CN115775597A

CN115775597A - Numerical simulation method for multiaxial stress state and freeze-thaw cycle coupling effect of concrete

Info

Publication number: CN115775597A
Application number: CN202211665300.2A
Authority: CN
Inventors: 王法承; 李博
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2022-12-23
Filing date: 2022-12-23
Publication date: 2023-03-10

Abstract

The disclosure relates to the field of concrete mechanics, in particular to a numerical simulation method for a multiaxial stress state and a freeze-thaw cycle coupling effect of concrete. The numerical simulation method comprises the following steps: establishing a simplified mesoscopic concrete finite element model by adopting a dimensionality simplification technology and a mesoscopic component simplification technology; setting parameters of the simplified mesoscopic concrete finite element model according to coupling effect parameters (including freeze-thaw cycle parameters and multiaxial stress state parameters); and performing concrete coupling effect finite element analysis (including concrete coupling effect damage analysis and mechanical property analysis after concrete coupling effect damage) on the simplified microscopic concrete finite element model subjected to parameter setting. The process realizes the numerical simulation of the coupling effect of the concrete multiaxial stress state and the freeze-thaw cycle in a simple and efficient mode, so that the analysis of the concrete freeze-thaw cycle is more in line with the actual stress condition, the calculation precision and the calculation efficiency are improved, and the method is suitable for engineering application.

Description

Numerical simulation method for multiaxial stress state and freeze-thaw cycle coupling effect of concrete

Technical Field

The disclosure relates to the field of concrete mechanics, in particular to a numerical simulation method for a multiaxial stress state and a freeze-thaw cycle coupling effect of concrete.

Background

The concrete can be in a complex multiaxial stress state and a freeze-thaw cycle coupling effect for a long time in the service life cycle of cold regions such as polar regions, oceans and plateaus. Along with the reduction of the temperature, the pore water in the concrete gradually freezes and expands, and the generated pore pressure and the multiaxial stress state of the concrete can generate a coupling effect. Compared with the coupling in a stress-free state, the coupling effect of the pore pressure and the multiaxial stress state of the concrete can cause more complex freeze-thaw damage to the concrete. Nowadays, the research on the anti-freezing performance of concrete mostly does not consider the influence of the coupling effect, and is different from the real situation. A small amount of research aiming at the coupling effect mostly adopts a test research mode, and has high cost and time and labor waste. An efficient research method aiming at the multiaxial stress state and the freeze-thaw cycle coupling effect of concrete is needed, the safe application of the concrete in cold regions is ensured, and the development and construction of extreme environments such as polar regions, oceans and plateaus are promoted.

Disclosure of Invention

In view of this, the present disclosure provides a technical solution for numerical simulation of a concrete multiaxial stress state and a freeze-thaw cycle coupling effect.

According to an aspect of the present disclosure, there is provided a method for numerically simulating a multiaxial stress state and a freeze-thaw cycle coupling effect of concrete, comprising:

establishing a simplified mesoscopic concrete finite element model by adopting a dimensionality simplification technology and a mesoscopic component simplification technology;

setting parameters of the simplified mesoscopic concrete finite element model according to coupling effect parameters, wherein the coupling effect parameters comprise freeze-thaw cycle parameters and multiaxial stress state parameters;

and carrying out concrete coupling effect finite element analysis on the simplified microscopic concrete finite element model subjected to parameter setting, wherein the concrete coupling effect finite element analysis comprises concrete coupling effect damage analysis and mechanical property analysis after the concrete coupling effect damage.

In one possible implementation, the creating a simplified mesoscopic concrete finite element model by using a dimensionality reduction technique and a mesoscopic component reduction technique includes:

under the condition that the three-dimensional concrete model is cylindrical, a two-dimensional finite element model section capable of reflecting three-dimensional performance is obtained for the three-dimensional concrete model by adopting a column symmetry technology;

and obtaining a two-dimensional symmetrical finite element model capable of reflecting three-dimensional performance by adopting an axisymmetric technology according to the section of the two-dimensional finite element model.

In one possible implementation, the creating a simplified mesoscopic concrete finite element model by using a dimensionality reduction technique and a mesoscopic composition reduction technique includes:

only arranging concrete units and pore units which are randomly distributed on the concrete units on the section of the two-dimensional finite element model;

and adopting an embedded constraint mode between the pore unit and the concrete unit.

In one possible implementation, the freeze-thaw cycle parameters include a freeze-thaw cycle temperature and a freeze-thaw cycle number; and according to the coupling effect parameters, setting the parameters of the simplified mesoscopic concrete finite element model, which comprises the following steps:

determining temperature change intervals of the pore units and the concrete units according to the freeze-thaw cycle temperature;

setting the linear expansion coefficient of the pore unit according to the temperature change interval and the number of freeze-thaw cycles;

and setting the elastic modulus of the pore unit according to the temperature change interval.

In a possible implementation manner, the performing parameter setting on the simplified meso-concrete finite element model according to the coupling effect parameter includes:

setting load or constraint conditions for the simplified mesoscopic concrete finite element model according to external multi-axis load or multi-axis constraint conditions applied to the three-dimensional concrete model;

the compressive stiffness recovery coefficient of the concrete is defined to be 0.6.

In one possible implementation, the concrete coupling effect damage analysis includes:

the degree and position distribution of compressive damage of concrete under multiaxial stress state and freeze-thaw cycle coupling effect;

the degree and position distribution of the tensile damage of the concrete under the multiaxial stress state and the freeze-thaw cycle coupling effect.

In a possible implementation manner, the analyzing the mechanical property of the damaged concrete coupling effect includes:

applying single-axis or multi-axis load to the finite element model after the concrete multi-axis stress state and the freeze-thaw cycle coupling effect damage to obtain the single-axis or multi-axis mechanical property of the concrete after the coupling effect damage;

and obtaining a calculation model of the multiaxial stress state and the freeze-thaw cycle coupling effect according to the uniaxial or multiaxial mechanical property of the concrete.

According to another aspect of the present disclosure, there is provided a device for numerical simulation of multiaxial stress state and freeze-thaw cycle coupling effect of concrete, comprising:

the model creating module is used for creating a simplified mesoscopic concrete finite element model by adopting a dimensionality simplification technology and a mesoscopic component simplification technology;

the parameter setting module is used for setting parameters of the simplified mesoscopic concrete finite element model according to coupling effect parameters, wherein the coupling effect parameters comprise freeze-thaw cycle parameters and multiaxial stress state parameters;

and the finite element analysis module is used for carrying out finite element analysis on the concrete coupling effect on the simplified microscopic concrete finite element model after parameter setting, and the finite element analysis on the concrete coupling effect comprises concrete coupling effect damage analysis and mechanical property analysis after the concrete coupling effect damage.

In one possible implementation, the model creation module is configured to:

In one possible implementation, the freeze-thaw cycle parameters include a freeze-thaw cycle temperature and a freeze-thaw cycle number; the parameter setting module is used for:

determining temperature change intervals of the pore unit and the concrete unit according to the freeze-thaw cycle temperature;

In a possible implementation manner, the parameter setting module is configured to:

setting load or constraint conditions for the simplified microscopic concrete finite element model according to external multi-axis load or multi-axis constraint conditions applied to the three-dimensional concrete model;

In a possible implementation manner, the mechanical property analysis after the concrete coupling effect damage includes:

According to another aspect of the present disclosure, there is provided an electronic device including: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to implement the above-described method when executing the memory-stored instructions.

According to another aspect of the present disclosure, there is provided a non-transitory computer readable storage medium having computer program instructions stored thereon, wherein the computer program instructions, when executed by a processor, implement the above-described method.

According to another aspect of the present disclosure, there is provided a computer program product comprising computer readable code, or a non-transitory computer readable storage medium carrying computer readable code, which when run in a processor of an electronic device, the processor in the electronic device performs the above method.

In the embodiment of the disclosure, a simplified microscopic concrete finite element model is created, parameters of the simplified microscopic concrete finite element model are set, and finally, concrete coupling effect finite element analysis is performed on the simplified microscopic concrete finite element model. In the model establishing process, the dimensionality simplification technology and the mesoscopic component simplification technology are combined, the dimensionality and the component complexity of the model are reduced while the three-dimensional coupling effect analysis function is maintained, the creating difficulty of the mesoscopic concrete finite element model is fully reduced, and the calculation efficiency of numerical simulation is greatly improved while the calculation precision is ensured; the embedded constraint of the pore unit and the concrete unit avoids repeated trial calculation and correction of constitutive relation parameters of the concrete material required by traditional replacement constraint, can directly apply conventional constitutive parameters of the material, is easy to determine and more reliable, and is more suitable for engineering application; in the parameter setting process, the established model is subjected to parameter setting according to the coupling effect parameters so as to further realize the numerical simulation of the concrete multiaxial stress state and the freeze-thaw cycle coupling effect, so that the concrete freeze-thaw cycle analysis is more in line with the actual stress condition, and the calculation precision is improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

Fig. 1 shows a flow chart of a method for numerical simulation of concrete multiaxial stress state and freeze-thaw cycle coupling effect according to an embodiment of the present disclosure.

FIG. 2 shows a schematic diagram of a two-dimensional finite element model obtained by a symmetric technique according to an embodiment of the present disclosure.

FIG. 3 shows a reasonably simplified schematic of a two-dimensional finite element model according to an embodiment of the present disclosure.

FIG. 4 illustrates a graph of relative compressive strength variation of a finite element model according to an embodiment of the present disclosure.

FIG. 5 shows a schematic diagram of a formula verification result according to an embodiment of the present disclosure.

Fig. 6 shows a flowchart of a numerical simulation method of the concrete filled steel tube multiaxial stress state and the freeze-thaw cycle coupling effect according to an application example of the present disclosure.

Fig. 7 illustrates a finite element model of a concrete filled steel tube element according to an application example of the present disclosure.

Fig. 8 shows a cloud of damage distributions obtained by analyzing a finite element model according to an application example of the present disclosure.

Fig. 9 shows a test data verification diagram of a concrete/concrete filled steel tube member according to an application example of the present disclosure.

Fig. 10 shows a block diagram of a numerical simulation apparatus for concrete multiaxial stress state and freeze-thaw cycle coupling effect according to an embodiment of the present disclosure.

FIG. 11 shows a block diagram of an electronic device according to an embodiment of the disclosure.

FIG. 12 shows a block diagram of an electronic device according to an embodiment of the present disclosure.

Detailed Description

Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the term "at least one" herein means any one of a plurality or any combination of at least two of a plurality, for example, including at least one of a, B, and C, and may mean including any one or more elements selected from the group consisting of a, B, and C.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present disclosure. It will be understood by those skilled in the art that the present disclosure may be practiced without some of these specific details. In some instances, methods, means, elements and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the subject matter of the present disclosure.

Concrete is the most commonly used building material in the basic construction of China, and is often applied to a plurality of structural forms such as a reinforced concrete structure, a steel pipe concrete structure, a section steel concrete structure and the like. Concrete is a heterogeneous composite material composed of aggregates, interface transition zones, pores, hardened cement paste and the like. The aggregate is a granular material which plays a role of a skeleton or filling in concrete, and is generally divided into a coarse aggregate (larger than 4.75 mm) and a fine aggregate (smaller than 4.75 mm) according to the particle size. The coarse aggregate generally refers to pebbles, broken stones and the like, and the fine aggregate generally refers to natural sand, artificial sand and the like.

The concrete is exposed outdoors, and the durability of the concrete is reduced by adverse factors such as wind, sunshine, environmental pollution, weather change and the like. Among them, the concrete used in cold regions such as polar regions, oceans and plateaus is generally damaged by freeze-thaw cycles, which affects the service life of the concrete structure. The method has great economic significance and social significance for the research on the concrete freeze-thaw cycle.

The concrete can be in a complex multi-axial stress state for a long time in the service process. As the temperature is reduced, pore water in the concrete gradually freezes and expands, and the generated pore pressure is coupled with the multiaxial stress state of the concrete. Compared with the coupling in a stress-free state, the coupling effect of the pore pressure and the multiaxial stress state of the concrete can cause more complex freeze-thaw damage to the concrete. Nowadays, the research on the frost resistance of concrete mostly does not consider the influence of the coupling effect, and is different from the real situation. A small amount of research aiming at the coupling effect mostly adopts a test research mode, and has high cost and time and labor waste. A small number of existing numerical simulation methods only aim at freeze-thaw cycle coupled in a stress-free state, the adopted three-dimensional mesoscopic model is complex, and the traditional two-dimensional model cannot reflect the coupling effect of the triaxial stress state and the freeze-thaw cycle. An efficient research method aiming at the multiaxial stress state and the freeze-thaw cycle coupling effect of concrete is urgently needed, the safe application of the concrete in cold regions is ensured, and the development and construction of extreme environments such as polar regions, oceans, plateaus and the like are promoted.

Fig. 1 is a flowchart illustrating a method for numerically simulating a concrete multiaxial stress state and a freeze-thaw cycle coupling effect according to an embodiment of the present disclosure, where the method may be applied to a device for numerically simulating a concrete multiaxial stress state and a freeze-thaw cycle coupling effect, and the device for numerically simulating a concrete multiaxial stress state and a freeze-thaw cycle coupling effect may be a terminal device, a server, or other processing devices. The terminal device may be a User Equipment (UE), a mobile device, a User terminal, a cellular phone, a cordless phone, a Personal Digital Assistant (PDA), a handheld device, a computing device, a vehicle-mounted device, a wearable device, or the like.

In some possible implementation manners, the numerical simulation method for the concrete multiaxial stress state and the freeze-thaw cycle coupling effect can be realized by means of calling computer readable instructions stored in a memory by a processor.

As shown in fig. 1, the method for numerically simulating the multiaxial stress state and the freeze-thaw cycle coupling effect of the concrete may include:

and S11, adopting a dimensionality simplification technology and a mesoscopic component simplification technology to create a simplified mesoscopic concrete finite element model.

The dimension simplification technology is a technology for analyzing the characteristics of an original dimension model by adopting a finite element model which can reduce the dimension and reflect the original dimension characteristics. Specifically, the characteristics of the N-dimensional model can be analyzed using a finite element model of M dimensions but reflecting the characteristics of N dimensions (M, N are positive integers, M < N). For the present disclosure, a two-dimensional, but three-dimensional, concrete finite element model may be used to analyze the properties of the three-dimensional concrete model. At present, aiming at the analysis of the multiaxial stress state and the freeze-thaw cycle coupling effect of concrete, a test research mode is adopted, the cost is high, time and labor are wasted, and the dynamic process of the freeze-thaw damage development of the concrete is difficult to explain from a microscopic angle. A small number of existing numerical simulation methods adopt a relatively complex three-dimensional microscopic model, and the existing models only aim at the freeze-thaw cycle of the stress-free state coupling and do not relate to the coupling effect of the multi-axis stress state and the freeze-thaw cycle; the traditional two-dimensional model cannot reflect the coupling effect of the multi-axis stress state and the freeze-thaw cycle. The method adopts the dimension simplification technology to establish the concrete finite element model, and can effectively reduce the complexity of the concrete finite element model.

In one example, the creating a simplified mesoscopic concrete finite element model using a dimensionality reduction technique and a mesoscopic composition reduction technique includes:

Wherein the three-dimensional concrete model is an actually existing model that is experimentally verified for numerical simulation results of the finite element model of the present disclosure. In one example, a real existing cylindrical three-dimensional concrete model can be obtained by stacking a certain two-dimensional cross section (i.e., two-dimensional finite element model cross section) based on the column symmetry, and since the stacked two-dimensional cross sections are identical, the analysis of the mechanical properties and the like of the three-dimensional concrete model can be obtained by analyzing the two-dimensional cross section. In one example, the overlay may be a stretch or a rotation of the two-dimensional cross-section. For the two-dimensional section, the two-dimensional section can be further reduced by an axisymmetric technique to obtain a two-dimensional section (i.e., a two-dimensional symmetric finite element model) with the smallest area capable of reflecting the three-dimensional performance. Therefore, a two-dimensional finite element model section capable of reflecting three-dimensional performance can be found in a cylindrical three-dimensional concrete model which exists in reality, a two-dimensional symmetrical finite element model capable of reflecting three-dimensional performance is established by adopting an axial symmetry technology for the two-dimensional finite element model section, and then finite element analysis of the three-dimensional concrete model can be realized by finite element analysis of the two-dimensional symmetrical finite element model. Specifically, the method for determining the two-dimensional finite element model section and the two-dimensional symmetric finite element model is not particularly limited, and can be determined according to specific actual conditions. Further, the shape of the three-dimensional concrete model is not specifically limited, and can be selected according to actual conditions, and correspondingly, when the three-dimensional concrete model is in other shapes than a cylindrical shape, the section of the two-dimensional finite element model and the acquisition mode of the two-dimensional symmetric finite element model can be flexibly determined according to the actual conditions.

FIG. 2 is a schematic diagram of a two-dimensional finite element model obtained by a dimension reduction technique. As shown in fig. 2, the two-dimensional symmetric finite element model is vertically symmetric on the basis of a horizontal axis to obtain a two-dimensional finite element model section, the cylindrical three-dimensional concrete model is obtained by performing column symmetric rotation operation on the two-dimensional finite element model section, and in the process of performing the axial symmetric and column symmetric operation, the multi-axial load and stress of the three-dimensional cylindrical concrete model can be converted into axial, radial and circumferential loads and stresses applied to the two-dimensional section. Therefore, the finite element analysis of the two-dimensional symmetrical finite element model obtained by the section of the two-dimensional finite element model can reflect the performance of the three-dimensional concrete model.

The two-dimensional finite element model section is obtained by adopting a column symmetry technology and the two-dimensional finite element model capable of reflecting three-dimensional performance is obtained by adopting an axial symmetry technology for a cylindrical three-dimensional concrete model. The process realizes the establishment of the two-dimensional symmetrical finite element model which keeps the analysis capability of the three-dimensional concrete coupling effect and reduces the complexity of the finite element analysis, the modeling method is simple, the modeling difficulty is reduced, and the calculation efficiency of the subsequent coupling effect analysis is improved.

The microscopic component simplification technology is a technology for only keeping components which determine the characteristics of the model to be analyzed and neglecting components which do not or have less effect on the characteristics of the model to be analyzed. The current research finds that the main factor of the concrete freeze-thaw damage mechanism is the freezing expansion of pore water. In concrete components, complicated macroscopic components such as coarse aggregates and fine aggregates have small influence in freeze-thaw damage, and have negligible effect on the coupling effect. In concrete structures, internal pores have a great influence on the frost resistance of concrete.

The traditional microscopic model of the concrete member is usually composed of a plurality of different materials such as mortar, aggregate (coarse aggregate and sand) and an interface transition area (including a transition area of the mortar and an aggregate interface), so that the finite element model of the concrete member is complex, the calculation convergence is poor, the consumed time is long, and the calculation complexity of obtaining the numerical simulation result of the concrete member in a freeze-thaw cycle environment through the finite element model is increased. During the process of establishing the mesoscopic concrete finite element model, only the pore elements determining the coupling effect and the concrete elements representing the concrete body may be retained, and in an example, the creating the simplified mesoscopic concrete finite element model by using the dimension reduction technique and the mesoscopic component reduction technique includes:

Specifically, based on a freeze-thaw cycle damage mechanism, a traditional concrete microscopic model can be reasonably simplified, a finite element model of a concrete member only provided with a pore unit and a concrete unit is established, and the finite element model is analyzed through finite element calculation software to obtain a simulation value of the concrete under the freeze-thaw cycle. FIG. 3 is a schematic illustration of a reasonable simplification of a two-dimensional finite element model. As shown in fig. 3, the finite element model before simplification includes random voids, concrete, coarse aggregate, sand, interface transition zone, hardened cement paste, etc., while the finite element model after simplification includes only random voids and concrete. In the embodiment, complicated modeling of microscopic components such as coarse aggregates and fine aggregates is not needed, and only random pores, which are the main factors causing durability damage to concrete through freeze-thaw cycles, are needed to be introduced, so that the rule of influence of the freeze-thaw cycles on the concrete member can be well reflected. In this embodiment, only the pore unit and the finite element model of the concrete unit representing the concrete body are retained to perform the influence of the coupling effect on the concrete characteristics, which is helpful to simplify the concrete finite element model and improve the calculation efficiency.

Specifically, the process of setting the pore units and the concrete units on the two-dimensional symmetric finite element model may include calculation of the number of the pore units and calculation of the positions of the pore units.

The number of the pore units is the number of the pore units in the two-dimensional symmetrical finite element model for finite element analysis. In an example, the total volume and the porosity of the three-dimensional concrete model may be obtained to obtain the total volume of the pore units in the three-dimensional concrete model, and then the number of the pore units in the three-dimensional concrete model is obtained by combining the volume of the single pore, and then the number of the pore units in the two-dimensional symmetric finite element model is obtained according to the number of the pore units in the three-dimensional concrete model. Specifically, the number of the pore units in the three-dimensional concrete model can be calculated according to the following formula:

N＝nV _c /V _p1 formula (1)

Wherein N is the number of pore units in the concrete member, N is the initial porosity of the concrete (without the influence of the air entraining agent), and V _c Is the volume of a concrete member, V _p1 Is the volume of a single pore.

The two-dimensional symmetric finite element model in fig. 2 is rotated to include only the upper half of the three-dimensional concrete model, so the number of the pore units in the two-dimensional symmetric finite element model in fig. 2 is one half of the number of the pore units in the three-dimensional concrete model in the shape of a cylinder.

In reality, the pores are randomly distributed in the concrete, and therefore, the pore units in the finite element model should be randomly distributed in the concrete units. In one example, a Monte Carlo method may be used to determine the specific location of each pore element to randomly distribute the pore elements in a three-dimensional finite element model. When the pore units are randomly distributed in the concrete member, the acquisition mode of the specific position of each pore unit is not particularly limited and can be selected according to actual conditions.

In the finite element model of the traditional concrete member, the pore units and the concrete units usually adopt a substituted constraint mode. When finite element calculation software is introduced into a finite element model, the material properties of the finite element model need to be set. The material properties of the concrete were obtained by experiments. In the test of measuring material parameters of concrete, the inside of the concrete is porous, so the measured parameter is the concrete containing the pores. If the model is modeled by adopting a method of replacing concrete by pores, the pores in the model can be distinguished from the concrete, a concrete unit becomes a compact material without pores, the material parameters (the compact material without pores) of the compact material are different from the material parameters (the material with pores) obtained by the test, complicated trial and error are needed for correction, and the compact material cannot be directly used.

In one example, the pore unit and the concrete unit adopt an embedded constraint mode, compared with the traditional substitution method, repeated trial calculation and correction are not needed for the change of the constitutive relation parameter of the concrete material caused by the substitution of the pore for the concrete, the conventional material constitutive parameter can be directly applied, and the method is easy to determine, more reliable and more suitable for engineering application.

In the embodiment, a microscopic component simplification technology is adopted, and in a two-dimensional symmetrical finite element model, the randomly distributed pore units are embedded and constrained to the concrete units, so that the most simplified model construction conforming to a multiaxial stress state and a freeze-thaw cycle coupling effect mechanism is realized, and the method has the characteristics of convenience and high efficiency in the aspects of model construction, parameter selection, calculation efficiency and the like, and is more suitable for engineering popularization and application.

And S12, setting parameters of the simplified microscopic concrete finite element model according to coupling effect parameters, wherein the coupling effect parameters comprise freeze-thaw cycle parameters and multiaxial stress state parameters.

The coupling effect parameters are parameters capable of influencing the freeze-thaw cycle and the multiaxial stress state coupling effect. To enable analysis of the coupling effect, in one example, the coupling effect parameters may include freeze-thaw cycle parameters and multi-axis stress state parameters. The freeze-thaw cycle parameters are parameters influencing the freeze-thaw cycle action, and the multi-axis stress state parameters are parameters influencing the multi-axis stress state action.

In actual engineering, concrete materials are generally in a multi-axis complex stress state in the process of freeze-thaw cycling. However, in the conventional concrete freeze-thaw cycle research, the influence of the coupling effect of the stress state and the freeze-thaw cycle is generally not considered, and a small amount of research only considers the coupling effect of the uniaxial stress and the freeze-thaw cycle through experiments and does not consider the coupling effect of the multiaxial stress and the freeze-thaw cycle. The research result cannot truly reflect the mechanical response of the concrete after the coupling action of the multiaxial stress state and the freeze-thaw cycle. The freeze-thaw damage rule of the concrete is the basis for the development and application of the concrete structure in the cold area, and the research on the freeze-thaw cyclic damage of the concrete which is more in line with the real situation can ensure that the design and the analysis of the structure are more accurate and reasonable, thereby having great engineering, social, economic and practical significance. The precondition of the concrete freeze-thaw cycle damage research conforming to the real condition is to consider the coupling effect of the concrete in the multiaxial stress state and the freeze-thaw cycle.

According to the method, the parameter setting of the simplified microscopic concrete finite element model is carried out according to the coupling effect parameters, the process embodies the coupling of freeze-thaw cycle and multiaxial stress state, so that the following finite element analysis process accords with the actual stress condition of the concrete, and the calculation precision is improved.

In one example, the freeze-thaw cycle parameters include a freeze-thaw cycle temperature and a freeze-thaw cycle number; and according to the coupling effect parameters, performing parameter setting on the simplified mesoscopic concrete finite element model, wherein the parameter setting comprises the following steps:

The freeze-thaw cycle temperature is a preset temperature interval for carrying out concrete coupling effect finite element analysis, and the temperature change interval is a temperature interval for generating the coupling effect in the freeze-thaw cycle temperature. The preset freeze-thaw temperature interval can be selected according to needs. In one example, 8 to-15 ℃ may be selected.

As mentioned above, the pore unit can well reflect the influence rule of the freeze-thaw cycle on the concrete member. Specifically, the elastic modulus and the linear expansion coefficient of the pore unit can reflect the influence of the pore unit on the concrete member in the process of freeze-thaw cycle. Therefore, the setting the parameters of the finite element model of the simplified meso-concrete according to the coupling effect parameters may include: and setting the elastic modulus and the linear expansion coefficient of the pore unit according to the freeze-thaw cycle parameters.

Because the concrete freeze-thaw damage mainly occurs in the freezing process, multiple freeze-thaw cycles can be simplified into a single freeze-thaw cycle. Based on a summary of a large number of experimental research results, it can be found that the number of freeze-thaw cycles corresponds to the linear expansion coefficient of the pore unit. Specifically, for ordinary concrete, the linear expansion coefficient of the pore unit corresponding to the freezing and thawing cycle times of 50 times is-0.00003/DEG C, the linear expansion coefficient of the pore unit corresponding to the freezing and thawing cycle times of 100 times is-0.00004/DEG C, and the linear expansion coefficients of the pore units under other freezing and thawing cycle times can be obtained by a linear difference method. In one example, multiple freeze-thaw cycles can be simplified into single freeze-thaw according to a preset freeze-thaw cycle number based on the relationship between the pore linear expansion coefficient and the freeze-thaw cycle number, so that the difficulty of calculation convergence caused by a large number of cycle numbers in the conventional freeze-thaw cycle analysis is solved, and the calculation efficiency is greatly improved.

Based on the pore water freezing expansion mechanism, the pores in the concrete can expand only within the temperature range of 0-70 ℃, so that the value of the linear expansion coefficient of the pore unit is changed. Specifically, the pore linear expansion coefficient is defined as a negative value in the range of 0 to-70 ℃ according to the relation, and the pore linear expansion coefficient is taken as ice in other temperature ranges. Therefore, different pore linear expansion coefficients in different temperature intervals are determined according to a pore water freezing expansion mechanism, and the freezing expansion amount of the pore unit can be obtained by combining the freezing and thawing cycle temperature interval, so that the influence degree of the freezing and thawing cycle is reflected.

In addition, the elastic modulus of the pore unit can be obtained according to a temperature change interval, specifically, the elastic modulus can be taken as ice at the temperature below 0 ℃, and the elastic modulus can be taken as 0 in other temperature ranges; the material parameters of the concrete elements may be selected according to conventional recommendations and will not be described in detail here.

In the method, the linear expansion coefficient and the elastic modulus of the pore units are set according to the freezing-thawing cycle temperature and the freezing-thawing cycle times, so that the influence on the concrete member in the freezing-thawing cycle process in the finite element analysis is realized according to the setting of the linear expansion coefficient and the elastic modulus of the pore units.

In one example, the parameter setting of the simplified mesoconcrete finite element model according to the coupling effect parameter comprises the following steps:

Specifically, the external multi-axis load or multi-axis constraint condition applied to the three-dimensional concrete model can be converted into the load or constraint condition applied to the simplified microscopic concrete finite element model directly through the finite element model, and then the load or constraint condition is set for the simplified microscopic concrete finite element model.

In the existing finite element analysis of concrete, a dead-live unit method (namely a method for deleting a concrete unit after the concrete damage exceeds a certain degree) is mostly adopted to consider the influence of the concrete material damage. However, the traditional living and dead cell method cannot consider the real situation that the cracked concrete can still bear partial pressure. In one example, in addition to the damage factor, a compressive stiffness recovery coefficient of the concrete is defined, and the real condition that the cracked concrete can still bear partial pressure is considered in the process of establishing the finite element model, so that the accuracy of the simulation method is improved. Specifically, the stiffness recovery coefficient includes: a tensile damage stiffness recovery coefficient, and a compressive damage stiffness recovery coefficient. In one example, according to a large number of tests and trial calculation results, the compressive stiffness recovery coefficient of the concrete can be defined to be 0.6, and better numerical simulation precision is obtained.

And S13, carrying out concrete coupling effect finite element analysis on the simplified microscopic concrete finite element model subjected to parameter setting, wherein the concrete coupling effect finite element analysis comprises concrete coupling effect damage analysis and mechanical property analysis after the concrete coupling effect is damaged.

The concrete damage caused by the concrete coupling effect can be tensile damage and compressive damage. Correspondingly, in an example, the concrete coupling effect damage analysis may include: the degree and position distribution of the compressive damage of the concrete under the multiaxial stress state and the freeze-thaw cycle coupling effect; the degree and position distribution of the tensile damage of the concrete under the multiaxial stress state and the freeze-thaw cycle coupling effect. According to the method, the crack development and damage change rule under the coupling effect of the freeze-thaw cycle and the multiaxial stress state can be obtained through the compression/tension damage degree and position distribution of the concrete under the multiaxial stress state and the freeze-thaw cycle coupling effect.

After the concrete coupling effect damage analysis is obtained, based on the damaged model, the working condition can be further applied to obtain the mechanical property of the material under the corresponding working condition after the coupling effect damage. In an example, the mechanical property analysis after the concrete coupling effect damage may include: applying single-axis or multi-axis load to the finite element model after the concrete multi-axis stress state and the freeze-thaw cycle coupling effect damage to obtain the single-axis or multi-axis mechanical property of the concrete after the coupling effect damage; and obtaining a calculation model of the multiaxial stress state and the freeze-thaw cycle coupling effect according to the uniaxial or multiaxial mechanical property of the concrete. The method is based on the damaged model, further applies working conditions, and can obtain the mechanical properties of the material under the corresponding working conditions after the damage of the coupling effect.

And the coupling effect finite element analysis is to perform finite element analysis on the simplified microscopic concrete finite element model after the parameters are set. Specifically, the finite element calculation software may be Abaqus, ANSYS, or the like. Besides using finite element calculation software to establish a finite element model, the finite element model can be established by modeling software such as AutoCAD, solidWorks, proe and the like, and then the finite element calculation software is introduced to carry out numerical simulation calculation. The selection of the modeling software and the finite element calculation software is not particularly limited in the disclosure, and can be selected according to actual conditions.

FIG. 4 is a graph showing the variation law of the compressive strength of the concrete obtained by the method under the coupling action of multi-axial stress and freeze-thaw cycle, wherein the axial load ratio is as follows: axial compressive stress/uniaxial compressive strength of unfrozen concrete; radial load ratio: radial compressive stress/uniaxial compressive strength of unfrozen concrete; relative compressive strength: uniaxial compressive strength of concrete/uniaxial compressive strength of unfrozen concrete after multiaxial stress and freeze-thaw cycle coupling. Furthermore, a calculation model of a multiaxial stress state and a freeze-thaw cycle coupling effect can be obtained according to the obtained uniaxial or multiaxial mechanical property of the concrete. Specifically, a relative compressive strength calculation model after the concrete multiaxial stress and freeze-thaw cycle coupling action can be further obtained through the principle of the concrete resisting the variation of the compressive strength under the multiaxial stress and freeze-thaw cycle coupling action. In one example, the computational model can be represented by equation (2):

wherein when alpha is more than or equal to 0.3 and beta is more than or equal to 0.1,

is the relative compressive strength of the concrete,

the concrete relative compressive strength without stress coupling, alpha is the axial load ratio, and beta is the radial load ratio.

Fig. 5 is a schematic diagram of a verification result of the formula (2), and it can be seen from fig. 5 that the relative compressive strength obtained by the formula (2) can be better matched with the relative compressive strength obtained by the test measurement, so that the numerical simulation method for the multiaxial stress state and the freeze-thaw cycle coupling effect of the concrete disclosed by the invention has higher accuracy, and more accurately reflects the influence of the complex multiaxial stress state and the freeze-thaw cycle coupling effect of the concrete on the concrete model.

In the embodiment of the disclosure, a simplified microscopic concrete finite element model is created, parameters of the simplified microscopic concrete finite element model are set, and finally, concrete coupling effect finite element analysis is performed on the simplified microscopic concrete finite element model. In the model establishing process, the dimensionality simplification technology and the mesoscopic component simplification technology are combined, the three-dimensional coupling effect analysis function is kept, and meanwhile, the difficulty in determining the dimensionality, the component complexity and the material parameters of the model is reduced, so that the difficulty in establishing the mesoscopic concrete finite element model is fully reduced, the calculation precision is guaranteed, and the calculation efficiency of numerical simulation is greatly improved; in the parameter setting process, the established model is subjected to parameter setting according to the coupling effect parameters so as to further realize the numerical simulation of the multiaxial stress state and the freezing-thawing cycle coupling effect of the concrete, so that the freezing-thawing cycle analysis of the concrete is more in line with the actual stress condition, and the calculation precision is improved.

By adopting the method, the mechanical property of the concrete under the coupling action of the complex multi-axis stress state and the freeze-thaw cycle can be quantitatively analyzed, and the method is also suitable for various confined concrete structures such as stirrup confined concrete, steel pipe concrete, hollow interlayer steel pipe concrete and the like, and is simple in modeling, high in calculation efficiency and convenient for engineering application.

Application scenario example

The confined concrete is a structural form which is most widely applied to concrete, and particularly can comprise various combined structures such as stirrup confined concrete, steel pipe concrete, hollow sandwich steel pipe concrete and the like, and concrete materials are in a complex multi-axial stress state for a long time in service in the structural form.

Fig. 6 is a flowchart illustrating an application example according to the present disclosure, and as shown in fig. 6, an embodiment of the present disclosure provides a numerical simulation method for concrete under a multiaxial stress state and a freeze-thaw cycle coupling effect, where the numerical simulation method may implement a freeze-thaw cycle numerical simulation analysis of concrete-filled steel tubes, and the numerical simulation may be performed by:

as shown in fig. 6, the process of the numerical simulation method for the freeze-thaw cycle of the steel pipe concrete can be roughly divided into three steps.

Step one, model creation. The method comprises the following steps:

and establishing a two-dimensional concrete filled steel tube finite element model capable of reflecting three-dimensional characteristics by means of large universal finite element calculation software Abaqus based on a dimensionality reduction technology and a microscopic component reduction technology. As shown in fig. 7, the finite element model includes only concrete elements, pore elements and steel pipe elements.

Wherein, the number of the pore units is calculated by formula (1); the concrete position of each pore on the concrete unit is determined by adopting a Monte Carlo method and based on Python secondary development; an embedded constraint mode is adopted between the concrete unit and the pore unit.

And step two, setting parameters. The method comprises the following steps:

and defining the material properties of pores, concrete and steel pipes. Specifically, multiple freezing-thawing cycles are simplified into single freezing-thawing, the relationship between the pore linear expansion coefficient and the freezing-thawing cycle times is established based on tests, a negative value is defined according to the relationship in the range of 0-70 ℃, and values are taken according to ice in other temperature ranges; the elastic modulus of the pore unit is taken as ice at the temperature below 0 ℃, and the elastic modulus of the pore unit is taken as 0 in the rest temperature range; concrete, steel pipe constitutive model and material parameters are selected according to traditional suggestions.

The concrete unit adopts a concrete damage plastic model, and defines tensile damage, compressive damage, a compressive stiffness recovery coefficient and a tensile stiffness recovery coefficient, wherein the compressive stiffness recovery coefficient of the concrete is 0.6.

A single temperature change was assigned to all concrete, steel pipe and void cells according to the freeze-thaw temperature interval.

According to the analysis working condition, the normal and tangential contact conditions of the steel pipe and the concrete section are defined through the external axial load applied to the steel pipe concrete. Specifically, a load is set on the steel pipe concrete finite element model in the step one. Fig. 7 is a finite element model of concrete filled steel tube with a load added.

And step three, finite element analysis. The method comprises the following steps:

after finite element analysis is carried out on the model, the distribution of compression damage and tension damage is output, and the crack development and damage change rule of the concrete under the coupling action of the multi-axis stress state and the freeze-thaw cycle can be obtained. Fig. 8 is a damage distribution cloud chart obtained by performing stress analysis on the finite element model, and the crack distribution and the damage degree of the concrete material subjected to the multiaxial stress state and the freeze-thaw cycle coupling effect can be obtained from fig. 8.

Based on the steel pipe concrete models damaged by the freeze-thaw cycles in different degrees, axial loading can be further performed to obtain a load-displacement curve and a compressive strength change rule of the steel pipe concrete after the freeze-thaw cycles.

Fig. 9 is a data validation result of the relative compressive strengths of the concrete member and the concrete filled steel tube member obtained by the scheme of the present disclosure. As shown in fig. 9, the ratio of the simulated value to the measured value of the relative compressive strength of the concrete member and the ratio of the simulated value to the measured value of the relative compressive strength of the concrete-filled steel tube member are both in the vicinity of 1, i.e., it indicates that the analysis process of the concrete/concrete-filled steel tube under the multi-axial stress state and the freeze-thaw cycle coupling effect is well restored by the solution of the present disclosure.

In the embodiment of the disclosure, a simplified microscopic concrete finite element model is created, parameters of the simplified microscopic concrete finite element model are set, and finally, concrete coupling effect finite element analysis is performed on the simplified microscopic concrete finite element model. In the model establishing process, the dimensionality simplification technology and the mesoscopic component simplification technology are combined, the dimensionality and the component complexity of the model are reduced while the three-dimensional coupling effect analysis function is kept, the creating difficulty of a simplified mesoscopic concrete finite element model is fully reduced, the calculation precision is ensured, and the calculation efficiency of numerical simulation is greatly improved; the embedded constraint of the pore unit and the concrete unit avoids repeated trial calculation and correction of the constitutive relation parameters of the concrete material required by traditional replacement constraint, can directly apply the conventional constitutive parameters of the material, is easy to determine and more reliable, and is more suitable for engineering application; in the parameter setting process, the established model is subjected to parameter setting according to the coupling effect parameters, so that the numerical simulation of the concrete multiaxial stress state and the freezing-thawing cycle coupling effect is further realized, the freezing-thawing cycle analysis of the concrete is more in line with the actual stress condition, and the calculation precision is improved.

It is understood that the above-mentioned embodiments of the method of the present disclosure can be combined with each other to form a combined embodiment without departing from the principle logic, which is limited by the space, and the detailed description of the present disclosure is omitted. Those skilled in the art will appreciate that in the above methods of the specific embodiments, the specific order of execution of the steps should be determined by their function and possibly their inherent logic.

In addition, the present disclosure also provides a device for numerical simulation of a multiaxial stress state and a freeze-thaw cycle coupling effect, an electronic device, a computer-readable storage medium, and a program, which can all be used to implement any one of the numerical simulations of a concrete multiaxial stress state and a freeze-thaw cycle coupling effect provided by the present disclosure, and the corresponding technical solutions and descriptions and corresponding descriptions of the method sections are referred to and are not repeated herein.

Fig. 10 shows a block diagram of a numerical simulation apparatus for concrete multiaxial stress state and freeze-thaw cycle coupling effect according to an embodiment of the present disclosure. The numerical simulation device for the concrete multiaxial stress state and the freeze-thaw cycle coupling effect can be terminal equipment, a server or other processing equipment and the like. The terminal device may be a User Equipment (UE), a mobile device, a User terminal, a cellular phone, a cordless phone, a Personal Digital Assistant (PDA), a handheld device, a computing device, a vehicle-mounted device, a wearable device, or the like.

In some possible implementations, the numerical simulation device for the concrete multiaxial stress state and the freeze-thaw cycle coupling effect may be implemented by means of a processor calling computer readable instructions stored in a memory.

As shown in fig. 10, the numerical simulation apparatus 100 for multiaxial stress state and freeze-thaw cycle coupling effect of concrete may include:

the model creating module 101 is used for creating a simplified mesoscopic concrete finite element model by adopting a dimensionality simplification technology and a mesoscopic component simplification technology;

the parameter setting module 102 is configured to perform parameter setting on the simplified microscopic concrete finite element model according to coupling effect parameters, where the coupling effect parameters include freeze-thaw cycle parameters and multi-axis stress state parameters;

and the finite element analysis module 103 is used for performing finite element analysis on the concrete coupling effect on the simplified microscopic concrete finite element model after parameter setting, wherein the finite element analysis on the concrete coupling effect comprises analysis on damage of the concrete coupling effect and analysis on mechanical properties after damage of the concrete coupling effect.

In one possible implementation, the model creation module is configured to:

setting the linear expansion coefficient of the pore unit according to the temperature change interval and the freezing-thawing cycle times;

the degree and position distribution of the compressive damage of the concrete under the multiaxial stress state and the freeze-thaw cycle coupling effect;

applying single-axis or multi-axis load to the finite element model after the concrete multi-axis stress state and the freeze-thaw cycle coupling effect damage to obtain the single-axis or multi-axis mechanical property of the concrete after the coupling effect damage; and obtaining a calculation model of the multiaxial stress state and the freeze-thaw cycle coupling effect according to the uniaxial or multiaxial mechanical property of the concrete.

Embodiments of the present disclosure also provide a computer-readable storage medium having stored thereon computer program instructions, which when executed by a processor, implement the above-mentioned method. The computer readable storage medium may be a non-volatile computer readable storage medium.

An embodiment of the present disclosure further provides an electronic device, including: a processor; a memory for storing processor-executable instructions; wherein the processor is configured to invoke the memory-stored instructions to perform the above-described method.

Embodiments of the present disclosure also provide a computer program product comprising computer readable code which, when run on an apparatus, a processor in the apparatus executes instructions for implementing numerical simulation of concrete multiaxial stress states and freeze-thaw cycle coupling effects as provided by any of the embodiments above.

Embodiments of the present disclosure also provide another computer program product for storing computer readable instructions that, when executed, cause a computer to perform operations for numerical simulation of concrete multiaxial stress states and freeze-thaw cycle coupling effects provided by any of the embodiments described above.

The electronic device may be provided as a terminal, server, or other form of device.

Fig. 11 illustrates a block diagram of an electronic device 800 in accordance with an embodiment of the disclosure. For example, the electronic device 800 may be a mobile phone, a computer, a digital broadcast terminal, a messaging device, a game console, a tablet device, a medical device, a fitness device, a personal digital assistant, and the like.

Referring to fig. 11, electronic device 800 may include one or more of the following components: a processing component 802, a memory 804, a power component 806, a multimedia component 808, an audio component 810, an input/output interface 812, a sensor component 814, and a communication component 816.

The processing component 802 generally controls overall operation of the electronic device 800, such as operations associated with display, telephone calls, data communications, camera operations, and recording operations. The processing component 802 may include one or more processors 820 to execute instructions to perform all or a portion of the steps of the methods described above. Further, the processing component 802 can include one or more modules that facilitate interaction between the processing component 802 and other components. For example, the processing component 802 can include a multimedia module to facilitate interaction between the multimedia component 808 and the processing component 802.

The memory 804 is configured to store various types of data to support operations at the electronic device 800. Examples of such data include instructions for any application or method operating on the electronic device 800, contact data, phonebook data, messages, pictures, videos, and so forth. The memory 804 may be implemented by any type or combination of volatile or non-volatile memory devices, such as Static Random Access Memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic or optical disks.

The power supply component 806 provides power to the various components of the electronic device 800. The power components 806 may include a power management system, one or more power supplies, and other components associated with generating, managing, and distributing power for the electronic device 800.

The multimedia component 808 includes a screen that provides an output interface between the electronic device 800 and a user. In some embodiments, the screen may include a Liquid Crystal Display (LCD) and a Touch Panel (TP). If the screen includes a touch panel, the screen may be implemented as a touch screen to receive an input signal from a user. The touch panel includes one or more touch sensors to sense touch, slide, and gestures on the touch panel. The touch sensor may not only sense the boundary of a touch or slide action, but also detect the duration and pressure associated with the touch or slide operation. In some embodiments, the multimedia component 808 includes a front facing camera and/or a rear facing camera. The front camera and/or the rear camera may receive external multimedia data when the electronic device 800 is in an operation mode, such as a shooting mode or a video mode. Each front camera and rear camera may be a fixed optical lens system or have a focal length and optical zoom capability.

The audio component 810 is configured to output and/or input audio signals. For example, the audio component 810 includes a Microphone (MIC) configured to receive external audio signals when the electronic device 800 is in an operational mode, such as a call mode, a recording mode, and a voice recognition mode. The received audio signal may further be stored in the memory 804 or transmitted via the communication component 816. In some embodiments, audio component 810 also includes a speaker for outputting audio signals.

The input/output interface 812 provides an interface between the processing component 802 and peripheral interface modules, which may be keyboards, click wheels, buttons, etc. These buttons may include, but are not limited to: a home button, a volume button, a start button, and a lock button.

The sensor assembly 814 includes one or more sensors for providing various aspects of state assessment for the electronic device 800. For example, the sensor assembly 814 may detect an open/closed state of the electronic device 800, the relative positioning of components, such as a display and keypad of the electronic device 800, the sensor assembly 814 may also detect a change in position of the electronic device 800 or a component of the electronic device 800, the presence or absence of user contact with the electronic device 800, orientation or acceleration/deceleration of the electronic device 800, and a change in temperature of the electronic device 800. Sensor assembly 814 may include a proximity sensor configured to detect the presence of a nearby object without any physical contact. The sensor assembly 814 may also include a light sensor, such as a CMOS or CCD image sensor, for use in imaging applications. In some embodiments, the sensor assembly 814 may also include an acceleration sensor, a gyroscope sensor, a magnetic sensor, a pressure sensor, or a temperature sensor.

The communication component 816 is configured to facilitate wired or wireless communication between the electronic device 800 and other devices. The electronic device 800 may access a wireless network based on a communication standard, such as WiFi,2G or 3G, or a combination thereof. In an exemplary embodiment, the communication component 816 receives a broadcast signal or broadcast related information from an external broadcast management system via a broadcast channel. In an exemplary embodiment, the communication component 816 further includes a Near Field Communication (NFC) module to facilitate short-range communications. For example, the NFC module may be implemented based on Radio Frequency Identification (RFID) technology, infrared data association (IrDA) technology, ultra Wideband (UWB) technology, bluetooth (BT) technology, and other technologies.

In an exemplary embodiment, the electronic device 800 may be implemented by one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), digital Signal Processing Devices (DSPDs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), controllers, micro-controllers, microprocessors or other electronic components for performing the above-described methods.

In an exemplary embodiment, a non-transitory computer-readable storage medium, such as the memory 804, is also provided that includes computer program instructions executable by the processor 820 of the electronic device 800 to perform the above-described methods.

Fig. 12 shows a block diagram of an electronic device 1900 according to an embodiment of the disclosure. For example, the electronic device 1900 may be provided as a server. Referring to fig. 12, electronic device 1900 includes a processing component 1922 further including one or more processors and memory resources, represented by memory 1932, for storing instructions, e.g., applications, executable by processing component 1922. The application programs stored in memory 1932 may include one or more modules that each correspond to a set of instructions. Further, the processing component 1922 is configured to execute instructions to perform the above-described method.

The electronic device 1900 may further include a power component 1926 configured to perform power management of the electronic device 1900, a wired or wireless network interface 1950 configured to connect the electronic device 1900 to a network, and an input-output interface 1958. Electronic device 1900 may operate based on an operating system, such as a Windows Server, stored in memory 1932 ^TM ，Mac OS X ^TM ，Unix ^TM ,Linux ^TM ，FreeBSD ^TM Or the like.

In an exemplary embodiment, a non-transitory computer readable storage medium, such as the memory 1932, is also provided that includes computer program instructions executable by the processing component 1922 of the electronic device 1900 to perform the above-described methods.

The present disclosure may be systems, methods, and/or computer program products. The computer program product may include a computer-readable storage medium having computer-readable program instructions embodied thereon for causing a processor to implement various aspects of the present disclosure.

The computer-readable storage medium may be a tangible device that can hold and store the instructions for use by the instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic memory device, a magnetic memory device, an optical memory device, an electromagnetic memory device, a semiconductor memory device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a Static Random Access Memory (SRAM), a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), a memory stick, a floppy disk, a mechanical coding device, such as punch cards or in-groove projection structures having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media as used herein is not to be interpreted as a transitory signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., optical pulses through a fiber optic cable), or an electrical signal transmitted through an electrical wire.

The computer-readable program instructions described herein may be downloaded from a computer-readable storage medium to a respective computing/processing device, or to an external computer or external storage device over a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. The network adapter card or network interface in each computing/processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in the respective computing/processing device.

The computer program instructions for carrying out operations of the present disclosure may be assembler instructions, instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C + +, python, java, etc., and a conventional procedural programming language such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, aspects of the disclosure are implemented by personalizing an electronic circuit, such as a programmable logic circuit, a Field Programmable Gate Array (FPGA), or a Programmable Logic Array (PLA), with state information of computer-readable program instructions, which can execute the computer-readable program instructions.

Various aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions.

These computer-readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer, programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer-readable medium storing the instructions comprises an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer, other programmable apparatus or other devices implement the functions/acts specified in the flowchart and/or block diagram block or blocks.

The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

The computer program product may be embodied in hardware, software or a combination thereof. In an alternative embodiment, the computer program product is embodied in a computer storage medium, and in another alternative embodiment, the computer program product is embodied in a Software product, such as a Software Development Kit (SDK), or the like.

The foregoing description of the embodiments of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or improvements to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A numerical simulation method for a concrete multiaxial stress state and a freeze-thaw cycle coupling effect is characterized by comprising the following steps:

2. The method of claim 1, wherein creating the simplified mesoscopic concrete finite element model using a dimensionality reduction technique and a mesoscopic component reduction technique comprises:

under the condition that the three-dimensional concrete model is cylindrical, a column symmetry technology is adopted for the three-dimensional concrete model to obtain a two-dimensional finite element model section capable of reflecting three-dimensional performance;

3. The method of claim 2, wherein the creating of the reduced mesoscopic concrete finite element model using the dimensionality reduction technique and the mesoscopic composition reduction technique comprises:

4. The method of claim 3, wherein the freeze-thaw cycle parameters include a freeze-thaw cycle temperature and a freeze-thaw cycle number; and according to the coupling effect parameters, setting the parameters of the simplified mesoscopic concrete finite element model, which comprises the following steps:

5. The method of claim 1, wherein the parameterizing the simplified mesoconcrete finite element model according to the coupling effect parameter comprises:

6. The method of claim 1, wherein the concrete coupling effect damage analysis comprises:

7. The method of claim 1, wherein the mechanical property analysis after the concrete coupling effect damage comprises:

8. A numerical simulation device for concrete multiaxial stress state and freeze-thaw cycle coupling effect is characterized by comprising:

the parameter setting module is used for carrying out parameter setting on the simplified microscopic concrete finite element model according to coupling effect parameters, wherein the coupling effect parameters comprise freeze-thaw cycle parameters and multi-axis stress state parameters;

and the finite element analysis module is used for carrying out finite element analysis on the concrete coupling effect on the simplified microscopic concrete finite element model after parameter setting, and the finite element analysis on the concrete coupling effect comprises concrete coupling effect damage analysis and mechanical property analysis after the concrete coupling effect is damaged.

9. An electronic device, comprising:

a processor;

a memory for storing processor-executable instructions;

wherein the processor is configured to implement the method of any one of claims 1 to 7 when executing the memory-stored instructions.

10. A non-transitory computer readable storage medium having computer program instructions stored thereon, wherein the computer program instructions, when executed by a processor, implement the method of any of claims 1 to 7.