A method of laying up a composite spar fibre continuity

Abstract

The application discloses a kind of guarantee composite wing spar fiber continuous laying method, and the composite wing spar includes wing spar web and wing spar edge strip, the both ends of web have bending, bending angle is alpha;The flanging of web two sides is edge strip;Laying method: S1, open the numerical model of wing spar in three-dimensional software and measure the length and width of edge strip, according to the measured value, draw rectangular sheet in three-dimensional software;S2, load rectangular sheet blanking drawing through blanking machine, cut out the unidirectional tape prepreg sheet for laying to form edge strip, the fiber in sheet is parallel to the long side of rectangle;S3, lay carbon fiber fabric on the mold, lay sheet on the fabric, repeat laying in the mode of several fabrics-some unidirectional tapes alternately;When laying prepreg, first lay in the non-bending area of fabric surface, then lay in bending area, when laying in bending area: the both ends of sheet are split into several narrow strips before laying on the fabric;S4, bagging after laying is completed, solidification.

Description

Technical Field

[0001] This invention relates to the field of composite material molding technology, and specifically to a method for laying composite material spar fibers continuously. Background Technology

[0002] Carbon fiber composites possess excellent fatigue resistance, corrosion resistance, design flexibility, and weight reduction efficiency. Currently, they have become an essential material for the structures of many advanced aircraft. As a large load-bearing component of an aircraft, the use of carbon fiber composites in the manufacture of wing spars can achieve the effects of weight reduction, increased lifting load, and extended service life.

[0003] Currently, most composite spars are manufactured using carbon fiber unidirectional tape and carbon fiber fabric. Specifically, the spar web primarily uses carbon fiber fabric, while the spar flanges, as critical load-bearing components, mainly use 0° unidirectional tape. In actual production, CATIA or Fibersim software is widely used to export the prepreg sheet program for part placement. However, when the spar web structure is curved, if CATIA or Fibersim software is used, the exported prepreg sheet drawing for the spar flange area will be curved, as shown below. Figure 1 As shown; then the machine will cut out a curved unidirectional tape prepreg according to the exported blanking diagram, and the subsequent layup personnel will lay this curved unidirectional tape prepreg on the mold; however, in this curved blanking diagram generated by 3D software, the fibers of the curved part of the flange sheet are completely discontinuous. The composite spar flange formed in this way will have all the fibers discontinuous in the curved part of the flange area, which will seriously affect the mechanical properties of the composite spar, reduce the load-bearing capacity, and is inconsistent with the designer's design intention. Summary of the Invention

[0004] The purpose of this invention is to address the problem that existing molding methods often lead to discontinuity of the spar edge fibers in the bent area when the composite spar structure is bent, which seriously affects the mechanical properties of the composite spar and reduces its load-bearing capacity. Therefore, this invention designs a laying method that can ensure the continuity of composite spar fibers, thus solving the above-mentioned problem.

[0005] This invention is achieved through the following technical solution:

[0006] Design a method for laying composite spar fibers to ensure continuity, characterized in that the composite spar includes a spar web and a spar flange, the two ends of the spar web have bending areas with a bending angle of α; the spar flange is a flange structure set on both sides of the spar web, which bends with the shape of the spar web.

[0007] The installation method includes the following steps:

[0008] S1. Open the digital model of the composite material spar in the 3D software, measure the length and width of the spar flange, and then draw the rectangular piece in the 3D software based on the measured values.

[0009] S2. Load the drawn rectangular sheet cutting diagram through the feeding machine, and cut out unidirectional tape prepreg sheets for laying to form the wing spar edge strip. The fibers in the unidirectional tape prepreg sheet are parallel to the long side of the rectangle at an angle of 0° (i.e., the unidirectional tape prepreg sheet uses 0° unidirectional tape).

[0010] S3. According to the drawing requirements, lay several layers of carbon fiber fabric to form the web of the wing beam on the laying mold, and then lay the unidirectional tape prepreg sheet on both sides of the surface of the carbon fiber fabric. Then, repeat the laying in an alternating manner of several layers of carbon fiber fabric and several layers of unidirectional tape prepreg sheet until all laying is completed.

[0011] Wherein: when laying the unidirectional tape prepreg sheet: first lay it in the non-bending area on the surface of the carbon fiber fabric, and then lay it in the bending area. When laying it in the bending area: split the two ends of the unidirectional tape prepreg sheet corresponding to the bending area to form several narrow strips and then lay them on the carbon fiber fabric in the bending area.

[0012] S4. After all the paving is completed, make vacuum bags and set the curing parameters according to the specifications of the paving material for curing.

[0013] Furthermore, a method for ensuring continuous fiber laying of composite spars is provided: carbon fiber prepreg layup can be performed using a cutting diagram exported from software.

[0014] Furthermore, a method for ensuring continuous fiber laying of composite spar beams is provided: the web of the spar beam is composed of a straight portion and bent portions disposed at both ends of the straight portion; the bent portions and the straight portion form a bending angle α.

[0015] Furthermore, a method for ensuring continuous fiber laying of composite spar beams is provided: the width of the narrow strip is set according to the bending angle α at both ends of the web of the spar beam; the larger the bending angle α, the smaller the width of the narrow strip is set; if 3°≤α≤6°, the width of the narrow strip is set to 20.0~30.0mm.

[0016] Furthermore, a method for ensuring continuous fiber laying of composite spar beams is provided: if 6°≤α≤10°, the width of the narrow strip is set to 10.0~20.0mm.

[0017] Furthermore, a method for ensuring continuous fiber placement of composite spar beams is provided: if α > 10°, the width of the narrow strip is set to < 10.0 mm.

[0018] Furthermore, a method for ensuring continuous fiber laying of composite spar beams is provided: the width of the upper layer of unidirectional prepreg sheet is not greater than that of the lower layer of unidirectional prepreg sheet.

[0019] Specifically, several layers of unidirectional tape prepreg are laid in layers from bottom to top. The present invention is designed so that the width of the upper layer of unidirectional tape prepreg is slightly smaller than that of the lower layer. This design allows the several unidirectional tape prepreg sheets to form a staggered structure similar to a step when they are laid in layers. This allows for a smooth transition between the carbon fiber fabric covering the several layers of unidirectional tape prepreg sheets and the stacked unidirectional tape prepreg sheets, which helps to eliminate the risk of interlayer bridging.

[0020] The beneficial effects of this invention are:

[0021] (1) In designing the blanking diagram of the unidirectional tape prepreg for laying the wing beam edge strip, the method of the present invention does not use the traditional software export method, but adopts the surveying method to measure the length and width of the wing beam edge strip in the composite material wing beam digital model, thereby making a rectangular blanking diagram parallel to the fibers in the unidirectional tape prepreg sheet, ensuring the continuity of the fibers and avoiding the impact of fiber discontinuity on the mechanical properties of the composite material wing beam.

[0022] (2) The method of this invention begins with the laying of unidirectional prepreg sheets in the central region (non-bending region). In the straight central region, unidirectional prepreg sheets are laid normally. Because the unidirectional tapes with large widths have poor deformation capacity, when laying in the bending region, the unidirectional prepreg sheets are split into several narrow strips of equal width. Utilizing the slight deformation capacity of these narrow strips, they are bent at a certain angle α and then laid on the carbon fiber fabric at the position corresponding to the wing sparb edge. This invention fully utilizes the slight bending capacity of the unidirectional prepreg sheets in the narrow strip shape, thereby ensuring that the fibers in the unidirectional prepreg sheets in the bending region remain continuous, without affecting the mechanical properties of the composite material wing sparb after molding.

[0023] (3) The unidirectional belt prepreg cutting diagram prepared in the method of the present invention has regular rectangular material sheets, which facilitates layout and also improves material utilization and saves raw material costs. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. 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.

[0025] Figure 1 This is a cutting diagram of the prepreg in the spar flange area, exported using CATIA or Fibersim software.

[0026] Figure 2 A schematic diagram of a composite material wing with a bending structure;

[0027] Figure 3 The rectangular sheet diagram is drawn using 3D software according to the method of this invention;

[0028] Figure 4 This is a schematic diagram of the structure of the unidirectional prepreg sheet in this invention;

[0029] Figure 5 This is a schematic diagram of the application method of the present invention.

[0030] The markings in the diagram are: 1 Composite material wing spade, 2 Rectangular sheet, 3 Unidirectional strip prepreg sheet, 4 Laying mold, 1-1 Wing spade web, 1-2 Wing spade flange, 3-1 Narrow strip, 1-1-1 Straight section, 1-1-2 Bending section. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "top," and "bottom," etc., indicating orientation or positional relationships, are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0033] Example 1

[0034] like Figures 2-5 As shown, a method for laying composite spar fibers that can ensure continuity is provided: the composite spar 1 includes: a spar web 1-1 and spar flange strips 1-2 with flange-like structures provided on both sides of the spar web 1-1; the spar web 1-1 is composed of a straight portion 1-1-1 and bent portions 1-1-2 provided at both ends of the straight portion 1-1-1, and the bent portions 1-1-2 and the straight portion 1-1-1 form a bending angle α;

[0035] The installation method includes the following steps:

[0036] S1. Use CATIA 3D software to open the digital model of composite spar 1, measure the bending angle α of spar web 1-1, and analyze the composite ply structure of spar web 1-1 and spar flange 1-2. At the same time, measure the length and width of spar flange 1-2. Then, in AutoCAD 3D software, draw the rectangular sheet 2 according to the measured length and width values ​​of spar flange 1-2.

[0037] S2. Load the drawn rectangular sheet 2 cutting diagram through the cutting machine, and cut out unidirectional tape prepreg sheet 3 for laying to form the wing beam edge strip 1-2 according to the size of the rectangular sheet 2. The fibers in the unidirectional tape prepreg sheet 3 are parallel to the long side of the rectangle and the angle is 0° (that is, the unidirectional tape prepreg sheet 3 adopts 0° unidirectional tape).

[0038] S3. According to the drawing requirements, lay several layers of carbon fiber fabric to form the web 1-1 of the wing beam on the laying mold 4 (the carbon fiber fabric prepreg layup can be cut and laid using the cutting diagram exported by CATIA or Fibersim software). Then, lay the unidirectional tape prepreg sheet 3 on both sides of the surface of the carbon fiber fabric. Then, repeat the laying in an alternating manner of several layers of carbon fiber fabric and several layers of unidirectional tape prepreg sheet until all the laying is completed.

[0039] Wherein: when the unidirectional tape prepreg sheet 3 is laid: first lay it in the non-bending area on the surface of the carbon fiber fabric, and then lay it in the bending area. When laying it in the bending area: split the two ends of the unidirectional tape prepreg sheet 3 corresponding to the bending area to form several narrow strips 3-1 and then lay them on the carbon fiber fabric in the bending area.

[0040] S4. After all the paving is completed, make vacuum bags and set the curing parameters according to the specifications of the paving material for curing.

[0041] Specifically, in the method provided in Embodiment 1 above, when laying the unidirectional prepreg sheet 3: ensure that the straight area at the center of the web of the wing beam is laid first; when laying at the curved position: first split both ends of the unidirectional prepreg sheet 3 into several narrow strips 3-1, and then determine the width of the narrow strip 3-1 according to the bending angle α of the web of the wing beam 1-1 and the slight deformation capability of the unidirectional prepreg sheet 3 in the narrow strip shape. The larger the bending angle α, the smaller the width of the narrow strip 3-1 is: when the bending angle α is 3 to 6°, the width of the narrow strip 3-1 is 20.0 to 30.0 mm; when the bending angle α is 6 to 10°, the width of the narrow strip 3-1 is 10.0 to 20.0 mm; when the bending angle α is greater than 10°, the width of the narrow strip 3-1 is less than 10.0 mm.

[0042] Specifically, in step S3 of embodiment 1 above: the width of the upper layer of unidirectional tape prepreg sheet 3 can be slightly smaller than the width of the lower layer of unidirectional tape prepreg sheet 3; this design enables several unidirectional tape prepreg sheets 3 to form a staggered structure suitable for a stepped structure when they are stacked, thereby enabling a smooth transition between the carbon fiber fabric covering several layers of unidirectional tape prepreg sheets 3 and the stacked several unidirectional tape prepreg sheets 3, which helps to eliminate the risk of interlayer bridging.

[0043] The composite material wing spar laying method provided by the present invention makes full use of the slight bending ability of the unidirectional tape prepreg sheet 3 in the narrow tape shape. The two ends of the originally relatively wide unidirectional tape prepreg are split into several narrow tapes and then bent into a certain angle α for laying. This can ensure the fiber continuity of the unidirectional tape material in the wing spar edge area, thereby effectively ensuring the mechanical properties of the formed composite material wing spar and meeting the designer's design intention.

[0044] This invention fully utilizes the slight bending capability of unidirectional tape prepreg in a narrow tape shape, so that the fibers in the narrow tape remain continuous after being bent at a certain angle α, avoiding the serious degradation of mechanical properties and the significant reduction in the load-bearing capacity of the composite spar caused by the discontinuity of the unidirectional tape prepreg fibers in the spar edge strip.

[0045] In step S3 of the above embodiment 1, the number of layups of carbon fiber fabric and unidirectional tape prepreg can be determined according to the actual design requirements of the composite material wing beam.

[0046] The above-described preferred embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of the invention. Any obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for ensuring continuous fiber laying of composite material spars, characterized in that, The composite material wing beam (1) includes a wing beam web (1-1) and a wing beam flange (1-2). The two ends of the wing beam web (1-1) have bending areas with a bending angle of α. The wing beam flange (1-2) is a flange structure provided on both sides of the wing beam web (1-1). The web plate (1-1) of the wing beam is composed of a straight part (1-1-1) and bent parts (1-1-2) provided at both ends of the straight part (1-1-1); the bent parts (1-1-2) and the straight part (1-1-1) form a bending angle α; The installation method includes the following steps: S1. Open the digital model of the composite material wing beam (1) in the three-dimensional software, and measure the length and width of the wing beam flange (1-2). Then, draw the rectangular piece (2) in the three-dimensional software according to the measured values. S2. Load the drawn rectangular sheet (2) through the feeding machine and cut out the unidirectional tape prepreg sheet (3) for laying to form the wing beam edge strip (1-2). The fibers in the unidirectional tape prepreg sheet are parallel to the long side of the rectangle and the angle is 0°. S3. Lay several layers of carbon fiber fabric for forming the web of the wing beam (1-1) on the laying mold (4), and then lay the unidirectional tape prepreg sheet (3) on both sides of the surface of the carbon fiber fabric. Then repeat the laying in an alternating manner of several layers of carbon fiber fabric and several layers of unidirectional tape prepreg sheet until all laying is completed. Among them, when the unidirectional tape prepreg sheet (3) is laid: first, it is laid in the non-bending area on the surface of the carbon fiber fabric, and then it is laid in the bending area. When laying in the bending area: the two ends of the unidirectional tape prepreg sheet (3) are split to form several narrow strips (3-1) and then laid on the carbon fiber fabric in the bending area. The width of the narrow strip (3-1) is set according to the bending angle α at both ends of the web plate (1-1) of the wing beam. The larger the bending angle α, the smaller the width of the narrow strip (3-1) is set. If 3°≤α≤6°, the width of the narrow strip (3-1) is set to 20.0~30.0mm. S4. After all the paving is completed, make vacuum bags and set the curing parameters according to the specifications of the paving material for curing.

2. The method for laying composite spar fibers according to claim 1, characterized in that, The carbon fiber fabric prepreg is cut and laid according to the cutting diagram exported by the software.

3. The method for laying composite spar fibers according to claim 1, characterized in that, If 6°≤α≤10°, then the width of the narrow band (3-1) is set to 10.0~20.0mm.

4. The method for laying composite spar fibers according to claim 1, characterized in that, If α > 10°, then the width of the narrow band (3-1) is set to < 10.0 mm.

5. The method for laying composite spar fibers according to claim 1, characterized in that, The width of the upper unidirectional prepreg sheet (3) is not greater than the width of the lower unidirectional prepreg sheet (3).

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