Z-pin Bridging Performance Prediction Method and System Considering Initial Curing Defects

Abstract

The present invention discloses a method and system for predicting the bridging performance of Z-pins considering initial curing defects. The method includes: establishing a geometric model of Z-pin toughened resin matrix composites; and successively dividing the geometric model into a laminate region, a Z-pin region, an eye-shaped resin-rich region, and a Z-pin-resin-rich interface region based on different component materials; considering the thermo-chemical-mechanical coupled deformation of each component material in the geometric model, calculating the residual stress caused by the mismatch of curing deformation of each component material; applying the residual stress as a load condition to the geometric model, and calculating the damage factor of the Z-pin-resin-rich interface region based on the damage criterion set for the Z-pin-resin-rich interface region; introducing the damage factor as an input parameter into the geometric model, applying a pull-out force to the Z-pin region, and calculating the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region; predicting the Z-pin bridging performance based on the Z-pin pull-out energy. The present invention can improve the prediction accuracy of the Z-pin bridging performance.

Description

Technical Field

[0001] The present invention relates to the technical field of Z-pin toughening, and particularly to a method and system for predicting the bridging performance of Z-pin considering initial curing defects. Background Art

[0002] The Z-pin toughening technology includes pre-vertically implanting pin needles into a prepreg ply and completing a co-curing reaction in an autoclave to lock each layer of unidirectional plate and achieve Z-direction reinforcement of the composite material. The Z-pin bridging effect means that when the composite material is subjected to an external force load, the Z-pin can act like a "bridge" to pull and bridge the upper and lower crack surfaces to resist the external force and prevent the crack from further expanding, achieving the effect of improving the interlaminar toughness of the composite material. At present, the Z-pin bridging effect mainly relies on experiments, which is extremely time-consuming and costly from specimen preparation to experimental testing. If the response of the Z-pin bridging effect can be calculated based on the original properties of its component materials, this process will be greatly simplified. The literature "Micro-mechanical modeling study of the influence of cure process on the interfacial cracking of Z-pinned laminates, Composite structures, 2022, 114889." confirms that during the co-curing process, due to the mismatch between the curing deformation of the Z-pin and the surrounding resin, curing defects such as high residual stress and local debonding are formed around the pin needles, which will greatly affect the bridging performance of the Z-pin. Therefore, if these initial curing defects can be fully considered, the prediction accuracy of the Z-pin bridging performance will be greatly improved. Summary of the Invention

[0003] Based on this, the present invention provides a method and system for predicting the bridging performance of Z-pin considering initial curing defects.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A method for predicting the bridging performance of Z-pin considering initial curing defects includes:

[0006] Establish a geometric model of Z-pin toughened resin matrix composite material; and based on the differences in component materials, sequentially divide the geometric model into a laminate region, a Z-pin region, an eye-shaped resin-rich region, and a Z-pin-resin-rich interface region; the component materials include resin and fiber;

[0007] Considering the thermo-chemical-mechanical coupled deformation of each component material in the geometric model, calculate the residual stress caused by the curing deformation mismatch of each component material;

[0008] Apply the residual stress as a loading condition on the geometric model, and calculate the damage factor of the Z-pin-rich resin interface region based on the damage criterion set for the Z-pin-rich resin interface region;

[0009] Introduce the damage factor as an input parameter into the geometric model, apply a pull-out force to the Z-pin region, and calculate the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region;

[0010] Predict the Z-pin bridging performance based on the Z-pin pull-out energy.

[0011] Optionally, considering the thermo-chemical-mechanical coupled deformation of each component material in the geometric model, calculate the residual stress caused by the curing deformation mismatch of each component material, specifically including:

[0012] Calculate the elastic modulus, thermal expansion coefficient, and chemical shrinkage coefficient of the resin in the co-curing reaction;

[0013] Calculate the elastic modulus, thermal expansion coefficient, and chemical shrinkage coefficient of the laminate region in the co-curing reaction;

[0014] Calculate the chemical shrinkage deformation based on the resin chemical shrinkage coefficient and the laminate region chemical shrinkage coefficient;

[0015] Calculate the thermal expansion deformation based on the resin thermal expansion coefficient and the laminate region thermal expansion coefficient;

[0016] Calculate the mechanical deformation based on the total deformation, the chemical shrinkage deformation, and the thermal expansion deformation;

[0017] Calculate the residual stress of each component material based on the resin elastic modulus, the laminate region elastic modulus, and the mechanical deformation.

[0018] Optionally, apply the residual stress as a loading condition on the geometric model, and calculate the damage factor of the Z-pin-rich resin interface region based on the damage criterion set for the Z-pin-rich resin interface region, specifically including:

[0019] Apply the residual stress as a loading condition on the geometric model, and determine the damaged area of the Z-pin-rich resin interface region based on the damage criterion set for the Z-pin-rich resin interface region;

[0020] Calculate the damage factor of the Z-pin-rich resin interface region based on the damaged area.

[0021] Optionally, the expression of the damage criterion is as follows:

[0022]

[0023] Among them, σ n 、σ s 、σ t are the residual stress components of the Z-pin-rich resin interface region along the vertical direction n and two tangential directions s and t, respectively. are the damage strengths of the Z-pin-rich resin interface region along the three directions of n, s, and t, respectively.

[0024] Optionally, introduce the damage factor as an input parameter into the geometric model, apply a pull-out force to the Z-pin region, and calculate the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region, specifically including:

[0025] Introduce the damage factor as an input parameter into the geometric model and calculate the reduced stiffness of the Z-pin-rich resin interface region;

[0026] Under the condition of stiffness reduction of the Z-pin-rich resin interface region, apply a pull-out force to the Z-pin region and calculate the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region.

[0027] Optionally, the expression of the pull-out damage criterion is as follows:

[0028]

[0029] Among them, P n 、P s 、P t are the pull-out forces applied to the Z-pin region along the vertical direction n and two tangential directions s and t, respectively. P s 0 、P t 0 are the pull-out strengths of the Z-pin region along the three directions of n, s, and t, respectively.

[0030] Optionally, the calculation formula of the Z-pin pull-out energy is as follows:

[0031]

[0032]

[0033] Among them, W pin is the Z-pin pull-out energy, h is the implantation depth of the Z-pin region, and P is the Z-pin pull-out force.

[0034] Optionally, the Z-pin bridging performance can be predicted based on the Z-pin pull-out energy, specifically including:

[0035] The higher the Z-pin pull-out energy, the better the Z-pin bridging performance;

[0036] The lower the Z-pin pull-out energy, the worse the Z-pin bridging performance.

[0037] The present invention also provides a Z-pin bridging performance prediction system considering initial curing defects, including:

[0038] A model construction and division module, configured to establish a geometric model of Z-pin toughened resin matrix composite; and successively divide the geometric model into a laminate region, a Z-pin region, an eye-shaped resin-rich region, and a Z-pin-resin-rich interface region based on different component materials; the component materials include resin and fiber;

[0039] A residual stress calculation module, configured to consider the thermo-chemical-mechanical coupled deformation of each component material in the geometric model and calculate the residual stress caused by the curing deformation mismatch of each component material;

[0040] A damage factor calculation module, configured to apply the residual stress as a load condition to the geometric model and calculate the damage factor of the Z-pin-resin-rich interface region based on the damage criterion set for the Z-pin-resin-rich interface region;

[0041] A Z-pin pull-out energy calculation module, configured to introduce the damage factor as an input parameter into the geometric model, apply a pull-out force to the Z-pin region, and calculate the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region;

[0042] A Z-pin bridging performance prediction module, configured to predict the Z-pin bridging performance based on the Z-pin pull-out energy.

[0043] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0044] The present invention first calculates the co-curing reaction of Z-pin toughened resin matrix composites, fully considering the thermo-chemical-mechanical coupling deformation of each component material to determine the residual stress of each component material. Then, the residual stress predicted in the previous step is applied as a load to the model, and through the calculation of the damage in the Z-pin-rich resin interface region, the damage factor of the Z-pin-rich resin interface region caused by the residual stress concentration is determined. Finally, the damage factor of the Z-pin-rich resin interface region predicted in the previous step is introduced into the model as an input parameter to reduce the stiffness of the Z-pin-rich resin interface region to equivalently characterize its curing defects. Under this condition, a pull-out load is applied to the Z-pin region to calculate the Z-pin pull-out energy, thereby accurately predicting the bridging performance of the Z-pin. By carrying out the co-curing calculation of Z-pin toughened resin matrix composites, the present invention quantitatively predicts the residual stress concentration and local debonding defects around the Z-pin, so that the bridging performance of the Z-pin can be predicted more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0046] Figure 1 It is a flowchart of the method for predicting the bridging performance of Z-pin considering initial curing defects provided by the present invention;

[0047] Figure 2 It is a schematic diagram of the residual stress result predicted by the present invention.

[0048] Figure 3 It is a schematic diagram of the damage result of the Z-pin-rich resin interface region predicted by the present invention.

[0049] Figure 4 It is a schematic diagram of the result of the Z-pin pull-out force-displacement curve predicted by the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0051] The object of the present invention is to provide a method and system for predicting the bridging performance of Z-pin considering initial curing defects, so as to improve the prediction accuracy of the bridging performance of Z-pin.

[0052] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] Embodiment 1

[0054] As Figure 1 shown, the method for predicting the bridging performance of Z-pin considering initial curing defects provided by the present invention includes the following steps:

[0055] Step 101: Establish a geometric model of Z-pin toughened resin matrix composite; and based on the differences in component materials, the geometric model is sequentially divided into a laminate region, a Z-pin region, an eye-shaped resin-rich region, and a Z-pin-resin-rich interface region; the component materials include resin and fiber.

[0056] In practical applications, according to the requirements for preparing specimens with a prepreg layup sequence of [0 16 / PTFE / 0 16 and a Z-pin diameter of 0.35 mm, a geometric model of Z-pin toughened resin matrix composite is established. The geometric model of Z-pin toughened resin matrix composite can be sequentially divided into a laminate region, a Z-pin region, an eye-shaped resin-rich region, and a Z-pin-resin-rich interface region according to the differences in component materials.

[0057] The laminate region is composed of a mixture of resin and fiber materials, the Z-pin region is composed of fiber materials, the eye-shaped resin-rich region is composed of resin materials, and the Z-pin-resin-rich interface region is a set special boundary region, and its mechanical behavior can be characterized by the cohesive force model.

[0058] Step 102: Considering the thermo-chemo-mechanical coupling deformation of each component material in the geometric model, calculate the residual stress caused by the curing deformation mismatch of each component material. Specifically, it includes: calculating the elastic modulus, thermal expansion coefficient, and chemical shrinkage coefficient of the resin in the co-curing reaction; calculating the elastic modulus, thermal expansion coefficient, and chemical shrinkage coefficient of the laminate region in the co-curing reaction; calculating the chemical shrinkage deformation based on the resin chemical shrinkage coefficient and the chemical shrinkage coefficient of the laminate region; calculating the thermal expansion deformation based on the resin thermal expansion coefficient and the thermal expansion coefficient of the laminate region; calculating the mechanical deformation based on the total deformation, chemical shrinkage deformation, and thermal expansion deformation; calculating the residual stress of each component material based on the resin elastic modulus, the elastic modulus of the laminate region, and the mechanical deformation. The predicted residual stress results are as Figure 2 shown.

[0059] In practical applications, a co-curing reaction model is established, fully considering the thermo-chemical-mechanical coupled deformation of each component material of the Z-pin toughened resin matrix composite, and calculating the residual stress distribution of each component material caused by the mismatch of curing deformation.

[0060] In the co-curing reaction, since the curing time-varying evolution characteristics of the fiber component material are not obvious, its change can be ignored; the curing time-varying evolution characteristics of the resin component material are obvious, and it will change from the initial viscous flow state to the intermediate rubber state, and then to the final glass state, accompanied by obvious thermal expansion deformation and chemical shrinkage deformation, so it needs to be considered emphatically.

[0061] The elastic modulus E of the resin under the curing real-time evolution characteristics is characterized by establishing a curing transient linear elastic model. r . The curing transient linear elastic model is:

[0062]

[0063] In the formula, is the elastic modulus of the resin in the viscous flow state, is the elastic modulus of the resin in the glass state, T* is the temperature difference between the curing instantaneous temperature and the resin glass state transformation, are the critical temperatures at the start and completion of the resin glass state transformation, respectively.

[0064] The thermal expansion deformation of the resin under the curing real-time evolution characteristics is characterized by establishing a thermal expansion model. The thermal expansion model is:

[0065] β r (α)=(1 - α)β r 0 +αβ r ∞ (2)

[0066] In the formula, α is the degree of cure, and β r (α) is the coefficient of thermal expansion of the resin varying with the degree of cure, and β r 0 is the initial coefficient of thermal expansion of the resin, and β r ∞ is the coefficient of thermal expansion of the resin at the completion of curing.

[0067] The shrinkage deformation of the resin caused by the phase transition is characterized by establishing a chemical shrinkage model. The chemical shrinkage model is:

[0068]

[0069] In the formula, γ r is the chemical shrinkage coefficient of the resin, and V r 0 is the initial volume of the resin, and Vr ∞ It is the volume when the resin curing is completed.

[0070] The elastic modulus of the laminate region is expressed as a mixture of the mechanical properties of the resin and fiber materials, and the expression is:

[0071]

[0072] In the formula, E 11 is the elastic modulus of the laminate along the fiber direction, E 22 is the elastic modulus of the laminate along the direction perpendicular to the fiber, E 33 is the elastic modulus of the laminate along the thickness direction. The subscripts f and r represent fiber and resin respectively, V f is the fiber volume fraction, v is the Poisson's ratio, K is the bulk modulus, and G is the shear modulus.

[0073] The thermal expansion performance of the laminate region is expressed as a mixture of the thermal expansion performances of the resin and fiber materials, and the expression is:

[0074]

[0075] In the formula, β 11 is the coefficient of thermal expansion of the laminate along the fiber direction, β 22 is the coefficient of thermal expansion of the laminate along the direction perpendicular to the fiber, β 33 is the coefficient of thermal expansion of the laminate along the thickness direction.

[0076] The chemical shrinkage performance of the laminate region is expressed as a mixture of the chemical shrinkage performances of the resin and fiber materials, and the expression is:

[0077]

[0078] In the formula, γ 11 is the chemical shrinkage coefficient of the laminate along the fiber direction, γ 22 is the chemical shrinkage coefficient of the laminate along the direction perpendicular to the fiber, γ 33 is the chemical shrinkage coefficient of the laminate along the thickness direction.

[0079] The calculation model of the residual stress of each component material of the Z-pin toughened resin matrix composite is:

[0080]

[0081] In the formula, the subscript i represents each component material, σ is the residual stress, ε mech is the mechanical deformation, ε total is the total deformation, ε th is the thermal expansion deformation, ε sh is the chemical shrinkage deformation, and T is the curing temperature.

[0082] Step 103: Apply the residual stress as a loading condition on the geometric model, and calculate the damage factor of the Z-pin-rich resin interface region based on the damage criterion set for the Z-pin-rich resin interface region. The predicted damage results of the Z-pin-rich resin interface region are as Figure 3 shown.

[0083] In practical applications, establish a local debonding model of the Z-pin, apply the residual stress predicted in the previous step as a loading condition on the model, determine the damaged area of the Z-pin-rich resin interface region by setting a damage criterion for the Z-pin-rich resin interface region, and calculate the damage factor of the Z-pin-rich resin interface region.

[0084] The Z-pin-rich resin interface region divides the accumulated residual stress into three parts through the cohesive force model. The cohesive force model is:

[0085]

[0086] In the formula, σ n , σ s , σ t are the component forces of the residual stress in the Z-pin-rich resin interface region along the vertical direction n and two tangent directions s and t respectively, K 0 nn , K 0 ss , K 0 tt are the initial stiffnesses of the Z-pin-rich resin interface region along the three directions of n, s, and t respectively, and ε n , ε s , ε t are the deformations of the Z-pin-rich resin interface region along the three directions of n, s, and t respectively.

[0087] The damage criterion is the quadratic stress criterion, and its expression is:

[0088]

[0089] In the formula, are the damage strengths of the Z-pin-rich resin interface region along the three directions of n, s, and t respectively.

[0090] The damage factor is represented by D, and its expression is:

[0091]

[0092] In the formula, A d is the damaged area of the Z-pin-rich resin interface region, A 0is the initial area of the measured Z-pin resin-rich interface region.

[0093] Step 104: Introduce the damage factor as an input parameter into the geometric model, apply a pull-out force to the Z-pin region, and calculate the Z-pin pull-out energy based on the set pull-out damage criterion for the Z-pin region. Specifically, it includes: introducing the damage factor as an input parameter into the geometric model and calculating the reduced stiffness of the Z-pin resin-rich interface region; applying a pull-out force to the Z-pin region under the condition of stiffness reduction of the Z-pin resin-rich interface region, and calculating the Z-pin pull-out energy based on the set pull-out damage criterion for the Z-pin region.

[0094] In practical applications, establish a Z-pin pull-out model, introduce the predicted damage factor of the Z-pin resin-rich interface region as an input parameter into the model, and equivalently characterize the influence of curing defects by reducing the stiffness of the Z-pin resin-rich interface region; then, in this case, apply pull-out forces P n 、P s 、P t in the n, s, and t directions to the Z-pin region, set the Z-pin pull-out damage criterion, perform Z-pin bridging performance calculations, output the Z-pin pull-out force-displacement curve graph, and calculate the Z-pin pull-out energy according to the curve graph. The predicted Z-pin pull-out force-displacement curve results are as Figure 4 shown.

[0095] The expression for the stiffness reduction of the Z-pin resin-rich interface region is:

[0096]

[0097] where K nn 、K ss 、K tt are the reduced stiffnesses of the Z-pin resin-rich interface region respectively.

[0098] The Z-pin pull-out damage criterion is the maximum stress criterion, and its expression is:

[0099]

[0100] where P n 、P s 、P t are the pull-out forces applied to the Z-pin region in the n, s, and t directions respectively, and P n 0 、P s 0 、P t 0They are the pull-out strengths of the Z-pin region in the n, s, and t directions respectively.

[0101] Furthermore, the expression for the Z-pin pull-out force is:

[0102]

[0103] The expression for the Z-pin pull-out energy is:

[0104]

[0105] In the formula, W pin is the Z-pin pull-out energy, h is the measured implantation depth of the Z-pin region, and P is the Z-pin pull-out force.

[0106] Step 105: Predict the Z-pin bridging performance based on the Z-pin pull-out energy.

[0107] When the Z-pin pull-out energy is higher, the bridging performance of the Z-pin is more excellent;

[0108] When the Z-pin pull-out energy is lower, the bridging performance of the Z-pin is poorer.

[0109] In the present invention, by carrying out co-curing calculations on Z-pin toughened resin matrix composites, the residual stress concentration and local debonding defects around the Z-pin are quantitatively predicted, so that the bridging performance of the Z-pin can be predicted more accurately. Compared with the experimental method, the method of the present invention not only details the important influence of the co-curing process on the Z-pin bridging performance, but also greatly shortens the R & D time and reduces the R & D cost. For example, in order to obtain the Z-pin bridging performance under various different materials, only by changing the material property parameters during the calculation process, the corresponding Z-pin bridging performance can be obtained quickly and accurately.

[0110] Embodiment 2

[0111] In order to execute the method corresponding to the above Embodiment 1 to achieve the corresponding functions and technical effects, the following provides a Z-pin bridging performance prediction system considering initial curing defects, including:

[0112] A model construction and division module, which is used to establish a geometric model of Z-pin toughened resin matrix composites; and based on the differences in the component materials, the geometric model is sequentially divided into a laminate region, a Z-pin region, an eye-shaped resin-rich region, and a Z-pin-resin-rich interface region; the component materials include resin and fiber;

[0113] A residual stress calculation module, which is used to consider the thermo-chemical-mechanical coupling deformation of each component material in the geometric model and calculate the residual stress caused by the curing deformation mismatch of each component material;

[0114] A damage factor calculation module, configured to apply the residual stress as a load condition on the geometric model, and calculate the damage factor of the Z-pin-rich resin interface region based on the damage criterion set for the Z-pin-rich resin interface region;

[0115] A Z-pin pull-out energy calculation module, configured to introduce the damage factor as an input parameter into the geometric model, apply a pull-out force to the Z-pin region, and calculate the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region;

[0116] A Z-pin bridging performance prediction module, configured to predict the Z-pin bridging performance based on the Z-pin pull-out energy.

[0117] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the system disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method part.

[0118] Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present invention. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for predicting the bridging performance of Z-pin considering initial curing defects, characterized in that, it includes: Establish a geometric model of Z-pin toughened resin matrix composite; And based on the different component materials, the geometric model is sequentially divided into a laminate region, a Z-pin region, an eye-shaped resin-rich region, and a Z-pin-resin-rich interface region; the component materials include resin and fiber; Considering the thermo-chemical-mechanical coupled deformation of each component material in the geometric model, calculate the residual stress caused by the mismatch of curing deformation of each component material; Apply the residual stress as a load condition to the geometric model, and based on the damage criterion set for the Z-pin-resin-rich interface region, calculate the damage factor of the Z-pin-resin-rich interface region; Introduce the damage factor as an input parameter into the geometric model, apply a pull-out force to the Z-pin region, and calculate the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region; Predict the Z-pin bridging performance based on the Z-pin pull-out energy.

2. The method for predicting the bridging performance of Z-pin considering initial curing defects according to claim 1, characterized in that, Considering the thermo-chemical-mechanical coupled deformation of each component material in the geometric model, calculating the residual stress caused by the mismatch of curing deformation of each component material specifically includes: Calculate the elastic modulus, thermal expansion coefficient, and chemical shrinkage coefficient of the resin in the co-curing reaction; Calculate the elastic modulus, thermal expansion coefficient, and chemical shrinkage coefficient of the laminate region in the co-curing reaction; Calculate the chemical shrinkage deformation based on the resin chemical shrinkage coefficient and the laminate region chemical shrinkage coefficient; Calculate the thermal expansion deformation based on the resin thermal expansion coefficient and the laminate region thermal expansion coefficient; Calculate the mechanical deformation based on the total deformation, the chemical shrinkage deformation, and the thermal expansion deformation; Calculate the residual stress of each component material based on the resin elastic modulus, the laminate region elastic modulus, and the mechanical deformation.

3. The method for predicting the bridging performance of Z-pin considering initial curing defects according to claim 1, characterized in that, Applying the residual stress as a load condition to the geometric model, and based on the damage criterion set for the Z-pin-resin-rich interface region, calculating the damage factor of the Z-pin-resin-rich interface region specifically includes: Apply the residual stress as a load condition to the geometric model, and based on the damage criterion set for the Z-pin-resin-rich interface region, determine the damaged area of the Z-pin-resin-rich interface region; Calculate the damage factor of the Z-pin-resin-rich interface region based on the damaged area.

4. The method for predicting the bridging performance of Z-pin considering initial curing defects according to claim 3, characterized in that, The expression of the damage criterion is as follows: Among them, σ n , σ s , σ t are the residual stress components of the Z-pin-rich resin interface region along the vertical direction n and two tangent directions s and t, respectively. are the damage strengths of the Z-pin-rich resin interface region along the three directions of n, s, and t, respectively.

5. The method for predicting the bridging performance of Z-pin considering initial curing defects according to claim 1, characterized in that, Introduce the damage factor as an input parameter into the geometric model, apply a pulling-out force to the Z-pin region, and calculate the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region, specifically including: Introduce the damage factor as an input parameter into the geometric model and calculate the reduced stiffness of the Z-pin-rich resin interface region; Under the condition of stiffness reduction in the Z-pin-rich resin interface region, apply a pulling-out force to the Z-pin region and calculate the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region.

6. The method for predicting Z-pin bridging performance considering initial curing defects according to claim 5, characterized in that the expression of the pull-out damage criterion is as follows: Among them, P n , P s , P t are the pull-out forces applied in the vertical direction n and two tangential directions s and t in the Z-pin region respectively. P s 0 , P t 0 are the pull-out strengths in the Z-pin region in the three directions of n, s, and t respectively.

7. The method for predicting Z-pin bridging performance considering initial curing defects according to claim 6, characterized in that the calculation formula of the Z-pin pull-out energy is as follows: Among them, W pin is the Z-pin pull-out energy, h is the implantation depth of the Z-pin region, and P is the Z-pin pull-out force.

8. The method for predicting Z-pin bridging performance considering initial curing defects according to claim 1, characterized in that predict the Z-pin bridging performance based on the Z-pin pull-out energy, specifically including: the higher the Z-pin pull-out energy, the better the Z-pin bridging performance; the lower the Z-pin pull-out energy, the worse the Z-pin bridging performance.

9. A system for predicting Z-pin bridging performance considering initial curing defects, characterized in that it includes: A model construction and division module for establishing a geometric model of Z-pin toughened resin matrix composite; And successively divide the geometric model into a laminate region, a Z-pin region, an eye-shaped resin-rich region, and a Z-pin-rich resin interface region based on the differences in component materials; the component materials include resin and fiber; A residual stress calculation module for considering the thermo-chemical-mechanical coupling deformation of each component material in the geometric model and calculating the residual stress caused by the curing deformation mismatch of each component material; A damage factor calculation module for applying the residual stress as a load condition to the geometric model and calculating the damage factor of the Z-pin-rich resin interface region based on the damage criterion set for the Z-pin-rich resin interface region; A Z-pin pull-out energy calculation module for introducing the damage factor as an input parameter into the geometric model, applying a pulling-out force to the Z-pin region, and calculating the Z-pin pull-out energy based on the pull-out damage criterion set for the Z-pin region; A Z-pin bridging performance prediction module for predicting the Z-pin bridging performance based on the Z-pin pull-out energy.

Images