A method and system for testing the resin wettability of carbon fiber prepreg

Abstract

This invention relates to the field of resin wettability testing technology, specifically to a method and system for testing the resin wettability of carbon fiber prepreg. The method acquires temperature data of the carbon fiber material and resin matrix during the curing and impregnation process; based on the intrinsic viscosity corresponding to the temperature data, it acquires the resin wettability rate, the efficient wettability time period, and the inefficient wettability time period; based on the difference between the actual and theoretical wettability length of the carbon fiber material at each moment in the inefficient wettability time period, it acquires a speed adjustment coefficient at each moment in the inefficient wettability time period; based on the resin wettability rate and the speed adjustment coefficient, it acquires the overall wettability length of the carbon fiber material, and thus obtains the resin wettability of the carbon fiber prepreg. This invention accurately corrects the resin wettability rate in the inefficient wettability time period by acquiring the speed adjustment coefficient, thereby accurately acquiring the resin wettability of the carbon fiber prepreg and effectively improving the accuracy of carbon fiber prepreg resin wettability testing.

Description

Technical Field

[0001] This invention relates to the field of resin wettability testing technology, specifically to a method and system for testing the resin wettability of carbon fiber prepreg. Background Technology

[0002] Carbon fiber prepreg is an intermediate material composed of carbon fiber reinforcement and a resin matrix, widely used in high-strength, lightweight applications such as aerospace, automotive, and sporting goods. As a key intermediate product in composite materials, the resin wettability of carbon fiber prepreg directly affects the mechanical properties of the final composite material. Therefore, accurate testing of the resin wettability of carbon fiber prepreg is necessary to optimize the overall performance of the composite material.

[0003] Existing methods for testing the resin wettability of carbon fiber prepregs, such as the water absorption method and capillary rise method, involve first removing the carbon fiber prepreg sample and then testing it under specific experimental conditions to obtain the resin wettability. However, in reality, the experimental testing environment differs from the environment in which the carbon fiber prepregs are produced. Different environments can affect the resin wettability measurement, making it impossible to accurately detect the resin wettability of carbon fiber prepregs using existing methods, which is detrimental to the accurate assessment of the carbon fiber prepreg's performance. Summary of the Invention

[0004] To address the technical problem that existing methods cannot accurately detect the resin wettability of carbon fiber prepregs, the present invention aims to provide a method and system for testing the resin wettability of carbon fiber prepregs. The specific technical solution adopted is as follows:

[0005] In a first aspect, one embodiment of the present invention provides a method for testing the resin wettability of carbon fiber prepreg, the method comprising the following steps:

[0006] Temperature data of carbon fiber material and resin matrix at each moment during the curing and impregnation process were obtained; the intrinsic viscosity of the resin matrix at different temperatures was tested using an Ubbelohde viscometer.

[0007] Based on the characteristic viscosity corresponding to the temperature data at each time point, the resin wetting rate at each time point is obtained;

[0008] Based on the characteristic viscosity corresponding to the temperature data at each moment, the efficient wetting time period and the inefficient wetting time period are obtained; based on the difference between the actual wetting length and the theoretical wetting length of the carbon fiber material at each moment in the inefficient wetting time period, the speed adjustment coefficient at each moment in the inefficient wetting time period is obtained; based on the resin wetting speed at each moment in the efficient wetting time period, the resin wetting speed at each moment in the inefficient wetting time period, and the speed adjustment coefficient, the overall wetting length of the carbon fiber material is obtained.

[0009] The resin impregnation degree of carbon fiber prepreg is obtained based on the overall impregnation length.

[0010] Furthermore, the method for obtaining the resin wetting rate is as follows:

[0011] The permeability of carbon fiber material at different temperatures was obtained through permeability testing. Based on the intrinsic viscosity and permeability of carbon fiber material corresponding to the temperature data at each time point, the resin wetting rate at each time point was obtained through the Darcy flow equation.

[0012] Furthermore, the method for obtaining the efficient infiltration time period and the inefficient infiltration time period is as follows:

[0013] The temperature data are arranged and fitted into a production temperature curve according to the acquisition time sequence. Based on the characteristic viscosity corresponding to the temperature data on the production temperature curve, the time period from the lowest melt viscosity to gelation of the resin matrix is ​​obtained as the efficient wetting time period.

[0014] The time period corresponding to the production temperature curve after removing the efficient wetting time period is taken as the inefficient wetting time period.

[0015] Furthermore, the method for obtaining the actual immersion length is as follows:

[0016] The resin impregnation length of the carbon fiber material at each time point was obtained using an electron microscope and used as the reference impregnation length of the carbon fiber material at each time point.

[0017] For any moment within the inefficient wetting period, the difference between that moment and the reference wetting length of the carbon fiber material at the previous adjacent moment is taken as the actual wetting length of the carbon fiber material at that moment.

[0018] Furthermore, the method for obtaining the theoretical wetting length is as follows:

[0019] The definite integral of the resin impregnation velocity from the initial moment to each moment is used as the target impregnation length of the carbon fiber material at each moment;

[0020] For any moment in the inefficient wetting period, the difference between that moment and the target wetting length of the carbon fiber material at the previous adjacent moment is taken as the theoretical wetting length of the carbon fiber material at that moment.

[0021] Furthermore, the method for obtaining the speed adjustment coefficient is as follows:

[0022] For any moment within the inefficient wetting period, the ratio of the actual wetting length to the ideal wetting length of the carbon fiber material at that moment is used as the speed adjustment coefficient at that moment.

[0023] Furthermore, the method for obtaining the overall immersion length is as follows:

[0024] The product of the resin wetting rate at each moment in the efficient wetting time period and the time interval between two adjacent moments is taken as the first local wetting length.

[0025] The sum of all the first local infiltration lengths is taken as the first infiltration length of the efficient infiltration time period;

[0026] The product of the resin wetting rate and the rate adjustment coefficient at each moment in the inefficient wetting period is used as the corrected resin wetting rate at each moment in the inefficient wetting period.

[0027] For any consecutive period of inefficient wetting, the definite integral of the modified resin wetting rate during that period of inefficient wetting is taken as the second local wetting length of that period of inefficient wetting.

[0028] The sum of the second local infiltration lengths of all inefficient infiltration time periods is taken as the second infiltration length of the inefficient infiltration time period.

[0029] The sum of the first impregnation length and the second impregnation length is taken as the overall impregnation length of the carbon fiber material.

[0030] Furthermore, the method for obtaining the resin wettability of carbon fiber prepreg based on the overall impregnation length is as follows:

[0031] Obtain the overall length of the carbon fiber material as the first length;

[0032] The ratio of the overall impregnation length to the first length is used as the resin impregnation degree of the carbon fiber prepreg.

[0033] Furthermore, the method for obtaining the intrinsic viscosity is as follows:

[0034] For any given temperature, the temperature in the Ubbelohde viscometer is kept constant, and the concentration of the resin matrix in the Ubbelohde viscometer is continuously diluted to obtain the specific viscosity at different concentrations of the resin matrix at that temperature.

[0035] The intrinsic viscosity of the resin matrix at this temperature was calculated using the Mark-Houwink equation.

[0036] Secondly, another embodiment of the present invention provides a carbon fiber prepreg resin wettability testing system, the system comprising: a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, it implements the steps of any of the above methods.

[0037] The present invention has the following beneficial effects:

[0038] This invention first obtains the resin wetting rate at each moment based on the intrinsic viscosity corresponding to the temperature data, which is beneficial for subsequent analysis of the wetting length of carbon fiber materials. Furthermore, based on the intrinsic viscosity corresponding to the temperature data at each moment, it obtains efficient and inefficient wetting time periods, enabling more accurate analysis of the wetting length of carbon fiber materials under different conditions, and thus more accurate detection of the resin wetting degree of carbon fiber prepregs. Then, based on the difference between the actual and theoretical wetting length of the carbon fiber material at each moment in the inefficient wetting time period, it obtains the speed adjustment coefficient at each moment in the inefficient wetting time period, accurately reflecting the true degree of resin wetting rate at each moment in the inefficient wetting time period, which is beneficial for… This invention allows for accurate analysis of the impregnation length of carbon fiber materials corresponding to inefficient impregnation periods. Furthermore, based on the resin impregnation rate at each moment during efficient impregnation periods, the resin impregnation rate at each moment during inefficient impregnation periods, and the rate adjustment coefficient, the overall impregnation length of the carbon fiber material is accurately obtained. This overall impregnation length is then used to accurately determine the resin wetting degree of the carbon fiber prepreg. This invention directly detects the resin wetting degree of the carbon fiber prepreg during the production process, avoiding the inaccurate detection of the resin wetting degree in existing methods that occur in specific experimental environments outside the production line. This effectively improves the accuracy of the resin wetting degree detection and facilitates a more accurate assessment of the performance of the carbon fiber prepreg. Attached Figure Description

[0039] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic flowchart of a method for testing the resin wettability of carbon fiber prepreg according to an embodiment of the present invention.

[0041] Figure 2 Schematic diagram of an Ubbelohde viscometer;

[0042] Figure 3 A flowchart illustrating a method for obtaining a speed adjustment coefficient according to an embodiment of the present invention;

[0043] Figure 4 This is a structural diagram of a carbon fiber prepreg resin wettability testing system provided in one embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of a computer device provided according to an embodiment of the present invention. Detailed Implementation

[0045] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a carbon fiber prepreg resin wettability testing method and system proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0047] The following description, in conjunction with the accompanying drawings, details the specific scheme of the resin wetting test method and system for carbon fiber prepreg provided by this invention.

[0048] Example 1:

[0049] This invention proposes a method for testing the resin wettability of carbon fiber prepregs. Please refer to [link / reference]. Figure 1 The diagram illustrates a schematic flowchart of a method for testing the resin wettability of carbon fiber prepreg according to an embodiment of the present invention. The method includes the following steps:

[0050] Step S1: Obtain temperature data of carbon fiber material and resin matrix at each moment during the curing and impregnation process; test the intrinsic viscosity of resin matrix at different temperatures using an Ubbelohde viscometer.

[0051] Specifically, the production process of carbon fiber prepreg involves first mixing resin with other reagents to prepare a resin matrix. Then, under specific temperature and pressure, the resin matrix and corresponding carbon fiber material are impregnated using a hot-melt impregnation method. The resulting material is the carbon fiber prepreg. During the manufacturing process, parameters such as temperature and pressure affect the impregnation effect. Therefore, before formally producing carbon fiber prepreg, this embodiment conducts multiple trial productions and adjusts the parameters in each trial production. The resin wetting degree of each trial production is then analyzed to determine the optimal production parameters. For ease of explanation, this embodiment uses a carbon fiber prepreg produced in one trial production as an example. It should be noted that subsequent descriptions refer to the carbon fiber prepreg produced in that trial production, and the analysis process for the resin wetting degree of each trial production is the same.

[0052] The process of obtaining carbon fiber prepreg is as follows: First, prepare unsized carbon fiber material without grooves on the surface, epoxy resin, curing agent, accelerator, and catalyst; then, mix the epoxy resin and curing agent in a specified ratio to form a resin matrix, and use a flat vulcanizing machine to form a resin film from the prepared resin matrix; place the carbon fiber material between two layers of resin film (through two rollers, referred to as preheating rollers), so that it is in full contact and preheated, and then send it into an autoclave. In the autoclave, the resin film and carbon fiber material are impregnated by the resin matrix under high temperature and high pressure; finally, use cooling rollers to cool the resin-impregnated carbon fiber material to room temperature to obtain the carbon fiber material.

[0053] To analyze the resin impregnation of the carbon fiber prepreg, this embodiment places an infrared thermal imager between the preheating roller, the autoclave, and the cooling roller. A fluorescent fiber optic sensor is embedded between the carbon fiber material and the resin film to acquire temperature data of the carbon fiber material and the resin matrix at each moment during the curing and impregnation process. The fluorescent fiber optic sensor is positioned in the middle of the carbon fiber material. This embodiment sets the time interval between adjacent temperature data acquisition moments to 2 seconds. The implementer can adjust the time interval according to actual conditions; it is not limited here. It should be noted that this embodiment sets the impregnation speed of the carbon fiber material and the resin film to 1 meter per minute. The implementer can adjust the impregnation speed according to actual conditions; it is not limited here.

[0054] In practice, the viscosity of the resin matrix varies at different temperatures, and different viscosities reflect different degrees of flowability of the resin matrix. The higher the viscosity, the worse the flowability of the resin matrix. In order to accurately analyze the resin wetting situation, this embodiment uses an Ubbelohde viscometer to test the intrinsic viscosity of the resin matrix at different temperatures.

[0055] The method for obtaining intrinsic viscosity is as follows: For any given temperature, a portion of the previously prepared resin matrix is ​​placed in a constant-temperature water bath at that temperature, while methyl ethyl ketone solvent is also placed in another constant-temperature water bath at the same temperature; for example... Figure 2 The diagram shows a schematic of an Ubbelohde viscometer. 10 ml of methyl ethyl ketone solvent is taken from the constant-temperature water bath using a pipette and injected into the Ubbelohde viscometer through the inlet tube. After maintaining the temperature for 15 minutes, a suction bulb is used to draw the methyl ethyl ketone solvent from the measuring tube, allowing it to rise to the upper optical level mark and then fall back down. This process is repeated multiple times; in this embodiment, it is set to 5 times. The implementer can adjust the number of repetitions according to actual conditions, which is not limited here. The average time taken for the methyl ethyl ketone solvent to rise from the upper optical level mark each time is obtained as the methyl ethyl ketone solvent outflow time. The implementer can set the content of methyl ethyl ketone solvent drawn by the pipette and the isothermal holding time according to the actual situation; no limitation is made here. It should be noted that the vent tube is closed when drawing the methyl ethyl ketone solvent with a bulb syringe. Next, 10 ml of resin matrix is ​​taken from the isothermal water bath using a pipette and injected into the Ubbelohde viscometer through the inlet tube. At this point, 10 ml of resin matrix is ​​added to the original 10 ml of methyl ethyl ketone solvent to dilute the resin matrix concentration. Then, the solution is mixed thoroughly and the vent tube is closed. The solution in the Ubbelohde viscometer is then drawn from the measuring tube using a bulb syringe, and the outflow time of the methyl ethyl ketone solvent is recorded. Methods for obtaining resin outflow time It should be noted that the solution in the Ubbelohde viscometer is always kept at a constant temperature.

[0056] Then based on relative viscosity Empirical formula: Calculate the relative viscosity of the resin matrix at this temperature; further, based on the specific viscosity... Empirical formula: The specific viscosity of the resin matrix at this temperature was calculated. Similarly, the relative viscosity and specific viscosity of the resin matrix at different concentrations at this temperature were measured. Finally, based on the definition of intrinsic viscosity (specific viscosity under infinite dilution of solution concentration), the intrinsic viscosity of the resin matrix at this temperature was calculated using the Mark-Houwink equation. : In the formula, This represents the specific viscosity of the resin matrix at the corresponding concentration at that temperature; C is the concentration of the resin matrix. The entire process for obtaining the intrinsic viscosity described above is a well-known technique and will not be elaborated further.

[0057] Thus, the intrinsic viscosity of the resin matrix at different temperatures was obtained.

[0058] Step S2: Obtain the resin wetting rate at each time step based on the characteristic viscosity corresponding to the temperature data at each time step.

[0059] Specifically, given that carbon fiber materials are produced in bundles, the flow of the resin matrix within them can be approximated as a fluid flow process within a porous medium. Therefore, the resin wetting velocity can be obtained using the Darcy flow equation. Based on the content published by authors Liu Xiao et al. in the journal "Research Progress in Permeability Measurement Technology of Fiber Preforms," ​​the resin wetting velocity at each instant can be obtained using the Darcy flow equation, based on the intrinsic viscosity corresponding to the temperature data at each instant. The formula for obtaining the resin wetting velocity using the Darcy flow equation is as follows: In the formula, Indicates the resin wetting rate; This indicates the permeability of carbon fiber materials, which varies depending on the arrangement of fiber bundles and porosity. This indicates the dynamic viscosity of the resin, which is the intrinsic viscosity of the resin matrix at the corresponding temperature. This represents the pressure gradient of the carbon fiber material.

[0060] The method for obtaining the permeability of carbon fiber materials is described in the aforementioned "Research Progress on Permeability Measurement Technology of Fiber Preforms". This embodiment uses a saturated permeability test as an example to determine the permeability of carbon fiber materials at different temperatures, and is not limited to this method. First, the relationship between the flow velocity and pressure gradient of the resin matrix along the fiber bundle axis is measured through a saturated permeability test. When the sample is fully saturated and all air is displaced from the flow channel, and when the monitored fluid pressure and volumetric flow rate are stable, the corresponding temperature can be calculated. Lower carbon fiber material permeability ;in, In the formula, This represents the flow rate per unit volume. Indicates the temperature of the resin matrix The intrinsic viscosity at the following levels; This represents the cross-sectional area of ​​the carbon fiber bundle in the carbon fiber material; This indicates the pressure difference between the resin matrix at both ends of the carbon fiber material; Indicates the thickness of carbon fiber material; where Q, S, Both h and are obtained directly. Temperature is calculated. Pressure gradient below : In the formula, Indicates vacuum pressure; Indicates external pressure; This represents the total length of the flow path, which is the total length of the carbon fiber material.

[0061] At this point, combined with temperature Pressure gradient below carbon fiber material penetration rate and intrinsic viscosity ,pass To obtain temperature The resin wetting rate below Given the temperature data of the carbon fiber material and resin matrix at each moment during the curing and impregnation process, the resin impregnation rate at each moment can be obtained.

[0062] It should be noted that the above content is all recorded in "Research Progress on Permeability Measurement Technology of Fiber Preforms" and is all well-known technology, so it will not be repeated here.

[0063] Step S3: Based on the intrinsic viscosity corresponding to the temperature data at each moment, obtain the efficient wetting time period and the inefficient wetting time period; based on the difference between the actual wetting length and the theoretical wetting length of the carbon fiber material at each moment in the inefficient wetting time period, obtain the speed adjustment coefficient at each moment in the inefficient wetting time period; based on the resin wetting speed at each moment in the efficient wetting time period, the resin wetting speed at each moment in the inefficient wetting time period, and the speed adjustment coefficient, obtain the overall wetting length of the carbon fiber material.

[0064] Specifically, during the curing and impregnation process of carbon fiber material and resin matrix, as the temperature begins to rise, the resin matrix gradually impregnates the carbon fiber material. The impregnation effect of the resin matrix on the carbon fiber material improves with increasing temperature. To ensure the impregnation effect, the temperature is maintained stable for a certain period. To prevent over-curing, the temperature needs to be gradually lowered. Throughout this process, the carbon fiber material remains within the resin matrix. Therefore, it is assumed that the impregnation of the carbon fiber material by the resin matrix is ​​always present, but it is divided into efficient and inefficient impregnation processes. It is known that the quality of impregnation is closely related to the intrinsic viscosity. Therefore, this embodiment first obtains the efficient and inefficient impregnation time periods based on the intrinsic viscosity corresponding to the temperature data at each moment.

[0065] It is known that the resin wetting rate is relatively stable during the efficient wetting period. Therefore, in this embodiment, the wetting length of the corresponding carbon fiber material during the efficient wetting period can be directly obtained based on the resin wetting rate and duration. However, the viscosity of the resin matrix is ​​unstable during the inefficient wetting period, which in turn leads to an unstable resin wetting rate. Theoretically, the wetting length of the corresponding carbon fiber material during the inefficient wetting period can be obtained by obtaining the definite integral of the resin wetting rate during consecutive inefficient wetting periods. However, in practice, due to the high resin viscosity at low temperatures and the potential for cross-linking reactions and degradation at high temperatures, which can cause a sudden increase in viscosity, the actual resin wetting rate may not reach the theoretical resin wetting rate, resulting in inaccurate analysis of the wetting length of the corresponding carbon fiber material during the inefficient wetting period. Therefore, this embodiment obtains the speed adjustment coefficient at each moment of the inefficient wetting period based on the difference between the actual and theoretical wetting length of the carbon fiber material at each moment within the inefficient wetting period. The resin wetting speed is then corrected using this speed adjustment coefficient, thereby accurately obtaining the corresponding wetting length of the carbon fiber material within the inefficient wetting period. Furthermore, this embodiment obtains the overall wetting length of the carbon fiber material based on the resin wetting speed at each moment of the efficient wetting period, the resin wetting speed at each moment of the inefficient wetting period, and the speed adjustment coefficient.

[0066] Preferably, in one feasible embodiment, the method for obtaining the efficient wetting time period and the inefficient wetting time period is as follows: Temperature data are arranged and fitted into a production temperature curve according to the acquisition time sequence. Based on the intrinsic viscosity corresponding to the temperature data on the production temperature curve, the time period from the lowest melt viscosity to gelation of the resin matrix is ​​obtained as the efficient wetting time period. The method for obtaining the efficient wetting time period is a well-known technique and will not be described in detail here. The time period corresponding to the production temperature curve after removing the efficient wetting time period is obtained as the inefficient wetting time period.

[0067] Preferably, in one possible implementation of this embodiment, the method for obtaining the speed adjustment coefficient is described in [reference needed]. Figure 3 The document presents a flowchart of a method for obtaining a speed adjustment coefficient, as provided in this embodiment. The method includes the following steps:

[0068] Step S301: Obtain the actual immersion length.

[0069] It should be noted that the top of the autoclave in this embodiment is transparent. An electron microscope obtains the resin impregnation length of the carbon fiber material at each moment from the top of the autoclave, which serves as the reference impregnation length for that moment. The reference impregnation length is the total impregnation length from the start of resin impregnation of the carbon fiber material to the corresponding moment. Furthermore, for any moment within the inefficient impregnation period, the difference between that moment and the reference impregnation length of the carbon fiber material at its preceding adjacent moment is taken as the actual impregnation length of the carbon fiber material at that moment. It should be noted that if there is no preceding adjacent moment, that moment is not analyzed.

[0070] Thus, the actual impregnation length of the carbon fiber material at each moment during the inefficient impregnation period is obtained.

[0071] Step S302: Obtain the theoretical immersion length.

[0072] The definite integral of the resin impregnation rate from the initial moment to each subsequent moment is taken as the target impregnation length of the carbon fiber material at each moment. The target impregnation length is theoretically the total impregnation length from the start of impregnation in the resin matrix to the corresponding moment. Furthermore, for any moment within the inefficient impregnation period, the difference between the target impregnation length of the carbon fiber material at that moment and its preceding adjacent moment is taken as the theoretical impregnation length of the carbon fiber material at that moment. It should be noted that if there is no preceding adjacent moment, that moment is not analyzed.

[0073] Thus, the theoretical wetting length of the carbon fiber material at each moment during the inefficient wetting period is obtained.

[0074] Step S303: Obtain the speed adjustment coefficient.

[0075] For any point in the inefficient wetting period, the closer the actual wetting length of the carbon fiber material is to the ideal wetting length, the more accurate the resin wetting rate at that point. Therefore, in this embodiment, the ratio of the actual wetting length to the ideal wetting length of the carbon fiber material at that point is used as the speed adjustment coefficient. The larger the speed adjustment coefficient, the more accurate the resin wetting rate obtained in step S2 at that point.

[0076] Thus, the velocity adjustment coefficient at each moment during the inefficient immersion period is obtained.

[0077] Preferably, in one feasible way of this embodiment, the method for obtaining the overall impregnation length is as follows: the product of the resin impregnation speed at each moment in the efficient impregnation time period and the time interval between two adjacent moments is taken as the first local impregnation length; as can be seen from step S1, the time interval between two adjacent moments in this embodiment is 2 seconds. The sum of all the first local wetting lengths is taken as the first wetting length of the efficient wetting time period, which is the wetting length of the carbon fiber material corresponding to the efficient wetting time period. To accurately obtain the wetting length of the carbon fiber material corresponding to the inefficient wetting time period, the product of the resin wetting rate and the rate adjustment coefficient at each moment in the inefficient wetting time period is first taken as the corrected resin wetting rate at each moment in the inefficient wetting time period, so that the wetting length of the carbon fiber material can be obtained more accurately through the resin wetting rate. Considering that there may be multiple inefficient wetting time periods in actual practice, for any consecutive inefficient wetting time period, the definite integral of the corrected resin wetting rate of the inefficient wetting time period is taken as the second local wetting length of the inefficient wetting time period. To determine the wetting length of the carbon fiber material corresponding to the complete inefficient wetting time period, the sum of the second local wetting lengths of all inefficient wetting time periods is taken as the second wetting length of the inefficient wetting time period. Finally, the sum of the first wetting length and the second wetting length is taken as the overall wetting length of the carbon fiber material.

[0078] Step S4: Obtain the resin impregnation degree of the carbon fiber prepreg based on the overall impregnation length.

[0079] Specifically, to determine the resin wetting degree of carbon fiber prepreg and accurately assess its performance, the overall length of the carbon fiber material is obtained as the first length. The ratio of the overall wetting length to the first length is then used as the resin wetting degree of the carbon fiber prepreg. A higher resin wetting degree indicates more reasonable production parameters, which is beneficial for setting optimal production parameters for the carbon fiber prepreg.

[0080] In summary, this embodiment obtains temperature data of the carbon fiber material and resin matrix during the curing and impregnation process; based on the intrinsic viscosity corresponding to the temperature data, it obtains the resin wetting rate, the efficient wetting time period, and the inefficient wetting time period; based on the difference between the actual and theoretical wetting length of the carbon fiber material at each moment in the inefficient wetting time period, it obtains the speed adjustment coefficient at each moment in the inefficient wetting time period; based on the resin wetting rate and the speed adjustment coefficient, it obtains the overall wetting length of the carbon fiber material, and thus obtains the resin wetting degree of the carbon fiber prepreg. This invention accurately corrects the resin wetting rate in the inefficient wetting time period by obtaining the speed adjustment coefficient, thereby accurately obtaining the resin wetting degree of the carbon fiber prepreg and effectively improving the accuracy of carbon fiber prepreg resin wetting degree detection.

[0081] Example 2:

[0082] This invention also proposes a resin wetting test system for carbon fiber prepregs; please refer to [link / reference]. Figure 4 The diagram shows a structural diagram of a carbon fiber prepreg resin wetting test system according to an embodiment of the present invention. The system includes: a data acquisition module 10, a resin wetting speed acquisition module 20, an overall wetting length acquisition module 30, and a data processing module 40.

[0083] The data acquisition module 10 is used to acquire temperature data of carbon fiber material and resin matrix at each moment during the curing and impregnation process; and to test the intrinsic viscosity of resin matrix at different temperatures using an Ubbelohde viscometer.

[0084] The resin impregnation rate acquisition module 20 is used to acquire the resin impregnation rate at each time step based on the characteristic viscosity corresponding to the temperature data at each time step.

[0085] The overall impregnation length acquisition module 30 is used to obtain the efficient impregnation time period and the inefficient impregnation time period based on the characteristic viscosity corresponding to the temperature data at each moment; to obtain the speed adjustment coefficient at each moment in the inefficient impregnation time period based on the difference between the actual impregnation length and the theoretical impregnation length of the carbon fiber material at each moment in the inefficient impregnation time period; and to obtain the overall impregnation length of the carbon fiber material based on the resin impregnation speed at each moment in the efficient impregnation time period, the resin impregnation speed at each moment in the inefficient impregnation time period, and the speed adjustment coefficient.

[0086] Data processing module 40 is used to obtain the resin impregnation degree of carbon fiber prepreg based on the overall impregnation length.

[0087] It should be noted that the system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer device can be divided into different functional modules to complete all or part of the functions described above. In addition, the carbon fiber prepreg resin wetting test system and the carbon fiber prepreg resin wetting test method embodiment provided in the above embodiments belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.

[0088] Example 3:

[0089] This invention also proposes a carbon fiber prepreg resin wettability testing device, which includes a memory and a processor. The memory stores executable program code, and the processor calls and executes the executable program code to perform a carbon fiber prepreg resin wettability testing method provided in the embodiments of this application. Specifically, the device may be a chip, component, or module. The chip may include a connected processor and memory; the memory stores instructions, and when the processor calls and executes the instructions, the chip can perform the carbon fiber prepreg resin wettability testing method provided in the above embodiments.

[0090] Furthermore, this application also protects a computer device; please refer to [link to relevant documentation]. Figure 5 The computer device includes a memory 401, a processor 402, and a computer program 403 stored in the memory 401 and running on the processor 402. When the processor 402 executes the computer program 403, the computer device can perform any of the carbon fiber prepreg resin wetting test methods described above.

[0091] Example 4:

[0092] The present invention also provides a computer-readable storage medium storing computer program code, which, when executed on a computer, causes the computer to perform the aforementioned method steps to implement the carbon fiber prepreg resin wetting test method provided in the above embodiments.

[0093] Example 5:

[0094] The present invention also provides a computer program product, which, when run on a computer, causes the computer to perform the above-mentioned related steps to implement the carbon fiber prepreg resin wetting test method provided in the above embodiments.

[0095] In this embodiment, the device, computer-readable storage medium, computer program product, or chip are all used to execute the corresponding methods provided above. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0096] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0097] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for testing the resin wettability of carbon fiber prepreg, characterized in that, The method includes the following steps: Temperature data of carbon fiber material and resin matrix at each moment during the curing and impregnation process were obtained; the intrinsic viscosity of the resin matrix at different temperatures was tested using an Ubbelohde viscometer. Based on the characteristic viscosity corresponding to the temperature data at each time point, the resin wetting rate at each time point is obtained; Based on the characteristic viscosity corresponding to the temperature data at each moment, the efficient wetting time period and the inefficient wetting time period are obtained; based on the difference between the actual wetting length and the theoretical wetting length of the carbon fiber material at each moment in the inefficient wetting time period, the speed adjustment coefficient at each moment in the inefficient wetting time period is obtained; based on the resin wetting speed at each moment in the efficient wetting time period, the resin wetting speed at each moment in the inefficient wetting time period, and the speed adjustment coefficient, the overall wetting length of the carbon fiber material is obtained. The resin impregnation degree of carbon fiber prepreg is obtained based on the overall impregnation length.

2. The method for testing the resin wettability of carbon fiber prepreg as described in claim 1, characterized in that, The method for obtaining the resin wetting rate is as follows: The permeability of carbon fiber material at different temperatures was obtained through permeability testing. Based on the intrinsic viscosity and permeability of carbon fiber material corresponding to the temperature data at each time point, the resin wetting rate at each time point was obtained through the Darcy flow equation.

3. The method for testing the resin wettability of carbon fiber prepreg as described in claim 1, characterized in that, The method for obtaining the efficient infiltration time period and the inefficient infiltration time period is as follows: The temperature data are arranged and fitted into a production temperature curve according to the acquisition time sequence. Based on the characteristic viscosity corresponding to the temperature data on the production temperature curve, the time period from the lowest melt viscosity to gelation of the resin matrix is ​​obtained as the efficient wetting time period. The time period corresponding to the production temperature curve after removing the efficient wetting time period is taken as the inefficient wetting time period.

4. The method for testing the resin wettability of carbon fiber prepreg as described in claim 1, characterized in that, The method for obtaining the actual immersion length is as follows: The resin impregnation length of the carbon fiber material at each time point was obtained using an electron microscope and used as the reference impregnation length of the carbon fiber material at each time point. For any moment within the inefficient wetting period, the difference between that moment and the reference wetting length of the carbon fiber material at the previous adjacent moment is taken as the actual wetting length of the carbon fiber material at that moment.

5. The method for testing the resin wettability of carbon fiber prepreg as described in claim 1, characterized in that, The method for obtaining the theoretical immersion length is as follows: The definite integral of the resin impregnation velocity from the initial moment to each moment is used as the target impregnation length of the carbon fiber material at each moment. For any moment in the inefficient wetting period, the difference between that moment and the target wetting length of the carbon fiber material at the previous adjacent moment is taken as the theoretical wetting length of the carbon fiber material at that moment.

6. The method for testing the resin wettability of carbon fiber prepreg as described in claim 1, characterized in that, The method for obtaining the speed adjustment coefficient is as follows: For any point in the inefficient wetting period, the ratio of the actual wetting length to the ideal wetting length of the carbon fiber material at that point is used as the speed adjustment coefficient at that point.

7. The method for testing the resin wettability of carbon fiber prepreg as described in claim 1, characterized in that, The method for obtaining the overall immersion length is as follows: The product of the resin wetting rate at each moment in the efficient wetting time period and the time interval between two adjacent moments is taken as the first local wetting length. The sum of all the first local infiltration lengths is taken as the first infiltration length of the efficient infiltration time period; The product of the resin wetting rate and the rate adjustment coefficient at each moment in the inefficient wetting period is used as the corrected resin wetting rate at each moment in the inefficient wetting period. For any consecutive period of inefficient wetting, the definite integral of the modified resin wetting rate during that period of inefficient wetting is taken as the second local wetting length of that period of inefficient wetting. The sum of the second local infiltration lengths of all inefficient infiltration time periods is taken as the second infiltration length of the inefficient infiltration time period. The sum of the first impregnation length and the second impregnation length is taken as the overall impregnation length of the carbon fiber material.

8. The method for testing the resin wettability of carbon fiber prepreg as described in claim 1, characterized in that, The method for obtaining the resin wettability of carbon fiber prepreg based on the overall impregnation length is as follows: Obtain the overall length of the carbon fiber material as the first length; The ratio of the overall impregnation length to the first length is used as the resin impregnation degree of the carbon fiber prepreg.

9. The method for testing the resin wettability of carbon fiber prepreg as described in claim 1, characterized in that, The method for obtaining the intrinsic viscosity is as follows: For any given temperature, the temperature in the Ubbelohde viscometer is kept constant, and the concentration of the resin matrix in the Ubbelohde viscometer is continuously diluted to obtain the specific viscosity at different concentrations of the resin matrix at that temperature. The intrinsic viscosity of the resin matrix at this temperature was calculated using the Mark-Houwink equation.

10. A carbon fiber prepreg resin wettability testing system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the carbon fiber prepreg resin wettability test method according to any one of claims 1-9.

Images