Flexible metal composite material skin structure capable of regulating and controlling local out-of-plane deformation

Abstract

The invention discloses a flexible metal composite material skin structure capable of regulating and controlling local out-of-plane deformation, and belongs to the technical field of metal skin structures. The paper-cut structure is introduced to the surface of the metal skin, the mechanical response of the paper-cut structure is regulated and controlled by changing characteristic parameters such as a paper-cut pattern and the thickness of the metal skin, so that the structure has the characteristics of high ductility and small plastic deformation, and the structure can recover to original deformation along with retraction of the driving device after expanding and protruding along with the driving device; and the aerodynamic configuration continuity of the wing is ensured. Basic requirements of flexible skin applied to the deformable wing are met, a feasible choice is provided for fusion of an air bag anti-icing and deicing mechanism and the deformable wing, and the method is expected to be widely applied to the fields of aviation, spacecraft deicing, deformable wings and the like.

Description

Technical Field

[0001] This invention relates to the field of metal skin structure technology, and in particular to a flexible metal composite material skin structure with adjustable local out-of-plane deformation. Background Technology

[0002] In the aerospace field, anti-icing systems involve multiple aspects such as flight safety, aerodynamic performance, and service life of aircraft. They have a very important impact on whether an aircraft can work normally and are an indispensable part of modern aircraft.

[0003] Among the various anti-icing technologies currently available, airbag anti-icing technology is one of the most widely used mechanical anti-icing technologies.

[0004] However, the airbag de-icing device also has certain shortcomings. Since the airbag device used for de-icing is installed on the surface of the aircraft wing, when it is not inflated, even if the de-icing airbag is close to the wing surface, it is difficult to completely fit the smooth aerodynamic shape of the wing. This will lead to a decrease in the smoothness of the wing surface and change the original streamline shape of the wing. Studies have shown that the airbag on the outer side of the wing has a very significant impact on the aerodynamic performance of the aircraft. Among them, the maximum lift coefficient loss exceeds 60%, which urgently needs to be improved. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by combining deformable wing technology with wing de-icing technology. By integrating airbags into the wing and hiding them inside, the smooth aerodynamic shape of the wing can be guaranteed, thereby improving the aerodynamic performance of the aircraft to a certain extent. In other words, a flexible metal composite material skin structure with adjustable local out-of-plane deformation is proposed.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A flexible metal composite skin structure with adjustable local out-of-plane deformation includes a locally deformable metal substrate workpiece, a driving device that drives the local deformation of the metal substrate workpiece, and a continuous surface material wrapped around the locally deformed area of ​​the metal substrate workpiece. The metal substrate workpiece is a thin workpiece with a thickness of t, where t is 0.04-0.10 mm; The surface of the metal substrate workpiece is sequentially divided into an outer fixed area, a middle paper-cutting area, and a central protruding area. The driving device is located inside the central protruding area and is used to drive the central protruding area to bulge outward vertically, while simultaneously causing the middle paper-cutting area to undergo gradient deformation. The continuous surface material covers the outer sides of the middle paper-cutting area and the central protruding area to improve the toughness of these two locally deformed areas.

[0007] Preferably, the material of the metal substrate workpiece includes, but is not limited to, 304 stainless steel.

[0008] Preferably, the driving device includes an airbag, a mechanical frame, or an actuator, which drives the surface to deform, thereby performing surface de-icing.

[0009] Preferably, the material of the continuous surface material includes, but is not limited to, rubber materials.

[0010] Preferably, the edge of the peripheral fixing area is provided with a mounting component, which includes evenly distributed through holes and screws or rivets that cooperate with and fix them, or the mounting component uses some sealing strips to cover and fix the peripheral fixing area, thereby realizing the installation of the skin structure.

[0011] Preferably, the intermediate paper-cutting area includes a retention area and a cutting gap band, forming a hollow paper-cutting structure, thereby forming a central protruding area and isolating it from the outer fixed area. Before installation, a driving device is pre-arranged, and after installation, the edge of the continuous surface material is installed on the surface of the outer fixed area by adhesive. That is, the design adopts the paper-cutting principle to achieve out-of-plane deformation perpendicular to the skin plane.

[0012] A further optimized solution is as follows: the shear gap is an arc-shaped gap with a width of d, where 5t≤d≤25t, and t is the thickness of the metal substrate workpiece. The ring width must be much larger than the material thickness to ensure that the middle paper-cutting area has sufficient length for bending deformation. If the width is too small, it will lead to excessive local stiffness and manufacturing difficulties; however, if the ring width is too large, it will lead to the individual rings being too "soft", resulting in poor stability under in-plane loads and potentially causing the overall deformation mode of the structure to become out of control. Three to six shear gaps are distributed in a ring outside the central protrusion area, forming a ring with equidistant discontinuous connecting segments and slit segments. The ratio of the slit segment length to the total length of the ring, i.e., the gap length ratio, is e, where 0.65 ≤ e ≤ 0.88. Within this range, the structure can achieve the best balance between realizing large deformation and ensuring structural integrity and fatigue life; e = 0.86 is a verified value that produces excellent deformation effects. If the gap ratio is too small, the structure lacks flexibility and is closer to a rigid ring with a narrow slit, making it difficult to achieve large deformation; if the gap ratio is too large, the connecting bridge becomes very short and thin, and its strength is insufficient to withstand cyclic loads, making it very easy to break during deformation, leading to structural failure. Multiple annular bands are equidistantly distributed outside the central protrusion area, with a gap of c between adjacent annular bands, where 2t ≤ c ≤ 10t, and t is the thickness of the metal substrate workpiece. This range of annular spacing ensures a smooth deformation transition, forming a continuous and controllable protruding surface. For example, if the protrusion height of the central protrusion area is required to be 5mm to achieve sufficient deformation for de-icing, it may be necessary to set up a corresponding number of n annular bands with a gap of c to meet the strength requirements of this deformation. Numerical simulation tests of the deformation should then be performed. Figure 3-5 As shown; if the ring spacing is too small, the material area between adjacent rings will be too narrow, becoming a weak point where stress concentration occurs, making it prone to fatigue failure, and requiring extremely high precision in precision manufacturing processes such as laser cutting; if the ring spacing is too large, it will result in sparse deformation areas, discontinuous protrusion shapes, and obvious "step-like" appearance, making it difficult to form a smooth aerodynamic surface. Deformation will also be excessively concentrated on a few rings.

[0013] Furthermore, the paper-cutting method: the cutting slit strip is cut by an arc-shaped blade with a width of d.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention combines paper-cut patterns with traditional flexible material skin structures. Through plastic deformation of the paper-cut area, the metal skin achieves out-of-plane deformation in the vertical plane direction. By changing the workpiece thickness and designing the parameters of the paper-cut pattern and the workpiece thickness, the corresponding mechanical response parameters are met, thereby achieving a stable and repeatable deformation pattern.

[0015] 2. By adjusting the geometric parameters of the paper-cutting pattern (thickness t, ring spacing c, ring width d, gap ratio e, etc.), the force-displacement response curve and final deformation shape of the structure can be precisely customized according to product requirements.

[0016] For example, thickness *t* is the primary controlling factor for stiffness, the gap ratio *e* directly determines the length of the connecting bridge and allows for fine-tuning of stiffness, and the ring width *d* and spacing *c* together determine the synergy and gradient of deformation. A suitable *d / c* ratio ensures that deformation is smoothly transmitted from the inside out, forming an ideal spherical protrusion rather than a step-like or conical distortion. These geometric parameters directly control the equivalent stiffness and deformation instability mode of the structure, and the parametric design method of this invention transforms trial-and-error design into predictable and optimizable scientific design. Attached Figure Description

[0017] Figure 1 This is a planar schematic diagram of a flexible metal composite skin structure with adjustable local out-of-plane deformation proposed in this invention before local deformation. Figure 2This is a three-dimensional schematic diagram of a flexible metal composite skin structure with adjustable local out-of-plane deformation proposed in this invention after local deformation. Figure 3 This is a numerical simulation diagram of the deformation of a flexible metal composite skin structure with adjustable local out-of-plane deformation obtained in Example 1 of the present invention; Figure 4 This is a numerical simulation diagram of the deformation of a flexible metal composite skin structure with adjustable local out-of-plane deformation obtained in Example 2 of the present invention. Figure 5 This is a numerical simulation diagram of the deformation of a flexible metal composite skin structure with adjustable local out-of-plane deformation obtained in Comparative Example 1 of this invention. Figure 6 This is a force-displacement response curve of a flexible metal composite skin structure with adjustable local out-of-plane deformation proposed in this invention at different thicknesses t; Figure 7 The force-displacement response curves of a flexible metal composite skin structure with adjustable local out-of-plane deformation proposed in this invention are obtained under different paper-cutting patterns.

[0018] In the diagram: 1: outer fixed area; 2: middle paper-cutting area; 201: reserved area; 202: cutting gap zone; 3: central raised area. Detailed Implementation

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Basic plan: A flexible metal composite skin structure with adjustable local out-of-plane deformation includes a locally deformable metal substrate workpiece, a driving device that drives the local deformation of the metal substrate workpiece, and a continuous surface material wrapped around the locally deformed area of ​​the metal substrate workpiece. The metal substrate workpiece is a thin workpiece with a thickness of t, where t is 0.04-0.10 mm; The surface of the metal substrate workpiece is divided into an outer fixed area 1, an inner paper-cutting area 2, and a central protruding area 3. The driving device is located inside the central protruding area 3 and is used to drive the central protruding area 3 to protrude vertically outward, while simultaneously causing the inner paper-cutting area 2 to undergo gradient deformation. Continuous surface material covers the outer sides of the inner paper-cutting area 2 and the central protruding area 3 to improve the toughness of these two locally deformed areas.

[0021] The materials of the metal-based workpiece include, but are not limited to, 304 stainless steel.

[0022] The driving device includes an airbag, a mechanical frame, or an actuator, which drives the surface to deform, thereby removing ice from the surface.

[0023] The materials used for continuous surface materials include, but are not limited to, rubber materials.

[0024] The edge of the outer fixing area 1 is provided with mounting parts, which include evenly distributed through holes and screws or rivets that cooperate with them for fixing, or the mounting parts use some sealing strips to cover and fix the outer fixing area 1, thereby realizing the installation of the skin structure.

[0025] The middle paper-cutting area 2 includes a retention area 201 and a cutting gap band 202, forming a hollow paper-cutting structure, thereby forming a central protruding area 3 and isolating it from the outer fixed area 1. That is, it adopts the paper-cutting principle to achieve out-of-plane deformation in the direction perpendicular to the skin plane.

[0026] Example 1: Based on the above basic scheme, the following parameters are further set: The metal substrate workpiece is made of 304 stainless steel with a thickness of t=0.04mm; The driving device is an actuator; The surface continuous material is nitrile rubber; Structural design: The mounting parts at the edge of the outer fixing area 1 are riveting structures with rivets and through holes; the driving device is pre-arranged before installation, and after installation, the edge of the continuous surface material is installed on the surface of the outer fixing area 1 by metal adhesive; The shear gap 202 is an arc-shaped gap with a width of d=1mm (25t). Four shear gaps 202 are distributed in a ring outside the central protrusion area 3, forming a ring-shaped band with equidistant discontinuities between the connecting section and the cutting section. The ratio of the length of the cutting section to the total length of the ring-shaped band, i.e., the gap length ratio, is e=0.86 (i.e., the gap length accounts for about 6 / 7 of the total length). Four annular bands are equidistantly distributed outside the central raised region 3, with a gap of c = 0.4 mm (10t) between adjacent annular bands. The required height of the central raised region 3 is 5 mm. Deformation analysis is as follows: Figure 3 As shown.

[0027] Example 2: Based on Example 1, the parameters are modified as follows: t=0.07mm, d=1.05mm (15t), c=0.35mm (5t), the rest is the same as in Example 1. Deformation analysis is as follows: Figure 4 As shown.

[0028] Comparative Example 1: Based on Example 1, the parameters were modified as follows: t=0.10mm, d=0.5mm (5t), c=0.20mm (2t), the rest is the same as in Example 1. Deformation analysis is as follows: Figure 5 As shown.

[0029] Comparative Example 2: Based on Example 2, the parameter was modified to: e=0.9 (that is, the gap length accounts for about 9 / 10 of the total length).

[0030] Comparative Example 3: Based on Example 1, the parameters were modified as follows: e=0.58, the rest is the same as in Example 2.

[0031] Example 3: Based on Example 2, the parameters are modified as follows: t=0.07mm, d=0.35mm (5t), c=0.14mm (2t), e=0.65, the rest is the same as in Example 1.

[0032] Example 4: Based on Example 1, the parameters are modified as follows: e=0.88, the rest is the same as in Example 2.

[0033] Comparative Example 4: Based on Example 1, the parameters were modified as follows: d=3.5mm (50t), the rest is the same as in Example 2.

[0034] Comparative Example 5: Based on Example 1, the parameters were modified as follows: c=1.4mm (20t), the rest is the same as in Example 2.

[0035] Summarize the data from Examples 1-4 and Comparative Examples 1-5, and combine them with... Figure 3-7 The following data was obtained, as shown in Table 1: Table 1. Influence of structural parameters on skin structure performance

[0036] Based on the above analysis, the following design principles can be summarized: 1. Compare Examples 1-2 with Comparative Example 1, and refer to... Figure 6 This indicates that thickness (t) is the determining factor of stiffness, and the bending stiffness of a structure is related to t. 3 It is directly proportional. Therefore, a small increase in t will lead to a sharp increase in stiffness; under the premise of meeting the load-bearing requirements, a smaller t should be selected to achieve low working force and large deformation.

[0037] And refer to Figure 3-5The slope of the force-displacement curve in the central convex region 3 gradually increases with thickness. This is related to the shape of the paper-cut pattern. At the beginning of deformation, the outer ring units, due to their longer gap lengths in individual cells, require less force for deformation and therefore deform preferentially. After reaching a certain deformation amount, the load reaches the critical buckling load of the inner ring gaps, causing the inner ring gaps to begin buckling deformation, thus increasing the slope of the curve. This phenomenon is beneficial for maintaining surface continuity. This will provide a reference for structures with good deformation characteristics.

[0038] 2. Compare Example 2 with Comparative Examples 2-3, and refer to... Figure 7 The results show that the gap length ratio *e* is a crucial factor in balancing rigidity and flexibility. *e* directly determines the length of the connecting bridge. In Comparative Example 3, *e* is too low, resulting in an excessively long connecting bridge and excessive stiffness. In Comparative Example 2, *e* is too high, leading to a short connecting bridge, which may cause stress concentration, short fatigue life, and unstable deformation. There exists a golden range for *e* (approximately 0.65~0.88), within which the structure can simultaneously achieve good deformation capacity and durability. Example 4, by finely adjusting *e* from 0.9 to 0.88, significantly improves performance, truly embodying this principle.

[0039] 3. Comparing Example 2 with Comparative Examples 1 and 4-5 shows that the ring width (d) and the ring spacing (c) jointly determine the deformation gradient: The effect of d on local flexibility: In Comparative Example 1, d is too small, and the cell cannot fully expand; in Comparative Example 4, d is too large, and the annular band itself becomes unstable.

[0040] c affects deformation coordination: in Comparative Example 1, c is too small, resulting in uncoordinated deformation and a stepped shape; in Comparative Example 5, c is too large, resulting in a small deformation area and a conical shape.

[0041] Therefore, d and c need to be proportionally matched to t. Preferably, d is between 5t and 25t, and c is between 2t and 10t, which ensures that the deformation is the result of the coordinated buckling of multiple annular bands, thus forming a smooth transition surface. Example 3 achieved acceptable performance based on the failure of Comparative Example 1 by rebalancing the parameters, precisely by utilizing this proportional relationship.

[0042] 4. Conclusion: Through the above systematic embodiments and comparative analyses, it is fully demonstrated that the various geometric parameters (t, d, c, e) in this invention do not exist in isolation, but are coupled together, jointly determining the final performance of the skin structure. Successful design lies in finding an optimal balance solution within the constraints of the above parameters for the target application (such as low driving force, high smoothness).

[0043] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A flexible metal composite material skin structure with adjustable local out-of-plane deformation, characterized in that, It includes a metal substrate workpiece with localized deformation, a driving device that causes localized deformation of the metal substrate workpiece, and a continuous surface material that surrounds the localized deformation area of ​​the metal substrate workpiece. The metal substrate workpiece is a thin workpiece with a thickness of t, where t is 0.04-0.10 mm; The surface of the metal substrate workpiece is divided into an outer fixed area (1), a middle paper-cutting area (2) and a central protruding area (3) in sequence, and the driving device is located inside the central protruding area (3).

2. The flexible metal composite material skin structure with adjustable local out-of-plane deformation according to claim 1, characterized in that, The material of the metal substrate workpiece includes, but is not limited to, 304 stainless steel.

3. The flexible metal composite material skin structure with adjustable local out-of-plane deformation according to claim 1, characterized in that, The drive unit includes an airbag, a mechanical frame, or an actuator.

4. The flexible metal composite material skin structure with adjustable local out-of-plane deformation according to claim 1, characterized in that, The material of the continuous surface material includes, but is not limited to, rubber.

5. The flexible metal composite material skin structure with adjustable local out-of-plane deformation according to claim 1, characterized in that, The edge of the peripheral fixed area (1) is provided with a mounting component, which includes uniformly distributed through holes and screws or rivets that cooperate with and fix them.

6. The flexible metal composite material skin structure with adjustable local out-of-plane deformation according to claim 1, characterized in that, The intermediate paper-cutting area (2) includes a retention area (201) and a cutting gap zone (202).

7. The flexible metal composite material skin structure with adjustable local out-of-plane deformation according to claim 6, characterized in that, The shear gap (202) is an arc-shaped gap with a width of d, where 5t≤d≤25t, and t is the thickness of the metal substrate workpiece; 3-6 shear gap bands (202) are distributed in a ring outside the central protrusion area (3), forming a ring band with equidistant discontinuities between the connecting section and the cut section, and the ratio of the length of the cut section to the total length of the ring band, i.e. the gap length ratio, is e, where 0.65≤e≤0.88; Multiple annular bands are equidistantly distributed outside the central protrusion area (3), and the gap between adjacent annular bands is c, where 2t≤c≤10t, and t is the thickness of the metal substrate workpiece.

8. The flexible metal composite material skin structure with adjustable local out-of-plane deformation according to claim 7, characterized in that, The shear gap (202) is cut by an arc-shaped cutter with a width of d.

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