond anchorage segments, with the center of each segment designated as a network node; the area governed by each network node is... , For the first The distance from each network node to the loading end. For indexes of network nodes;

[0127] The bond stress and relative position slip of each network node are obtained based on the constitutive relationship of relative slip and geopolymer coating bond slip at failure.

[0128] The formula for calculating relative position slip is:

[0129] ;

[0130] in, Under the relative slip condition at failure, the first The relative positions of the nodes slide. This refers to the free end slip under relative slip at the time of failure. This refers to the loading end slippage under relative slippage at the time of failure;

[0131] The entropy-change order constraint is constructed as follows:

[0132] ;

[0133] ;

[0134] ;

[0135] ;

[0136] in, To represent the orderliness of entropy change, Under the relative slip condition at failure, the first Bond stress at each node, The entropy of the bond stress distribution. To preset the entropy of bond stress distribution, To represent the threshold of entropy change orderliness, These are the weight parameters.

[0137] Let be the probability of bond stress distribution at different anchorage locations, and its entropy be . For the entire slip-bonded system, a higher entropy in the distribution probability means a more uneven distribution of relative position slip; conversely, a lower entropy indicates a more uniform distribution of relative position slip. The same applies to bond stress. The larger the entropy, the more uneven the distribution of bond stress; conversely, the smaller the entropy, the more uniform the distribution of bond stress. A constitutive relationship exists between relative slip and bond stress. Based on the formula for calculating relative position slip, a similar constitutive relationship exists between relative position slip and bond stress. The uniformity of the distribution between relative position slip and bond stress can be mapped based on this constitutive relationship. Since both relative position slip and bond stress are normalized before entropy calculation, their overall distribution exhibits a similarity based on the constitutive relationship. Specifically, the difference in entropy between the two distributions will not be too large; the most ideal situation is... Therefore, analysis is required. To ensure the rationality of the constitutive relation; for a real physical slip-bond system constitutive model, the overall bond stress distribution should be ordered before specimen failure, therefore, the following is set. To ensure the rationality of the system stress distribution;

[0138] Since the relationships in this embodiment are all obtained through fitting, the relationships obtained by fitting are usually smooth, and a single fitted curve will not have the unreasonable changes mentioned above. However, the constitutive relationship in this embodiment is not a single fitted curve, but the product of two fitted curves, and one fitted curve is represented in the form of a piecewise function. The constitutive relationship obtained in this way may not be smooth and reasonable. It is necessary to use reasonableness constraints to judge the reasonableness of the constitutive relationship. If it is unreasonable, the constitutive relationship needs to be corrected a second time.

[0139] Step 5: Identify anomalous nodes based on the entropy change characteristics of network nodes. Based on the minimum modification recovery model, apply sparsification adjustment only to the region under the jurisdiction of the anomalous node to restore the entropy change order constraint of the constitutive relation at the minimum cost, and derive the recovered geopolymer coating bond-slip constitutive relation.

[0140] Furthermore, determine whether the entropy change order constraint is satisfied when the failure occurs. If it is satisfied, it is considered that there are no abnormal network nodes, and the constitutive relationship of the geopolymer coating adhesion slip described in step 3 is directly derived.

[0141] If the entropy change order constraint is not satisfied, then the entropy change characteristic is calculated using the following formula:

[0142] ;

[0143] in, For the first The entropy change characteristics of each node; according to Sort the network nodes in descending order, and then... One network node is identified as an abnormal network node. To Round up;

[0144] and Having a similar form, the latter is a summation of the former, while the former reflects a single node pair. The larger the value of the contribution, the greater the contribution. right The greater the contribution, the more likely the system will not satisfy the entropy-change order constraint. Network nodes with high values ​​should be prioritized for adjustment; since the constitutive relation in this embodiment is fitted using actual experimental data, even if situations arise that do not satisfy the entropy change order constraint, they will not be too serious, and usually... It will not exceed 20%. (Through) Depending on the specific situation of unreasonable order, an appropriate number of network nodes can be selected for adjustment.

[0145] Generate anomaly nodes that satisfy the entropy-change ordering constraint to adjust the initial population. Each individual in the anomaly node-adjusted initial population is represented as... , The first in the initial population Individual, Represents the first in the initial population Individual, the first For each anomalous network node, the bond stress adjustment amount is generated along with the bond stress adjustment amount. The randomly generated adjustment amount is no more than 10% of the absolute value of its own bond stress. The generated bond stress adjustment amount is substituted into the specific network node to update the adjusted bond stress. The entropy change ordering is calculated based on the adjusted bond stress. Individuals that satisfy the entropy change ordering constraint are retained. This process is repeated until the anomalous node adjusts the initial population to reach the preset number.

[0146] by Using a genetic algorithm to optimize the initial population with the minimum as the optimization objective, the optimal individual is obtained. Minimizing the optimization objective is to ensure that the constitutive relation is corrected with the minimum adjustment amount, so as to avoid excessive correction, which could lead to a situation where the constitutive relation, although ordered and reasonable, does not conform to experimental laws.

[0147] The optimal individual is represented as , For the optimal individual, For the first Optimal bond stress adjustment for anomalous network nodes This is an index for abnormal network nodes. This represents the total number of abnormal network nodes.

[0148] Given a defined initial population and optimization objective, the existing technology uses a genetic algorithm to optimize and obtain the optimal individual. Specifically, it involves: calculating the optimization objective value for each individual in the initial population for anomaly node adjustment; selecting individuals for crossover and mutation operations using methods such as roulette or tournament selection based on minimizing the optimization objective value; placing the mutated individuals into the iterative population; and selecting a certain ratio (usually 1:1) of individuals from both the iterative population and the initial population for anomaly node adjustment to form a new initial population for anomaly node adjustment, with the number of individuals in the new initial population being the same as the number of individuals in the original initial population. This process is repeated until a preset number of iterations is reached. Finally, the individual with the smallest optimization objective value from the last iteration population is selected as the optimal individual. This is the existing technology and will not be elaborated upon further.

[0149] Furthermore, the specific adjustment principle is to maintain the bond-slip constitutive relationship of the geopolymer coating in non-abnormal network nodes and their respective jurisdictions, in accordance with... The adjustment size is used to adjust the adhesion-slip constitutive relation of the geopolymer coating for each abnormal network node and its jurisdiction.

[0150] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0151] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0152] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0153] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that cannot be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for constructing a bond-slip constitutive model of a geopolymer coating, characterized in that, The specific steps include: Step 1: Conduct a center pull-out test on the concrete specimens of the polymer-coated steel reinforcement to obtain the center pull-out test data, which includes the slip at the loaded end, the slip at the free end, and the bond stress data. Step 2: Calculate the relative slip based on the slip at the loaded end and the slip at the free end, obtain the average bond stress based on the bond stress data, analyze the relative slip and the average bond stress to obtain the relationship between the relative slip length and the average bond stress, and correct the relationship between the relative slip length and the average bond stress using the geopolymer influence coefficient; Step 3: Analyze the bond stress data to obtain the relationship between relative anchorage position and relative bond stress; based on the corrected relationship between relative slip length and average bond stress, and the relationship between relative anchorage position and relative bond stress, construct the bond-slip constitutive relationship of the geopolymer coating; Step 4: Divide the bond anchorage length of the reinforcing bar into M equally spaced network nodes, determine the area under the jurisdiction of each network node, calculate the relative position slip based on the slip at the loaded end and the slip at the free end, and regard the relative position slip of each node as the node flow and the bond stress as the node edge weight to construct entropy change order constraint; Step 5: Identify anomalous nodes based on the entropy change characteristics of network nodes. Based on the minimum modification recovery model, apply sparsification adjustment only to the region under the jurisdiction of the anomalous node to restore the entropy change order constraint of the constitutive relation at the minimum cost, and derive the recovered geopolymer coating bond-slip constitutive relation.

2. The method according to claim 1, wherein, The logic for obtaining the center pull-out test data is as follows: 1.1 Prepare concrete specimens of polymer-coated steel bars. The two ends of the steel bars that pass through the specimen are designated as the free end and the loaded end, respectively. The section of the steel bars that extends into the specimen and is bonded to the concrete is designated as the bonded section, and the section of the steel bars that extends into the specimen and is not bonded to the concrete is designated as the unbonded section. Several strain gauges are placed in the bonded section of the steel bars. 1.2 Place the specimen on the steel pier at the bottom of the reaction frame, with the loading end of the reinforcing bar extending downwards out of the reaction frame and fixed at the lower clamp of the universal tensile and compressive testing machine. The top of the reaction frame is fixed at the upper clamp of the universal tensile and compressive testing machine by clamping screws. Install displacement gauge No. 1 at the free end of the reinforcing bar, install displacement gauge No. 2 on the upper surface of the specimen, and install displacement gauges No. 3 and No. 4 on the upper surface of the specimen extending out of the steel pier. 1.3 Start the universal tensile and compressive testing machine, pull the loading end of the steel bar downward at a loading rate of 1 mm / min, and obtain the strain data measured by the strain gauges and the displacement data measured by each displacement gauge in real time until the specimen fails. 1.4 Analyze strain and displacement data to obtain real-time data on loaded end slip, free end slip, and bond stress.

3. The method according to claim 2, wherein, The formula for calculating the slip at the free end is: ； wherein, is the free end slip, is the displacement derived from No. 1 displacement gauge, is the displacement derived from No. 2 displacement gauge; The formula for calculating the slip at the loading end is: ； wherein, is the slip at the loading end, is the unbonded length of the reinforcement, i.e. the length of the unbonded section, is the bond anchorage length of the reinforcement, i.e. the length of the bonded section, , are the derived displacements of the 3rd and 4th displacement gauges, respectively. The strain data includes the strain magnitude and the distance from the strain point to the loading end; the strain data is analyzed according to elasticity theory and internal force balance relationship to obtain bond stress data, which includes bond stress and the distance from the strain point to the loading end, and the strain point is the strain gauge installation point of the steel bar bonded section.

4. The method according to claim 3, wherein, Calculate the relative slip and the average bond stress at the same moment. Input the relative slip and average bond stress from multiple center pull-out tests into linear fitting software to obtain the relationship between the relative slip length and the average bond stress. The fitting result is expressed as: ； ； wherein is the average cohesive stress at a relative slip of 0.1 mm, is the average cohesive stress at a relative slip, , , , is a pending coefficient, fitted by specific experimental data; The relationship between slip length and average bond stress is corrected using the geopolymer influence coefficient, and is expressed as follows: ； in, For the corrected relative slip Average bond stress at time This is relative slip; Geopolymer influence coefficient is: ； in, The geopolymer influence coefficient, The aspect ratio of the geopolymer coating. The number of geopolymer coating layers. , The correction coefficients were obtained by fitting the center pull-out test data using the least squares method.

5. The method for constructing a constitutive model of a geopolymer coating bond slip according to claim 4, characterized in that, The formula for calculating the relative anchorage position is: ； in, For relative anchoring positions, The distance from the strain point to the loading end; The formula for calculating relative bond stress is: ； in, The average bond stress is expressed as At that time, relative anchoring position Relative bond stress at the location, The average bond stress is expressed as At that time, relative anchoring position Bond stress at the location; Calculate the relative anchorage position and relative bond stress at each strain point. Input the relative anchorage position and relative bond stress at the relative anchorage position into image fitting software to obtain the relative anchorage position-relative bond stress curve. Simplify the relative anchorage position-relative bond stress curve by applying a broken line function to obtain the simplified relative anchorage position-relative bond stress curve, representing the relative anchorage position-relative bond stress as multiple segments. Piecewise function of the expression ,in, , is the fitting constant.

6. The method for constructing a constitutive model of a geopolymer coating bond slip according to claim 5, characterized in that, The constitutive relation of the bond-slip of the geopolymer coating is: ； in, For relative slip At that time, relative anchoring position Bond stress at the location.

7. The method for constructing a constitutive model of a geopolymer coating bond slip according to claim 6, characterized in that: The bond anchorage length of the reinforcing bars is divided into M equal-length bond anchorage segments, with the center of each segment designated as a network node; the area governed by each network node is... , For the first The distance from each network node to the loading end. For indexes of network nodes; The relative slip at specimen failure is obtained, and the bond stress and relative position slip of each network node are obtained based on the relative slip at failure and the constitutive relationship of the geopolymer coating bond slip. The formula for calculating relative position slip is: ； in, Under the relative slip condition at failure, the first The relative positions of the nodes slide. This refers to the free end slip under relative slip at the time of failure. This refers to the loading end slippage under relative slippage at the time of failure; The entropy-change order constraint is constructed as follows: ； ； ； ； in, To represent the orderliness of entropy change, Under the relative slip condition at failure, the first Bond stress at each node, The entropy of the bond stress distribution. To preset the entropy of bond stress distribution, To represent the threshold of entropy change orderliness, These are the weight parameters.

8. The method for constructing a constitutive model of a geopolymer coating bond slip according to claim 7, characterized in that, Determine whether the entropy change order constraint is satisfied when the failure occurs. If it is satisfied, it is considered that there are no abnormal network nodes, and the adhesion-slip constitutive relation of the geopolymer coating described in step 3 is directly derived. If the entropy change order constraint is not satisfied, then the entropy change characteristic is calculated using the following formula: ； in, For the first The entropy change characteristics of each node; according to Sort the network nodes in descending order, and then... One network node is identified as an abnormal network node. To Round up; Generate anomaly nodes that satisfy the entropy-change ordering constraint to adjust the initial population. Each individual in the anomaly node-adjusted initial population is represented as... , The first in the initial population Individual, Represents the first in the initial population Individual, the first The amount of bond stress adjustment for each abnormal network node, in order to Using a genetic algorithm to optimize the initial population with the goal of minimizing the population size, the optimal individual is obtained. The optimal individual is represented as... , For the optimal individual, For the first Optimal bond stress adjustment for anomalous network nodes This is an index for abnormal network nodes. This represents the total number of abnormal network nodes.

9. The method for constructing a constitutive model of a geopolymer coating bond slip according to claim 8, characterized in that, The specific adjustment principle is to maintain the bond-slip constitutive relationship of the geopolymer coating in non-abnormal network nodes and their respective areas, in accordance with... The adjustment size is used to adjust the adhesion-slip constitutive relation of the geopolymer coating for each abnormal network node and its jurisdiction.

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