A method for residual stress regulation of carbon fiber composite laminates in multi-field and multi-parameter coupling

Abstract

The application provides a residual stress regulation method for a carbon fiber composite laminated plate in a multi-field and multi-parameter coupling mode, which is suitable for carbon fiber composite materials and products with anisotropy and thin-wall characteristics after forming. The method includes seven single-multi condition coupling forms of high-low temperature fields and load fields, and the multi-parameters of the load field include a vibration frequency f, an exciting force F and a clamping point position P on a platform. The multi-parameters of the temperature field include any node from a cryogenic temperature Tc (-196 DEG C) to a high temperature Th (220 DEG C), a temperature rising rate hr and a temperature falling rate cr. The vibration process parameters can be inserted into the time axis of the global high-low temperature, and the mechanism of the complex regulation process coupling to the material and the product is realized. Through the method, the full-field residual stress of the carbon fiber composite material can be regulated and controlled, and the deformation of the product can be controlled, so that the comprehensive performance and the service life of the product are improved.

Description

Technical Field

[0001] This invention relates to the field of residual stress control technology for carbon fiber composite laminates, and in particular to a method for controlling residual stress in laminates using multi-field and multi-parameter coupling. Background Technology

[0002] Carbon fiber composites are widely used in advanced manufacturing fields such as aerospace, electronics, and automobiles. However, during their curing and molding process, due to the mismatch in thermal expansion coefficients between the fibers and the matrix, different angles of layup-lamination, and the material and mold, as well as the complex manufacturing process involving the coupling of multiple field parameters such as heating-heating-cooling + high pressure, the internal components of the composite material generate an uneven residual stress field in order to maintain their own equilibrium. The presence of these residual stresses greatly reduces the strength and precision of the composite material and may induce problems such as matrix microcracks, interface debonding, and overall deformation and warping, affecting the quality and service life of the composite material and its products.

[0003] Therefore, for carbon fiber composites and their laminates with determined optimal manufacturing processes and performance properties, the residual stress control methods commonly used for isotropic materials are applied to anisotropic carbon fiber composites. A multi-field parameter coupling approach, including cryogenic-thermal-vibration methods, is employed to control residual stress and homogenize the residual stress distribution between fibers and the matrix, and between layers. This allows for earlier and more proactive control of stress generation and propagation, enabling materials and products to possess both excellent mechanical properties and stability. This also lays the methodological foundation for the high-quality, high-precision, and high-efficiency application of composite materials and their products in the aerospace field. Summary of the Invention

[0004] The purpose of this invention is to address the problem of uneven residual stress distribution and deformation exceeding the requirements in carbon fiber composite materials between fibers and matrix layers. A multi-field, multi-parameter coupled residual stress control method for carbon fiber composite laminates is proposed.

[0005] To address the aforementioned technical problems, this invention provides a method for controlling residual stress in laminated plates through multi-field, multi-parameter coupling, comprising the following steps:

[0006] (1) First, carbon fiber laminates with different angle layup configurations are selected. The angle layup includes UDL [θ1 / …… / θ1]s or MDL [θ1 / θ2 / θ3…… / θ i ]s, where the fiber angle arrangement and the total number of layers can be set and modified according to actual needs;

[0007] (2) The initial residual stress RS and deformation d of the composite laminate specimens of fixed process batches shall be detected and analyzed. No less than 3 parallel tests shall be carried out under each condition, and the average value σ0 shall be taken as the control group of the basic data.

[0008] (3) Set up a multi-parameter load field, including whether the specimen is clamped c, the platform vibration frequency f, the exciter eccentricity angle θ, the excitation force F, and the clamping point P on the platform. Through such vibration parameters, the vibration aging process control research can be realized.

[0009] (4) Set up a multi-parameter temperature field, including the heating rate hr for high temperature, the aging temperature Th for high temperature, the cooling rate cr for cryogenic temperature, the aging temperature Tc for cryogenic temperature, and whether air cooling is required after the process is completed.

[0010] (5) Using the process parameters in (3) and (4) above, multi-field coupling mode control is carried out, including 7 process types such as vibration aging VSR-#1, high temperature aging TSR-#2, low temperature aging CSR-#3, cold and hot aging CTSR-#4, thermal vibration aging TVSR-#5, cold vibration aging CVSR-#6 and cold-heat-vibration coupling aging CTVSR-#7;

[0011] (6) Detect the internal residual stress distribution and deformation of the specimen after adjusting multiple process parameters, record the data for each parameter, and record them as σ according to the process type. #1 -σ #7 ;

[0012] (7) Analyze the effect after regulation and compare it with the initial (before regulation) data. Analyze the efficiency η after regulation by using the method of setting fixed parameters and comparing different process forms;

[0013]

[0014] In the formula, η is the elimination rate of the regulation. The residual stress is due to different process configurations. This represents the magnitude of the initial residual stress.

[0015] (8) Through the detection and analysis of the above (1) to (7) steps, the residual stress control process of carbon fiber laminates with different configurations can be satisfied.

[0016] The beneficial effects of this invention are as follows: the invention enables comprehensive, multi-parameter residual stress control research after the fabrication of carbon fiber composite laminates with different thicknesses and angles. The method can complete material pre-testing, control, and analysis with high quality and efficiency, overcoming the shortcomings of cumbersome processes and uncertain parameters. It not only provides methodological support for designers but also shortens the manufacturing cycle and reduces costs. Attached Figure Description

[0017] Figure 1 This is a technical flowchart of a multi-field, multi-parameter coupled residual stress control method for carbon fiber composite laminates.

[0018] Figure 2 Methods for selecting vibration platform locations and setting exciter eccentricity angle;

[0019] Figure 3 The frequency and acceleration distributions at various points and eccentric angles;

[0020] Figure 4 Methods for setting parameters for high and low temperature field loads;

[0021] Figure 5 This represents the result of the gradient residual stress distribution along the depth of the composite material. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings and examples. However, the scope of protection of the present invention is not limited to the specific implementation methods. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the implementation cases.

[0023] like Figure 1 The diagram shown is a technical flowchart of a multi-field, multi-parameter coupled residual stress control method for carbon fiber composite laminates; it specifically includes the following steps:

[0024] Step (1): First, select carbon fiber laminates with different angle layup configurations. The angle layup includes UDL [θ1 / …… / θ1]s or MDL [θ1 / θ2 / θ3…… / θ i ]s, where the fiber angle arrangement and the total number of layers can be set and modified according to actual needs;

[0025] Step (2): Using the composite laminate selected in step (1), the blank material of the fixed curing process batch is processed into specimens of the same size, and the initial residual stress RS and deformation d are detected and analyzed. No less than 3 sets of parallel tests should be carried out under each condition, and the average value σ0 is taken as the control group of the basic data.

[0026] Step (3): Further, such as Figure 2 As shown, a multi-parameter load field is set. This includes parameters such as whether the specimen is clamped (c), the change in platform vibration frequency (f) caused by the rotational speed, the exciter eccentricity angle θ = 5° / 10° / 20° / 30°..., the change in induced excitation force F, and the clamping point P on the platform (left side 123, middle 456, right side 789). Through the coupling effect of these vibration parameters, the vibration aging process control research can be realized.

[0027] Intuitive, such as Figure 3 The figure shows the characteristic curves and corresponding resonance peaks of the clamping point P, eccentricity angle θ, frequency f, and acceleration a obtained in step (3) above. However, it is not limited to... Figure 3 Several forms in [the text].

[0028] Step (4): As Figure 4 As shown, a multi-parameter temperature field is set, including the high-temperature heating rate hr, the high-temperature aging temperature Th, the cryogenic cooling rate cr, the cryogenic aging temperature Tc, and whether air cooling is performed after the process is completed ac. The combination forms include full-process thermal aging, full-process cryogenic aging, thermal cycling aging, and vibration aging parameters inserted at nodes during any intermediate heat preservation time period.

[0029] Step (5): Using the process parameters in (3) and (4) above, multi-field coupling mode control is performed, including 7 process types: vibration aging VSR-#1, high temperature aging TSR-#2, low temperature aging CSR-#3, cold and hot aging CTSR-#4, thermal vibration aging TVSR-#5, cold vibration aging CVSR-#6, and cold-heat-vibration coupling aging CTVSR-#7;

[0030] Step (6): Detect the internal residual stress distribution and deformation of the specimen after adjusting multiple process parameters, record the data for each parameter, and record them as σ according to the process type. #1 -σ #7 The residual stress obtained from the sampling in its three directions is shown in Figure (5).

[0031] Step (7): Analyze the effect after adjustment and compare it with the initial data. Analyze the efficiency η after adjustment by using the method of setting fixed parameters and comparing different process forms;

[0032]

[0033] In the formula, η is the elimination rate of the regulation. The residual stress is due to different process configurations. This represents the magnitude of the initial residual stress.

[0034] Step (8): Through the detection and analysis of the above steps (1) to (7), the residual stress control process of carbon fiber laminates with different configurations can be satisfied.

[0035] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that some local modifications or changes can still be made without departing from the principles and basic characteristics of the invention; all of these fall within the scope of protection of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is determined by the appended claims. Parts not covered in this invention are the same as or can be implemented using existing technology.

Claims

1. A method for controlling residual stress in carbon fiber composite laminates through multi-field and multi-parameter coupling, characterized in that, Includes the following steps: (1) First, select carbon fiber laminates with different angles. The angles include UDL [θ1 / …… / θ1]s or MDL [θ1 / θ2 / θ3…… / θi]s. The arrangement of fiber angles and the total number of layers can be set and modified according to actual needs. (2) The initial residual stress RS and deformation d of the composite laminate specimens of fixed process batches shall be detected and analyzed. No less than 3 parallel tests shall be carried out under each condition, and the average value σ0 shall be taken as the control group of the basic data. (3) Set up a multi-parameter load field, including whether the specimen is clamped c, the platform vibration frequency f, the exciter eccentricity angle θ, the excitation force F, and the clamping position P on the platform. Through such vibration parameters, the vibration aging process control research can be realized. (4) Set up a multi-parameter temperature field, including the heating rate hr for high temperature, the aging temperature Th for high temperature, the cooling rate cr for cryogenic temperature, the aging temperature Tc for cryogenic temperature, and whether air cooling is required after the process is completed. (5) Using the process parameters in (3) and (4) above, multi-field coupling mode control is carried out, including 7 process types such as vibration aging VSR-#1, high temperature aging TSR-#2, low temperature aging CSR-#3, cold and hot aging CTSR-#4, thermal vibration aging TVSR-#5, cold vibration aging CVSR-#6 and cold-heat-vibration coupling aging CTVSR-#7; (6) Detect the internal residual stress distribution and deformation of the specimen after the adjustment of multiple process parameters, and make records for each parameter, and record them as σ#1-σ#7 according to the process type; (7) Analyze the effect after adjustment and compare it with the initial data. Analyze the efficiency η after adjustment by using the method of setting fixed parameters and comparing different process forms: In the formula, η is the controlled elimination rate, σi is the residual stress of different process configurations, and σ0 is the initial residual stress; (8) Through the detection and analysis of the above (1) to (7) steps, the residual stress control process of carbon fiber laminates with different configurations can be satisfied.

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