Finite element simulation method for warehouse separation seam of foundation slab through warehouse jumping method

Abstract

The invention discloses a finite element simulation method for a warehouse dividing seam of a foundation slab in a warehouse jumping method. The finite element simulation method comprises the following steps: a common warehouse seam structure of the foundation slab comprises a warehouse block A, a warehouse block B, a contact surface, a water stop steel plate and a slab reinforcing steel bar; a solid unit is adopted to simulate a bin block, a viscous unit is adopted to simulate a contact surface, a bushing unit is adopted to simulate a water stop steel plate, and a truss unit is adopted to simulate a steel bar; the method comprises the following steps: simulating the bond slip characteristic of a warehouse dividing seam through a viscous unit, and determining traction-separation constitutive model parameters through inversion by adopting a PSO-SVM (Particle Swarm Optimization-Support Vector Machine) algorithm according to a uniaxial tension test result; according to the finite element simulation method for the partition seam of the foundation slab adopting the skip bay method, the contact surface, the water stop steel plate, the slab reinforcing steel bar and other detailed components can be considered at the same time, the mechanical property of the partition seam can be finely simulated by simulating the bonding-sliding property of the contact surface and the water stop steel plate, and the mechanical parameters of a viscous unit can be rapidly and accurately determined. Therefore, the accuracy of finite element simulation of the foundation slab based on the skip bay method is improved.

Description

Technical Field

[0001] The invention relates to the technical field of numerical simulation of building structures, and in particular to a finite element simulation method for compartment seams of a foundation bottom plate using a skip compartment method. Background Art

[0002] The skip bin method controls cracks according to the principle of "releasing first and then resisting", and is constructed according to the principle of "block planning, block construction, layered pouring, and overall forming". By dividing the large volume of concrete into several small bins, they are connected as a whole after the short-term temperature stress and shrinkage stress are released. This avoids cracking due to temperature stress or hardening shrinkage during the pouring of the large volume foundation slab. Accordingly, due to different pouring times, bin gaps need to be set between different bin blocks.

[0003] For large-area foundation slabs, there are many compartments and compartment joints, which have a significant impact on the overall stress of the slab. Therefore, the influence of compartment joints needs to be considered in the early stress analysis. However, at present, the simulation of compartment joints in the stress simulation of structural slabs is relatively rough, and there is a lack of finite element refined simulation methods that consider the bonding characteristics of compartment joints. At the same time, it is difficult to determine the relevant mechanical parameters of compartment joints, resulting in inaccurate overall stress analysis of the foundation slab. Summary of the invention

[0004] The purpose of the present invention is to provide a finite element simulation method for compartment joints of a foundation slab using a skip-compartment method to address the above-mentioned deficiencies, thereby solving the problem that the simulation of compartment joints in the stress simulation of the structural slab at the current stage is relatively rough, there is a lack of a finite element refined simulation method that considers the bonding characteristics of the compartment joints, and at the same time, the relevant mechanical parameters of the compartment joints are difficult to determine, resulting in inaccurate overall stress analysis of the foundation slab.

[0005] The present invention is achieved through the following scheme:

[0006] A finite element simulation method for compartment joints of a foundation bottom plate using a skip-bin method comprises the following steps: the commonly used compartment joint structures of the foundation bottom plate include a compartment block A, a compartment block B, a contact surface, a water-stop steel plate and bottom plate reinforcement; solid units are used to simulate the compartment blocks, viscous units are used to simulate the contact surface, bushing units are used to simulate the water-stop steel plate, and truss units are used to simulate the reinforcement; the adhesion-slip characteristics of the compartment joints are simulated by viscous units, and the PSO-SVM algorithm is used to inversely determine the parameters of the traction-separation constitutive model according to the results of a uniaxial tension test.

[0007] In the above steps, the viscous unit adopts the traction separation criterion to simulate its damage evolution: At the same time, the secondary stress criterion is used as the damage initiation criterion: After the initial damage occurs, the interface stiffness degradation rate is described by the damage evolution criterion.

[0008] In the above steps, the uniaxial tensile test is specifically as follows: test blocks A and B are used to simulate bin blocks A and B respectively. The casting time sequence and interface treatment method are the same as the actual project. The two ends of bin blocks A and B are bonded and fixed to the upper bracket and the lower bracket respectively. A universal testing machine is used to support the two ends of the upper and lower brackets. The force and displacement data are read synchronously during the loading process.

[0009] The viscous unit uses the traction separation criterion to simulate its damage evolution as follows:

[0010]

[0011] In the formula, t n ,t s ,t t are the stresses in the normal direction and two tangential directions of the contact surface; K nn , K ss , K tt are the contact stiffness in three directions respectively; δ n ,δ s ,δ t They are the contact displacements in three directions.

[0012] The secondary stress criterion is used as the damage initiation criterion:

[0013]

[0014] In the formula, are the peak stresses in the normal direction and the two tangential directions, respectively.

[0015] Under the linear damage criterion, the damage variable D follows the following evolution law:

[0016]

[0017] In the formula, is the effective contact displacement at complete destruction; is the maximum effective contact displacement of the contact during the loading process; is the effective contact displacement when initial damage occurs.

[0018] In the above steps, K nn , K ss , K tt , The interface parameters are determined by inversion using the PSO-SVM algorithm;

[0019] The specific steps include:

[0020] S1: Start;

[0021] S2: Determine the value range of interface parameters;

[0022] S3: Use the LHS sampling algorithm to extract and set the parameter combinations used in the uniaxial tension numerical model, and extract and set n groups of parameter combinations in total:

[0023] S4: According to the uniaxial tension test of compartment joints, a uniaxial tension finite element model of compartment joints is established: test block A and test block B are simulated by solid units respectively; the test contact surface is simulated by contact surface viscosity unit, and its unit parameters are set according to the parameter combination extracted in S3; the upper bracket and the lower bracket are simulated by solid units respectively; after substituting each test parameter combination, axial tension loads are applied at both ends for simulation, so as to obtain a sample database;

[0024] S5: Substitute the sample database into the SVM model for training; select the kernel function of the SVM model, set the initial penalty parameters and kernel function parameters of the SVM model, and use them to initialize the PSO algorithm particle swarm;

[0025] S6: Run the PSO algorithm to calculate the individual optimum and the global optimum, calculate the particle fitness, iteratively update the particle fitness until it meets the termination condition, and then map the optimal particle to the penalty parameter and kernel function parameter of the SVM model;

[0026] S7: Input the uniaxial tension test data into the interface parameter inversion SVM model to obtain the optimal interface parameter values;

[0027] S8: Substitute the optimal interface parameters into the uniaxial tension numerical model of compartment joints and compare with the uniaxial tension test data to verify the effect;

[0028] S9: End.

[0029] In S3, it is:

[0030] a. Divide each parameter m into n equal probability intervals:

[0031]

[0032] b. For the i-th interval, the cumulative probability of sampling can be written as:

[0033]

[0034] c. Use the inverse probability distribution function F-1 to convert the probability into a sample value x:

[0035] m i =F -1 (p i )

[0036] The n values ​​obtained for each variable m are paired with the n values ​​of the other variables randomly or in some specific order.

[0037] In the above steps, the steel truss unit is embedded, the waterproof steel plate is simulated by the bushing unit, and the displacement-force curve of the bushing unit is:

[0038] p=2dlsτ(x)

[0039] Wherein, l is the anchoring length; d is the bushing unit distribution interval; l is the length of the waterproof steel plate 2-2 embedded in the bin block A or the bin block B, s is the circumference of the steel plate section within the spacing distance d of the steel plate; τ(x) is the bonding stress curve between the steel plate and the concrete.

[0040] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0041] 1. The finite element simulation method of the base plate of the skip-bin method adopted in this scheme can simultaneously consider the contact surface, water-stop steel plate, bottom plate steel bar and other detailed components, and can finely simulate the mechanical properties of the base plate by simulating the bond-slip characteristics of the contact surface and the water-stop steel plate, and can also quickly and accurately determine the mechanical parameters of the viscous unit. This improves the accuracy of the finite element simulation of the base plate of the skip-bin method. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic diagram of the compartment seam structure;

[0043] Figure 2 This is a structural schematic diagram of another embodiment of the present application;

[0044] Figure 3 This is a schematic diagram of the uniaxial tension test of compartment joints;

[0045] Figure 4 This is the flow chart of the algorithm for inversion of mechanical parameters of the viscous unit of the compartment joint;

[0046] Figure 5 It is the uniaxial tension finite element model of compartment joint;

[0047] Markings in the figure: 1-1, block A; 1-2, block B; 2-1, contact surface; 2-2, water stop steel plate; 3, bottom plate steel bar; 4, block entity unit; 5, viscosity unit; 6, bushing unit; 7, truss unit; 8-1, test block A; 8-2, test block B; 9, test contact surface; 10-1, upper bracket; 10-2, lower bracket; 11-1, test block A entity unit; 11-2, test block B entity unit; 12, test contact surface viscosity unit; 13-1, upper bracket entity unit; 13-2, lower bracket entity unit. DETAILED DESCRIPTION

[0048] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0049] Any feature disclosed in this specification (including any additional claims and abstract), unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0050] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0051] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0052] Example 1

[0053] like Figure 1 to Figure 5 As shown, the present invention provides a technical solution:

[0054] A finite element simulation method for a base floor compartment seam of a skip-compartment method comprises the following steps:

[0055] The commonly used compartment joint structure of the foundation slab includes compartment block A1-1, compartment block B1-2, contact surface 2-1, waterstop steel plate 2-2 and bottom plate steel bar 3; the solid unit 4 is used to simulate the compartment block, the viscous unit 5 is used to simulate the contact surface 2-1, the bushing unit 6 is used to simulate the waterstop steel plate 2-2, and the truss unit 7 is used to simulate the steel bar; the viscous unit 5 is used to simulate the bond-slip characteristics of the compartment joint, and according to the results of the uniaxial tension test, the PSO-SVM (particle swarm-support vector machine) algorithm is used to inversely determine the parameters of the traction-separation constitutive model.

[0056] This method solves the problem of refined finite element simulation of compartment joints; the present invention can simultaneously consider detailed components such as the contact surface 2-1, water-stop steel plate 2-2, and bottom plate steel bars 3 of the compartment joints, and can finely simulate the mechanical properties of the compartment joints by simulating the bonding-slip characteristics of the contact surface 2-1 and the water-stop steel plate 2-2, and can also quickly and accurately determine the mechanical parameters of the viscous unit 5.

[0057] In the above steps, the traction separation criterion is used to simulate the damage evolution of the viscous element 5:

[0058]

[0059] In the formula, t n ,t s ,t t are the stresses in the normal and two tangential directions of the contact surface 2-1; K nn , K ss , K tt are the contact stiffness in three directions respectively; δ n ,δ s ,δ t They are the contact displacements in three directions.

[0060] The secondary stress criterion is used as the damage initiation criterion:

[0061]

[0062] In the formula, are the peak stresses in the normal direction and the two tangential directions, respectively.

[0063] After the initial damage occurs, the interface stiffness degradation rate is described by the damage evolution criterion:

[0064]

[0065] In the formula, is the contact stress without considering damage.

[0066] Under the linear damage criterion, the damage variable D follows the following evolution law:

[0067]

[0068] In the formula, is the effective contact displacement at complete destruction; is the maximum effective contact displacement of the contact during the loading process; is the effective contact displacement when initial damage occurs.

[0069] In the above steps, the uniaxial tension test is specifically as follows: test blocks A8-1 and B8-2 are used to simulate bin blocks A1-1 and B1-2 respectively, and the casting time sequence and interface treatment method are the same as the actual project. The two ends of bin blocks A1-1 and B1-2 are respectively bonded and fixed on the upper bracket 10-1 and the lower bracket 10-2, and a universal testing machine is used to support the two ends of the upper and lower brackets 10-2. The force and displacement data are read synchronously during the loading process.

[0070] In the above steps, K nn , K ss , K tt , The interface parameters are determined by inversion using the PSO-SVM algorithm;

[0071] The specific steps include:

[0072] S1: Start;

[0073] S2: Determine the value range of the interface parameters as shown in Table 1.

[0074] S3: Use the LHS sampling algorithm to extract and set the parameter combinations used in the uniaxial tension numerical model, and extract and set n groups of parameter combinations in total:

[0075] S4: According to the uniaxial tension test of compartment joints ( Figure 3 ) and establish a uniaxial tension finite element model of compartment joints ( Figure 5 ): The test block A8-1 and the test block B8-2 are simulated by the test block A entity unit 11-1 and the test block B entity unit 11-2 respectively; the test contact surface 9 is simulated by the contact surface 2-1 viscosity unit 5, and its unit parameters are set according to the parameter combination extracted in S3; the upper bracket 10-1 and the lower bracket 10-2 are simulated by the upper bracket entity unit 13-1 and the lower bracket entity unit 13-2 respectively; after substituting each test parameter combination, axial tensile loads are applied at both ends of the upper bracket entity unit 13-1 and the lower bracket entity unit 13-2 to simulate, thereby obtaining a sample database;

[0076] S5: Substitute the sample database into the SVM model for training. Select the kernel function of the SVM model, set the initial penalty parameters and kernel function parameters of the SVM model, and use them to initialize the PSO algorithm particle swarm;

[0077] S6: Run the PSO algorithm to calculate the individual optimum and the global optimum, calculate the particle fitness, iteratively update the particle fitness until it meets the termination condition, and then map the optimal particle to the penalty parameter and kernel function parameter of the SVM model;

[0078] S7: Input the uniaxial tension test data into the interface parameter inversion SVM model to obtain the optimal interface parameter values;

[0079] S8: Substitute the optimal interface parameters into the uniaxial tension numerical model of compartment joints and compare with the uniaxial tension test data to verify the effect;

[0080] S9: End;

[0081] Table 1

[0082]

[0083]

[0084] In S3, it is:

[0085] a. Divide each parameter m into n equal probability intervals:

[0086]

[0087] b. For the i-th interval, the cumulative probability of sampling can be written as:

[0088]

[0089] c. Use the inverse probability distribution function F-1 to convert the probability into a sample value x:

[0090] m i =F -1 (p i ) (7)

[0091] The n values ​​obtained for each variable m are paired with the n values ​​of the other variables randomly or in some specific order.

[0092] In the above steps, the waterproof steel plate is simulated by bushing unit 6, and the displacement-force curve of bushing unit 6 is:

[0093] p=2dlsτ(x) (8)

[0094] Wherein, l is the anchoring length; d is the distribution interval of bushing unit 6; l is the length of the waterproof steel plate embedded in the block A1-1 or the block B1-2; s is the circumference of the steel plate section within the spacing distance d of the steel plate; τ(x) is the bonding stress curve between the steel plate and the concrete.

[0095] In the above steps, the steel bar truss unit 7 is in an embedded form.

[0096] The finite element simulation method of the base plate compartment joint of the skip-bin method adopted in this scheme can simultaneously consider the contact surface 2-1, the water-stop steel plate 2-2, the bottom plate steel bar 3 and other detailed components, and can finely simulate the mechanical properties of the compartment joint by simulating the bonding-slip characteristics of the contact surface 2-1 and the water-stop steel plate 2-2, and can also quickly and accurately determine the mechanical parameters of the viscous unit 5. Thereby improving the accuracy of the finite element simulation of the base plate of the skip-bin method.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A finite element simulation method for the compartment seam of the base plate of the skip-compartment method, characterized in that: The following steps are involved: The commonly used compartment joint structure of the foundation slab includes compartment block A, compartment block B, contact surface, waterstop steel plate and bottom plate steel bars. Solid units are used to simulate the compartment blocks, viscous units are used to simulate the contact surface, bushing units are used to simulate the waterstop steel plate, and truss units are used to simulate the steel bars. Viscous units are used to simulate the bond-slip characteristics of the compartment joints. According to the results of uniaxial tension tests, the PSO-SVM algorithm is used to inversely determine the parameters of the traction-separation constitutive model.

2. The finite element simulation method for the base plate compartment seam of the skip-compartment method according to claim 1, characterized in that: The viscous element uses the traction separation criterion to simulate its damage evolution: At the same time, the quadratic stress criterion is adopted as the damage initiation criterion: after the initial damage occurs, the interface stiffness degradation rate is described by the damage evolution criterion.

3. The finite element simulation method for the base plate compartment seam of the skip-compartment method according to claim 2 is characterized by: The specific uniaxial tension test is as follows: test blocks A and B are used to simulate bin blocks A and B respectively. The casting time sequence and interface treatment method are the same as the actual project. The two ends of bin blocks A and B are bonded and fixed to the upper bracket and the lower bracket respectively. A universal testing machine is used to support the two ends of the upper and lower brackets, and the force and displacement data are read synchronously during the loading process.

4. The finite element simulation method for the base plate compartment seam of the skip-compartment method according to claim 3 is characterized by: The viscous unit uses the traction separation criterion to simulate its damage evolution as follows: Where, t n ,t s ,t t are the stresses in the normal direction and two tangential directions of the contact surface; K nn , K ss , K tt are the contact stiffness in three directions respectively; δ n , δ s , δ t They are the contact displacements in three directions.

5. The finite element simulation method for the base plate compartment seam of the skip compartment method according to claim 4 is characterized by: The secondary stress criterion is used as the damage initiation criterion: In the formula, are the peak stresses in the normal direction and the two tangential directions, respectively.

6. The finite element simulation method for the base plate compartment seam of the skip-compartment method according to claim 5, characterized in that: Under the linear damage criterion, the damage variable D follows the following evolution law: In the formula, is the effective contact displacement at complete destruction; is the maximum effective contact displacement of the contact during the loading process; is the effective contact displacement when initial damage occurs.

7. The finite element simulation method for the compartment seam of the base plate of the skip compartment method according to claim 6 is characterized by: K nn , K ss , K tt , The interface parameters are determined by inversion using the PSO-SVM algorithm.

8. The finite element simulation method for the base plate compartment seam of the skip-compartment method according to claim 7, characterized in that: The specific steps include: S1: Start; S2: Determine the value range of interface parameters; S3: Use the LHS sampling algorithm to extract and set the parameter combinations used in the uniaxial tension numerical model, and extract and set n groups of parameter combinations in total: S4: According to the uniaxial tension test of compartment joints, a uniaxial tension finite element model of compartment joints is established: test block A and test block B are simulated by solid units respectively; the test contact surface is simulated by contact surface viscosity unit, and its unit parameters are set according to the parameter combination extracted in S3; the upper bracket and the lower bracket are simulated by solid units respectively; after substituting each test parameter combination, axial tension loads are applied at both ends for simulation, so as to obtain a sample database; S5: Substitute the sample database into the SVM model for training; select the kernel function of the SVM model, set the initial penalty parameters and kernel function parameters of the SVM model, and use them to initialize the PSO algorithm particle swarm; S6: Run the PSO algorithm to calculate the individual optimum and the global optimum, calculate the particle fitness, iteratively update the particle fitness until it meets the termination condition, and then map the optimal particle to the penalty parameter and kernel function parameter of the SVM model; S7: Input the uniaxial tension test data into the interface parameter inversion SVM model to obtain the optimal interface parameter values; S8: Substitute the optimal interface parameters into the uniaxial tension numerical model of compartment joints and compare with the uniaxial tension test data to verify the effect; S9: End.

9. The finite element simulation method for the compartment seam of the base plate of the skip compartment method according to claim 8, characterized in that: In S3, it is: a. Divide each parameter m into n equal probability intervals: b. For the i-th interval, the cumulative probability of sampling can be written as: c. Use the inverse probability distribution function F-1 to convert the probability into a sample value x: m i =F -1 (p i ) The n values ​​obtained for each variable m are paired with the n values ​​of the other variables randomly or in some predetermined order.

10. The finite element simulation method for the compartment seam of the base plate of the skip compartment method according to claim 9, characterized in that: In the above steps, the steel truss unit is embedded, the waterproof steel plate is simulated by the bushing unit, and the displacement-force curve of the bushing unit is: p=2dlsτ(x) Wherein, l is the anchoring length; d is the bushing unit distribution interval; l is the length of the waterproof steel plate 2-2 embedded in the bin block A or the bin block B, s is the circumference of the steel plate section within the spacing distance d of the steel plate; τ(x) is the bonding stress curve between the steel plate and the concrete.

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