Composite material T-shaped section ring frame and stringer deformation control method
By simplifying the cross-section of the composite T-shaped ring frame and correcting its thermal expansion coefficient, the closing problem caused by curing deformation of large-sized composite ring frames is solved, and precise deformation control is achieved, reducing development costs and cycles.
Patent Information
- Application Number
- CN202510215142.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2025-06-06
AI Technical Summary
In composite material structures, especially large-size composite ring frames, severe closing due to curing deformation problems, affecting the accuracy of product size and making it difficult to meet design and use requirements.
By assuming that the equivalent thermal expansion coefficients of the web and edge plate of the T-shaped cross-section ring frame are consistent, the cross-section of the ring frame is simplified, and by modifying the equivalent cross-section thickness of the R-angle filler, the equivalent thermal expansion coefficient is corrected to the consistent thermal expansion coefficient of the edge plate and web, thereby achieving accurate deformation control of the ring frame.
The precise deformation control without changing the original laying is achieved, which avoids the problem of overcorrecting the laying and greatly reduces the development cost and cycle of large-size composite T-shaped ring frames.
Smart Images
Figure CN120096119A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of manufacturing composite material T-shaped ring frames, and in particular relates to a composite material T-shaped cross-section ring frame and a stringer deformation control method. Background Art
[0002] Composite structures are widely used in the development of commercial space rocket body structures due to their low weight, high strength and high stiffness. As the size of the rocket body gradually increases, the impact of the curing deformation of the composite structure on the structure is gradually magnified, and avoiding the curing deformation of the composite structure has become a difficulty in the development of large composite structures. Due to the anisotropy of the composite material, structural asymmetry, resin curing shrinkage, uneven temperature field, uneven pressure field and mold factors during the curing process, the parts after curing are deformed, which not only affects the surface contour and dimensional accuracy of the parts, but also causes assembly gaps or interference, and in severe cases may cause the parts to be scrapped. In composite structures, the curing deformation problem of the ring frame is more serious. In order to meet the lightweight requirements of commercial aerospace, large-size and high-precision composite structures are gradually applied to large rocket cabins. As the size of the composite structure increases, the impact of curing deformation on the composite structure is gradually magnified, and the molding size control of parts such as composite stringers and ring frames has become a difficulty in the development of large composite cabin structures. In composite structures, the curing deformation problem of the ring frame is more serious. Large-sized composite ring frames will have serious closing due to the problem of curing deformation, resulting in product dimensions that cannot meet design requirements and usage requirements. In the prior art, numerical solution technology is generally used to solve the theoretical value, and the test database is used to correct it, and finally the parts are manufactured by trial mold. Dealing with the problem of curing deformation includes two problems: prediction and correction of curing deformation. Among them, the prediction of curing deformation faces the problem that traditional calculation methods involve many input parameters, complex calculation procedures, and are not suitable for direct engineering applications. The method of modifying the ply is used to achieve curing deformation correction, which is suitable for curing deformation correction of thick plate composite materials, but it is easy to overcorrect for thin plate composite materials. Summary of the invention
[0003] In view of this, the present invention aims to overcome the defects in the prior art and proposes a method for controlling the deformation of a composite material T-section ring frame and a truss.
[0004] To achieve the above object, the technical solution created by the present invention is implemented as follows:
[0005] A method for controlling deformation of a composite material T-section ring frame and stringers, comprising the following steps:
[0006] S1: Assuming that the equivalent thermal expansion coefficients of the web and edge plates of the T-section ring frame are consistent, the ring frame has no obvious solidification deformation, and the ring frame section is simplified;
[0007] S2: Fill the cavity between the flange plate, web plate ply and the edge of the mold with resin, which is equivalent to the resin film ply in the center of the flange plate laminate;
[0008] S3: Flatten the cross-sectional area of the R-angle filler to a 0° unidirectional tape ply, place it in the edge plate laminate ply at the centroid position of the R-angle filler, and calculate the equivalent ply of the R-angle filler;
[0009] S4: Calculate the equivalent thermal expansion coefficient;
[0010] S5; by modifying the equivalent cross-sectional thickness of the R-angle filler, the equivalent thermal expansion coefficient is corrected to make the thermal expansion coefficients of the edge plate and the web plate consistent;
[0011] S6: Calculate the cross-sectional area of the R corner filler.
[0012] Furthermore, the equivalent resin film thickness corresponding to the edge cavity is calculated as, t q1 =(S q1 +S q2 ) / L 1 ;t q2 =(S q3 ) / L 2 Among them, L 1 is the width of the mold edge plate, L 2 is the die web height, S q1 is the area of the edge cavity 1 of the edge plate, S q2 is the area of the edge cavity 2 of the edge plate, S q3 is the area of the cavity 3 at the edge of the web, t q1 is the equivalent ply thickness of the edge cavity of the flange plate, t q2 is the equivalent ply thickness of the web edge cavity.
[0013] Furthermore, the equivalent ply formula for calculating R-angle filler is: R =S R / L 1 ; where t R It is the equivalent ply thickness of the R corner filler of the edge plate.
[0014] Furthermore, the thermal expansion coefficient, elastic modulus, shear modulus, and Poisson's ratio of the equivalent ply of the R-angle filler are consistent with those of the 0° direction ply of the unidirectional tape.
[0015] Furthermore, the thermal expansion coefficient, elastic modulus, shear modulus, and Poisson's ratio of the edge cavity equivalent ply are consistent with those of the unidirectional tape ply at 90°.
[0016] Furthermore, the material parameters of the equivalent resin film layer filled with the cavity resin are consistent with the material parameters of the resin film between the T-shaped ring frame edge plate, the web plate and the mold surface.
[0017] Furthermore, when simplifying the cross section of the ring frame, the direction in which the T-shaped ring frame is perpendicular to the T-shaped cross section is 0°, and the direction in the laminate perpendicular to 0° is 90°.
[0018] Compared with the prior art, the present invention has the following advantages:
[0019] The ring frame deformation control method provided by the present invention realizes accurate deformation control without changing the original ply, avoids the problem of overcorrection in modifying the ply, and greatly reduces the development cost and cycle of large-size composite material T-shaped ring frames. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:
[0021] Figure 1 This is a schematic cross-sectional view of the composite material T-shaped ring frame created by the present invention;
[0022] Figure 2 A simplified schematic diagram of a cross section of a composite material T-shaped ring frame created by the present invention. DETAILED DESCRIPTION
[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.
[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.
[0025] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.
[0026] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.
[0027] For composite T-shaped ring frame structures made of the same material, due to the use of a female mold + male mold molding scheme, the temperature is evenly transferred, and the difference in curing reaction is ignored. This paper assumes that if the cooling shrinkage of the web and edge plates of the T-shaped section is consistent, then the curing shrinkage of the web and edge plates is also consistent. The curing deformation problem is simplified to a cooling shrinkage problem. A deformation control method for a large-size thin-walled composite T-shaped section ring frame Figure 1 and Figure 2 As shown, the following steps are included:
[0028] S1: Assume that the equivalent thermal expansion coefficients of the web and edge plates of the T-shaped ring frame are consistent, and the ring frame has no obvious curing deformation; define the direction of the T-shaped ring frame perpendicular to the T-shaped section as 0°, and define the direction perpendicular to 0° in the laminate as 90°. The process state of the ring frame section before simplification is as follows: Figure 1 . The L 1 is the width of the mold edge plate, L 2 is the width of the die web, S q1 is the area of the edge cavity 1 of the edge plate, S q2 is the area of the edge cavity 2 of the edge plate, S q3 is the area of the cavity 3 at the edge of the web, S R is the cross-sectional area of the R angle filler; e1 is the thickness of the resin film 1, and the t e2 is the thickness of the resin film 2, and the t e3 is the thickness of the resin film 3.
[0029] S2: Flatten the cross-sectional area of the R-angle filler to form a 0° unidirectional tape ply, and place it in the edge plate laminate ply at the centroid of the R-angle filler. Calculate the equivalent ply of the R-angle filler as follows:
[0030] t R =S R / L 1
[0031] Where t R S is the equivalent ply thickness of the R filler at the edge plate, Ris the cross-sectional area of the R-angle filler. The thermal expansion coefficient, elastic modulus, shear modulus, and Poisson's ratio of the equivalent ply of the R-angle filler are consistent with those of the 0° direction ply of the unidirectional tape. The elastic modulus E of the equivalent ply of the R-angle filler along the ring frame L , R angle filler equivalent ply vertical hoop direction elastic modulus E r , Poisson's ratio of the equivalent pavement surface of R angle filler υ LT and TL , the shear modulus G of the equivalent pavement surface of the R corner filler LT .
[0032] Considering the resin film between the T-shaped ring frame edge plate, the web plate and the mold surface, the resin film thickness t is defined e1 ,t e2 ,t e3 The elastic modulus, shear modulus and Poisson's ratio of the resin film are consistent with those of the 90° unidirectional tape. The elastic modulus E of the resin film along the ring frame r , elastic modulus E of the resin film in the vertical hoop direction r , Poisson's ratio in the in-plane direction υ LT and TL , the shear modulus G of the resin film in the in-plane direction LT ;
[0033] S3: The resin filling of the cavity between the web and edge panels and the corresponding mold edge is equivalent to the resin film layer; considering the difference between the blanking size of the T-shaped ring frame web and edge panels and the mold width, the resin filling of the cavity between the edge panel layer and the mold edge is equivalent to the resin film layer, which is placed in the center of the edge panel and web laminate. The equivalent resin film thickness corresponding to the edge cavity is calculated as follows:
[0034] t q1 =(S q1 +S q2 ) / L 1 ;t q2 =(S q3 ) / L 2 ;
[0035] The L 1 is the width of the mold edge plate, L 2 is the die web height, S q1 is the area of the cavity 1 at the edge of the plate, S q2 is the area of the edge cavity 2 of the edge plate, S q3 is the area of the cavity 3 at the edge of the web, t q1 is the equivalent ply thickness of the edge cavity of the flange plate, t q2 is the equivalent ply thickness of the cavity at the edge of the web. The material parameters of the equivalent resin film ply for cavity resin filling are consistent with the material parameters of the resin film between the T-shaped ring frame edge plate, the web and the mold surface.
[0036] S4: Calculate the equivalent thermal expansion coefficient;
[0037] Thickness of each layer t R ,t e1 ,t e2 ,t e3 ,t q1 ,t q2 , the axial elastic modulus, hoop elastic modulus, in-plane Poisson's ratio, in-plane shear modulus of each layer and the original layer combination of the composite T-shaped ring frame flange and web. Assuming that the flange has m layers of original layers, the original thickness of the flange is t1~tm, and the original layer of the web is n layers, and the original thickness of the web is u1~un, then the flange layer after fusion process parameters is [t e1 / t 1 / t 2 / ... / t m / 2 / t q1 / t R / t m / 2+1 / ... / t m / t e3 ], the web ply is [t e1 / u 1 / u 2 / ... / u n / 2 / t q2 / u n / 2+1 / ... / u n / t e2 ].
[0038] According to the above parameters, the equivalent thermal expansion coefficient of the web and flange is calculated by the following formula 1-6 to obtain the equivalent thermal expansion coefficient of the flange α 1 and web equivalent thermal expansion coefficient α 2 .
[0039] According to the classical laminate theory, the laminate stiffness is calculated as the following formula 1-6, where Aij is an element in the laminate stiffness matrix A, and i and j are the row and column indexes of the stiffness matrix, respectively, corresponding to the stiffness relationship of the composite laminate in different directions. For a laminate with symmetrical and balanced plies, i and j are 1, 2, and 6, respectively. is the eccentric stiffness coefficient matrix of each layer of the laminate The elements in , i and j are the row and column indices of the stiffness matrix, corresponding to the stiffness relationship in different directions of the composite laminate. For a laminate with symmetrical and balanced plies, i and j are 1, 2, and 6 respectively. The total number of laminates is n, and the index k is calculated from 1 to n. The t (k) is the thickness of each layer of the laminate, and the index k from 1 to n corresponds to the thickness of different layers.
[0040]
[0041] Calculate the eccentric stiffness coefficient matrix of each layer As shown in the following formula, the index k from 1 to n corresponds to different plies.
[0042]
[0043] The T (k) is the stress conversion matrix of the kth layer, which is calculated as follows, where θ is the ply direction of each layer.
[0044]
[0045] The Q (k) is the stiffness coefficient matrix of the kth layer, calculated as follows, where E L is the elastic modulus in the fiber direction of the unidirectional prepreg, where E r is the elastic modulus of the unidirectional prepreg in the direction perpendicular to the fiber, where υ LT and TL is the Poisson's ratio in the in-plane direction of the unidirectional tape prepreg, where G LT It is the shear modulus of the unidirectional tape prepreg in the in-plane direction.
[0046]
[0047] The Δ t The calculation is as follows
[0048] Δ t =1-υ LT υ TL (5)
[0049] The calculation formula of equivalent thermal expansion coefficient of composite material ply is as follows: -1 is the inverse matrix of the laminate stiffness matrix A.
[0050]
[0051] The direction of the T-shaped ring frame perpendicular to the T-shaped section is defined as 0°, and the direction perpendicular to 0° in the laminate is defined as 90°.
[0052] Substituting formula (3) and (4) into formula (2), the eccentric stiffness coefficient matrix of each layer is calculated: Substitute into formula (6).
[0053] Take the inverse matrix of the laminate stiffness matrix A in formula 1 and substitute it into formula (6).
[0054] The α in the formula (6) (k) is the thermal expansion coefficient of the vertical ring frame section of each layer. The total number of laminate layers is n, and the index k is obtained from 1 to n by experiments.
[0055] In the formula (6), t (k) is the thickness of each layer, the total number of laminate layers is n, and the index k from 1 to n corresponds to the specific product design. The product design and process solution details in this article only correspond to t (k) changes.
[0056] S5; by modifying the cavity size between the edge plate, the web plate ply and the corresponding mold edge, the equivalent thermal expansion coefficient is corrected to make the thermal expansion coefficients of the edge plate and the web plate consistent;
[0057] S6: Finally, calculate the laying width of the web and flange plates.
[0058] The formula for calculating the equivalent layer of R angle filler is: R =S R / L 1 ;
[0059] Where, t R S is the equivalent ply thickness of the R filler at the edge plate, R is the cross-sectional area of R corner filler.
[0060] The thermal expansion coefficient, elastic modulus, shear modulus and Poisson's ratio of the equivalent ply of the R-angle filler are consistent with those of the 0° direction ply of the unidirectional tape. It should be noted that in the present invention, the edge plate and the web are fixed terms for the T-shaped structure in the art. In addition, the edge plate and the web formed by curing of the multi-layer composite material can also be understood as a laminate.
[0061] Filling the cavity between the edge plate, web plate and mold edge with resin is equivalent to the resin film layer at the center of the edge plate laminate. The material parameters of the resin film layer equivalent to the cavity resin filling are consistent with the material parameters of the resin film between the T-shaped ring frame edge plate, web plate and mold surface.
[0062] The equivalent resin film thickness corresponding to the edge cavity is calculated as:
[0063] t q1 =(S q1 +S q2 ) / L 1 ;t q2 =(S q3 ) / L 2 ;
[0064] Among them, L 1 is the width of the mold edge plate, L 2 is the die web height, S q1 is the area of the edge cavity 1 of the edge plate, S q2 is the area of the edge cavity 2 of the edge plate, S q3 is the area of the cavity 3 at the edge of the web, t q1is the equivalent ply thickness of the edge cavity of the flange plate, t q2 is the equivalent ply thickness of the cavity at the edge of the web. The material parameters of the equivalent resin film ply for cavity resin filling are consistent with the material parameters of the resin film between the T-shaped ring frame edge plate, the web and the mold surface.
[0065] The ring frame deformation control method provided by the present invention realizes accurate deformation control without changing the original ply, avoids the problem of overcorrection in modifying the ply, and greatly reduces the development cost and cycle of large-size composite material T-shaped ring frames.
[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for controlling deformation of a composite material T-section ring frame and stringer, characterized in that: The steps include: S1: Assuming that the equivalent thermal expansion coefficients of the web and edge plates of the T-section ring frame are consistent, the ring frame has no obvious solidification deformation, and the ring frame section is simplified; S2: Fill the cavity between the flange plate, web plate ply and the edge of the mold with resin, which is equivalent to the resin film ply in the center of the flange plate laminate; S3: Flatten the cross-sectional area of the R-angle filler to a 0° unidirectional tape ply, place it in the edge plate laminate ply at the centroid position of the R-angle filler, and calculate the equivalent ply of the R-angle filler; S4: Calculate the equivalent thermal expansion coefficient; S5; by modifying the equivalent cross-sectional thickness of the R-angle filler, the equivalent thermal expansion coefficient is corrected to make the thermal expansion coefficients of the edge plate and the web plate consistent; S6: Calculate the cross-sectional area of the R corner filler.
2. A method for controlling deformation of composite material T-section ring frame and stringer according to claim 1, characterized in that: The equivalent resin film thickness corresponding to the edge cavity is calculated as, t q1 =(S q1 +S q2 ) / L1;t q2 =(S q3 ) / L2; where L1 is the width of the mold edge plate, L2 is the height of the mold web, S q1 is the area of the edge cavity 1 of the edge plate, S q2 is the area of the edge cavity 2 of the edge plate, S q3 is the area of the cavity 3 at the edge of the web, t q1 is the equivalent ply thickness of the edge cavity of the flange plate, t q2 is the equivalent ply thickness of the web edge cavity.
3. A method for controlling deformation of composite material T-section ring frame and stringer according to claim 1, characterized in that: The formula for calculating the equivalent layer of R angle filler is: R =S R / L1; where t R It is the equivalent ply thickness of the R corner filler of the edge plate.
4. A method for controlling deformation of composite material T-section ring frame and stringer according to claim 1, characterized in that: The thermal expansion coefficient, elastic modulus, shear modulus and Poisson's ratio of the equivalent ply of R-angle filler are consistent with those of the 0° direction ply of unidirectional tape.
5. A method for controlling deformation of composite material T-section ring frame and stringer according to claim 1, characterized in that: The thermal expansion coefficient, elastic modulus, shear modulus and Poisson's ratio of the edge cavity equivalent ply are consistent with those of the 90° direction ply of the unidirectional tape.
6. A method for controlling deformation of composite material T-section ring frame and stringer according to claim 1, characterized in that: The material parameters of the equivalent resin film layer for cavity resin filling are consistent with the material parameters of the resin film between the T-shaped ring frame edge plate, the web plate and the mold surface.
7. A method for controlling deformation of composite material T-section ring frame and stringer according to claim 1, characterized in that: When simplifying the ring frame section, the direction in which the T-shaped ring frame is perpendicular to the T-shaped section is 0°, and the direction in the laminate that is perpendicular to 0° is 90°.