CN117901449A - Composite material hyperbolic stringer laying tool and molding process method - Google Patents

Abstract

The invention belongs to the technical field of composite material forming processes, and particularly relates to a composite material hyperbolic stringer laying tool and a forming process method. The invention introduces the corrugated surface on the paving surface with enough precision, realizes automatic paving of the fiber on the corrugated paving surface through AFP, realizes material compensation, ensures that the material with enough length forms corresponding geometric configuration when the thermal diaphragm is preformed, and does not cause excessive stretching of the fiber, thereby improving the thermal diaphragm forming process of the part and improving the forming efficiency and quality.

Description

Composite material hyperbolic stringer laying tool and molding process method

Technical Field

The invention belongs to the technical field of composite material forming processes, and particularly relates to a composite material double-curved stringer laying tool and a forming process method.

Background

Stringer parts are one of the most important and widely used longitudinal load bearing members in the construction of wings, fuselages, etc. of aircraft. The hat type stringer is a main supporting structure of an aircraft fuselage, the cross section of the hat type stringer is hat type or omega type, compared with the common hat type stringer, the double-curved stringer has certain curvature in the length direction and the width direction, the structure of the existing double-curved stringer is mostly prepared by adopting a composite material, and the preparation difficulty is higher due to the double-curved configuration.

At present, the composite material manufacturing schemes of the parts generally include the following steps:

Firstly, manually paving and pressurizing by adopting a rubber bag expansion method, wherein the method is easy to generate the problems of part surface wrinkles, uneven thickness control, poor molding quality caused by uneven R angle pressurization and the like;

Secondly, on a flat plate die, an ATL automatic tape laying and laying are adopted to form a planar pre-laid plate, and then a thermal diaphragm machine is adopted to prepare the plate, and the problem that an R angle bridge and wrinkles between a cap waist and a rim can not be compacted in place is difficult to solve due to the hyperbolic characteristic of the plate;

Thirdly, the planar material sheet paved by the automatic tape paving machine is prepared into a preformed body by a hot molding method, and the method can solve the problems of R-angle bridging and wrinkling, but has high cost of dies and tools which are required to be input at one time for a plurality of stringers, and has poor economical efficiency.

Disclosure of Invention

The invention aims to solve the problems that the hyperbolic stringer in the prior art is easy to cause excessive stretching of fibers and change of fiber design angles during hot diaphragm or hot die pressing, and the problems that the R area bridging and wrinkling are difficult to solve by a hot diaphragm process, the die cost of the hot die pressing process is high and the like.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the utility model provides a frock is laid to combined material hyperbolic stringer, it has the ripple face to lay the frock surface design through ripple face topological design method, the ripple face is used for laying the accurate plane of system area ripple and is laid the plywood in advance at the frock surface of laying, provides the supplementary surplus of laminating with part forming die surface for accurate plane is laid the plywood heat diaphragm in advance.

Preferably, the corrugated surface topology design method comprises the following steps:

s11, dividing the profile section of the part and the surface of the layer by taking a constant length as a dividing line;

S12, deriving points formed by the parting line, the section and the surface of the pavement into a waveform calculation application program;

s13, calculating coordinate difference values of points on the two curved surfaces through a waveform calculation application program;

S14, importing waveform geometry into a model through a Catia super-copy Powercopy tool, namely importing data information processed by a computing application program into Catia;

S15, inputting a difference value of each wave band in the super-copy, defining wavelength or arc length, and controlling the wavelength or arc length to be equal to or close to the section length;

S16, creating a corrugated surface by using the contour line, namely the wavy line, and forming the surface profile of the laying tool for introducing the corrugation.

Preferably, the laying tool is formed by CNC processing of wood substitutes.

The composite material double-curved stringer forming process includes the following steps:

s1, preparing a laying tool: designing the surface profile of the laying tool by a corrugated surface topology design method, and finishing processing; when the isolation film is used, a layer of isolation film is laid on the surface of the tool, and is subjected to sealing treatment, and the isolation film is laid on the surface of the tool in a wrinkle-free manner through vacuumizing;

S2, preparing a quasi-planar pre-layering plate: wire is laid layer by layer on the surface of the tool through automatic wire laying equipment, and the preparation of the pre-laid plate is completed;

S3, preparing a preformed blank: taking down the pre-laminated plate, placing the pre-laminated plate on a pre-forming die, heating and softening the material sheet through an infrared lamp, pressing and attaching the pre-laminated plate and an R angle of the die by using an auxiliary pressing roller, and then performing thermal diaphragm pre-forming on the material sheet;

s4, bag making and curing: after the preforming is finished, paving auxiliary materials, making bags, sending the mould into an autoclave, and curing according to a curing system of the materials;

S5, demolding and trimming: after the part is solidified, demoulding and trimming are carried out to obtain the composite material double-curved stringer part.

Preferably, in the step S2, narrow-band materials of M21C are adopted, the width is 6.35mm plus or minus 0.125mm, and the wires are laid layer by layer on the surface of the tool in the sequence of [45/-45/0/0/90/0/0/-45/45] through a 16-axis AFP wire laying machine.

Preferably, the auxiliary pressing roller in the step S3 is made of PU, and the cross-sectional shape of the auxiliary pressing roller is matched with the shape of the hyperbolic stringer.

After the technical scheme is adopted, the composite material double-curved stringer laying tool and the forming process method provided by the invention have the following beneficial effects:

1) The invention provides a topology design method for introducing a corrugated surface on a laying tool, which comprises the steps of dividing an outline section and a laying surface of a part, calculating a coordinate difference value on two curved surfaces, controlling the length of a wavelength or an arc length to be equal to or close to the length of the section through a calculation program, namely, creating the corrugated surface by using a wavy line as the surface of the laying tool, and realizing that the difference value between the actual laying length and the required length is less than 0.1mm, thereby meeting the requirement of material storage precision compensation of fibers on the laying surface when a double-curved stringer structural part is laid on a pre-laying plate; the method can be popularized and applied to other structures such as stringers, frames and the like with curvature to carry out contour compensation on the paving surface; therefore, the invention solves the problem of the difference of the lengths of different materials required by the top, the waist (side) and the legs of the stringer caused by the hyperbolic structural configuration of the part, ensures that when the thermal diaphragm is manufactured, the pre-laminated plate has enough geometric configuration of the hyperbolic stringer formed by the length of the materials, improves the efficiency and the quality of the pre-forming, and has simpler manufacturing process and more economic cost; the problems of excessive fiber stretching, fiber design angle change and the like caused by bending deformation of the thermal diaphragm are fundamentally solved;

2) The invention provides a method for paving a pre-paving plate on a quasi-plane through automatic wire paving, when a narrow-band fiber is paved by means of an AFP wire paving machine, the control of interlaminar compaction along the fiber direction and the Z direction of a paving surface is realized, the paving of the quasi-plane pre-paving plate on the wavy paving surface is realized, and as the interlaminar bonding pressure is uniformly controlled, the paved material has accurate allowance compensation with a target geometric configuration, and interlaminar sliding and high-quality and high-efficiency preforming of the fiber in the thermal diaphragm process are facilitated; therefore, the method for preparing the pre-laminated board by automatic wire laying provided by the invention realizes the automatic laying of the hyperbolic stringer-shaped part on the laying surface with the introduced ripple compensation, solves the problems of low manual laying efficiency and unstable quality, and solves the problem that ATL automatic laying belt cannot be freely laid on the non-planar laying surface;

3) The invention provides a preformed auxiliary press roller scheme of a double-curved stringer, which adopts PU and other materials with certain flexibility and deformability, can adapt to tiny cross section dimensional changes of the double-curved stringer in the length direction, can be added with press rollers with different outline profiles to press a material sheet in an R angle area when the geometric configuration of different double-curved stringer structures is changed greatly, and is used for assisting in solving the problems that the R angle area is easy to bridge and is not stuck to a mould when a thermal diaphragm is heated; the scheme has the advantages of simple and easy realization process, low cost and stable and controllable quality, can assist the thermal diaphragm, and further solves the problems of bridging and wrinkling of the R region and uneconomical investment cost of the thermal molding disposable die.

Drawings

FIG. 1 is a side view of a profile of a double-curved stringer of the present invention;

FIG. 2 is a schematic illustration of the design cut of the corrugated surface of a double-curved stringer lay-up tool of the present invention;

FIG. 3 is an isometric view of an automated placement tooling for a double-curved stringer of the present invention;

FIG. 4 is a schematic illustration of an automated placement tooling for a double-curved stringer of the present invention;

FIG. 5 is a side cross-sectional view of section A-A of FIG. 4;

FIG. 6 is a side cross-sectional view of B-B in FIG. 4;

FIG. 7 is a schematic diagram of the automated wire laying compaction principle of the present invention on a corrugated surface;

FIG. 8 is a schematic view of a doubly curved stringer preform and curing tooling of the present invention;

FIG. 9 is a schematic view of a bi-curved stringer preform auxiliary nip roll of the present invention;

FIG. 10 is a side cross-sectional view of section A-A of FIG. 9;

FIG. 11 is a flow chart of a topological design of the automated placement tool of the present invention for introducing corrugated surfaces.

Wherein: 1-top of the stringer, 2-side of the stringer (2-1, 2-2 is the profile of the stringer side to stringer leg lay-up surface), 3-stringer leg (3-1 is the profile of the stringer leg lay-up surface), 4-AFP roller (stopped), 5-AFP roller, 6-corrugated surface (6-1, 6-2, 6-3 collectively representing the undulations of the lay-up surface), 7-carbon fiber tape, 8-lay-up tooling (with 6-1, 6-2, 6-3 collectively comprising the lay-up surface), 9-preform and cure tooling, 10-auxiliary roller.

Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown, and in which embodiments of the invention are shown, by way of illustration only, and not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

In the description of the present invention, it should be understood that the azimuth or positional relationships indicated by the azimuth terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal", and "top, bottom", etc., are generally based on the azimuth or positional relationships shown in the drawings, merely to facilitate description of the present invention and simplify the description, and these azimuth terms do not indicate and imply that the apparatus or elements referred to must have a specific azimuth or be constructed and operated in a specific azimuth, and thus should not be construed as limiting the scope of protection of the present invention; the orientation word "inner and outer" refers to inner and outer relative to the contour of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "upper surface on … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In addition, the terms "first", "second", etc. are used to define the components, and are only for convenience of distinguishing the corresponding components, and the terms have no special meaning unless otherwise stated, and therefore should not be construed as limiting the scope of the present invention.

The invention provides a composite material double-curved stringer laying tool which is used for automatically laying double-curved stringers, and according to the geometric configuration of the double-curved stringers, by adopting the tool corrugated surface topological design method provided by the invention, as shown in figure 11, corrugated surfaces are accurately introduced into the laying surface of the laying tool, CNC processing is completed, wood can be replaced by the material of the laying tool, and by adopting the design of the corrugated surfaces, when the laying tool is used for automatically laying wires, a quasi-planar pre-laying plate with corrugations is laid, so that the material is reserved, so that the material can be fully unfolded in the process of a thermal diaphragm, the compensating allowance is just attached to the surface of a part forming die, no corrugation exists, and excessive stretching of fibers is avoided, thereby fundamentally solving the problems of R angle and corrugation of bridging parts due to poor interlayer sliding effect caused by traction of fibers in a material sheet in the process of the double-curved stringer thermal diaphragm.

Specifically, the corrugated surface topology design method comprises the following steps:

S11, as shown in FIG. 2, dividing the profile section of the part and the surface of the layer by taking a constant length as a dividing line, generally setting the constant length range to be 10mm-100mm according to the curvature change of the part in the length direction, and setting the interval of the dividing line with the constant length in the width direction to be 5mm-50mm according to the curvature change of the part in the width direction;

S12, deriving points formed by the parting line, the section and the surface of the pavement into a waveform calculation application program;

s13, calculating coordinate difference values of points on the two curved surfaces through a waveform calculation application program;

S14, importing waveform geometry into a model through a Catia super-copy Powercopy tool, namely importing data information processed by a computing application program into Catia;

S15, inputting a difference value of each wave band in the super-copy, defining wavelength or arc length, and controlling the wavelength or arc length to be equal to or close to the section length;

S16, creating a corrugated surface by using the contour line, namely the wavy line, and forming the surface profile of the laying tool for introducing the corrugation.

As shown in fig. 1, the double-curved stringer may be divided into a stringer top 1, a stringer side 2 and a stringer leg 3 according to the profile characteristics, as shown in fig. 3, the laying surface of the automated placement tool is composed of three areas corresponding to the stringer top 1, the stringer side 2 and the stringer leg 3, as shown in fig. 4-6, by sectioning the automated placement tool, it can be seen that the laying surfaces of different areas of the double-curved stringer have different wave wavelengths (or arc lengths), the laying surface of the stringer top 1 coincides with the section, the difference is zero, no wave fluctuation is required, the difference between the surfaces of the two stringer sides 2 becomes gradually greater until the difference between the stringer legs 3 reaches a maximum, i.e., the transition 2-1 and 2-2 of the wave peaks and wave troughs of the wave form from the stringer side 2 to the stringer leg 3 can be seen, and the difference 3-1 also tends to be uniform in the section plane due to the tendency to the plane of the section.

The topological design method of the corrugated surface accords with a geometric mathematical algorithm, and can achieve the difference value between the wavelength (wavy contour line) and the section length below 0.1mm, so that the requirement of precision compensation when the fiber stores materials on a hyperbolic structure can be met.

Furthermore, the topological design method of the automatic laying tool corrugated surface can ensure that automatic fiber laying equipment can realize automatic fiber laying on the corrugated laying surface, and in the fiber laying process, when the roller passes through the trough and the crest of the corrugated surface, the roller can be compacted on the laying surface by carrying the fiber, and the roller for compacting has certain flexibility and deformability, ensures uniform bonding pressure among the pre-laminated layers, is more convenient for fiber interlayer sliding in the thermal diaphragm process, and is beneficial to improving the preforming efficiency and quality.

The invention provides a composite material double-curved stringer forming process method, which is structurally characterized in that the cross section is hat-shaped or omega-shaped, the length and width directions are of a certain curvature, the method adopts automatic wire laying equipment to prepare a pre-laid plate on a composite material double-curved stringer laying tool, the geometric shape is formed by a thermal diaphragm and auxiliary compression roller method, and the forming process method comprises the following steps of:

S1, preparing a laying tool: by the corrugated surface topology design method, the surface contour of the paving surface of the automatic paving tool is designed according to the outline contour (figure 1) of a target product, the size of the corrugated surface meets the rolling requirement of the roller of the automatic wire paving equipment shown in figure 7, CNC processing is finished, and wood is selected as a material; when the isolation film is used, a layer of isolation film is laid on the surface of a tool (shown in figure 3), and is subjected to sealing treatment, and the isolation film is laid on the surface of the tool in a wrinkle-free manner by vacuumizing, so that the pre-laid plate is conveniently separated from the surface of the paving plate;

S2, preparing a quasi-planar pre-layering plate: adopting M21C narrow-band material, wherein the width is 6.35mm plus or minus 0.125mm, using a 16-axis AFP wire laying machine, laying wires layer by layer on the surface of an automatic laying tool (figure 3) according to the sequence of [45/-45/0/0/90/0/0/-45/45], and completing the preparation of a pre-laid plate;

S3, preparing a preformed blank: taking down the pre-laminated board, placing the pre-laminated board on a pre-forming and curing tool 9, heating and softening the material sheet through an infrared lamp, compacting and attaching the pre-laminated board and an R angle of the tool by using an auxiliary pressing roller 10 shown in fig. 9, and then performing thermal diaphragm pre-forming on the material sheet;

S4, bag making and curing: after the preforming is finished, paving auxiliary materials, making bags, feeding a preforming and curing tool 9 into an autoclave, and curing according to a curing system of the materials;

S5, demolding and trimming: after the part is solidified, demoulding and trimming are carried out to obtain the composite material double-curved stringer (figure 1) part.

Further, the auxiliary pressing roller 10 is made of PU, and has a cross-sectional shape following the shape of the hyperbolic stringer, and a certain deformation capability, and is used for assisting in rolling the R angle during the thermal diaphragm, so as to further solve the problem of R angle wrinkles in the thermal diaphragm process.

In summary, the invention is used in the field of automatic manufacturing of aviation composite materials, a quasi-plane pre-paving plate reserved with material reserve is prepared by automatically paving wires on a paving tool accurately introducing a corrugated surface, the geometric shape of a product is finally formed by hot diaphragm technology and rolling auxiliary forming, and then bag and solidification forming are carried out, so that the material with enough length can be formed into a corresponding geometric shape when the hot diaphragm is preformed, excessive stretching of fibers can not be caused, the hot diaphragm forming technological process of parts is improved, the forming efficiency and quality are improved, and the input cost of disposable tools and hot molding equipment is greatly reduced.

The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical scheme of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.

Claims (6)

1. The utility model provides a frock is laid to combined material hyperbolic stringer, its characterized in that, lay the frock surface and design through ripple face topological design method have the ripple face, the ripple face is used for laying the quasiplane pre-lay plate of making area ripple at the frock surface of laying, provides the supplementary surplus that laminates with part forming die surface for quasiplane pre-lay plate heat diaphragm in-process.

2. The composite material double-curved stringer laying tool of claim 1, wherein: the corrugated surface topology design method comprises the following steps:

s11, dividing the profile section of the part and the surface of the layer by taking a constant length as a dividing line;

S12, deriving points formed by the parting line, the section and the surface of the pavement into a waveform calculation application program;

s13, calculating coordinate difference values of points on the two curved surfaces through a waveform calculation application program;

S14, importing waveform geometry into a model through a Catia super-copy Powercopy tool, namely importing data information processed by a computing application program into Catia;

S15, inputting a difference value of each wave band in the super-copy, defining wavelength or arc length, and controlling the wavelength or arc length to be equal to or close to the section length;

S16, creating a corrugated surface by using the contour line, namely the wavy line, and forming the surface profile of the laying tool for introducing the corrugation.

3. The composite material double-curved stringer laying tool of claim 1, wherein: the laying tool is formed by machining wood substitutes through CNC.

4. A process for forming a composite material double-curved stringer, characterized in that the process adopts the composite material double-curved stringer laying tool as set forth in any one of claims 1-3 for forming, comprising the following steps:

s1, preparing a laying tool: designing the surface profile of the laying tool by a corrugated surface topology design method, and finishing processing; when the isolation film is used, a layer of isolation film is laid on the surface of the tool, and is subjected to sealing treatment, and the isolation film is laid on the surface of the tool in a wrinkle-free manner through vacuumizing;

S2, preparing a quasi-planar pre-layering plate: wire is laid layer by layer on the surface of the tool through automatic wire laying equipment, and the preparation of the pre-laid plate is completed;

S3, preparing a preformed blank: taking down the pre-laminated plate, placing the pre-laminated plate on a pre-forming die, heating and softening the material sheet through an infrared lamp, pressing and attaching the pre-laminated plate and an R angle of the die by using an auxiliary pressing roller, and then performing thermal diaphragm pre-forming on the material sheet;

s4, bag making and curing: after the preforming is finished, paving auxiliary materials, making bags, sending the mould into an autoclave, and curing according to a curing system of the materials;

S5, demolding and trimming: after the part is solidified, demoulding and trimming are carried out to obtain the composite material double-curved stringer part.

5. The method for forming the composite material double-curved stringer according to claim 4, wherein the method comprises the following steps: in the step S2, narrow-band materials of M21C are adopted, the width is 6.35mm plus or minus 0.125mm, and wires are laid layer by layer on the surface of the tool in the sequence of [45/-45/0/0/90/0/0/-45/45] through a 16-axis AFP wire laying machine.

6. The method for forming the composite material double-curved stringer according to claim 4, wherein the method comprises the following steps: in the step S3, the auxiliary pressing roller is made of PU materials, and the section shape of the auxiliary pressing roller is matched with the shape of the hyperbolic stringer.