Shear and compression combined energy absorber

Abstract

This invention discloses a shear and compression combined energy absorber, comprising a flat cap and an actuating cap located at the upper and lower ends, a cutter located inside the actuating cap, and a fiber composite tube for cutting and compaction. The cutter includes a cylinder and a cutting blade inside the cylinder. The upper end of the fiber composite tube is fixedly connected to the lower end of the flat cap, and the lower end is inserted into the upper end of the cylinder and rests against the cutting blade. The actuating cap, cylinder, and fiber composite tube are connected together by a shear pin, and the lower end of the cylinder is fixedly connected to the actuating cap. The flat cap is used to press down on the fiber composite tube after the shear pin is broken by an impact load and is inserted into the actuating cap itself. The inner bottom surface of the actuating cap is provided with a guide curved surface for guiding the strips cut from the composite tube to flip upward. The cutting blade and the upper part of the cylinder are thin-walled structures that can be crushed by the flat cap, and the lower part of the cylinder is a thickened structure that can limit the stroke of the flat cap. This energy absorber combines shear and compression energy absorption methods, enabling efficient energy transfer and dissipation.

Description

Technical Field

[0001] This invention relates to energy absorbers, and more specifically to a combined shear and compression energy absorber. Background Technology

[0002] Energy absorbers typically work by processes such as plastic deformation, fracture, or friction of materials, converting impact energy into other forms of energy and dissipating it. They are widely used in key components in the aerospace field, playing an important role in aircraft takeoff and landing, emergency landing, collision protection, and helicopter seat cushioning.

[0003] Currently, common types of energy absorbers for aircraft seats mainly include extrusion tube expansion energy absorbers, flip tube energy absorbers, rolling ring energy absorbers, crushable cylindrical tube energy absorbers, and cutting energy absorbers. These energy absorbers each have their own characteristics and are widely used in various aircraft seat designs. However, these single-type energy absorbers often have some limitations. For example, cutting energy absorbers have relatively limited impact resistance, especially under high-energy impacts, they are prone to plastic failure or fracture, resulting in a decrease in energy absorption efficiency. Crusherable cylindrical tube energy absorbers often require a large space, and in some cases, their energy absorption efficiency is not as good as that of cutting energy absorbers. Summary of the Invention

[0004] The purpose of this invention is to provide a shear and compression combined energy absorber, which combines shear and compression energy absorption methods to achieve efficient energy transfer and dissipation.

[0005] The technical solution adopted in this invention is:

[0006] A shear and compression combined energy absorber includes a flat cap and an actuating cap located at the upper and lower ends, a cutter located inside the actuating cap, and a fiber composite tube for cutting and compacting. The cutter includes a cylinder with openings at both ends and a cutting blade axially disposed inside the cylinder. The upper end of the fiber composite tube is fixedly connected to the lower end of the flat cap, and the lower end is inserted into the upper end of the cylinder and abuts against the cutting blade. The upper end of the actuating cap, the upper end of the cylinder, and the lower end of the fiber composite tube are connected together by a shear pin, and the lower end of the cylinder is fixedly connected to the actuating cap. The flat cap is used to press down on the fiber composite tube after the shear pin is destroyed by the impact load and is inserted into the actuating cap itself. The bottom surface of the actuating cap is provided with a guide curved surface for guiding the strips cut from the composite tube to flip upward. The cutting blade and the upper part of the cylinder are thin-walled structures that can be crushed by the flat cap, and the lower part of the cylinder is a thickened structure that can limit the stroke of the flat cap.

[0007] Preferably, it also includes a positioning ring. There is an annular space between the cylinder and the actuating cap. The positioning ring fits into the annular space and is connected to the upper end of the actuating cap, the upper end of the cylinder, and the lower end of the limiting composite material tube via the shear pin. After the shear pin is broken, the positioning ring falls into the bottom of the annular space. The annular space is used to accommodate the upper part of the cylinder material after being crushed by the flattening cap. The positioning ring is made of metal.

[0008] Preferably, the upper end of the thickened structure at the bottom of the cylinder is a guide fillet that can guide the strips cut from the composite material tube to shift inward.

[0009] Preferably, the guide surface is arranged in a ring around the inner bottom surface of the actuating cap, and its cross-section is semi-circular.

[0010] Preferably, the cutting blade is in the form of a grid and extends to the lower end of the cylinder.

[0011] Preferably, the lower end face of the flat cap is provided with a slot, the outer diameter of which matches the inner diameter of the actuating cap, and the upper end of the fiber composite tube is inserted into the slot and then fixed by screws.

[0012] Preferably, the lower end of the cylinder is fixed to the actuating cap by screws.

[0013] Preferably, the flat cap, the actuating cap, and the cutter are made of metal.

[0014] Preferably, the upper end of the flat cap and the lower end of the actuating cap are provided with lugs for external installation.

[0015] The beneficial effects of this invention are:

[0016] This energy absorber combines shearing and compression to achieve efficient energy transfer and dissipation. When subjected to impact loads, the fiber composite tube is not only cut by the cutting blade but also squeezed between the flat cap and the actuating cap, causing the fiber composite to tear, bend, delaminate, and break, thus absorbing energy. In addition, the upper thin-walled section of the cutter is crushed and undergoes plastic deformation, thus absorbing energy. Furthermore, the friction generated between the fiber composite and the upper thin-walled section of the cutter during movement also absorbs impact energy. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the disassembled shear and compression combined energy absorber.

[0018] Figure 2 This is a cross-sectional view of the shear and compression combined energy absorber when it is not subjected to impact load.

[0019] Figure 3 This is a cross-sectional view of the lower end face of the flat cap in the shear and compression combined energy absorber when it contacts the upper end face of the cylinder.

[0020] Figure 4This is a cross-sectional view of the flat cap inserted into the actuator cap at a certain distance in the shear and compression combined energy absorber.

[0021] In the figure: 1-flat cap; 2-fiber composite tube; 21-strip; 3-positioning ring; 4-cutter; 41-cylinder; 42-cutting blade; 5-actuator; a-mounting hole for shear pin; b-guide surface; c-guide fillet; d-annular space. Detailed Implementation

[0022] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0023] This application provides a shear and compression combined energy absorber, the purpose of which is to combine the two energy absorption methods of shear and compression to achieve efficient energy transfer and dissipation, such as... Figures 1 to 4 As shown, it includes a flat cap 1, an actuating cap 5, a cutter, and a fiber composite tube 2; wherein: the flat cap 1 and the actuating cap 5 are located at the upper and lower ends, respectively. Figures 1 to 4 The cutter is located inside the actuating cap 5. The cutter includes a cylinder 41 and a cutting blade 42. The cylinder 41 is open at both ends. The cutting blade 42 is axially positioned inside the cylinder 41. The cutting blade 42 and the upper part of the cylinder 41 are thin-walled structures that can be crushed by the flat-pressing cap 1. The lower part of the cylinder 41 is a thickened structure that can limit the stroke of the flat-pressing cap 1. See Figures 1 to 4 The fiber composite tube 2 is used for cutting and compaction. The upper end of the fiber composite tube 2 is fixedly connected to the lower end of the flat cap 1, and the lower end is inserted into the upper end of the cylinder 41 and abuts against the cutting blade 42. The upper end of the actuating cap 5, the upper end of the cylinder 41, and the lower end of the fiber composite tube 2 are connected together by a shear pin. The lower end of the cylinder 41 is fixedly connected to the actuating cap 5. (See...) Figures 1 to 4 The flat cap 1 is used to press down the fiber composite tube 2 after the shear pin is broken by the impact load, and it also fits into the actuating cap 5. The inner bottom surface of the actuating cap 5 is provided with a guide surface b for guiding the strips 3 cut from the composite tube 2 to flip upwards, see Figures 2 to 4 This energy absorber combines shear and compression energy absorption methods, enabling efficient energy transfer and dissipation. Under impact load, the fiber composite tube 2 is both cut by the cutting blade 42 and compressed between the flat cap 1 and the actuating cap 5, causing tearing, bending, delamination, and fiber breakage in the fiber composite material, thus absorbing energy. Furthermore, the upper thin-walled section of the cutter is crushed, undergoing plastic deformation and absorbing energy. Additionally, friction generated between the fiber composite material and the upper thin-walled section of the cutter during movement also absorbs impact energy. This energy absorber has a relatively simple structure, simultaneously achieving both shear and compression energy absorption within the actuating cap 5. It is easy to assemble and can be used as a basic energy absorption unit in more complex structural designs.

[0024] like Figures 1 to 4As shown, in a preferred embodiment of this application, a positioning ring 4 is added to the above basic solution. The positioning ring 4 is preferably made of a metal material, such as... Figures 1 to 4 As shown, there is an annular space d between the cylinder 41 and the actuating cap 5. The positioning ring 4 fits within the annular space d and is connected to the upper end of the actuating cap 5, the upper end of the cylinder 41, and the lower end of the limiting composite material tube 2 via the shear pin. Figure 3 As shown, after the shear pin is broken, the positioning ring 4 falls into the bottom end of the annular cavity d, as... Figure 4 As shown, the annular space d is used to accommodate the upper material of the cylinder 41 after it has been crushed by the flat cap 1. To prevent the crushed upper material of the cylinder 41 from affecting the compression of the fiber composite tube 2, the annular space d is provided. The annular space d can accommodate the crushed upper material of the cylinder 41, but it will create a gap between the cylinder 41 and the actuating cap 5, which will affect the structural stability at the moment of impact and may cause the limiting composite tube 2 and the cylinder 41 to deviate slightly to the side. Therefore, a positioning ring 4 is added to tightly connect the actuating cap 5 and the cylinder 41 and eliminate the gap at their ends. In this way, at the moment of impact, the limiting composite tube 2 and the cylinder 41 can be prevented from deviating to the side. Furthermore, after the shear pin is broken, the positioning ring 4 falls into the bottom of the annular space d, and the positioning ring 4 will not affect the subsequent energy absorption action.

[0025] like Figures 2 to 4 As shown, in this embodiment, preferably, the upper end of the thickened structure at the lower part of the cylinder 41 is a guide fillet c that can guide the strips 3 cut from the composite material tube 2 to shift inward. This guide fillet c allows the strips 3 to shift inward before entering the guide curved surface b, which improves the efficiency and success rate of the strips 3 flipping upward.

[0026] like Figures 2 to 4 As shown, in this embodiment, preferably, the guide surface b is arranged in a ring around the inner bottom surface of the actuating cap 5, and its cross-section is semi-circular, which can flip all the strips 3 synchronously from the periphery to the center.

[0027] like Figures 2 to 4 As shown, in this embodiment, preferably, the cutting blade 42 is in the form of a grid and extends to the lower end of the cylinder 41, which can perform secondary cutting on the strip 3 after it is flipped upward.

[0028] Under impact load: the shear pin is broken by force, and the connection constraint between the actuator cap 5, positioning ring 4, cylinder 41, and limiting composite material tube 2 is released, and the positioning ring 4 falls into the bottom end of the annular cavity d; then, the pressure cap 1 presses down on the fiber composite material tube 2, and the fiber composite material tube 2 is cut into strips 3 by the cutting blade 42 during the downward movement. The strips 3 are first offset inward under the action of the guide rounded corner c, and then flipped upward under the action of the guide curved surface b, and then passed through the cutting blade 42 again and were cut again. In this process, the tearing, bending, and fiber breakage of the fiber composite material tube 2 are used to absorb energy; as the impact process continues, until the lower end face of the flat pressure cap 1 contacts the upper end face of the cylinder 41 and begins to cooperate with the insertion of the actuator cap 5, then, as the flat pressure cap 1 As the material moves downward, the thin-walled section of the cylinder 41 is first crushed and deformed, and the crushed and deformed material is squeezed into the annulus d. The upper part of the cutting blade 42 is then crushed and deformed under the action of increased force. As the impact process proceeds, when the bottom end of the flat cap 1 moves to a certain position, the strip 3 touches the inner surface of the flat cap 1. Both ends of the strip 3 are subjected to force at the same time. At this time, the upper part of the cutter is gradually crushed and plastic deformation will also further squeeze and destroy the strip 3. The debris generated by the strip 3 gradually fills the thickened section at the bottom of the cylinder 41 and is gradually compacted, further absorbing energy. When the thin-walled structure of the cutter is completely compressed and deformed, the stroke of the flat cap 1 is restricted by the thickened structure at the bottom of the cylinder 41. At this time, the debris generated by the destruction of the fiber composite tube 2 has also been compacted, and the energy absorption work ends.

[0029] like Figures 2 to 4 As shown, in this embodiment, preferably: the lower end face of the flat cap 1 is provided with a slot, the outer diameter of which matches the inner diameter of the actuating cap 5, and the upper end of the fiber composite tube 2 is inserted into the slot and then fixed by screws.

[0030] like Figures 2 to 4 As shown, in this embodiment, preferably, the lower end of the cylinder 41 is fixed to the actuating cap 5 by screws.

[0031] In this embodiment, the flat cap 1, the actuating cap 5, and the cutter are preferably made of metal. The upper end of the flat cap 1 and the lower end of the actuating cap 5 can be provided with lugs for external installation.

[0032] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A shear and compression combined energy absorber, characterized in that: The device includes a flat cap and an actuating cap located at the top and bottom ends, a cutter located inside the actuating cap, and a fiber composite tube for cutting and compacting. The cutter includes a cylinder with openings at both ends and a cutting blade axially disposed inside the cylinder. The upper end of the fiber composite tube is fixedly connected to the lower end of the flat cap, and the lower end is inserted into the upper end of the cylinder and abuts against the cutting blade. The upper end of the actuating cap, the upper end of the cylinder, and the lower end of the fiber composite tube are connected together by a shear pin, and the lower end of the cylinder is fixedly connected to the actuating cap. The flat cap is used to press down on the fiber composite tube after the shear pin is broken by the impact load and it is inserted into the actuating cap itself. The bottom surface of the actuating cap is provided with a guide curved surface for guiding the strips cut from the composite tube to flip upward. The cutting blade and the upper part of the cylinder are thin-walled structures that can be crushed by the flat cap, and the lower part of the cylinder is a thickened structure that can limit the stroke of the flat cap. It also includes a positioning ring. There is an annular space between the cylinder and the actuating cap. The positioning ring fits in the annular space and is connected to the upper end of the actuating cap, the upper end of the cylinder, and the lower end of the fiber composite tube through the shear pin. After the shear pin is broken, the positioning ring falls into the bottom end of the annular space. The annular space is used to accommodate the upper part of the cylinder material after being crushed by the flat pressure cap. The positioning ring is made of metal. The upper end of the thickened structure at the bottom of the cylinder is a guide fillet that can guide the strips cut from the composite material tube to shift inward; The cutting blades are in a grid pattern and extend to the lower end of the cylinder.

2. The shear and compression combined energy absorber as described in claim 1, characterized in that: The guiding surface is arranged in a ring around the inner bottom surface of the actuator cap, and its cross-section is semi-circular.

3. The shear and compression combined energy absorber as described in claim 1, characterized in that: The lower end face of the flat cap is provided with a slot, and its outer diameter matches the inner diameter of the actuating cap. The upper end of the fiber composite tube is inserted into the slot and then fixed by screws.

4. The shear and compression combined energy absorber as described in claim 1, characterized in that: The lower end of the cylinder is fixed to the actuating cap by screws.

5. The shear and compression combined energy absorber as described in claim 1, characterized in that: The flat cap, actuator cap, and cutter are made of metal.

6. The shear and compression combined energy absorber as described in claim 1, characterized in that: The upper end of the flat cap and the lower end of the actuating cap are provided with lugs for external installation.

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