A method for optimizing shear and seismic performance of restructured bamboo-concrete connection nodes

Abstract

The invention discloses a method for optimizing the shear and seismic performance of a reconstructed bamboo-concrete connection node in the technical field, and relates to the technical field of connection node performance optimization. The invention provides a scientific basis and technical support for the design of a reconstructed bamboo-concrete beam-column combination node by selecting and testing a connection mode, collecting and analyzing shear strength data, calculating and optimizing a dynamic-static comparison coefficient, applying a finite element numerical simulation and an optimization algorithm, and constructing a seismic performance test and a comprehensive evaluation model. The implementation of the method can not only significantly improve the shear and seismic performance of the combination node, optimize the connection form and size value of the node, but also provide a reliable performance evaluation tool for engineering practice through a comprehensive seismic performance index model, and has important academic value and engineering application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of connection node performance optimization, and in particular to a method for optimizing the shear and seismic performance of a reconstructed bamboo-concrete connection node. Background Art

[0002] With the utilization of renewable resources and the enhancement of environmental awareness, reconstructed bamboo has received widespread attention as a new type of green building material in construction projects. Reconstructed bamboo not only has good mechanical properties and durability, but also can significantly reduce the negative impact of traditional building materials on the environment. At the same time, as one of the most commonly used materials in modern construction, concrete occupies an important position in structural engineering due to its high strength and durability. However, how to effectively combine reconstructed bamboo and concrete to form a beam-column composite node with excellent shear and seismic performance is still an important research topic. The existing reconstructed bamboo-concrete connection methods mainly include pin connection, tenon-nail connection and steel plate connection. These connection methods have their own characteristics, but in actual engineering applications, a single connection method often has performance deficiencies when facing complex loads.

[0003] In the prior art, the publication number is CN116257950A, and the name is a method for predicting the elastic stiffness of a reconstructed bamboo-steel plywood bolt connection node. The method optimizes the calculation parameters to simplify the calculation process, so that the connection elastic stiffness of the reconstructed bamboo-steel plywood connection form can be simply and quickly predicted during the design process, thereby increasing the safety of such connection design; solving the problem that the connection stiffness of the steel plywood connection form is difficult to calculate, and directly calculating the connection stiffness according to the structural design when the bamboo-steel plywood bolt connection is reconstructed, thereby providing a reference for such connection design.

[0004] There are some significant deficiencies in the application of a single connection method in reconstructed bamboo-concrete composite nodes. First, although the pin connection method is easy to construct, its shear resistance and stability are poor under dynamic loads, and the connection is prone to loosening or failure. Secondly, although the tenon-nail connection method can improve the stiffness of the node, its manufacturing process is complicated and it is prone to fatigue damage under high-frequency vibration. Thirdly, the implanted steel plate connection method can significantly enhance the overall stiffness and durability of the node, but its construction cost is high, and it is easy to produce stress concentration under complex loads, leading to local damage. In addition, the existing connection method lacks a systematic evaluation method when facing static and dynamic loads, making it difficult to accurately predict the long-term performance and seismic resistance of the node. The above shortcomings limit the widespread application of reconstructed bamboo-concrete composite nodes in actual engineering.

[0005] The above information disclosed in the above Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0006] The object of the present invention is to provide a method for optimizing the shear and seismic performance of a reconstructed bamboo-concrete connection node to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for optimizing the shear and seismic performance of a reconstructed bamboo-concrete connection node, comprising the following specific steps:

[0009] Step S1: the reconstructed bamboo-concrete beam-column composite nodes are connected in sequence using pin connection, tenon-nail connection, steel plate connection, and a combination of at least two connection methods, and the same static load test and dynamic load test are performed on the composite nodes of each connection method;

[0010] Step S2: collecting the shear strength of each combined node connection mode under static load test and dynamic load test, and using the shear strength obtained from each connection mode as similar comparison data;

[0011] Step S3: calculating the average value and standard deviation of the shear strength of the static load test in the same type of comparison data, and the average value and standard deviation of the shear strength under the dynamic load test;

[0012] Step S4: in the same type of comparison data, a first difference between the static and dynamic load tests about the average value of the shear strength and a second difference about the standard deviation of the shear strength are calculated, and the two differences are combined to generate a first static-dynamic comparison coefficient, which is used to evaluate the stiffness change trend of the selected combined node connection mode under different load conditions;

[0013] Step S5: in the same type of comparison data, a first ratio between the average value and the standard deviation of the shear strength under the static load test is calculated, and a second ratio between the average value and the standard deviation of the shear strength under the dynamic load test is calculated, and a second dynamic-static comparison coefficient is generated by combining the first ratio and the second ratio. The second dynamic-static comparison coefficient is used to evaluate the change trend of the shear performance of the selected combined node connection mode under different load conditions;

[0014] Step S6: using finite element analysis to simulate different size values ​​of the combined nodes of each connection mode to predict the shear strength of the combined nodes under static load tests and dynamic load tests respectively;

[0015] Step S7: according to the occasions of static and dynamic loads, an optimization algorithm is used in numerical simulation to find the optimal connection form and combined node size value corresponding to the first static-dynamic comparison coefficient and the second static-dynamic comparison coefficient;

[0016] Step S8: According to the optimal connection form and the combined node size value, a reconstructed bamboo-concrete beam-column combined node test sample is prepared and an earthquake simulation test is carried out to obtain earthquake-resistant test data, the earthquake-resistant test data is analyzed and processed, and an earthquake-resistant performance evaluation index is calculated;

[0017] Step S9: The first dynamic-static comparison coefficient, the second dynamic-static comparison coefficient and the seismic performance evaluation index are combined and analyzed, and a comprehensive seismic performance index model for evaluating the seismic performance of the current combined node test sample is constructed by using statistical analysis or machine learning methods.

[0018] Furthermore, pin connection, tenon-nail connection and implanted steel plate connection are used in turn, and the same static load test and dynamic load test are carried out for the combined nodes of each connection method, including:

[0019] It is assumed that both the static load test and the dynamic load test are conducted n times, forming a test number set {1, 2, ..., i, ..., n}; where i represents the index of the i-th test number;

[0020] The combined node connection method includes any one of pin connection, tenon-nail connection and implanted steel plate connection, or a combination of at least two of the connection methods; the combined node connection methods are marked to form a set {1, 2, ..., j, ..., 8}; wherein j represents the index of the j-th combined node connection method, and 8 represents the total number of combined connection indexes;

[0021] Apply a gradually increasing static load to the jth type of combined node connection mode, and set the basic applied load of the static load test to F0 static , the applied load of the j-th type of combined node connection in the i-th static load test is expressed as F static,i,j , the calculation formula is as follows:

[0022] F static,i,j =F0 static (1+i×2%)

[0023] Apply a periodically changing dynamic load to the j-th type of combined node connection mode, and set the basic applied load of the dynamic load test to F0 dynamic , the applied load of the j-type combined node connection mode in the i-th dynamic load test is expressed as F dynamic,i,j , the calculation formula is as follows:

[0024] F dynamic,i,j =F0 dynamic (1+Asin(ωi+φ))

[0025] Among them, A is the amplitude coefficient, ω is the angular frequency, and φ is the initial phase.

[0026] Furthermore, the shear strength of each combined node connection method under static load test and dynamic load test is collected, and the shear strength obtained by each connection method is used as the same type of comparison data, including:

[0027] The static shear strength of the j-th type of combined node connection in the i-th static load test is denoted as τ static,i,j , the calculation formula is as follows:

[0028]

[0029] Where As is the effective area of ​​the connection interface;

[0030] The dynamic shear strength of the j-th type of combined node connection in the i-th dynamic load test is denoted as τ dynamic,i,j , the calculation formula is as follows:

[0031]

[0032] The static shear strength τ of the j-type combined node connection mode in the n-th test static,i,j and dynamic shear strength τ dynamic,i,j As the same type of comparison data, it is further referred to as the j-th type of comparison data.

[0033] Furthermore, the average value and standard deviation of the shear strength of the static load test in the same type of comparison data, as well as the average value and standard deviation of the shear strength under the dynamic load test are calculated; specifically including:

[0034] Static shear strength τ static,i,j The average values ​​are as follows:

[0035]

[0036] Dynamic shear strength τ dynamic,i,j The average values ​​are as follows:

[0037]

[0038] Static shear strength τ static,i,j The standard deviation of is as follows:

[0039]

[0040] Dynamic shear strength τ dynamic,i,j The standard deviation of is as follows:

[0041]

[0042] in, represents the average shear strength of the static load test in the jth type of comparison data, σ static,jrepresents the standard deviation of the shear strength of the static load test in the jth type of comparison data; represents the average shear strength of the dynamic load test in the jth type of comparison data, σ dynamic,j Represents the standard deviation of the shear strength of the dynamic load test in the jth type of comparison data.

[0043] Furthermore, a first dynamic-static comparison coefficient is generated, which is used to evaluate the stiffness change trend of the selected combined node connection mode under different load conditions, specifically including:

[0044] Calculate the first difference of the average shear strength in the jth type of comparison data

[0045]

[0046] Calculate the second difference Δσ of the standard deviation of shear strength in the jth type of comparison data j :

[0047] Δσ j =|σ static,j -σ dynamic,j |

[0048] For the first difference and the second difference Δσ j Applying the logistic function, we get the following calculation formula:

[0049]

[0050] in, and L(Δσ j ) are logistic function output values ​​of the first difference and the second difference respectively;

[0051] Use the weighted average method; set and L(Δσ j ) are positive numbers a1 and a2, so that a1+a2=1, and the first dynamic and static comparison coefficient of the j-th comparison data is defined as K1 j , the calculation formula is as follows:

[0052]

[0053] K1 j The value range of is limited to (0,1); based on experimental verification or expert group analysis, determine the standard stiffness values ​​of the j-th type of combined node connection mode under static and dynamic loads respectively;

[0054] When 0.45≤K1 jWhen ≤0.53, it is the middle value interval, indicating that the performance of this combined node connection mode under static and dynamic loads is consistent, and the stiffness variation range fluctuates within ±5% of the corresponding stiffness standard value, which is suitable for occasions that evenly bear static and dynamic loads;

[0055] When 0.53<K1 j When <1, it means that the combined node connection mode is suitable for occasions where static loads are dominant; the stiffness increase under static loads exceeds 10% of the corresponding stiffness standard value; it is suitable for environments that are frequently subjected to static loads;

[0056] When 0<K1 j When <0.45, it means that this connection method is suitable for applications where dynamic loads are dominant; the stiffness increase under dynamic loads exceeds 15% of the corresponding stiffness standard value, and is suitable for environments that are frequently subjected to dynamic loads.

[0057] Furthermore, a second dynamic-static comparison coefficient is generated, which is used to evaluate the shear performance change trend of the selected combined node connection mode under different load conditions, including:

[0058] Calculate the first ratio R between the mean and standard deviation of the shear strength under static load test in the jth type of comparison data static,j :

[0059]

[0060] Calculate the second ratio R between the mean and standard deviation of the shear strength under dynamic load test in the jth type of comparison data dynamic,j :

[0061]

[0062] And the following exponential function is applied to the first ratio and the second ratio:

[0063]

[0064] Using the weighted average method, set E(R static,j ) and E(R dynamic,j ) The weight coefficients are positive numbers b1 and b2, so that b1+b2=1; define the second dynamic and static comparison coefficient of the j-th comparison data as K2 j , the calculation formula is as follows:

[0065] K2 j =b1×E(R static,j )+b2×E(R dynamic,j )

[0066] K2 jApply the logistic function to limit its output value to the range of (0,1);

[0067]

[0068] Among them, K2′ j is the second dynamic-static comparison coefficient after normalization by logistic function, η1 is the scaling adjustment coefficient;

[0069] K2′ j The value range is divided into multiple intervals, and the shear performance change trend of each interval is quantitatively described: based on experimental verification or expert group analysis, the standard value of the shear performance of the j-th type of combined node connection mode under static and dynamic loads is determined;

[0070] When 0<K2′ j When ≤0.45, under dynamic load, the shear resistance exceeds the corresponding shear resistance standard value by 11%; it is suitable for environments that are frequently subjected to dynamic loads;

[0071] When 0.45<K2′ j When ≤0.59, it is the middle value interval. Under static and dynamic loads, the shear performance fluctuation range is within ±6% of the corresponding shear performance standard value, indicating that the combined node connection method exhibits consistent shear performance under static and dynamic loads; it is suitable for occasions that evenly bear static and dynamic loads;

[0072] When 0.59<K2′j<1, under static load, the shear resistance exceeds the corresponding shear resistance standard value by 12%; it is suitable for environments that are frequently subjected to static loads.

[0073] Furthermore, finite element analysis is used to simulate different size values ​​of the combined nodes of each connection method to predict the shear strength of the combined nodes under static load tests and dynamic load tests respectively; specifically, the following are included:

[0074] 3.1) Establish a 3D geometric model based on the connection mode and the size of the combined nodes; for each connection mode, define models of different sizes;

[0075] 3.2) Define the properties of reconstructed bamboo and concrete materials:

[0076] 3.3) Mesh division of key combination node areas:

[0077] 3.4) Set boundary conditions and load application:

[0078] The predicted shear strength under static load test is recorded as τ′ static,i,j ;

[0079] The predicted shear strength under dynamic load test is recorded as τ′dynamic,i,j :

[0080]

[0081] Among them, F max is the maximum load of the static load; F dynamic (t peak ) is the load at the peak moment of dynamic load; A contact is the effective contact area of ​​the combined node connection interface, and A contact Equal to As.

[0082] Furthermore, according to the occasions of static and dynamic loads, an optimization algorithm is used in numerical simulation to find the optimal connection form and combined node size value corresponding to the first dynamic-static comparison coefficient and the second dynamic-static comparison coefficient, specifically including:

[0083] 4.1) Optimization algorithm selects genetic algorithm;

[0084] 4.2) Optimization objectives and constraints:

[0085] Optimization goal: According to the occasions of static and dynamic loads, different first dynamic-static comparison coefficients K1 are respectively j and the second dynamic-static comparison coefficient K2′ j The corresponding optimal connection form and combined node size value;

[0086] When the situation is dominated by static loads: maximize K1 j and K2′ j , to enhance static shear and seismic performance;

[0087] When dynamic loads are the main factor: Minimize K1 j and K2′ j , to enhance dynamic shear and seismic performance;

[0088] When the situation is uniform load: ensure K1 j and K2′ j In the middle range, to perform consistently under static and dynamic loads;

[0089] Constraints: The connection method and size parameters must meet the structural design requirements;

[0090] 4.3) Optimal solution extraction:

[0091] Combine static and dynamic load conditions and use optimization algorithms to obtain the optimal K1 j and K2′ j value, extract the optimal connection method and combined node size.

[0092] Furthermore, the seismic test data is analyzed and processed to calculate the seismic performance evaluation index, including:

[0093] The seismic test data include acceleration, strain value, and displacement value;

[0094] The seismic performance evaluation index is denoted as S seismic , the formula is as follows:

[0095]

[0096] Where N′ is the number of trials; q i′ is the maximum acceleration of the i′th test; q ref is the reference acceleration value; d i′ is the maximum displacement value of the i′th test; d ref is the reference displacement value; e i′ is the maximum strain value of the i′th test, e ref is the reference strain value;

[0097] S seismic The value range is limited to (0,1);

[0098] When S seismic The closer it is to 0, the worse the seismic performance of the composite node under seismic load;

[0099] When S seismic The closer it is to 1, the better the seismic performance of the composite node under seismic load.

[0100] Furthermore, a comprehensive seismic performance index model for evaluating the seismic performance of the current composite node test samples is constructed, including:

[0101] The comprehensive seismic performance index is defined as I seismic , the calculation formula is as follows:

[0102]

[0103] Among them, w1, w2, and w3 are the positive weight parameters of the first dynamic-static comparison coefficient, the second dynamic-static comparison coefficient, and the seismic performance evaluation index, respectively. is the calculated maximum value, and satisfies w1+w2+w3=1;

[0104] I seismic The value range of is limited to the range of (0,1);

[0105] When I seismic The closer it is to 0, the worse the comprehensive seismic performance of the composite node under seismic load;

[0106] When I seismicThe closer it is to 1, the better the comprehensive seismic performance of the composite node under seismic load.

[0107] Compared with the prior art, the beneficial effects of the present invention are: through systematic experiments and numerical simulations, combined with optimization algorithms and machine learning methods, the shear and seismic performance of different connection methods are comprehensively evaluated and optimized; through the selection and testing of connection methods, the collection and analysis of shear strength data, the calculation and optimization of dynamic and static comparison coefficients, the application of finite element numerical simulation and optimization algorithms, and the construction of seismic performance tests and comprehensive evaluation models, a scientific basis and technical support are provided for the design of reconstructed bamboo-concrete beam-column composite nodes. The implementation of this method can not only significantly improve the shear and seismic performance of the composite node, optimize the connection form and size value of the node, but also provide a reliable performance evaluation tool for engineering practice through a comprehensive seismic performance index model, which has important academic value and engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0108] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0109] Figure 1 It is a schematic diagram of the overall method flow of the present invention. DETAILED DESCRIPTION

[0110] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0111] Example 1

[0112] See also Figure 1 , the present invention provides a technical solution:

[0113] A method for optimizing the shear and seismic performance of a reconstructed bamboo-concrete connection node, comprising the following specific steps:

[0114] Step S1: the reconstructed bamboo-concrete beam-column composite nodes are connected in sequence using pin connection, tenon-nail connection, steel plate connection, and a combination of at least two connection methods, and the same static load test and dynamic load test are performed on the composite nodes of each connection method;

[0115] Step S2: collecting the shear strength of each combined node connection mode under static load test and dynamic load test, and using the shear strength obtained from each connection mode as similar comparison data;

[0116] Step S3: calculating the average value and standard deviation of the shear strength of the static load test in the same type of comparison data, and the average value and standard deviation of the shear strength under the dynamic load test;

[0117] Step S4: in the same type of comparison data, a first difference between the static and dynamic load tests about the average value of the shear strength and a second difference about the standard deviation of the shear strength are calculated, and the two differences are combined to generate a first static-dynamic comparison coefficient, which is used to evaluate the stiffness change trend of the selected combined node connection mode under different load conditions;

[0118] Step S5: in the same type of comparison data, a first ratio between the average value and the standard deviation of the shear strength under the static load test is calculated, and a second ratio between the average value and the standard deviation of the shear strength under the dynamic load test is calculated, and a second dynamic-static comparison coefficient is generated by combining the first ratio and the second ratio. The second dynamic-static comparison coefficient is used to evaluate the change trend of the shear performance of the selected combined node connection mode under different load conditions;

[0119] Step S6: using finite element analysis to simulate different size values ​​of the combined nodes of each connection mode to predict the shear strength of the combined nodes under static load tests and dynamic load tests respectively;

[0120] Step S7: according to the occasions of static and dynamic loads, an optimization algorithm is used in numerical simulation to find the optimal connection form and combined node size value corresponding to the first static-dynamic comparison coefficient and the second static-dynamic comparison coefficient;

[0121] Step S8: According to the optimal connection form and the combined node size value, a reconstructed bamboo-concrete beam-column combined node test sample is prepared and an earthquake simulation test is carried out to obtain earthquake-resistant test data, the earthquake-resistant test data is analyzed and processed, and an earthquake-resistant performance evaluation index is calculated;

[0122] Step S9: The first dynamic-static comparison coefficient, the second dynamic-static comparison coefficient and the seismic performance evaluation index are combined and analyzed, and a comprehensive seismic performance index model for evaluating the seismic performance of the current combined node test sample is constructed by using statistical analysis or machine learning methods.

[0123] Further explanation: pin connection, tenon-nail connection and implanted steel plate connection are used in sequence, and the same static load test and dynamic load test are carried out for the combined nodes of each connection method, including:

[0124] It is assumed that both the static load test and the dynamic load test are conducted n times, forming a test number set {1, 2, ..., i, ..., n}; where i represents the index of the i-th test number;

[0125] The combined node connection method includes any one of pin connection, tenon-nail connection and implanted steel plate connection, or a combination of at least two of the connection methods; the combined node connection methods are marked to form a set {1, 2, ..., j, ..., 8}; wherein j represents the index of the j-th combined node connection method, and 8 represents the total number of combined connections;

[0126] When j=1, it means that only pin connection is adopted;

[0127] When j = 2, it means that only tenon-nail connection is used;

[0128] When j=3, it means that the connection is made by implanting steel plate alone;

[0129] When j=4, it means that the combination adopts pin connection and tenon-nail connection;

[0130] When j=5, it means that the combination adopts pin connection and implanted steel plate connection;

[0131] When j=6, it means that the combination adopts tenon-nail connection and implanted steel plate connection;

[0132] When j=7, it means that the combination adopts pin connection, tenon-nail connection, and implanted steel plate connection.

[0133] Apply a gradually increasing static load to the jth type of combined node connection mode, and set the basic applied load of the static load test to F0 static , the applied load of the j-th type of combined node connection in the i-th static load test is expressed as F static,i,j , the calculation formula is as follows:

[0134] F static,i,j =F0 static (1+i×2%)

[0135] Apply a periodically changing dynamic load to the j-th type of combined node connection mode, and set the basic applied load of the dynamic load test to F0 dynamic , the applied load of the j-type combined node connection mode in the i-th dynamic load test is expressed as F dynamic,i,j , the calculation formula is as follows:

[0136] F dynamic,i,j =F0 dynamic (1+Asin(ωi+φ))

[0137] Wherein, A is the amplitude coefficient, which indicates the amplitude of load change, 0.01≤A≤0.72; in this embodiment, A is set to 0.2;

[0138] ω is the angular frequency, which determines the cycle of load change; in this embodiment, every 10 times is a complete cycle, then

[0139] φ is the initial phase. It determines the starting position of the load change; in this embodiment, it is set to 0, indicating that the change starts from the starting point of the sine wave; the following F of this example is obtained dynamic,i,j ;

[0140]

[0141] It needs to be determined that F0 dynamic (1+Asin(ωi+φ))>0.

[0142] Further explanation: the shear strength of each combined node connection method under static load test and dynamic load test is collected, and the shear strength obtained by each connection method is used as the same type comparison data, specifically including:

[0143] The static shear strength of the j-th type of combined node connection in the i-th static load test is denoted as τ static,i,j , the calculation formula is as follows:

[0144]

[0145] Where As is the effective area of ​​the connection interface; the unit is square meters (m 2 );

[0146] Dynamic load cells and high-speed cameras were used to record the response of the composite joints under dynamic loads;

[0147] The dynamic shear strength of the j-th type of combined node connection in the i-th dynamic load test is denoted as τ dynamic,i,j , the calculation formula is as follows:

[0148]

[0149] Where As is the effective area of ​​the connection interface; the unit is square meters (m 2 );

[0150] Record and organize the data of static load test and dynamic load test;

[0151] The static shear strength τ of the j-type combined node connection mode in the n-th test static,i,j and dynamic shear strength τ dynamic,i,j As the same type of comparison data, it is further referred to as the j-th type of comparison data.

[0152] Further explanation: the average value and standard deviation of the shear strength of the static load test in the same type of comparison data, as well as the average value and standard deviation of the shear strength under the dynamic load test are calculated; specifically including:

[0153] Determine j∈{1,2,…,8};

[0154] Static shear strength τ static,i,j The average values ​​are as follows:

[0155]

[0156] Dynamic shear strength τ dynamic,i,j The average values ​​are as follows:

[0157]

[0158] Static shear strength τ static,i,j The standard deviation of is as follows:

[0159]

[0160] Dynamic shear strength τ dynamic,i,j The standard deviation of is as follows:

[0161]

[0162] in, represents the average shear strength of the static load test in the jth type of comparison data, σ static,j represents the standard deviation of the shear strength of the static load test in the jth type of comparison data; represents the average shear strength of the dynamic load test in the jth type of comparison data, σ dynamic,j Represents the standard deviation of the shear strength of the dynamic load test in the jth type of comparison data.

[0163] Further explanation: the first dynamic-static comparison coefficient is generated, and the first dynamic-static comparison coefficient is used to evaluate the stiffness change trend of the selected combined node connection mode under different load conditions, specifically including:

[0164] Calculate the first difference of the average shear strength in the jth type of comparison data

[0165]

[0166] Calculate the second difference Δσ of the standard deviation of shear strength in the jth type of comparison data j :

[0167]

[0168] For the first difference and the second difference Δσj Applying the logistic function, we get the following calculation formula:

[0169]

[0170]

[0171] in, and L(Δσ j ) are the logistic function output values ​​of the first difference and the second difference respectively; used to limit the output value range to (0,1);

[0172] Use the weighted average method; set and L(Δσ j ) are positive numbers a1 and a2, so that a1+a2=1. In this embodiment, a1 and a2 are both 0.5, and data in different ranges are uniformly normalized; the first dynamic and static comparison coefficient of the j-th comparison data is defined as K1 j , the calculation formula is as follows:

[0173]

[0174] Based on the data preprocessing method, K1 j The value range of is limited to (0,1); based on experimental verification or expert group analysis, determine the standard stiffness values ​​of the j-th type of combined node connection mode under static and dynamic loads respectively;

[0175] When 0.45≤K1 j When ≤0.53, it is the middle value interval, indicating that the performance of this combined node connection mode under static and dynamic loads is consistent, and the stiffness variation range fluctuates within ±5% of the corresponding stiffness standard value, which is suitable for occasions that evenly bear static and dynamic loads;

[0176] When 0.53<K1 j When <1, it means that the combined node connection mode is suitable for occasions where static loads are dominant; static loads mainly mean that static loads account for more than 52% of the total load types; the stiffness increase under static loads exceeds 10% of the corresponding stiffness standard value; it means that the combined node connection mode exhibits higher stiffness under static loads and is suitable for environments that are frequently subjected to static loads, such as high-rise buildings and warehouses;

[0177] When 0<K1 jWhen <0.45, it means that the connection method is suitable for applications where dynamic loads are dominant; when the stiffness increase under dynamic loads exceeds 15% of the corresponding stiffness standard value, it means that the combined node connection method exhibits higher stiffness under dynamic loads and is suitable for environments that are frequently subjected to dynamic loads. For example, bridges and buildings in earthquake zones; dynamic loads mainly mean that dynamic loads account for more than 52% of the total load types. The "frequent" in the above content means that the probability of occurrence is more than 60%.

[0178] Further test contents are as follows:

[0179] In order to verify the stiffness variation trend of different composite node connection methods under different load conditions and generate the first static-dynamic comparison coefficient, the experimental objects are eight different types of reconstructed bamboo-concrete composite nodes, which are named "pin connection", "tenon-nail connection", "planted steel plate connection", "pin + tenon-nail connection", "pin + planted steel plate connection", "tenon-nail + planted steel plate connection" and "pin + tenon-nail + planted steel plate connection". The experiment was carried out in a laboratory with simulated static and dynamic load conditions. The experimental equipment includes static load application device, dynamic load vibration table, shear strength tester and data acquisition system.

[0180] The experimental steps are as follows:

[0181] Eight different types of reconstructed bamboo-concrete composite node samples were prepared, and 10 samples were taken for each type to ensure the consistency and representativeness of the samples.

[0182] The specific size of the sample is 300mm×300mm×300mm, which meets the testing requirements of the experimental equipment.

[0183] Static load test:

[0184] Fix the sample on the static load application device, apply static load step by step, and record the shear strength at each load point.

[0185] Each sample was loaded and unloaded multiple times to ensure data accuracy and repeatability.

[0186] Calculate the mean and standard deviation of shear strength for each type of composite joint;

[0187] Dynamic load test:

[0188] The sample is fixed on a dynamic load vibration table to simulate dynamic loads of different frequencies, and the shear strength at each load point is recorded.

[0189] Each sample was loaded and unloaded multiple times to ensure data accuracy and repeatability.

[0190] Calculate the mean and standard deviation of shear strength for each type of composite joint;

[0191] Based on experimental data and expert group analysis, the standard stiffness values ​​of each type of composite node under static and dynamic loads are determined;

[0192] Table 1 below records the average and standard deviation of the shear strength of eight types of combined nodes under static and dynamic load conditions, as well as the calculated first dynamic-static comparison coefficient;

[0193] Table 1

[0194]

[0195]

[0196] According to the experimental results and the calculated first dynamic-static comparison coefficient K1 j , the following conclusions are drawn:

[0197] For pin connections:

[0198] K1 j =0.6655, which is between 0.53 and 1, indicating that this combined node connection method is suitable for occasions dominated by static loads; under static loads, the stiffness increase exceeds 10% of the stiffness standard value; it is suitable for environments such as high-rise buildings and warehouses that are frequently subjected to static loads.

[0199] For dowel-nail connections:

[0200] K1 j =0.6180, which is between 0.53 and 1, indicating that this combined node connection method is suitable for occasions dominated by static loads, and its applicable environment is the same as that of pin connection.

[0201] For steel plate connection:

[0202] K1 j =0.6655, which is also between 0.53 and 1, indicating that the composite node exhibits higher stiffness under static load and is suitable for environments that are frequently subjected to static loads.

[0203] For pin + tenon-nail connections:

[0204] K1 j =0.6779, which is between 0.53 and 1, indicating that the composite node exhibits superior performance under static load environment and is suitable for high-rise buildings and warehouses that are frequently subjected to static loads.

[0205] For pin + implant plate connection:

[0206] K1 j=0.6779, which is also between 0.53 and 1. It is suitable for occasions where static loads are dominant and is better than separate pin connections and implanted steel plate connections.

[0207] For dowel-nail + implanted steel plate connections:

[0208] K1 j =0.6602, which is between 0.53 and 1, indicating that the composite node exhibits higher stiffness under static load environment and is suitable for high-rise buildings and warehouses with mainly static loads.

[0209] For dowel + tenon-nail + implant plate connection:

[0210] K1 j =0.6779, which is also between 0.53 and 1, indicating that the composite node exhibits the most superior stiffness performance under static load conditions and is suitable for high-rise buildings and warehouses with mainly static loads.

[0211] Experimental data show that the composite node has high stiffness under static load environment and is suitable for occasions dominated by static loads such as high-rise buildings and warehouses, thus providing scientific basis and technical support.

[0212] Further explanation: the second dynamic-static comparison coefficient is generated. The second dynamic-static comparison coefficient is used to evaluate the shear performance change trend of the selected combined node connection mode under different load conditions, including:

[0213] Calculate the first ratio R between the mean and standard deviation of the shear strength under static load test in the jth type of comparison data static,j :

[0214]

[0215] Calculate the second ratio R between the mean and standard deviation of the shear strength under dynamic load test in the jth type of comparison data dynamic,j :

[0216]

[0217] And the following exponential function is applied to the first ratio and the second ratio:

[0218]

[0219] Using the weighted average method, set E(R static,j ) and E(R dynamic,j ) The weight coefficients are positive numbers b1 and b2, respectively, so that b1+b2=1; in this embodiment, b1 and b2 are both 0.5, and the data in different ranges are uniformly normalized; the second dynamic and static comparison coefficient of the j-th comparison data is defined as K2 j, the calculation formula is as follows:

[0220] K2 j =b1×E(R static,j )+b2×E(R dynamic,j )

[0221] Due to the characteristics of the exponential function, e x The value range is (0,∞), and K2 is processed by weight and exponential function or dimensional means. j Limited to the range (0,1);

[0222] K2 j Apply the logistic function to limit its output value to the range of (0,1);

[0223]

[0224] Among them, K2′ j is the second dynamic-static comparison coefficient after logistic function normalization, η1 is the scaling adjustment coefficient; η1 is used to avoid K2 j When it is too large, all K2′ j Approaching 1; the specific value of η1 is determined by the expert group through experimental data;

[0225] K2′ j The value range is divided into multiple intervals, and the shear and seismic performance change trends in each interval are quantitatively described: Based on experimental verification or expert group analysis, the standard values ​​of shear performance of the j-th type of combined node connection mode under static and dynamic loads are determined;

[0226] When 0<K2′ j When ≤0.45, under dynamic load, the shear performance exceeds the corresponding shear performance standard value by 11%; it means that the combined node connection method exhibits higher shear performance and better seismic performance under dynamic load; it is suitable for environments that are frequently subjected to dynamic loads; such as bridges and buildings in earthquake zones;

[0227] When 0.45<K2′ j When ≤0.59, it is the middle value interval. Under static and dynamic loads, the shear performance fluctuation range is within ±6% of the corresponding shear performance standard value, indicating that the combined node connection method exhibits consistent shear performance under static and dynamic loads; it is suitable for occasions that evenly bear static and dynamic loads, such as ordinary building structures;

[0228] When 0.59<K2′ j When <1, under static load, the shear performance exceeds the corresponding shear performance standard value by 12%, indicating that the combined node connection method exhibits higher shear performance under static load; it is suitable for environments that are frequently subjected to static loads, such as high-rise buildings and warehouses;

[0229] The word “frequently” in the above content means that the probability of occurrence is above 60%.

[0230] Further test contents are as follows:

[0231] In order to verify the shear performance variation trend of different composite node connection methods under static and dynamic load conditions, the test objects are eight different types of reconstructed bamboo-concrete composite nodes, named "pin connection", "tenon-nail connection", "planted steel plate connection", "pin + tenon-nail connection", "pin + planted steel plate connection", "tenon-nail + planted steel plate connection", "pin + tenon-nail + planted steel plate connection" and "experimental control group". The experiment was conducted in a laboratory with simulated static and dynamic load conditions. The experimental equipment includes static load application device, dynamic load vibration table, shear strength tester and data acquisition system.

[0232] The experimental steps are as follows:

[0233] Eight different types of reconstructed bamboo-concrete composite node samples were prepared, and 10 samples were taken for each type to ensure the consistency and representativeness of the samples.

[0234] The specific size of the sample is 300mm×300mm×300mm, which meets the testing requirements of the experimental equipment.

[0235] Fix the sample on the static load application device, apply static load step by step, and record the shear strength at each load point.

[0236] Each sample was loaded and unloaded multiple times to ensure data accuracy and repeatability.

[0237] Calculate the mean and standard deviation of shear strength for each type of composite joint;

[0238] The sample is fixed on a dynamic load vibration table to simulate dynamic loads of different frequencies, and the shear strength at each load point is recorded.

[0239] Each sample was loaded and unloaded multiple times to ensure data accuracy and repeatability.

[0240] Calculate the mean and standard deviation of shear strength for each type of composite joint;

[0241] calculating a first ratio between the mean value and the standard deviation of the shear strength under the static load test and a second ratio between the mean value and the standard deviation of the shear strength under the dynamic load test;

[0242] Based on experimental data and expert group analysis, the standard values ​​of shear performance and seismic performance under static and dynamic loads for each type of combined node connection method were determined.

[0243] Table 2 below records the average and standard deviation of the shear strength of eight types of combined nodes under static and dynamic load conditions, as well as the calculated second dynamic-static comparison coefficient;

[0244] In this embodiment, η1=50000;

[0245] Table 2

[0246]

[0247]

[0248] This table and analysis can help guide the selection of appropriate connection methods in different circumstances to optimize structural performance.

[0249] Further explanation: Finite element analysis is used to simulate different size values ​​of the combined nodes of each connection method to predict the shear strength of the combined nodes under static load test and dynamic load test respectively; specifically, it includes:

[0250] 3.1) Model geometry construction:

[0251] Select software: Use commercial finite element analysis software. The finite element analysis software of this embodiment is selected from ANSYS, ABAQUS, and COMSOL;

[0252] Define geometric dimensions: Establish a 3D geometric model based on the connection mode and the size of the combined nodes; define models of different sizes for each connection mode; in this embodiment, set the following basic standard sizes, and increase or decrease the sizes based on the basic standard sizes;

[0253] Pin connection model: diameter D = 10mm, 12mm, 15mm;

[0254] Tenon-nail connection model: tenon width W = 20mm, 25mm, 30mm;

[0255] Steel plate connection model: steel plate thickness T = 5mm, 7mm, 10mm;

[0256] 3.2) Define the properties of reconstructed bamboo and concrete materials:

[0257] Reconstructed bamboo material properties: elastic modulus E = 10 GPa, Poisson's ratio ν = 0.3;

[0258] Concrete material properties: elastic modulus E = 30 GPa, Poisson's ratio ν = 0.2;

[0259] Steel properties: elastic modulus E = 200 GPa, Poisson's ratio ν = 0.3;

[0260] 3.3) Mesh division of key combination node areas:

[0261] Mesh type: three-dimensional solid elements are used. In this embodiment, three-dimensional solid elements are selected from C3D8 and SOLID186;

[0262] Mesh size: For critical joint areas, a fine mesh with a cell size of 1-2 mm is used; for non-critical areas, a mesh with a cell size of 5-10 mm is used;

[0263] 3.4) Set boundary conditions and load application:

[0264] Boundary conditions: fixed support on one side of the reconstructed bamboo-concrete beam-column foundation; freedom constraints at the loading point;

[0265] Static load: gradually apply a vertical downward static shear force, with a maximum load of F_max = 10kN;

[0266] Dynamic load: Apply dynamic shear force conforming to a sinusoidal waveform, with a frequency of f = 1 Hz and an amplitude of A = 5 kN;

[0267] 3.5) Solution type:

[0268] Static analysis: Linear static analysis (Static Structural Analysis) is used to simulate static load tests;

[0269] Dynamic analysis: Use transient dynamic analysis (Transient Dynamic Analysis) to simulate dynamic load tests;

[0270] 3.6) Solution settings:

[0271] Static analysis: Set the number of load steps and time steps, gradually apply static shear force, and solve stress, strain, and displacement fields;

[0272] Dynamic analysis: set the number of time steps and time step length, apply sinusoidal dynamic shear force, and solve the transient response;

[0273] 3.7) Result extraction and shear strength prediction:

[0274] Extract stress field: Extract the maximum shear stress value τ of the key joint area in the model max ;

[0275] Shear strength calculation: According to the extracted maximum shear stress value τ max , predicting shear strength;

[0276] The predicted shear strength under static load test is recorded as τ′ static,i,j ;

[0277] The predicted shear strength under dynamic load test is recorded as τ′ dynamic,i,j :

[0278]

[0279] Among them, F max is the maximum load of the static load; F dynamic (t peak ) is the load at the peak moment of dynamic load; A contact is the effective contact area of ​​the combined node connection interface, and A contact Equal to As.

[0280] The predicted shear strength value of each static load numerical simulation test shall be recorded;

[0281] The predicted values ​​of each dynamic load numerical simulation test shall be recorded.

[0282] An optimization algorithm is used in numerical simulation to find the optimal connection form and combined node size value corresponding to the first static-dynamic ratio coefficient and the second static-dynamic ratio coefficient according to the static and dynamic load occasions.

[0283] Further explanation: According to the occasions of static and dynamic loads, an optimization algorithm is used in numerical simulation to find the optimal connection form and combined node size value corresponding to the first dynamic-static ratio coefficient and the second dynamic-static ratio coefficient, specifically including:

[0284] 4.1) Optimization algorithm selection Genetic Algorithm (GA);

[0285] Genetic algorithms have global search capabilities and can handle complex optimization problems with multiple variables and multiple constraints, and are suitable for various connection modes and size optimization in the present invention;

[0286] 4.2) Optimization objectives and constraints:

[0287] Optimization goal: According to the occasions of static and dynamic loads, different first dynamic-static comparison coefficients K1 are respectively j and the second dynamic-static comparison coefficient K2′ j The corresponding optimal connection form and combined node size value;

[0288] When the situation is dominated by static loads: maximize K1 j and K2′ j , to enhance static shear and seismic performance;

[0289] When dynamic loads are the main factor: Minimize K1 j and K2′ j, to enhance dynamic shear and seismic performance;

[0290] When the situation is uniform load: ensure K1 j and K2′ j In the middle range, to perform consistently under static and dynamic loads;

[0291] Constraints: The connection method and size parameters must meet the structural design requirements;

[0292] The optimization process is as follows:

[0293] Initialize the population: Generate the initial population, including combinations of different connection methods and sizes;

[0294] Fitness function: Calculate the fitness value of each individual, using K1 j and K2′ j is the target value;

[0295] Selection, crossover and mutation: Generate a new generation of population through selection, crossover and mutation operations;

[0296] Iterative solution: Repeat the above process until the convergence condition is met;

[0297] 4.3) Optimal solution extraction:

[0298] Combine static and dynamic load conditions and use optimization algorithms to obtain the optimal K1 j and K2′ j value, extract the optimal connection method and combined node size.

[0299] 4.4) Performance Verification:

[0300] Finite element verification is performed on the optimal connection method and size to ensure that its shear and seismic performance meets the design requirements.

[0301] It is further explained that according to the optimal connection form and the combined node size value, the reconstructed bamboo-concrete beam-column combined node test sample is prepared and an earthquake simulation test is carried out to obtain the seismic test data, and the seismic test data is analyzed and processed to calculate the seismic performance evaluation index, which specifically includes:

[0302] Prepare the recombined bamboo, concrete and other necessary materials according to the optimal connection form and combined node size values;

[0303] According to the optimized connection form and combined node size, the reconstructed bamboo-concrete beam-column combined node was manufactured to ensure the accuracy and consistency of the test samples;

[0304] Use a professional earthquake simulation test bench to conduct the experiment. In this embodiment, a shaking table is selected;

[0305] Simulate earthquake loads and conduct multiple tests with different earthquake intensities and frequencies to cover common earthquake conditions;

[0306] Install strain gauges, acceleration sensors and displacement sensors at key locations of combined nodes to record test data in real time, including displacement, acceleration and strain;

[0307] Use the data acquisition system to record the load, displacement, acceleration and strain data generated during the earthquake simulation in real time to ensure the integrity and accuracy of the data;

[0308] Preprocess seismic test data, including denoising, smoothing and normalization;

[0309] The seismic test data include acceleration, strain value, and displacement value;

[0310] According to the test data, the seismic performance evaluation index is recorded as S seismic , the formula is as follows:

[0311]

[0312] Where N′ is the number of trials; q i′ is the maximum acceleration of the i′th test; q ref is the reference acceleration value; d i′ is the maximum displacement value of the i′th test; d ref is the reference displacement value; e i′ is the maximum strain value of the i′th test, e ref is the reference strain value;

[0313] S seismic The value range is limited to (0,1);

[0314] When S seismic The closer it is to 0, the worse the seismic performance of the composite node under seismic load. At this time, the maximum acceleration, maximum displacement and maximum strain in the test data far exceed the reference value, indicating that the composite node is prone to damage under seismic load and has poor seismic performance.

[0315] When S seismic The closer it is to 1, the better the seismic performance of the composite node under seismic load; at this time, the maximum acceleration, maximum displacement and maximum strain in the test data are close to the reference value, indicating that the composite node can maintain good stability and integrity under seismic load and has excellent seismic performance.

[0316] It is further explained that a comprehensive seismic performance index model for evaluating the seismic performance of the current composite node test sample is constructed, specifically including:

[0317] The comprehensive seismic performance index is defined as Iseismic , the calculation formula is as follows:

[0318]

[0319] Among them, w1, w2, and w3 are the positive weight parameters of the first dynamic-static comparison coefficient, the second dynamic-static comparison coefficient, and the seismic performance evaluation index, respectively. To calculate the maximum value, and satisfy w1+w2+w3=1; in this embodiment, w1, w2, and w3 are 0.3, 0.3, and 0.4 respectively;

[0320] I seismic The value range of is limited to the range of (0,1);

[0321] When I seismic The closer it is to 0, the worse the comprehensive seismic performance of the composite node under seismic load;

[0322] When I seismic The closer it is to 1, the better the comprehensive seismic performance of the composite node under seismic load.

[0323] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0324] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0325] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for optimizing the shear and seismic performance of reconstructed bamboo-concrete connection nodes, characterized in that: The specific steps include: Step S1: the reconstructed bamboo-concrete beam-column composite nodes are connected in sequence using pin connection, tenon-nail connection, steel plate connection, and a combination of at least two connection methods, and the same static load test and dynamic load test are performed on the composite nodes of each connection method; Step S2: collecting the shear strength of each combined node connection mode under static load test and dynamic load test, and using the shear strength obtained from each connection mode as similar comparison data; Step S3: calculating the average value and standard deviation of the shear strength of the static load test in the same type of comparison data, and the average value and standard deviation of the shear strength under the dynamic load test; Step S4: in the same type of comparison data, a first difference between the static and dynamic load tests about the average value of the shear strength and a second difference about the standard deviation of the shear strength are calculated, and the two differences are combined to generate a first static-dynamic comparison coefficient, which is used to evaluate the stiffness change trend of the selected combined node connection mode under different load conditions; Calculate the first difference of the average shear strength in the jth type of comparison data ; Calculate the second difference of the standard deviation of shear strength in the jth type of comparison data ; For the first difference and the second difference Applying the logistic function, we get the following calculation formula: ； ； in, and Logistic function output values ​​for the first difference and the second difference, respectively; Use the weighted average method; set and The weight coefficients are positive numbers a1 and a2, so that a1+a2=1, and the first dynamic and static comparison coefficient of the j-th comparison data is defined as , the calculation formula is as follows: ； Will The value range of is limited to (0,1); Step S5: in the same type of comparison data, a first ratio between the average value and the standard deviation of the shear strength under the static load test is calculated, and a second ratio between the average value and the standard deviation of the shear strength under the dynamic load test is calculated, and a second dynamic-static comparison coefficient is generated by combining the first ratio and the second ratio. The second dynamic-static comparison coefficient is used to evaluate the change trend of the shear performance of the selected combined node connection mode under different load conditions; Calculate the first ratio between the mean and standard deviation of the shear strength under static load test in the jth type of comparison data ; Calculate the second ratio between the mean and standard deviation of the shear strength under dynamic load test in the jth type of comparison data ; And the following exponential function is applied to the first ratio and the second ratio: ； ； Using the weighted average method, set and The weight coefficients are positive numbers b1 and b2, so that b1+b2=1; the second dynamic and static comparison coefficient of the j-th comparison data is defined as , the calculation formula is as follows: ； right Apply the logistic function to limit its output value to the range of (0,1); ； in, is the second dynamic-static comparison coefficient after normalization by logistic function, is the scaling adjustment factor; Step S6: using finite element analysis to simulate different size values ​​of the combined nodes of each connection mode to predict the shear strength of the combined nodes under static load tests and dynamic load tests respectively; Step S7: according to the occasions of static and dynamic loads, an optimization algorithm is used in numerical simulation to find the optimal connection form and combined node size value corresponding to the first static-dynamic comparison coefficient and the second static-dynamic comparison coefficient; Step S8: According to the optimal connection form and the combined node size value, a reconstructed bamboo-concrete beam-column combined node test sample is prepared and an earthquake simulation test is carried out to obtain earthquake-resistant test data, the earthquake-resistant test data is analyzed and processed, and an earthquake-resistant performance evaluation index is calculated; Step S9: The first dynamic-static comparison coefficient, the second dynamic-static comparison coefficient and the seismic performance evaluation index are combined for analysis, and a comprehensive seismic performance index model for evaluating the seismic performance of the current combined node test sample is constructed using statistical analysis or machine learning methods.

2. The method for optimizing the shear and seismic performance of reconstructed bamboo-concrete connection nodes according to claim 1, characterized in that: Pin connection, tenon-nail connection and implanted steel plate connection are used in turn, and the same static load test and dynamic load test are carried out for the combined nodes of each connection method, including: It is assumed that both the static load test and the dynamic load test are conducted n times, forming a test number set {1, 2, ..., i, ..., n}; where i represents the index of the i-th test number; The combined node connection method includes any one of pin connection, tenon-nail connection and implanted steel plate connection, or a combination of at least two of the connection methods; the combined node connection methods are marked to form a set {1, 2, ..., j, ..., 8}; wherein j represents the index of the j-th combined node connection method, and 8 represents the total number of combined connection indexes; Apply a gradually increasing static load to the jth type of combined node connection mode, and set the basic applied load of the static load test to , the applied load of the j-th type of combined node connection in the i-th static load test is expressed as , the calculation formula is as follows: ； A periodically changing dynamic load is applied to the j-th type of combined node connection mode, and the basic applied load of the dynamic load test is set as , the applied load of the j-type combined node connection mode in the i-th dynamic load test is expressed as , the calculation formula is as follows: ； Where A is the amplitude coefficient, is the angular frequency, The initial phase.

3. The method for optimizing the shear and seismic performance of a reconstructed bamboo-concrete connection node according to claim 2, characterized in that: The shear strength of each combined node connection method under static load test and dynamic load test is collected, and the shear strength obtained by each connection method is used as the same type of comparison data, including: The static shear strength of the j-type combined node connection in the i-th static load test is recorded as , the calculation formula is as follows: ； Where As is the effective area of ​​the connection interface; The dynamic shear strength of the j-th type of combined node connection in the i-th dynamic load test is recorded as , the calculation formula is as follows: ； The static shear strength of the j-type combined node connection in n tests and dynamic shear strength As the same type of comparison data, it is further referred to as the j-th type of comparison data.

4. The method for optimizing shear and seismic performance of reconstructed bamboo-concrete connection nodes according to claim 3, characterized in that: Calculate the mean and standard deviation of the shear strength of the static load test in the same type of comparison data, as well as the mean and standard deviation of the shear strength under the dynamic load test; specifically including: Static shear strength The average values ​​are as follows: ； Dynamic shear strength The average values ​​are as follows: ； Static shear strength The standard deviation of is as follows: ； Dynamic shear strength The standard deviation of is as follows: ； in, represents the average shear strength of the static load test in the jth type of comparison data, represents the standard deviation of the shear strength of the static load test in the jth type of comparison data; represents the average shear strength of the dynamic load test in the jth type of comparison data, Represents the standard deviation of the shear strength of the dynamic load test in the jth type of comparison data.

5. The method for optimizing the shear and seismic performance of reconstructed bamboo-concrete connection nodes according to claim 4, characterized in that: Generate the first dynamic-static comparison coefficient, which is used to evaluate the stiffness change trend of the selected combined node connection method under different load conditions, including: Define the first difference The calculation formula is as follows: ； Define the second difference The calculation formula is as follows: ； Based on experimental verification or expert group analysis, determine the standard values ​​of stiffness of the j-type combined node connection mode under static and dynamic loads; when When , it is the middle value interval, indicating that the performance of this combined node connection mode under static and dynamic loads is consistent, and the stiffness variation range fluctuates within ±5% of the corresponding stiffness standard value, which is suitable for occasions where static and dynamic loads are uniformly borne; when When , it means that this combined node connection mode is suitable for occasions where static loads are dominant; the stiffness increase under static loads exceeds 10% of the corresponding stiffness standard value; it is suitable for environments that are frequently subjected to static loads; when When , it means that this connection method is suitable for applications where dynamic loads are dominant; the stiffness increase under dynamic loads exceeds 15% of the corresponding stiffness standard value, and is suitable for environments that are frequently subjected to dynamic loads.

6. The method for optimizing shear and seismic performance of reconstructed bamboo-concrete connection nodes according to claim 5, characterized in that: Generate the second dynamic-static comparison coefficient, which is used to evaluate the shear performance change trend of the selected combined node connection method under different load conditions, including: Define the first ratio The calculation formula is as follows: ； Define the second ratio The calculation formula is as follows: ； Will The value range is divided into multiple intervals, and the shear performance change trend of each interval is quantitatively described: based on experimental verification or expert group analysis, the standard value of the shear performance of the j-th type of combined node connection mode under static and dynamic loads is determined; when When the load is dynamic, the shear resistance exceeds the corresponding standard value of shear resistance by 11%; it is suitable for environments that are frequently subjected to dynamic loads; when When , it is the middle value interval. Under static and dynamic loads, the shear performance fluctuation range is within ±6% of the corresponding shear performance standard value, indicating that the combined node connection method exhibits consistent shear performance under static and dynamic loads; it is suitable for occasions that evenly bear static and dynamic loads; when When under static load, the shear resistance exceeds the corresponding shear resistance standard value by 12%; it is suitable for environments that are frequently subjected to static loads.

7. The method for optimizing shear and seismic performance of reconstructed bamboo-concrete connection nodes according to claim 6, characterized in that: Finite element analysis is used to simulate different size values ​​of the combined nodes of each connection method to predict the shear strength of the combined nodes under static load tests and dynamic load tests respectively; specifically including: 3.1) Establish a 3D geometric model based on the connection method and the size of the combined nodes; for each connection method, define models of different sizes; 3.2) Define the properties of reconstructed bamboo and concrete materials: 3.3) Mesh division of key combination node areas: 3.4) Set boundary conditions and load application: The predicted shear strength under static load test is recorded as ; The predicted shear strength under dynamic load test is recorded as : ； ； in, is the maximum load of the static load; is the load at the peak moment of the dynamic load; is the effective contact area of ​​the combined node connection interface, and Equal to As.

8. The method for optimizing shear and seismic performance of reconstructed bamboo-concrete connection nodes according to claim 7, characterized in that: According to the occasions of static and dynamic loads, an optimization algorithm is used in numerical simulation to find the optimal connection form and combined node size value corresponding to the first dynamic-static comparison coefficient and the second dynamic-static comparison coefficient, including: 4.1) Optimization algorithm selection: Genetic algorithm; 4.2) Optimization objectives and constraints: Optimization goal: According to the occasions of static and dynamic loads, different first dynamic-static comparison coefficients are respectively and the second dynamic-static comparison coefficient The corresponding optimal connection form and combined node size value; When the situation is dominated by static loads: Maximize and , to enhance static shear and seismic performance; When dynamic loads are the main factor: Minimize and , to enhance dynamic shear and seismic performance; When the situation is uniform load: ensure and In the middle range, to perform consistently under static and dynamic loads; Constraints: The connection method and size parameters must meet the structural design requirements; 4.3) Optimal solution extraction: Combine static and dynamic load conditions and use optimization algorithms to obtain the best and value, extract the optimal connection method and combined node size.

9. The method for optimizing shear and seismic performance of reconstructed bamboo-concrete connection nodes according to claim 8, characterized in that: The seismic test data is analyzed and processed to calculate the seismic performance evaluation index, including: The seismic test data include acceleration, strain value, and displacement value; The seismic performance evaluation index is recorded as , the formula is as follows: ； in, is the number of trials; It is The maximum acceleration of the test; is the reference acceleration value; It is The maximum displacement value of the test; is the reference displacement value; It is The maximum strain value of the test, is the reference strain value; The value range is limited to (0,1); when The closer it is to 0, the worse the seismic performance of the composite node under seismic load; when The closer it is to 1, the better the seismic performance of the composite node under seismic load.

10. The method for optimizing shear and seismic performance of reconstructed bamboo-concrete connection nodes according to claim 9, characterized in that: A comprehensive seismic performance index model is constructed to evaluate the seismic performance of the current composite node test sample, including: The comprehensive seismic performance index is defined as , the calculation formula is as follows: ； in, are the positive weight parameters of the first dynamic-static comparison coefficient, the second dynamic-static comparison coefficient and the seismic performance evaluation index, respectively. is the calculated maximum value and satisfies ; The value range of is limited to the range of (0,1); when The closer it is to 0, the worse the comprehensive seismic performance of the composite node under seismic load; when The closer it is to 1, the better the comprehensive seismic performance of the composite node under seismic load.

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