Polyacrylic acid / chitosan hydrogel material mechanical property prediction method and related device

Abstract

The invention discloses a polyacrylic acid / chitosan hydrogel material mechanical property prediction method and a related device, and the method comprises the following steps: carrying out a hydrogel tensile experiment on a polyacrylic acid / chitosan hydrogel sample to obtain hydrogel force-displacement data; performing parameter fitting on the hydrogel force-displacement data to obtain a fitting result; establishing a hydrogel geometric model, and dispersing the hydrogel geometric model into a finite element mesh model; setting a material coefficient of the hydrogel geometric model to determine a material constitutive model; setting boundary conditions and initial conditions for the hydrogel geometric model; and calculating the hydrogel geometric model by applying a central difference method to obtain the stress-strain response of the polyacrylic acid / chitosan hydrogel material in a stress state, and the method can predict the mechanical properties of the polyacrylic acid / chitosan hydrogel material under different parameters.

Description

Technical Field

[0001] This invention belongs to the field of material mechanical property prediction technology, and relates to a method and related apparatus for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials. Background Technology

[0002] Current research on hydrogels tends to focus on preparation techniques and functional applications. However, hydrogels have a wide range of applications and complex mechanical environments. Different sizes and process parameters can affect their mechanical properties. Characterizing the mechanical properties of hydrogels often involves preparing samples and conducting a large number of experiments. The experimental conditions affect the results of material performance, and the process is time-consuming and costly, which hinders the development of new hydrogel materials.

[0003] In the application of hydrogels, deformation and failure are often involved, affecting the stability and reliability of the materials. However, the mechanical testing of hydrogels under different conditions is challenging, costly, and uses expensive raw materials, hindering large-scale production. The mechanical properties of hydrogels are influenced by a combination of factors, including process parameters, external loads, and the environment, and often exhibit hyperelastic properties such as high nonlinearity and large deformation, making the prediction of their mechanical response under different conditions even more complex. While traditional experimental methods can obtain some data on the mechanical properties of hydrogels, they often require significant time, effort, and resources, and struggle to comprehensively and systematically reveal the mechanisms and underlying laws governing the influence of various factors on their mechanical properties. Furthermore, in practical applications, to better adapt hydrogels to the specific needs of different fields—such as adapting to the mechanical environments of different tissues in the biomedical field and withstanding various complex stress-strain conditions in flexible electronics—it is essential to deeply analyze the hyperelastic mechanism of hydrogels and accurately predict their mechanical responses under different parameters. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and related apparatus for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials. This method and apparatus can predict the mechanical properties of polyacrylic acid / chitosan hydrogel materials under different parameters.

[0005] To achieve the above objectives, this invention discloses a method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials, comprising:

[0006] A tensile test was performed on the polyacrylic acid / chitosan hydrogel sample to obtain hydrogel force-displacement data.

[0007] The force-displacement data of the hydrogel is fitted with parameters to obtain the fitting results of the force-displacement data of the hydrogel.

[0008] Based on the actual analysis requirements, a hydrogel geometric model is established, and the hydrogel geometric model is discretized into a finite element mesh model.

[0009] Based on the fitting results of the hydrogel force-displacement data, the material coefficients of the hydrogel geometric model are set to determine the material constitutive model.

[0010] Based on the material constitutive model, boundary conditions and initial conditions are set for the hydrogel geometric model according to the actual mechanical property analysis requirements.

[0011] The central difference method was applied to the geometric model of the hydrogel for calculation, and an iterative calculation method was used to obtain the stress-strain response of the polyacrylic acid / chitosan hydrogel material under stress.

[0012] A further improvement of the method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials described in this invention is as follows:

[0013] Furthermore, the process of performing parameter fitting on the hydrogel force-displacement data to obtain the fitting result is as follows:

[0014] The force-displacement data of the hydrogel were parametrically fitted using the Mooney-Rivlin strain energy function in the hyperelastic material model built into the ABAQUS finite element software, and the fitting results were obtained.

[0015] Furthermore, the process of establishing a hydrogel geometric model based on actual analytical needs is as follows:

[0016] Based on the actual analysis requirements, a hydrogel geometric model was created in the ABAQUS CAE interface.

[0017] Furthermore, the process of setting the material coefficients of the hydrogel geometric model to determine the material constitutive model is as follows:

[0018] The Mooney-Rivlin strain energy function in the hyperelastic model is selected, and the material coefficients of the hydrogel geometry model are set to determine the material constitutive model.

[0019] Furthermore, it also includes:

[0020] The damage failure criteria for the mesh material within the finite element mesh model are set, and strain is used as the material damage variable to establish a material damage model.

[0021] Furthermore, it also includes:

[0022] Construct material stress cloud maps, strain cloud maps, stress-strain data, and stress-strain trends over time under different initial conditions.

[0023] This invention discloses a system for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials, comprising:

[0024] The experimental module is used to perform a tensile test on the polyacrylic acid / chitosan hydrogel sample to obtain hydrogel force-displacement data.

[0025] The fitting module is used to perform parameter fitting on the hydrogel force-displacement data to obtain the fitting result of the hydrogel force-displacement data.

[0026] The first module is used to establish a hydrogel geometric model according to actual analysis needs, and to discretize the hydrogel geometric model into a finite element mesh model.

[0027] The setting module is used to set the material coefficients of the hydrogel geometric model based on the fitting results of the hydrogel force-displacement data, so as to determine the material constitutive model;

[0028] The setting module is used to set boundary conditions and initial conditions for the hydrogel geometric model based on the material constitutive model and the actual mechanical property analysis requirements.

[0029] The calculation module is used to perform calculations on the hydrogel geometric model using the central difference method and an iterative calculation method to obtain the stress-strain response of the polyacrylic acid / chitosan hydrogel material under stress.

[0030] A further improvement of the mechanical property prediction system for polyacrylic acid / chitosan hydrogel materials described in this invention is as follows:

[0031] Furthermore, it also includes:

[0032] The second module is used to set the damage failure criteria of the mesh material in the finite element mesh model, and to establish the material damage model by taking strain as the material damage variable.

[0033] The present invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method for predicting the mechanical properties of the polyacrylic acid / chitosan hydrogel material.

[0034] This invention discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials.

[0035] The present invention has the following beneficial effects:

[0036] The method and apparatus for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials described in this invention, in practical operation, establishes damage variables based on physical meaning and then introduces damage evolution into a finite element model to achieve a full-field dynamic quantitative description of the damage state of the hydrogel material. Employing explicit dynamic methods and iterative calculations, it more realistically simulates the entire process of the material from damage initiation to final fracture, predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials under different parameters, thereby improving the accuracy of failure prediction. This invention, through the combination of damage modeling, material model optimization, and explicit dynamic solution techniques, significantly improves the accuracy and efficiency of predicting the mechanical properties of polyacrylic acid / chitosan hydrogels, and is particularly suitable for fields requiring high reliability design, such as biomedical materials. Attached Figure Description

[0037] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 Flowchart for finite element analysis of the mechanical properties of polyacrylic acid / chitosan hydrogel;

[0039] Figure 2 A schematic diagram of the tensile specimen dimensions and finite element model of polyacrylic acid / chitosan hydrogel;

[0040] Figure 3 This is a schematic diagram of the process of polyacrylic acid / chitosan hydrogel being stretched until it breaks.

[0041] Figure 4 Stress distribution diagram of polyacrylic acid / chitosan hydrogels of different widths under 100% strain;

[0042] Figure 5 A schematic diagram of a finite element model of a polyacrylic acid / chitosan hydrogel with a single-sided notch;

[0043] Figure 6 Stress distribution at the tip of the notch for polyacrylic acid / chitosan hydrogels with different height-to-width ratios (HWR) and preset notch length-to-width ratios (NWR) at a displacement of 20 mm. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0046] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0047] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0048] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0049] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0051] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0052] Example 1

[0053] The method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials according to the present invention includes the following steps:

[0054] 1) Prepare polyacrylic acid / chitosan hydrogel specimens for tensile testing. The maximum length and width of the polyacrylic acid / chitosan hydrogel specimens are 152 mm and 25 mm, respectively, and the thickness is 5 mm. Specific dimensions are as follows: Figure 2 As shown, a tensile test of the polyacrylic acid / chitosan hydrogel sample was conducted to obtain fitting results based on the hydrogel force-displacement data.

[0055] 2) The force-displacement data of the hydrogel were parameter-fitted using the Mooney-Rivlin strain energy function in the hyperelastic material model built into the ABAQUS finite element software, as shown in the following expression:

[0056] W=C 10 (I1-3)+C 01 (I2-3)

[0057] Among them, material parameter C 10 and C 01 Depends on the initial shear modulus μ, where I1 and I2 are the first and second strain invariants, respectively. The Mooney-Rivlin strain energy function material coefficients C obtained by fitting experimental data are...10 and C 01 The specific values ​​are 0.02996 and 0.004028, respectively.

[0058] 3) Based on the actual analysis requirements, a hydrogel geometric model is established in the ABAQUS CAE interface, and the hydrogel geometric model is discretized into a finite element mesh model.

[0059] 4) Based on the fitting results of the hydrogel force-displacement data, select the Mooney-Rivlin strain energy function in the hyperelastic model, set the material coefficients of the hydrogel geometric model, and determine the material constitutive model.

[0060] 5) Based on the material constitutive model, and according to the actual mechanical property analysis requirements, set boundary conditions and initial conditions such as constraints, applied loads, mesh type and mesh size for the hydrogel geometric model.

[0061] Specifically, the bottom rectangular section is constrained in all directions with zero degrees of freedom, i.e., completely fixed. Simultaneously, a reference point (RP-1) is set at the other end and coupled to the rectangular section, constraining the degrees of freedom in the X and Z directions. A displacement load is applied to the reference point in the Y direction, and a displacement load is applied upwards from the bottom end to achieve a tensile simulation. The model mesh is set to an 8-node hexahedral linear reduced integral element (C3D8R) with a mesh size of 0.5 mm.

[0062] 6) Establish the damage failure criterion for the mesh material in the finite element mesh model, and use strain as the material damage variable to establish a material damage model.

[0063] The VUSDFLD subroutine, written in Fortran, converts the maximum principal strain criterion into a complete set of governing equations, with the damage variable set as the material's maximum principal strain ε. max The value is 1.6. The maximum principal strain criterion expression for describing the damage state of hydrogel materials is:

[0064]

[0065] Where, ε x , ε y γ xy There are three independent plane strain components, when the maximum principal strain ε of the material is... max Exceeding the ultimate tensile strain (critical strain) ε u , i.e. ε max >ε u When this happens, a specific point within the unit will fracture.

[0066] 7) In the analysis step settings module, create a "Dynamic, Explicit" analysis step to analyze the hydrogel geometric model, and select the "Geometric Nonlinearity" option. The maximum number of increment steps set in the analysis step is 2000, and the minimum number of increment steps is 1×10⁻⁶. -6 In addition to the output variables set, check the "SATUS" variable in the "Status / Field / User / Time" tab of the Field Output Request module to facilitate cell deletion operations during analysis.

[0067] 8) Create a job in the ABAQUS CAE job interface and open the "Edit Job" window. Select the "General" tab and import the VUSDFLD subroutine. Use "Dynamic, Explicit" analysis to calculate the hydrogel geometric model using the central difference method. Employ an iterative calculation method to gradually update the stress-strain state until the model fails or meets preset conditions. During the calculation process, delete elements that meet the failure conditions to obtain the stress-strain response of the hydrogel material under stress.

[0068] 9) Perform post-processing operations on the calculated hydrogel geometric model;

[0069] Output variables are extracted from the output database to obtain mechanical property parameters such as material stress cloud diagrams, strain cloud diagrams, stress-strain data, and stress-strain variation trends over time under different initial conditions.

[0070] like Figure 2 As shown, in a uniaxial tensile test, the rectangular sections at the top and bottom of the specimen need to be clamped. To reproduce this in the finite element simulation, boundary conditions are set for the model. The bottom rectangular section is constrained in all directions with zero degrees of freedom, i.e., completely fixed. Simultaneously, a reference point (RP-1) is set at the other end and coupled to the rectangular section, constraining the degrees of freedom in the X and Z directions. A displacement load is applied to the reference point in the Y direction, causing the bottom end to move upwards, thus achieving the tensile simulation. The model mesh is set to 8-node hexahedral linear reduced integral elements (C3D8R) with a mesh size of 0.5 mm. To reduce computation time, the rectangular portions at the top and bottom of the model are meshed with coarsened mesh.

[0071] In the material properties settings module, select the option containing C. 10 and C 01 A two-parameter Mooney-Rivilin model was used as a hyperelastic model for the polyacrylic acid / chitosan hydrogel material, with parameters such as state variables for element deletion and user-defined fields set. In the analysis step settings module, a "Dynamic, Explicit" analysis step was created to analyze the model, and the "Geometric Nonlinearity" option was selected. The maximum increment step size was set to 2000, and the minimum increment step size was set to 1 × 10⁻⁶. -6In addition to setting the output variables, check the "SATUS" variable in the "Status / Field / User / Time" tab of the Field Output Request module to facilitate cell deletion during analysis. Finally, click the "Job" module to create a job and open the "Edit Job" window. Select the "General" tab and import the VUSDFLD subroutines that need to be called. After completing all the above settings, submit the task for calculation and analysis.

[0072] Figure 3 This diagram illustrates the process of a polyacrylic acid / chitosan hydrogel being stretched until fracture. At the beginning of the stretching process, the hydrogel deforms, and a significant stress concentration occurs in the neck region. As stretching continues, cracks begin to appear in the neck region. It can be seen that mesh elements with maximum principal strain exceeding the critical strain are removed, indicating that this region experienced high stress and strain before fracture. With continued stretching, the cracks propagate rapidly, eventually leading to the hydrogel's fracture. The entire simulation process is essentially the same as the tensile test. During stretching, the distribution of stress and strain in the hydrogel is not completely uniform, which may reflect the inherent inhomogeneity of the material, such as differences in microstructure or crosslinking density within the material.

[0073] Example 2

[0074] The effect of width on the tensile fracture properties of polyacrylic acid / chitosan hydrogel was analyzed. With the length (15 mm) and thickness (2 mm) kept constant, hydrogel models with three different widths of 5 mm, 10 mm and 15 mm were established. Figure 4 This diagram shows the stress distribution of polyacrylic acid / chitosan hydrogels of different widths at 100% strain under the same length condition. Under the same strain condition, the stress distribution of the hydrogels differs significantly with increasing sample width. In a 15mm wide hydrogel, the stress value at the center is 237.61 kPa, while the stress value in a 10mm wide hydrogel is 219.54 kPa, and the stress value in a 5mm wide sample is 217.62 kPa. This indicates that as the width increases, the stress in the middle part of the hydrogel also increases, and the stress distribution becomes more concentrated. This will lead to earlier fracture of wider hydrogels, i.e., a smaller maximum strain. Due to Poisson's ratio, the deformation in the loading direction and the non-loading direction are different. The calculated stress values ​​of the hydrogel show a non-uniform distribution across the cross-section. The wider the sample, the greater its absolute value of deformation under tension; therefore, increasing the width of the hydrogel will reduce the maximum strain at the same initial length.

[0075] Example 3

[0076] This embodiment establishes a finite element model of a specimen with a single-sided notch. Figure 5This diagram illustrates the model's geometric dimensions, boundary conditions, and mesh generation. The model thickness is kept constant at 2 mm, the height h is set to 75 mm, and w and a represent the model width and the preset notch length, respectively. The bottom edge of the model is subject to a fully fixed constraint, while a displacement load is applied to the top edge. The model is meshed using C3D8R elements with a mesh size of 0.5 mm. Geometric models with different widths w and preset notch lengths a are established to analyze the effects of different HWR (the ratio of model height to width) and NWR (the ratio of preset notch length to width) on the tensile properties of the hydrogel.

[0077] Figure 6 The stress distribution diagrams show the hydrogel under different dimensional parameters. When HWR = 2 remains constant, as NWR increases from 0.3 to 0.8, the area of ​​the high-stress region near the hydrogel notch gradually increases, and the stress concentration intensifies. When NWR = 0.5 remains constant, as HWR increases from 2 to 5, the area of ​​the high-stress region near the hydrogel notch gradually decreases, and the stress concentration intensifies. It can be seen that the stress distribution is more uniform away from the notch root, with stress concentrated at the notch root. This is because the presence of the notch causes geometric discontinuity in the structure, leading to stress redistribution. Furthermore, as the overall geometry of the hydrogel changes, the stress transmission path also changes, resulting in significant changes in stress concentration at these discontinuities.

[0078] Example 4

[0079] The mechanical property prediction system for polyacrylic acid / chitosan hydrogel materials of the present invention includes:

[0080] The experimental module is used to perform a tensile test on the polyacrylic acid / chitosan hydrogel sample to obtain hydrogel force-displacement data.

[0081] The fitting module is used to perform parameter fitting on the hydrogel force-displacement data to obtain the fitting result of the hydrogel force-displacement data.

[0082] The first module is used to establish a hydrogel geometric model according to actual analysis needs, and to discretize the hydrogel geometric model into a finite element mesh model.

[0083] The setting module is used to set the material coefficients of the hydrogel geometric model based on the fitting results of the hydrogel force-displacement data, so as to determine the material constitutive model;

[0084] The setting module is used to set boundary conditions and initial conditions for the hydrogel geometric model based on the material constitutive model and the actual mechanical property analysis requirements.

[0085] The calculation module is used to perform calculations on the hydrogel geometric model using the central difference method and an iterative calculation method to obtain the stress-strain response of the polyacrylic acid / chitosan hydrogel material under stress.

[0086] This embodiment also includes:

[0087] The second module is used to set the damage failure criteria of the mesh material in the finite element mesh model, and to establish the material damage model by taking strain as the material damage variable.

[0088] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0089] Example 5

[0090] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of a method for predicting the mechanical properties of a polyacrylic acid / chitosan hydrogel material. For example, the method includes: performing a tensile test on the polyacrylic acid / chitosan hydrogel sample to obtain hydrogel force-displacement data; performing parameter fitting on the hydrogel force-displacement data to obtain a fitting result based on the hydrogel force-displacement data; establishing a hydrogel geometric model according to actual analysis requirements, and discretizing the hydrogel geometric model into a finite element mesh model; setting material coefficients of the hydrogel geometric model based on the fitting result of the hydrogel force-displacement data to determine a material constitutive model; setting boundary conditions and initial conditions for the hydrogel geometric model based on the material constitutive model and according to actual mechanical property analysis requirements; and applying the central difference method to calculate the hydrogel geometric model using an iterative calculation method to obtain the stress-strain response of the polyacrylic acid / chitosan hydrogel material under stress. The memory may include main memory, such as high-speed random access memory (RAM), or non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which may be an industry-standard architecture bus, a peripheral component interconnection standard bus, or an extended industry-standard architecture bus. The bus can be categorized as an address bus, data bus, or control bus. The memory stores programs; specifically, the program may include program code, which includes computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0091] Example 6

[0092] A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a method for predicting the mechanical properties of a polyacrylic acid / chitosan hydrogel material. For example, the method includes: performing a tensile test on the polyacrylic acid / chitosan hydrogel sample to obtain hydrogel force-displacement data; performing parameter fitting on the hydrogel force-displacement data to obtain a fitting result based on the hydrogel force-displacement data; establishing a hydrogel geometric model according to actual analysis requirements, and discretizing the hydrogel geometric model into a finite element mesh model; setting material coefficients of the hydrogel geometric model based on the fitting result of the hydrogel force-displacement data to determine a material constitutive model; setting boundary conditions and initial conditions for the hydrogel geometric model based on the material constitutive model and according to actual mechanical property analysis requirements; and applying the central difference method to the hydrogel geometric model and using an iterative calculation method to obtain the stress-strain response of the polyacrylic acid / chitosan hydrogel material under stress. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0093] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0094] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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 program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, 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, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0095] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0096] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0097] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0098] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0099] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials, characterized in that, include: A tensile test was performed on the polyacrylic acid / chitosan hydrogel sample to obtain hydrogel force-displacement data. The force-displacement data of the hydrogel is fitted with parameters to obtain the fitting results of the force-displacement data of the hydrogel. Based on the actual analysis requirements, a hydrogel geometric model is established, and the hydrogel geometric model is discretized into a finite element mesh model. Based on the fitting results of the hydrogel force-displacement data, the material coefficients of the hydrogel geometric model are set to determine the material constitutive model. Based on the material constitutive model, boundary conditions and initial conditions are set for the hydrogel geometric model according to the actual mechanical property analysis requirements. The central difference method was applied to the geometric model of the hydrogel for calculation, and an iterative calculation method was used to obtain the stress-strain response of the polyacrylic acid / chitosan hydrogel material under stress.

2. The method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials according to claim 1, characterized in that, The process of performing parameter fitting on the hydrogel force-displacement data to obtain the fitting result is as follows: The force-displacement data of the hydrogel were parametrically fitted using the Mooney-Rivlin strain energy function in the hyperelastic material model built into the ABAQUS finite element software, and the fitting results were obtained.

3. The method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials according to claim 1, characterized in that, The process of establishing a hydrogel geometric model based on actual analysis needs is as follows: Based on the actual analysis requirements, a hydrogel geometric model was created in the ABAQUS CAE interface.

4. The method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials according to claim 1, characterized in that, The process of setting the material coefficients of the hydrogel geometric model to determine the material constitutive model is as follows: The Mooney-Rivlin strain energy function in the hyperelastic model is selected, and the material coefficients of the hydrogel geometry model are set to determine the material constitutive model.

5. The method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials according to claim 1, characterized in that, Also includes: The damage failure criteria for the mesh material within the finite element mesh model are set, and strain is used as the material damage variable to establish a material damage model.

6. The method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials according to claim 1, characterized in that, Also includes: Construct material stress cloud maps, strain cloud maps, stress-strain data, and stress-strain trends over time under different initial conditions.

7. A system for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials, characterized in that, include: The experimental module is used to perform a tensile test on the polyacrylic acid / chitosan hydrogel sample to obtain hydrogel force-displacement data. The fitting module is used to perform parameter fitting on the hydrogel force-displacement data to obtain the fitting result of the hydrogel force-displacement data. The first module is used to establish a hydrogel geometric model according to actual analysis needs, and to discretize the hydrogel geometric model into a finite element mesh model. The setting module is used to set the material coefficients of the hydrogel geometric model based on the fitting results of the hydrogel force-displacement data, so as to determine the material constitutive model; The setting module is used to set boundary conditions and initial conditions for the hydrogel geometric model based on the material constitutive model and the actual mechanical property analysis requirements. The calculation module is used to perform calculations on the hydrogel geometric model using the central difference method and an iterative calculation method to obtain the stress-strain response of the polyacrylic acid / chitosan hydrogel material under stress.

8. The system for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials according to claim 7, characterized in that, Also includes: The second module is used to set the damage and failure criteria of the mesh material in the finite element mesh model, and to establish the material damage model by taking strain as the material damage variable.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials as described in any one of claims 1-6.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for predicting the mechanical properties of polyacrylic acid / chitosan hydrogel materials as described in any one of claims 1-6.

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