Non-uniform corrugated thin-walled energy absorption tube with rounded corner transition

Abstract

The utility model discloses a kind of non-uniform corrugated thin-walled energy-absorbing tubes with fillet transition, belong to thin-walled energy-absorbing tube technical field, it includes elliptical arc pipe section and fillet transition section alternately connected along pipe axis direction, and fillet transition section smoothly connects the elliptical arc pipe section on its two sides.The non-uniform corrugated thin-walled energy-absorbing tube provided by the utility model combines the advantages of corrugation and transition surface, the introduction of fillet transition section effectively reduces the stress concentration at traditional wave crest, so that energy-absorbing tube forms continuous, smooth progressive folding mode in compression process, thereby reducing initial peak load and improving energy absorption stability in plateau stage, so that the average crushing force and specific energy absorption of energy-absorbing tube are excellent, load stability and energy-absorbing efficiency are high, and local instability is inhibited.In practical application, load stability and energy-absorbing performance of energy-absorbing tube can be adjusted by optimizing corrugation parameters, such as elliptical arc curvature, fillet radius, wave crest spacing, etc.

Description

Technical Field

[0001] This utility model relates to a non-uniform corrugated thin-walled energy-absorbing tube with rounded corner transition, belonging to the technical field of thin-walled energy-absorbing tubes. Background Technology

[0002] Thin-walled structures have been widely used in automotive crash absorbers, aerospace structural components, and rail transit anti-climb devices due to their excellent energy absorption efficiency, lightweight, and low cost. Recent studies on thin-walled energy-absorbing elements with different cross-sectional shapes, such as circular, square, and hexagonal shapes, have shown that cross-sectional geometry significantly affects energy absorption capacity and folding patterns, with circular tubes typically exhibiting a more stable progressive folding pattern. However, traditional straight-walled thin-walled tubes still suffer from problems such as high initial peak load, large fluctuations in force-displacement curves, and uncontrollable instability modes during crushing, limiting their application in high-safety-level energy absorption applications.

[0003] To improve structural energy absorption performance and achieve controllable deformation modes, researchers have proposed various triggering or regulating structures, such as introducing indentations, holes, origami folds, and corrugations into the tube body to reduce initial peak loads, smooth the deformation process, and improve energy absorption efficiency. Studies on corrugated tubes, such as sinusoidal and bell-shaped corrugated tubes, show that adjusting the corrugated geometric parameters such as amplitude, period, and radius of curvature can effectively improve the stability and predictability of the folding mode. However, most existing corrugated tubes use a single period and regular waveform, such as sinusoidal or cosine corrugated tubes. Their geometric characteristics are simple, and the structural response mode still suffers from significant peak load fluctuations, unstable energy absorption platforms, and stress concentration caused by abrupt curvature changes between peaks and troughs. These shortcomings make it difficult to achieve a balance between stability and energy absorption efficiency under more complex loading conditions. Utility Model Content

[0004] In order to solve the problems existing in the prior art, this utility model provides a non-uniform corrugated thin-walled energy-absorbing tube with rounded corner transition, which can improve the energy absorption efficiency and load stability of the overall structure.

[0005] This utility model achieves the above objectives by adopting the following technical solutions: A non-uniform corrugated thin-walled energy-absorbing tube with rounded corner transition includes elliptical arc tube segments and rounded corner transition segments alternately connected along the tube axis. The rounded corner transition segments are used to smoothly connect the elliptical arc tube segments on both sides to form a continuous and smooth corrugated shape.

[0006] The elliptical arc pipe segment is formed by rotating an elliptical arc around the pipe axis. The major axis of the ellipse is arranged along the pipe axis, and the minor axis is perpendicular to the pipe axis. The arching direction of the elliptical arc faces the inside of the pipe to form convex corrugations distributed along the axial direction.

[0007] The elliptical arc is the arc segment between the two vertices of the major axis of an ellipse, and its corresponding elliptical arc spans an angle of less than 180°. By adjusting the ratio of the major and minor axes of the ellipse and the radius of the rounded corners, the ripple shape and curvature continuity can be changed, thereby optimizing the energy absorption characteristics.

[0008] Furthermore, each elliptical arc is symmetrical about the cross-section of the tube passing through the center of the elliptical arc.

[0009] Furthermore, the extension distance of a single elliptical arc tube segment along the tube axis is d1, the extension distance of a single rounded transition segment along the tube axis is d2, and the total length of the tube body is D; preferably, d1 / d2>2, so that the elliptical arc tube segment constitutes the main structural part of the energy-absorbing tube, thereby dominating the overall deformation mode during axial compression.

[0010] Furthermore, multiple elliptical arc tube segments and rounded corner transition segments are arranged alternately along the axial direction. The total extension distance of the elliptical arc tube segments along the tube axis accounts for 60% to 85% of the total length of the tube body, and the total extension distance of the rounded corner transition segments accounts for 15% to 40%. This ratio setting can ensure that the corrugation shape is not uniformly distributed and maintains continuous curvature transition, which is conducive to achieving orderly and stable plastic folding and energy absorption.

[0011] The beneficial effects of this utility model include, but are not limited to: The non-uniform corrugated thin-walled energy-absorbing tube provided by this utility model is a non-uniform corrugated energy-absorbing tube composed of an elliptical arc tube section and a rounded transition section. It combines the advantages of corrugation and transition curved surface, and has the dual characteristics of axial periodicity and curvature non-uniformity. It not only maintains the controllable folding deformation mode of traditional corrugated tubes, but also improves the energy absorption efficiency and load stability of the overall structure through rounded transition.

[0012] Specifically, the introduction of rounded transition sections effectively reduces stress concentration at traditional crests, enabling the energy-absorbing tube to form a continuous and stable progressive folding pattern during compression. This reduces the initial peak load and improves energy absorption stability during the plateau phase, resulting in superior average crushing force and specific energy absorption, high load stability and energy absorption efficiency, and suppression of local instability. In practical applications, the stress stability and energy absorption performance of the energy-absorbing tube can be adjusted by optimizing corrugation parameters (including elliptical arc curvature, rounded transition radius, and crest spacing), thereby achieving performance optimization and adaptive design of the structure under different working conditions.

[0013] Furthermore, the non-uniform corrugated thin-walled energy-absorbing tube with rounded corner transition provided by this utility model has a simple structure and can be directly mass-produced by rolling or other forming processes, which significantly improves the ease of manufacturing and engineering applicability. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 A schematic diagram of the non-uniform corrugated thin-walled energy-absorbing tube with rounded corner transition provided by this utility model; Figure 2 This is a schematic diagram showing the changes in the structural parameters of the energy-absorbing tube; Figure 3 This is a schematic diagram of the compression test loading. Figure 4 This is a schematic diagram of the experimental and simulated deformation of a bamboo-joint corrugated pipe under uniaxial compression. Figure 5 The effect of the number of corrugated periodic units N on the deformation mode of the energy absorber. Figure 6 The effect of peak height A on the deformation mode of the energy absorber tube; Figure 7 The effect of the fillet radius R on the deformation mode of the energy absorber; Figure 8 The effect of the number N of the corrugated periodic unit on the performance of the energy absorber; Figure 9 The effect of peak height A on the performance of the energy absorber tube; Figure 10 The effect of the fillet radius R on the performance of the energy absorber tube; In the diagram, 1 represents the elliptical arc tube segment; 200 represents the rounded transition segment. Detailed Implementation

[0015] To clearly illustrate the technical features of this solution, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0016] It should be noted that many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0017] During significant deformation of structures and materials, energy dissipation can occur in various forms, such as plastic energy dissipation, viscous deformation energy, frictional energy dissipation, or fracture energy dissipation. Among these energy absorption mechanisms, this invention primarily focuses on energy dissipation caused by structural plastic deformation, where geometric parameters have a significant impact on the plastic deformation of the structure.

[0018] like Figure 1As shown, the non-uniform corrugated thin-walled energy-absorbing tube with rounded corner transition provided by this utility model includes elliptical arc tube segments 100 and rounded corner transition segments 200 alternately connected along the tube axis. The elliptical arc tube segments 100 are formed into a three-dimensional solid by rotating an elliptical arc around a central tube axis. The rounded corner transition segments 200 smoothly connect the elliptical arc tube segments on both sides to form an energy-absorbing tube with a continuous curvature change. The major axis of the elliptical arc is parallel to the tube axis, and the minor axis is perpendicular to the tube axis. The elliptical arc arches inward towards the tube, while the rounded corner transition segments arch outward towards the tube.

[0019] The fillet radius of the fillet transition section 200 is selected based on the geometric dimensions of the adjacent elliptical arc pipe sections to achieve a smooth transition connection between adjacent elliptical arc pipe sections.

[0020] The rounded transition section, resembling the node of a bamboo joint, significantly improves stress concentration distribution, disperses the buckling initiation point axially, thereby delaying local instability and enhancing overall structural stability. The crest is the highest point of the elliptical arc arching inwards from the tube, such as... Figure 2 As shown, A represents the crest height, R represents the fillet radius of the rounded transition section, N represents the number of corrugated periodic units along the tube axis, and B represents half of the axial spacing between adjacent crests. In practical applications, the stress characteristics and energy absorption performance of the energy-absorbing tube can be optimized by adjusting parameters such as the elliptical arc curvature, fillet radius, crest spacing, and number of corrugated periodic units.

[0021] Specifically, by controlling the ratio of the major axis to the minor axis of the ellipse, the local curvature distribution can be adjusted: when the ratio of the major axis to the minor axis is small (i.e., the curvature is large), the inward arching of the wave crest is more obvious, which is conducive to inducing controllable folding deformation and dispersing impact load; when the ratio is large (i.e., the curvature is small), the pipe wall tends to be flat, which helps to improve the overall stiffness and deformation stability.

[0022] Furthermore, an elliptical arc is an arc segment between two vertices of the major axis of an ellipse, and the corresponding elliptical arc spans an angle of less than 180°.

[0023] Furthermore, each elliptical arc is symmetrical about the cross-section of the tube passing through the center of the elliptical arc.

[0024] Furthermore, the extension distance of a single elliptical arc tube segment along the tube axis is d1, the extension distance of a single rounded transition segment along the tube axis is d2, and the total length of the energy-absorbing tube is D. Preferably, d1 / d2 > 2, to ensure that the elliptical arc tube segment occupies the main part of the overall structure, thereby dominating the energy absorption and deformation mode during axial compression. Further, multiple elliptical arc tube segments and rounded transition segments are alternately connected along the tube axis, with the total extension distance of the elliptical arc tube segments accounting for 60%–85% of the total length of the energy-absorbing tube, and the total extension distance of the rounded transition segments accounting for 15%–40%. This proportional setting ensures a continuous curvature transition while allowing the corrugation shape to be non-uniformly distributed, taking into account both the overall stiffness of the structure and its energy absorption stability.

[0025] The following section will focus on the controlled design of the geometric parameters of the energy absorber and the calculation of the corresponding numerical model to explore the key factors affecting the structural impact resistance and energy absorption performance.

[0026] Figure 3 The diagram shows the loading of the compression test, which mainly consists of the upper pressure plate 1 of the testing machine, the test piece 2, and the lower pressure plate 3 of the testing machine.

[0027] The experiment employed a displacement loading mode, compressing the specimen at a rate of 1 mm / min. Since different structural parameters significantly affect the energy absorption capacity and load-bearing performance of the energy-absorbing tube, this loading device effectively tests the tube's performance in terms of compressive strength and energy absorption.

[0028] Example 1: In this embodiment, the energy-absorbing tube has a height of 100 mm, and the number of corrugated periodic units along the tube axis is 3. The major axis of the elliptical arc is parallel to the tube axis. This embodiment investigates the experimental and simulated deformation under uniaxial compression, and the results are as follows: Figure 4 As shown.

[0029] As the load gradually increases, stress concentration first occurs at the bamboo-joint rounded transition section of the energy-absorbing tube, where local buckling and initial wrinkling occur first. Subsequently, the buckling deformation extends axially layer by layer to adjacent elliptical arc tube segments, forming an orderly folding pattern induced by the bamboo-joint rounded corner and developing sequentially along the tube wall. Throughout the compression process, the structure maintains good axisymmetry and does not exhibit obvious overall instability, demonstrating stable layer-by-layer collapse energy absorption characteristics.

[0030] Example 2: This embodiment explores the effects of the number of corrugated periodic units, the degree of curvature of the elliptical arc tube segment, and the radius of the fillet on the structural impact resistance and energy absorption performance.

[0031] like Figures 5-7As shown, when the number of corrugated periodic units increases, the deformation mode of the energy-absorbing tube can change from an asymmetric mode to a symmetric mode, and the stress at the rounded transition section first concentrates and then guides the orderly deformation of the tube wall.

[0032] like Figures 8-10 As shown, peak force (PCF) decreases with increasing number of corrugated periodic units, while specific energy absorption (SEA), average crushing force (MCF), and total energy absorption (EA) show a trend of first increasing and then decreasing. The energy absorption performance reaches its maximum at the optimal number of corrugated periodic units.

[0033] When the degree of curvature of the elliptical arc is small, the pipe wall is close to a straight wall structure, the axial stiffness is uniform, and the deformation mode is mainly symmetrical annular buckling.

[0034] When the degree of curvature is moderate, stress concentration depressions are first generated in the local area of ​​the rounded corner transition section, which induces the adjacent elliptical arc tube sections to bend in a coordinated manner, realizing the gradual folding of "rounded corner transition section induction - elliptical arc tube section following".

[0035] When the bending is too large, the local stiffness drops sharply, and the deformation mode is prone to asymmetric instability, resulting in the premature appearance of peak force.

[0036] A well-designed fillet radius can balance stress concentration and deformation continuity, ensure the local buckling sequence, and guide the uniform folding of the pipe wall.

[0037] In summary, this invention achieves a controllable and stable progressive folding pattern by optimizing structural design parameters such as the number of corrugated periodic units, elliptical arc curvature, and elliptical parameters. During axial compression, this structure effectively disperses stress concentration, significantly reduces peak force fluctuations, and improves specific energy absorption and overall impact resistance, thus providing a reliable theoretical basis and experimental verification for the design of high-performance energy-absorbing thin-walled structures.

[0038] In the description of this utility model, it should be understood that the terms "center", "inner", "outer", "axial", "radial", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model.

[0039] In this utility model, unless otherwise explicitly specified and limited, the terms "setting," "installing," "connecting," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0040] Any aspects of this utility model not described in detail are common knowledge to those skilled in the art.

Claims

1. A non-uniform corrugated thin-walled energy-absorbing tube with rounded corner transition, characterized in that, It includes elliptical arc pipe segments and rounded transition segments that are alternately connected along the pipe axis. The rounded transition segments are used to smoothly connect the elliptical arc pipe segments on both sides. The elliptical arc pipe segments are formed by rotating an elliptical arc around the pipe axis. The major axis of the ellipse is parallel to the pipe axis, and the elliptical arc arches towards the inside of the pipe.

2. The non-uniform corrugated thin-walled energy absorber with rounded corner transition according to claim 1, characterized in that, The elliptical arc is symmetrical about the cross-section of the tube passing through the center of the elliptical arc.

3. The non-uniform corrugated thin-walled energy absorber with rounded corner transition according to claim 1, characterized in that, The total extension distance of the elliptical arc pipe segment along the pipe axis accounts for 60% to 85% of the total length of the pipe.

4. The non-uniform corrugated thin-walled energy absorber with rounded corner transition according to claim 1, characterized in that, The elliptical arc is the arc segment between the two vertices of the major axis of the ellipse.

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