Automatic fiber placement method of composite material honeycomb sandwich structure

Abstract

The invention discloses an automatic fiber placement method of a composite material honeycomb sandwich structure, the honeycomb sandwich structure comprises an upper skin, a honeycomb core, adhesive films and a lower skin, the adhesive films are respectively laid between the honeycomb core and the upper skin and between the honeycomb core and the lower skin, and the peripheral side of the honeycomb core is provided with an inclined surface; the method comprises the following steps that S1, the periphery of the honeycomb structure is filled with twisted wires; and S2, accurately adjusting the posture of the compression roller during uphill through automatic fiber placement simulation software. The posture of the compression roller during uphill is accurately adjusted through automatic fiber laying simulation software, and continuous and uniform fiber laying is ensured; the innovative'filling and twisting wire 'technology is applied to the oblique angle areas of the side edges of the periphery of the honeycomb, the bridging risk is reduced, the overall structural strength and performance are enhanced, and compared with a traditional method, the manufacturing precision is improved, and the structural stability is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of composite honeycomb sandwich structure manufacturing technology, and in particular to an automatic wire laying method for a composite honeycomb sandwich structure. Background Art

[0002] Composite honeycomb sandwich structures are widely used in aircraft skin structures with their "sandwich" structure (including outer panels, honeycomb cores and inner panels). Automatic fiber placement technology is revolutionizing the manufacturing process of composite materials with its high efficiency, precision, good consistency and material saving characteristics. The core of this technology lies in the precise control of the position and path of the fiber bundles, as well as ensuring the close bonding and precise orientation of the fibers. The current automated fiber placement system has problems with ply bridging and honeycomb crushing when processing special components, especially honeycomb sandwich skins, making it difficult to ensure the consistency of the quality of honeycomb sandwich structure products and the efficiency of large-scale production.

[0003] In the process of using automatic fiber placement technology to prepare composite honeycomb sandwich structures, (1) the first technical difficulty is that when the pressure roller transitions from a flat area to an inclined surface, especially at the intersection of the flat surface and the uphill section, the "bridging" phenomenon of the fiber bundles often occurs. This is mainly because the pressure distribution of the pressure roller is uneven, which makes it impossible for the fiber bundles to be laid smoothly along the predetermined path. (2) The second technical difficulty involves the movement path planning of the pressure roller in the flat, uphill and downhill areas. Ideally, the normal vector on the movement trajectory of the pressure roller is always perpendicular to the current laying plane, but in actual operation, this ideal state is often affected by factors such as mechanical interference. In order to cope with these interferences, the posture of the automatic fiber placement head must be adjusted. However, adjusting the posture may cause excessive pressure on the side of the honeycomb structure during the climbing process, thereby causing local collapse of the honeycomb core and affecting the overall performance of the structure. Summary of the invention

[0004] The purpose of the present invention is to solve the following two technical problems: (1) How to effectively avoid the fiber bundle bridging phenomenon in the transition zone between the plane and the uphill; (2) How to formulate a roller motion path planning strategy that can meet the wire laying requirements and protect the honeycomb structure from damage, while taking into account the interference of the actual working environment, as well as the corresponding automatic wire laying system posture adjustment control, so as to improve the manufacturing quality and production efficiency of the composite honeycomb sandwich structure.

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an automatic wire laying method for a composite honeycomb sandwich structure. The automatic wire laying simulation software is used to accurately adjust the posture of the pressure roller when going uphill to ensure continuous and uniform fiber laying. The innovative "filling and twisting wire" technology is applied to the angled areas on the sides of the honeycomb to reduce the risk of bridging and enhance the overall structural strength and performance. Compared with traditional methods, the manufacturing accuracy is improved and the structural stability is enhanced.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] An automatic wire laying method for a composite honeycomb sandwich structure, the honeycomb sandwich structure comprising an upper skin, a honeycomb core, an adhesive film, and a lower skin, adhesive films are laid between the honeycomb core and the upper skin and the lower skin, respectively, and the honeycomb core has inclined surfaces on all sides; the method comprises the following steps:

[0008] Step S1: Filling twisted wires around the honeycomb structure;

[0009] Step S2: Accurately adjust the roller posture when going uphill through the automatic wire laying simulation software.

[0010] Further, in step S1:

[0011] Step S11: After the lower skin is laid and the adhesive film is installed, additional fibers, i.e., filling twisted wires, are cleverly inserted into the angled areas around the honeycomb structure. By adding one or more additional fibers, they are filled and wound along the angled areas that the pressure roller cannot directly contact, thus filling the dead corners that the pressure roller cannot directly contact, ensuring that every corner in the negative curvature area can obtain sufficient fiber coverage and uniform pressure distribution.

[0012] Further, in step S2:

[0013] Step S21: using the method of experiment and data analysis, measuring the relationship between the laying pressure and the compression width of the pressure roller of the fiber placement head through a compression test, and using this as a basis to determine the appropriate "advance amount", and establishing the appropriate "advance amount" by applying pressure to the pressure roller of the fiber placement head and detecting the deformation of the pressure roller;

[0014] Step S22: By finely adjusting the relative / mutual relationship between the "advance amount", "delay amount" and "bias vector", the posture control of the pressure roller is realized, so that the pressure roller seems to sense the change of the inclined surface / slope in advance, so that when the fiber placement head climbs the side of the honeycomb structure, it can predict the terrain change, start climbing or adjust the posture in advance, and actively adjust to a backward forward posture, that is, a "lifted" state, and then appropriately delay the restoration to the original position when going downhill to maintain the continuity and uniformity of fiber laying; "advance amount" refers to the pressure roller starting to climb or adjust the posture in advance before the intersection of the plane and the inclined surface, "delay amount" refers to the continued pressure distance after the pressure roller leaves the inclined surface / slope, and "bias vector" refers to the angle between the direction of ...

[0015] Step S23: Use simulation compilation software to fine-tune the wire laying path, and achieve the effect of optimizing the wire laying process by presetting and simulating the ideal posture and speed movement trajectory of the wire laying head roller when the honeycomb sandwich structure goes uphill.

[0016] Furthermore, when the "bias vector" is 45°, rectangular outward expansion boundaries are formed on all sides of the honeycomb core, and the axis of the pressure roller is at 45° to one of the outward expansion boundaries; the extension of the honeycomb boundary is expanded to further reduce the compaction area and ensure the continuity and uniformity of fiber laying.

[0017] The automatic wire laying method of a composite honeycomb sandwich structure of the present invention has the following beneficial technical effects:

[0018] (1) The automatic fiber placement simulation software is used to accurately adjust the roller posture when going uphill to ensure continuous and uniform fiber placement. This method draws on the "twisting" principle in the weaving process, and by adding one or more additional fibers, fills and wraps along the dead space that the roller cannot directly contact. In this way, even in the negative curvature area, it can ensure that every place is fully covered with fibers and has uniform pressure distribution. This not only solves the blind spot problem of fiber placement, but also improves the integrity and stability of the honeycomb sandwich structure, thereby improving the overall structural strength and performance. The implementation of this method depends on the precise calculation and control of the placement path, as well as the timely intervention and removal of the filling and twisting wires. "Adjustment of the roller posture" and "filling and twisting wires" are interrelated key technical features.

[0019] (2) The innovative “filling twisted wire” technology is applied to the angled areas around the sides of the honeycomb to reduce the risk of bridging, enhance the overall structural strength and performance, and improve manufacturing accuracy and structural stability compared to traditional methods. This parameter setting method based on scientific data drive makes the posture adjustment of the pressure roller more intelligent and precise, effectively overcomes the laying difficulties caused by the negative curvature area in the honeycomb sandwich structure, and realizes seamless laying of complex geometric shapes, thereby improving the quality and reliability of the composite honeycomb sandwich structure. “Pressure roller posture adjustment” and “filling twisted wire” are interrelated key technical features. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the main structure of the composite honeycomb sandwich structure of the present invention;

[0021] Figure 2 It is a schematic diagram of a top view of the composite honeycomb sandwich structure of the present invention;

[0022] Figure 3 It is a schematic diagram of the deformation of the pressure roller of the present invention;

[0023] Figure 4 This is a schematic diagram of the movement path of the pressure roller of the wire laying head of the present invention;

[0024] Figure 5 This is a schematic diagram of the movement path of the pressure roller of the wire laying head of the present invention;

[0025] Figure 6 This is a schematic diagram of the simulation of the path and posture planning of the pressure roller of the wire laying head of the present invention;

[0026] Figure 7 It is a schematic diagram of the movement path of the pressure roller of the wire laying head of the present invention. DETAILED DESCRIPTION

[0027] In order to make the technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described in detail in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present invention, which are only used to explain the present invention, not to limit the present invention. It should be noted that, for the convenience of description, only the parts / structures related to the present invention are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0028] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present invention should be the common meanings understood by ordinary technicians in the field to which the present invention belongs.

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0030] like Figure 1-7 As shown, an automatic wire laying method for a composite honeycomb sandwich structure, the honeycomb sandwich structure includes an upper skin, a honeycomb core, an adhesive film, and a lower skin, adhesive films are laid between the honeycomb core and the upper skin and the lower skin, respectively, and the honeycomb core has inclined surfaces on all sides; the method includes the following steps:

[0031] Step S1: Filling twisted wires around the honeycomb structure;

[0032] Step S11: After the lower skin is laid and the adhesive film is installed, additional fibers, i.e., filling twisted fibers, are cleverly inserted into the beveled areas around the honeycomb structure. By adding one or more additional fibers, the beveled areas that the pressure roller cannot directly contact are filled and wound to fill the dead corners that the pressure roller cannot directly contact, thereby ensuring that every corner in the negative curvature area can obtain sufficient fiber coverage and uniform pressure distribution;

[0033] Step S2: Accurately adjust the roller posture when going uphill through the automatic wire laying simulation software;

[0034] Step S21: using the method of experiment and data analysis, measuring the relationship between the laying pressure and the compression width of the pressure roller of the fiber placement head through a compression test, and using this as a basis to determine the appropriate "advance amount", and establishing the appropriate "advance amount" by applying pressure to the pressure roller of the fiber placement head and detecting the deformation of the pressure roller;

[0035] Step S22: By finely adjusting the relative / mutual relationship between the "advance amount", "delay amount" and "bias vector", the posture control of the pressure roller is realized, so that the pressure roller seems to sense the change of the inclined surface / slope in advance, so that when the fiber placement head climbs the side of the honeycomb structure, it can predict the terrain change, start climbing or adjust the posture in advance, and actively adjust to a backward forward posture, that is, a "lifted" state, and then appropriately delay the restoration to the original position when going downhill to maintain the continuity and uniformity of fiber laying; "advance amount" refers to the pressure roller starting to climb or adjust the posture in advance before the intersection of the plane and the inclined surface, "delay amount" refers to the continued pressure distance after the pressure roller leaves the inclined surface / slope, and "bias vector" refers to the angle between the direction of ...

[0036] Step S23: Use simulation compilation software to fine-tune the wire laying path, and achieve the effect of optimizing the wire laying process by presetting and simulating the ideal posture and speed movement trajectory of the wire laying head roller when the honeycomb sandwich structure goes uphill.

[0037] In one embodiment, when the "bias vector" is 45°, a rectangular expansion boundary is formed on the four sides of the honeycomb core, and the axis of the pressure roller is 45° to one of the expansion boundaries; the extension of the honeycomb boundary is expanded to further reduce the compaction area and ensure the continuity and uniformity of fiber laying. In theory and practice, it shows a good fiber laying effect, improving the manufacturing quality and efficiency of the composite honeycomb sandwich structure.

[0038] The automatic wire laying method of a composite honeycomb sandwich structure of the present invention has the following beneficial technical effects:

[0039] (1) The automatic fiber placement simulation software is used to accurately adjust the roller posture when going uphill to ensure continuous and uniform fiber placement. This method draws on the "twisting" principle in the weaving process, and by adding one or more additional fibers, fills and wraps along the dead space that the roller cannot directly contact. In this way, even in the negative curvature area, it can ensure that every place is fully covered with fibers and has uniform pressure distribution. This not only solves the blind spot problem of fiber placement, but also improves the integrity and stability of the honeycomb sandwich structure, thereby improving the overall structural strength and performance. The implementation of this method depends on the precise calculation and control of the placement path, as well as the timely intervention and removal of the filling and twisting wires. "Adjustment of the roller posture" and "filling and twisting wires" are interrelated key technical features.

[0040] (2) The innovative “filling twisted wire” technology is applied to the angled areas around the sides of the honeycomb to reduce the risk of bridging, enhance the overall structural strength and performance, and improve manufacturing accuracy and structural stability compared to traditional methods. This parameter setting method based on scientific data drive makes the posture adjustment of the pressure roller more intelligent and precise, effectively overcomes the laying difficulties caused by the negative curvature area in the honeycomb sandwich structure, and realizes seamless laying of complex geometric shapes, thereby improving the quality and reliability of the composite honeycomb sandwich structure. “Pressure roller posture adjustment” and “filling twisted wire” are interrelated key technical features.

[0041] The above-mentioned implementation modes are for explanation of the present invention rather than limitation of the present invention. It can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An automatic wire laying method for a composite honeycomb sandwich structure, the honeycomb sandwich structure comprising an upper skin, a honeycomb core, an adhesive film, and a lower skin, adhesive films are laid between the honeycomb core and the upper skin and the lower skin, respectively, and the honeycomb core has inclined surfaces on all sides; It includes the following steps: Step S1: Filling twisted wires around the honeycomb structure; Step S2: Accurately adjust the roller posture when going uphill through the automatic wire laying simulation software.

2. The automatic wire laying method for a composite honeycomb sandwich structure according to claim 1, characterized in that: in, In step S1: Step S11: After the lower skin is laid and the adhesive film is installed, additional fibers, i.e., filling twisted wires, are cleverly inserted into the angled areas around the honeycomb structure. By adding one or more additional fibers, they are filled and wound along the angled areas that the pressure roller cannot directly contact, thus filling the dead corners that the pressure roller cannot directly contact, ensuring that every corner in the negative curvature area can obtain sufficient fiber coverage and uniform pressure distribution.

3. The automatic wire laying method for a composite honeycomb sandwich structure according to claim 2, characterized in that: in, In step S2: Step S21: using the method of experiment and data analysis, measuring the relationship between the laying pressure and the compression width of the laying head roller through compression test, and using this as a basis to determine the appropriate "advance amount", and establishing the appropriate "advance amount" by applying pressure to the laying head roller and detecting the deformation of the roller; Step S22: by finely adjusting the relative / mutual relationship between the "advance amount", "delay amount" and "bias vector", the posture control of the pressure roller is realized, so that the pressure roller seems to sense the change of the inclined surface / slope in advance, so that when the fiber placement head climbs the side of the honeycomb structure, it can predict the terrain change, start climbing or adjust the posture in advance, and actively adjust to a backward forward posture, that is, a "lifted" state, and then appropriately delay the restoration to the original position when going downhill to maintain the continuity and uniformity of fiber laying; "advance amount" refers to the pressure roller starting to climb or adjust the posture in advance before the intersection of the plane and the inclined surface, "delay amount" refers to the continued pressure distance after the pressure roller leaves the inclined surface / slope, and "bias vector" refers to the angle between the vector line and the laying direction, and the vector line is perpendicular to the axis of the pressure roller; Step S23: Use simulation compilation software to fine-tune the wire laying path, and achieve the effect of optimizing the wire laying process by presetting and simulating the ideal posture and speed movement trajectory of the wire laying head roller when the honeycomb sandwich structure goes uphill.

4. The automatic wire laying method for a composite honeycomb sandwich structure according to claim 3, characterized in that: When the "bias vector" is 45°, a rectangular expansion boundary is formed on all sides of the honeycomb core, and the axis of the pressure roller is at 45° to one of the expansion boundaries; the extension of the honeycomb boundary is expanded to further reduce the compaction area and ensure the continuity and uniformity of fiber laying.

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