A method for preparing padding structure in parametric elastic knitted fabric

Abstract

This invention discloses a method for preparing the padding structure in parametric elastic knitted fabrics, belonging to the field of knitted elastic fabric design in the textile industry. The invention involves: S1: selecting and matching the raw yarns for the knitting structure and the raw yarns for the padding to determine the performance indicators of the corresponding raw yarns; S2: designing the padding structure; S3: constructing a nonlinear elastic behavior model; S4: predicting the nonlinear elastic behavior; and S5: determining the design scheme. Based on parametric elastic knitting design and yarn selection, the mechanical behavior of elastic knitted fabrics can be controlled, providing an effective approach for the design and production of elastic knitted fabrics with controllable nonlinear elastic behavior to meet practical needs.

Description

Technical Field

[0001] This invention relates to a method for preparing a parametric elastic knitted fabric structure, specifically a method for preparing a padding structure in a parametric elastic knitted fabric. By combining the yarn material and the padding structure characteristics of the elastic knitted fabric, the nonlinear elastic mechanical behavior of the elastic knitted fabric can be predicted quickly and accurately, belonging to the field of knitted elastic fabric design in the textile industry. Background Technology

[0002] Elastic knitted fabrics, due to their excellent elastic mechanical behavior, are widely used in clothing, underwear, sportswear, compression stockings, and other products. Among these, the padding structure is one of the most important structural elements in elastic knitted fabrics. The padding structure is a patterned structure in which one or more padding yarns form open loops on certain loops of the fabric, while the remaining loops remain as floats on the reverse side of the fabric. The advantages of using padding structures in elastic knitted fabrics include: 1) a smooth and flat fabric surface with good thermal insulation; 2) the padding yarns are not easily unraveled, only unraveling in the reverse knitting direction; 3) the padding yarns can form patterns such as horizontal stripes, vertical stripes, squares, and diamonds; 5) the structural units include loops, loops, and floats, thus ensuring the elasticity of the knitted fabric. It is suitable for the production of elastic tights and other underwear, as well as sportswear, T-shirts, etc.

[0003] When designing and manufacturing elastic knitted fabrics, their elastic mechanical behavior needs to be determined based on the usage conditions. For example, pressure therapy materials utilize elastic fabrics to apply continuous pressure to the wound healing site to inhibit scar hyperplasia and promote scar maturation. They also have effects such as reducing edema, relieving pain, and stabilizing muscles, bones, and joints. Clinical trials have shown that different pressure values ​​have varying effects on disease recovery in different patients. For instance, 15–25 mmHg of pressure is commonly used clinically, and it is generally believed that higher pressure increases effectiveness and promotes scar maturation. However, pressure exceeding 40 mmHg can cause discomfort and potential harm, such as blistering, sensory abnormalities, abnormal bone growth, and limb necrosis. Therefore, effective pressure monitoring plays a crucial role in the precise, safe, and effective implementation of pressure therapy. This necessitates a more systematic study of the mechanical properties of pressure therapy materials to achieve controllable pressure performance for precise treatment management.

[0004] Currently, the production process and design technology of elastic knitted fabrics are complex, and it is difficult to maintain stable quality. In particular, the design and preparation of the padding structure generally rely on experience and small-scale sample production. That is, first design parameters, prepare a small sample, test the performance of the small sample, modify the parameters of the small sample, and then prepare again, until the performance requirements are met. This is time-consuming and material-intensive, and it cannot meet the requirements of rapid design and production.

[0005] Although the existing technology "Design and Experimental Study of Flexible Knee Joint Assistive Devices with Variable Stiffness, Zhao Chenyu, Jilin University, 2022" involves fabric structure, it mainly studies the variation of fiber angle in the fabric structure to characterize the change in softness, and simulates the softness of the fabric using the finite element method. Therefore, a method for preparing a parametric elastic knitted fabric padding structure is needed. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of existing technologies and provide a method for preparing the padding structure in parametric elastic knitted fabrics. Specifically, based on parametric elastic knitting design and raw material yarn selection, it studies different properties of fabric hyperelasticity, analyzes the content variations of padding yarns and ground yarns in the fabric through fabric structure analysis, and calculates and predicts the nonlinear elastic behavior of the fabric based on mathematical modeling methods. Furthermore, it controls the mechanical behavior of the elastic knitted fabric, providing an effective approach for the design and production of elastic knitted fabrics with controllable nonlinear elastic behavior, and effectively simplifies traditional design and preparation methods to meet practical needs.

[0007] To achieve the above technical objectives, the following technical solution is proposed:

[0008] The primary objective of this technical solution is to provide a method for preparing a padding structure in a parametric elastic knitted fabric, comprising the following steps:

[0009] S1: Select the appropriate weave yarn and padding yarn, and determine the corresponding yarn performance indicators, including yarn diameter, Poisson's ratio, and modulus of elasticity; among which,

[0010] Yarn diameter: can be estimated by linear density and bulk density, or by testing with an optical microscope;

[0011] Poisson's ratio: determined by the material of the raw yarn (for example, the value is 0.30 for spandex and nylon filaments), that is, obtained by looking up a table based on the yarn material;

[0012] Elastic modulus: It can be found in a table based on the material of the raw yarn, or it can be tested by the following method: the test length is 50mm, the tensile test speed is 100mm / min, and the stress-strain curve is obtained. The stress-strain slope between 50% and 70% of the strain is taken as the Young's modulus of the yarn. The elastic modulus parameter obtained by this method can effectively ensure accuracy, so it is preferred.

[0013] S2: Determine the loop length of the ground yarn and the overhang length and float length of the padding yarn to obtain the length ratio of the ground yarn to the padding yarn; then, based on the yarn diameter in step S1, obtain the volume ratio of the ground yarn to the padding yarn.

[0014] The determination of the loop length of the ground yarn and the lengths of the overhangs and floats of the padding yarn is based on the processing equipment – ​​the knitting machine model parameters. The ground yarn can only form one type of loop structure, and the padding yarn can only form two types of structures: overhangs and floats. Therefore, the length ratio between the yarns is determined by the processing equipment model parameters. However, it can also be obtained by observing and measuring small samples, but this increases the complexity of the process and reduces efficiency.

[0015] Within a complete weave cycle of a padding structure, the structural parameters padding ratio (p) and float ratio (f) are defined. Padding ratio (p) = number of ground yarns / number of padding yarns, and float ratio (f) = number of floats / number of overhangs. Both padding ratio (p) and float ratio (f) are design parameters that determine the number of ground loops, padding yarn overhangs, and floats within the padding structure.

[0016] With the raw yarn remaining constant, knitted fabrics with different nonlinear elastic behaviors can be designed by changing the structural parameters of padding ratio (p) and float ratio (f). In addition, the model and size of the knitting machine basically determine the loop length a, the length of the suspension arc b, and the length of the float c of the ground structure.

[0017] Among them, the ratio of the number of coils, floats and suspension arcs was determined: the padding structure was designed, that is, the structural parameters padding ratio (p) and suspension arc ratio (f) were determined;

[0018] Determining the length of each of the three types of units: Determining the loop length of the ground yarn and the overhang length and float length of the padding yarn determines the length of each structural unit. With the quantity ratio of the three types of units and the length of each unit, the length ratio of the two types of yarns in the fabric can be calculated, and then, based on the yarn diameter, the volume ratio of the two types of yarns can be obtained.

[0019] S3: Based on the mixing ratio (the elastic modulus in step S1 and the volume ratio in step S2), the theoretical elastic modulus of the elastic knitted fabric is obtained;

[0020] Wherein, the theoretical elastic modulus of elastic knitted fabric = elastic modulus of padding yarn * volume fraction of padding yarn + elastic modulus of ground yarn * volume fraction of ground yarn.

[0021] S4: Based on the hyperelastic constitutive model, predict the nonlinear elastic behavior of elastic knitted fabrics;

[0022] Based on the Cauchy Strain Tensor theory, hyperelastic constitutive equations for three pad structures—Neo-Hookean, Mooney-Rivlin, and Ogden—were established to determine the quantitative relationship between stress and strain, specifically including:

[0023] 1) Due to the nonlinear elastic behavior and orthogonal anisotropy (direction-dependent) material properties of weft-knitted fabrics, the fundamental functional quantitative relationship between stress and strain in knitted fabrics under uniaxial action is as follows:

[0024] The Cauchy strain tensor is used to describe the large deformation behavior of knitted hyperelastic materials. The strain tensor is independent of the coordinate system and is expressed by the following equation (1):

[0025] B = FF T (1);

[0026] Where B is the Cauchy strain tensor and F is the deformation gradient. To further analyze its mechanical behavior, the strain invariant is calculated using the following formula (2):

[0027]

[0028] Where I1, I2, and I3 are the 1st, 2nd, and 3rd Cauchy strain tensor invariants, respectively, and λ1, λ2, and λ3 are the 1st, 2nd, and 3rd principal tensions, respectively. In Cauchy strain theory, the relationship between the principal tensions of λi (i = 1, 2, 3) and the principal strains of εi (i = 1, 2, 3) is defined as follows (3):

[0029] λ i =1+ε i (3);

[0030] 2) Establish quantitative relationships between stress and strain in constitutive models of three types of padded knitted fabrics: Neo-Hookean, Mooney-Rivlin, and Ogden.

[0031] 1. Neo-Hookean model

[0032] The strain energy density function of the Neo-Hookean model is as follows (4):

[0033]

[0034] Where W is the strain energy density function, and C1 and D1 are the material constants corresponding to the torsional and volumetric responses, respectively. It is the first invariant of the Cauchy-Green deformation tensor, where J is the volume ratio. J can be expressed using the Cauchy strain tensor as follows (5):

[0035]

[0036] The relationship between stress and strain energy density function is defined as follows (6):

[0037]

[0038] Therefore, the relationship between principal stress and tension is as follows (7):

[0039]

[0040] For materials under uniaxial action, the principal tension relationship is as follows (8):

[0041]

[0042] Therefore, in the tensile direction, the relationship between the principal stress and the material strain is as follows (9):

[0043]

[0044] 2. Mooney-Rivlin model

[0045] The strain energy density function (W) of the Mooney-Rivlin model is expressed as a linear combination of two invariants of the Cauchy-Green deformation tensor, as shown in equation (10):

[0046]

[0047] Among them, C2, C 10 D1 and C2 are material constants. 10 Related to the torsional deformation response, D1 represents the volumetric response. and These are the first and second invariants of the deviation component of the Cauchy-Green deformation tensor, where J is the volume ratio;

[0048] In the Mooney-Rivlin model J is the same as the Neo-Hookean model. It can also be expressed using the Cauchy strain tensor as shown in equation (11):

[0049]

[0050] Under uniaxial tension, the relationship between stress and principal tension is as follows (12):

[0051]

[0052] Simplified as follows (13):

[0053]

[0054] 3. Ogden model

[0055] In the first-order Ogden model, the strain energy density is expressed by principal tension as follows (14):

[0056]

[0057] Where μ1 and α are material constants determined empirically. During uniaxial tension, the relationship between stress and strain in the fabric is as follows (15):

[0058]

[0059] To quantify the parameters of the hyperelastic model, the Young's modulus and Poisson's ratio of the knitted fabric are determined using the composite mixture rule, as shown in equation (16):

[0060]

[0061] In the formula, E and v represent Young's modulus and Poisson's ratio, and the symbols f, g, and i correspond to the knitted fabric, the ground yarn, and the padding yarn, respectively. Therefore, the Lame parameters of the knitted fabric are as follows (17):

[0062]

[0063] To maintain consistency with linear elasticity, the relationship between C1, D1, and the Lame parameters in the Neo-Hookean model is as follows (18):

[0064]

[0065] Similarly, in the Mooney-Rivlin model, C1, C 10 The relationship between D1 and the Lame parameter is as follows (19):

[0066]

[0067] C2 and C were determined using the least squares method. 10 The relationship between μ1, α, D1, and the Lame parameters in the Ogden model is as follows (20):

[0068]

[0069] In the first-order Ogden model, μ (μ = μ1α) can be obtained by equation (15); μ1 can be obtained by equation (20); the value of α can be calculated by using the strain energy density fitting function of tools such as MATLAB;

[0070] S5: Based on the nonlinear elastic behavior of the elastic knitted fabric predicted in step S4, determine whether it meets the design requirements, and finally determine the design scheme.

[0071] If the design requirements are met, it is the final design solution;

[0072] If the design requirements are not met, modify the design parameters and repeat steps S1-S4 until the design requirements are met.

[0073] The design requirements specifically include:

[0074] Assuming all ground yarns have equal loop lengths, all padding yarns have equal overhang lengths, and all padding yarns have equal float lengths, therefore, within a complete weave cycle, the ground yarn length l g and padding yarn length l i They are respectively shown in equation (21):

[0075]

[0076] Where a is the loop length of the ground yarn, b is the overhang length of the padding yarn, c is the float length of the padding structure, and p and f are parametric design parameters.

[0077] For uniaxial tension, the first principal stress (σ1) represents the tensile stress, and the first principal tension (λ1) represents the tensile strain. The relationship between stress and tensile deformation is determined according to equations (9), (13), and (15). The relationship between constitutive parameters, geometric parameters (loop length and yarn diameter) and mechanical properties (Young's modulus and Poisson's ratio) of the hyperelastic model is derived through hyperelastic theory and hybrid laws.

[0078] Therefore, a functional relationship can be derived:

[0079] σ=F(ε,c,w,d g ,d i E g E i ,v g ,v i );

[0080] Where σ and ε are uniaxial tensile stress and strain, respectively, p and f represent parametric design coefficients, and d g and d i These are the diameters of the ground yarn and the padding yarn, respectively;

[0081] In addition, E g E i v g and v i These are Young's modulus and Poisson's ratio for the ground yarn and the padding yarn, respectively.

[0082] When the geometric parameters (yarn diameter and loop length) and material properties (Young's modulus and Poisson's ratio) are defined according to the yarn structure, the stress-strain curves of different parameter designs (p and f) can be determined by the derived hyperelastic constitutive model. Similarly, the design parameters p and f can be determined by changing the yarn material.

[0083] The second objective of this technical solution is to provide: a computer device, the computer device including a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, causing the processor to perform the steps of any of the methods described in the above technical solutions.

[0084] The third objective of this technical solution is to provide: a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, it implements the steps of any of the methods described in the above technical solutions.

[0085] The fourth objective of this technical solution is to provide an information data processing terminal for a method of preparing a padding structure in a parametric elastic knitted fabric.

[0086] In this technical solution, the terms involved are defined as follows:

[0087] Elastic knitted fabric: a type of fabric that can stretch significantly when subjected to external force and quickly return to its original shape after the external force is removed. It has a high elongation rate (elastic modulus) and elastic recovery rate.

[0088] Padding structure: a type of knitted fabric weave in which one or more padding yarns form overhangs on the loops at regular intervals, and are connected by floats on the reverse side of the fabric. Padding structure requires at least two types of yarn: one padding yarn to form the overhangs and floats, and another weave yarn to form the basic knitted fabric structure.

[0089] Ground structure: The basic structure of padding structure. Common basic structures include plain knit, padded knit, tuck knit, and rib knit.

[0090] Ground weave yarn: The yarn that forms the base structure of the padding structure is called ground weave yarn;

[0091] Padding yarn: Yarns that form overhangs and floats on the base weave are called padding yarns. The overhangs and floats of padding yarns must be attached to the loops of the base weave;

[0092] For all the above terms, please refer to the textbook "Knitting" published by China Textile Publishing House, "Textbook for the Construction of First-Class Disciplines in Textile Science and Engineering and Textile Engineering for First-Class Undergraduate Majors", ISBN: 9787518098033.

[0093] The beneficial technical effects of adopting this technical solution are as follows:

[0094] I. This invention, through the design of parametric knitted fabric structures, can accurately predict the elastic behavior of fabrics under large deformations, thereby shortening the research and development cycle of elastic fabrics, greatly optimizing the preparation scheme, and further realizing the automation and intelligence of the production process.

[0095] Second, the parametric design method in this invention allows for the design and / or production of fabrics or garments without wasting raw materials. This not only effectively avoids the waste of manpower and resources caused by repeated sampling, but also prevents the accumulation of inventory of similar products. Furthermore, it allows users to interactively participate in the product development process. While better serving consumers, it also brings more profits to enterprises and effectively reduces costs to meet the requirements of process-oriented production.

[0096] Third, the digital application of this invention in the design and development process can efficiently complete the sampling work, promote the digital and intelligent transformation and upgrading of the textile industry, not only benefit customers' personalized experience feedback, but also realize a digital supply chain management model, and ultimately achieve intelligent economics of parameters. Attached Figure Description

[0097] Figure 1 This is a typical padded structure diagram of the actual elastic knitted fabric involved in this invention;

[0098] Figure 2 This is a structural diagram of the padding tissue model involved in this invention;

[0099] Figure 3 This is a design flowchart of the present invention;

[0100] Figure 4 This is a diagram of the padding structure in Embodiment 5 of the present invention (a is a design diagram, b is a simulation diagram);

[0101] Figure 5 This is a schematic diagram of the ground yarn loop length a, the suspension arc length b, and the float length c of the padding structure in Embodiment 5 of the present invention.

[0102] Figure 6 These are actual images of elastic knitted fabrics with different structural parameters in Embodiment 5 of the present invention;

[0103] Figure 7 This is a comparison diagram of the stress-strain characteristics of three macroscopic models for different elastic knitted fabrics in Embodiment 5 of the present invention;

[0104] Figure 8 This is a stress-strain curve diagram of the actual experimental test of elastic knitted fabrics with different structural parameters in Embodiment 5 of the present invention;

[0105] Figure 9 This is an error analysis diagram showing the actual elastic knitted fabrics with different structural parameters compared to the model in Embodiment 5 of the present invention. Detailed Implementation

[0106] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0107] Example 1

[0108] This embodiment provides a method for preparing a padding structure in a parametric elastic knitted fabric, such as... Figure 1-3 As shown, it includes the following steps:

[0109] S1: Select the appropriate weave yarn and padding yarn, and determine the corresponding yarn performance indicators, including yarn diameter, Poisson's ratio, and modulus of elasticity; among which,

[0110] Yarn diameter: can be estimated by linear density and bulk density, or by testing with an optical microscope;

[0111] Poisson's ratio: determined by the material of the raw yarn (for example, the value is 0.30 for spandex and nylon filaments), that is, obtained by looking up a table based on the yarn material;

[0112] Elastic modulus: It can be found in a table based on the material of the raw yarn, or it can be tested by the following method: the test length is 50mm, the tensile test speed is 100mm / min, and the stress-strain curve is obtained. The stress-strain slope between 50% and 70% of the strain is taken as the Young's modulus of the yarn. The elastic modulus parameter obtained by this method can effectively ensure accuracy, so it is preferred.

[0113] S2: Determine the loop length of the ground yarn and the overhang length and float length of the padding yarn to obtain the length ratio of the ground yarn to the padding yarn; then, based on the yarn diameter in step S1, obtain the volume ratio of the ground yarn to the padding yarn.

[0114] The determination of the loop length of the ground yarn and the lengths of the overhangs and floats of the padding yarn is based on the processing equipment – ​​the knitting machine model parameters. The ground yarn can only form one type of loop structure, and the padding yarn can only form two types of structures: overhangs and floats. Therefore, the length ratio between the yarns is determined by the processing equipment model parameters. However, it can also be obtained by observing and measuring small samples, but this increases the complexity of the process and reduces efficiency.

[0115] Within a complete weave cycle of a padding structure, the structural parameters padding ratio (p) and float ratio (f) are defined. Padding ratio (p) = number of ground yarns / number of padding yarns, and float ratio (f) = number of floats / number of overhangs. Both padding ratio (p) and float ratio (f) are design parameters that determine the number of ground loops, padding yarn overhangs, and floats within the padding structure.

[0116] With the raw yarn remaining constant, knitted fabrics with different nonlinear elastic behaviors can be designed by changing the structural parameters of padding ratio (p) and float ratio (f). In addition, the model and size of the knitting machine basically determine the loop length a, the length of the suspension arc b, and the length of the float c of the ground structure.

[0117] Among them, the ratio of the number of coils, floats and suspension arcs was determined: the padding structure was designed, that is, the structural parameters padding ratio (p) and suspension arc ratio (f) were determined;

[0118] Determining the length of each of the three types of units: Determining the loop length of the ground yarn and the overhang length and float length of the padding yarn determines the length of each structural unit. With the quantity ratio of the three types of units and the length of each unit, the length ratio of the two types of yarns in the fabric can be calculated, and then, based on the yarn diameter, the volume ratio of the two types of yarns can be obtained.

[0119] S3: Based on the mixing ratio (the elastic modulus in step S1 and the volume ratio in step S2), the theoretical elastic modulus of the elastic knitted fabric is obtained;

[0120] Wherein, the theoretical elastic modulus of elastic knitted fabric = elastic modulus of padding yarn * volume fraction of padding yarn + elastic modulus of ground yarn * volume fraction of ground yarn.

[0121] S4: Based on the hyperelastic constitutive model, predict the nonlinear elastic behavior of elastic knitted fabrics;

[0122] Based on the Cauchy Strain Tensor theory, hyperelastic constitutive equations for three pad structures—Neo-Hookean, Mooney-Rivlin, and Ogden—were established to determine the quantitative relationship between stress and strain, specifically including:

[0123] 1) Due to the nonlinear elastic behavior and orthogonal anisotropy (direction-dependent) material properties of weft-knitted fabrics, the fundamental functional quantitative relationship between stress and strain in knitted fabrics under uniaxial action is as follows:

[0124] The Cauchy strain tensor is used to describe the large deformation behavior of knitted hyperelastic materials. The strain tensor is independent of the coordinate system and is expressed by the following equation (1):

[0125] B = FF T (1);

[0126] Where B is the Cauchy strain tensor and F is the deformation gradient. To further analyze its mechanical behavior, the strain invariant is calculated using the following formula (2):

[0127]

[0128] Where I1, I2, and I3 are the 1st, 2nd, and 3rd Cauchy strain tensor invariants, respectively, and λ1, λ2, and λ3 are the 1st, 2nd, and 3rd principal tensions, respectively. In Cauchy strain theory, the relationship between the principal tensions of λi (i = 1, 2, 3) and the principal strains of εi (i = 1, 2, 3) is defined as follows (3):

[0129] λ i =1+ε i (3);

[0130] 2) Establish quantitative relationships between stress and strain in constitutive models of three types of padded knitted fabrics: Neo-Hookean, Mooney-Rivlin, and Ogden.

[0131] 1. Neo-Hookean model

[0132] The strain energy density function of the Neo-Hookean model is as follows (4):

[0133]

[0134] Where W is the strain energy density function, and C1 and D1 are the material constants corresponding to the torsional and volumetric responses, respectively. It is the first invariant of the Cauchy-Green deformation tensor, where J is the volume ratio. J can be expressed using the Cauchy strain tensor as follows (5):

[0135]

[0136] The relationship between stress and strain energy density function is defined as follows (6):

[0137]

[0138] Therefore, the relationship between principal stress and tension is as follows (7):

[0139]

[0140] For materials under uniaxial action, the principal tension relationship is as follows (8):

[0141]

[0142] Therefore, in the tensile direction, the relationship between the principal stress and the material strain is as follows (9):

[0143]

[0144] 2. Mooney-Rivlin model

[0145] The strain energy density function (W) of the Mooney-Rivlin model is expressed as a linear combination of two invariants of the Cauchy-Green deformation tensor, as shown in equation (10):

[0146]

[0147] Among them, C2, C 10 D1 and C2 are material constants. 10 Related to the torsional deformation response, D1 represents the volumetric response. and These are the first and second invariants of the deviation component of the Cauchy-Green deformation tensor, where J is the volume ratio;

[0148] In the Mooney-Rivlin model J is the same as the Neo-Hookean model. It can also be expressed using the Cauchy strain tensor as shown in equation (11):

[0149]

[0150] Under uniaxial tension, the relationship between stress and principal tension is as follows (12):

[0151]

[0152] Simplified as follows (13):

[0153]

[0154] 3. Ogden model

[0155] In the first-order Ogden model, the strain energy density is expressed by principal tension as follows (14):

[0156]

[0157] Where μ1 and α are material constants determined empirically. During uniaxial tension, the relationship between stress and strain in the fabric is as follows (15):

[0158]

[0159] To quantify the parameters of the hyperelastic model, the Young's modulus and Poisson's ratio of the knitted fabric are determined using the composite mixture rule, as shown in equation (16):

[0160]

[0161] In the formula, E and v represent Young's modulus and Poisson's ratio, and the symbols f, g, and i correspond to the knitted fabric, the ground yarn, and the padding yarn, respectively. Therefore, the Lame parameters of the knitted fabric are as follows (17):

[0162]

[0163] To maintain consistency with linear elasticity, the relationship between C1, D1, and the Lame parameters in the Neo-Hookean model is as follows (18):

[0164]

[0165] Similarly, in the Mooney-Rivlin model, C1, C 10 The relationship between D1 and the Lame parameter is as follows (19):

[0166]

[0167] C2 and C were determined using the least squares method. 10 The relationship between μ1, α, D1, and the Lame parameters in the Ogden model is as follows (20):

[0168]

[0169] In the first-order Ogden model, μ (μ = μ1α) can be obtained by equation (15); μ1 can be obtained by equation (20); the value of α can be calculated by using the strain energy density fitting function of tools such as MATLAB;

[0170] S5: Based on the nonlinear elastic behavior of the elastic knitted fabric predicted in step S4, determine whether it meets the design requirements, and finally determine the design scheme.

[0171] If the design requirements are met, it is the final design solution;

[0172] If the design requirements are not met, modify the design parameters and repeat steps S1-S4 until the design requirements are met.

[0173] The design requirements specifically include:

[0174] Assuming all ground yarns have equal loop lengths, all padding yarns have equal overhang lengths, and all padding yarns have equal float lengths, therefore, within a complete weave cycle, the ground yarn length l g and padding yarn length l i They are respectively shown in equation (21):

[0175]

[0176] Where a is the loop length of the ground yarn, b is the overhang length of the padding yarn, c is the float length of the padding structure, and p and f are parametric design parameters.

[0177] For uniaxial tension, the first principal stress (σ1) represents the tensile stress, and the first principal tension (λ1) represents the tensile strain. The relationship between stress and tensile deformation is determined according to equations (9), (13), and (15). The relationship between constitutive parameters, geometric parameters (loop length and yarn diameter) and mechanical properties (Young's modulus and Poisson's ratio) of the hyperelastic model is derived through hyperelastic theory and hybrid laws.

[0178] Therefore, a functional relationship can be derived:

[0179] σ=F(ε,c,w,d g ,d i E g E i ,v g ,v i );

[0180] Where σ and ε are uniaxial tensile stress and strain, respectively, p and f represent parametric design coefficients, and d g and d i These are the diameters of the ground yarn and the padding yarn, respectively;

[0181] In addition, E g E i v g and v i These are Young's modulus and Poisson's ratio for the ground yarn and the padding yarn, respectively.

[0182] When the geometric parameters (yarn diameter and loop length) and material properties (Young's modulus and Poisson's ratio) are defined according to the yarn structure, the stress-strain curves of different parameter designs (p and f) can be determined by the derived hyperelastic constitutive model. Similarly, the design parameters p and f can be determined by changing the yarn material.

[0183] Example 2

[0184] Based on Embodiment 1, this embodiment provides: a computer device, the computer device including a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, causing the processor to perform the steps of any of the methods described in the above technical solutions.

[0185] Example 3

[0186] Based on Embodiment 1, this embodiment provides: a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for preparing the padding structure in the parameterized elastic knitted fabric according to any one of the above technical solutions.

[0187] Example 4

[0188] Based on Example 1, this example provides: an information data processing terminal for a method of preparing a padding structure in a parameterized elastic knitted fabric.

[0189] Example 5

[0190] This embodiment provides a method for preparing a padding structure in a parameterized elastic knitted fabric, specifically including:

[0191] Knitting machine specifications: Sock machine, cylinder diameter 6 inches, machine size E20;

[0192] Raw material yarn parameters: The base yarn is made of polyamide double-wrapped polyurethane yarn with a linear density of 40D / 40D / 40D, and the padding yarn is made of polyamide double-wrapped polyurethane yarn with a linear density of 520D / 20D / 20D.

[0193] The average diameters of the ground yarn and the padding yarn are 0.30±0.03mm and 0.41±0.02mm, respectively; the Young's modulus is 0.13MPa and 1.40MPa, respectively; and the Poisson's ratio is 0.30 and 0.30, respectively.

[0194] like Figure 5 As shown, a is the loop length of the ground yarn, b is the overhang length of the padding yarn, and c is the float length of the padding structure, calculated according to the ratio 4:2:1.

[0195] Among them, the design and simulation of padding structures for fabrics with nine different structural parameters p and f are involved, such as... Figure 4 As shown; nine different elastic knitted fabrics with structural parameters p and f, such as Figure 6 As shown; and, the comparison results of the stress-strain characteristics of three macroscopic models for different elastic knitted fabrics, as shown in the figure; Figure 7As shown; stress-strain results of experimental tests on elastic knitted fabrics with different structural parameters are as follows. Figure 8 As shown; finally, error analysis was performed between the actual elastic knitted fabrics and the model with different structural parameters, and the results are as follows. Figure 9 As shown;

[0196] and Figure 7 As can be seen from the results, the simulation results of the Neo-Hookean model and the Mooney-Rivlin model are quite similar, while the results of the Ogden model are significantly different from the other two models, but all of them have the nonlinear characteristics that elastic fabrics should have.

[0197] Figure 8-9 The results show that all nine types of padded elastic knitted fabrics exhibit nonlinear elastic behavior. The nonlinear elastic behavior is similar to the simulation results. Error analysis indicates that the Mooney-Rivlin model has the smallest error (9.26%) across the entire stress range; the Neo-Hookean model has the second largest error (9.46%); and the Ogden model has the largest error, but it does not exceed 14.48%.

[0198] Therefore, the present invention is used for the design of padding structure in elastic knitted fabrics, which has good accuracy and usability, not only realizing intelligent and economical parameters, but also effectively ensuring the production quality and efficiency of padding structure, and meeting the requirements of process production.

[0199] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and inclusions made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method of producing a gusset structure in a parametric elastic knitted fabric, characterized by, Includes the following steps: S1: Select the ground yarn and padding yarn, and determine the corresponding yarn performance indicators: yarn diameter, Poisson's ratio and elastic modulus; The test method for elastic modulus includes: the test specification length is 50 mm, the tensile test speed is 100 mm / min, the stress-strain curve is obtained, and the stress-strain slope between 50% and 70% of the strain is taken as the Young's modulus of the yarn, thus obtaining the elastic modulus. S2: Determine the loop length of the ground yarn and the overhang length and float length of the padding yarn to obtain the length ratio of the ground yarn to the padding yarn; then, based on the yarn diameter in step S1, obtain the volume ratio of the ground yarn to the padding yarn. S3: Based on the elastic modulus in step S1 and the volume ratio in step S2, obtain the theoretical elastic modulus of the elastic knitted fabric; S4: Based on the hyperelastic constitutive model, predict the nonlinear elastic behavior of elastic knitted fabrics; Based on the Cauchy Strain Tensor theory, hyperelastic constitutive equations for three types of pad structures—Neo-Hookean, Mooney-Rivlin, and Ogden—were established to determine the quantitative relationship between stress and strain. S5: Based on the nonlinear elastic behavior of the elastic knitted fabric predicted in step S4, determine whether it meets the design requirements, and finally determine the design scheme. If the design requirements are met, it becomes the final design scheme, and the parametric elastic knitted fabric structure is prepared. If the design requirements are not met, modify the design parameters and repeat steps S1-S4 until the design requirements are met. Finally, prepare the parametric elastic knitted fabric structure.

2. The method of claim 1, wherein the spacer stitch structure is formed in the parameterized elastic knitted fabric. In step S2, the loop length of the ground yarn and the overhang and float length of the padding yarn are determined according to the knitting machine model parameters.

3. The method of claim 2, wherein the spacer stitch structure is formed by knitting the first and second courses in the first and second rows, respectively, and the third course in the third row. In step S2, within a complete fabric cycle of a padding structure, the structural parameters padding ratio and float ratio are defined, where padding ratio = number of ground yarns / number of padding yarns, and float ratio = number of floats / number of overhangs.

4. The method of claim 1, wherein the spacer stitch structure is formed in the parameterized elastic knitted fabric. In step S3, the theoretical elastic modulus of the elastic knitted fabric = elastic modulus of the padding yarn * volume fraction of the padding yarn + elastic modulus of the ground yarn * volume fraction of the ground yarn.

5. A computer device comprising a memory and a processor, the memory storing a computer program, wherein when the computer program is executed by the processor, the processor causes the processor to perform the steps of the method for preparing the padding structure in the parametric elastic knitted fabric according to any one of claims 1-4.

6. A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for preparing the padding structure in the parameterized elastic knitted fabric according to any one of claims 1-4.

7. An information data processing terminal for a method of preparing a parametric elastic knitted fabric structure, comprising the steps of the method for preparing a padding structure in a parametric elastic knitted fabric as described in any one of claims 1-4.

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