Multi-dimensional variable cross-section dispersed force transfer reinforcing structure

Abstract

The invention discloses a multi-dimensional variable-cross-section dispersed force transfer reinforcing structure, which is applied to a section with large concentrated force and large-cross-section load effects, solves the problem of cross-section transfer of large concentrated force and large-cross-section force, and belongs to the technical field of carrier rocket structure design. A multi-dimensional variable cross-section dispersed force transmission reinforcing structure comprises a front shell section, a rear shell section, a force transmission structure, a dispersed force transmission reinforcing frame and a shear pin. A force transmission structure is installed on the front shell section and used for transmitting concentrated force, and a dispersed force transmission reinforcing frame is installed on the front shell section and enables the concentrated force to act on a skin of the front shell section in a dispersed shear flow mode. The front shell section and the rear shell section are connected through a butt joint screw, an anti-shearing pin is installed at the end frame where the front shell section and the rear shell section are connected, and shearing force is transmitted through the anti-shearing pin; and the rear shell section is reinforced through a variable cross-section inclined strut structure. Through the design of the multi-dimensional variable-cross-section dispersed force transfer reinforced structure, structural deformation caused by large concentrated force and large-cross-section load is effectively reduced, and the structural rigidity is improved by more than one time.

Description

Technical Field

[0001] This invention relates to a multi-dimensional variable cross-section distributed force transmission reinforcement structure, which is applied to sections subjected to large concentrated forces and large cross-sectional loads, and belongs to the field of launch vehicle structural design technology. Background Technology

[0002] Thin-walled stiffened cylindrical shell structures primarily bear distributed axial bending and shear loads, but they are also subject to large concentrated forces. To meet the strength and reliability requirements of the structure, specific structural components are needed to distribute concentrated loads. The radial rib structure, widely used in the traditional short-shell design connecting interstage sections and rocket propellant tanks, effectively diffuses unilateral concentrated forces. Existing topology optimization designs mainly focus on optimizing individual structures, with less consideration given to the joint optimization of multiple sections or structural assemblies. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and solve the problem of transmitting large concentrated forces and large cross-sectional forces across sections.

[0004] The objective of this invention is achieved through the following technical solutions:

[0005] A multidimensional variable cross-section distributed force transmission reinforcement structure includes a front shell section, a rear shell section, a force transmission structure, a distributed force transmission reinforcement frame, and a shear pin.

[0006] A force transmission structure is installed on the front shell section to transmit concentrated force, and a force-dispersing reinforcement frame is installed on the front shell section to disperse the concentrated force and apply it to the front shell section skin.

[0007] The front and rear shell sections are connected by butt bolts, and shear pins are installed at the end frames where the front and rear shell sections connect to transfer shear force. The rear shell section is reinforced by a variable cross-section diagonal bracing structure.

[0008] A multidimensional variable cross-section distributed force transmission enhancement method includes:

[0009] (1) Once the location of the concentrated force is determined, the stress on each section of the structure is determined; the overall deformation of the circular shell is obtained based on the finite element calculation, and the concentrated force is diffused by allocating the length of the sections and designing the docking surfaces, taking advantage of the load-bearing characteristics of the structural elements.

[0010] (2) The reinforced frame disperses the concentrated force into shear flow and transmits it to the segment skin. At the same time, the reinforced frame can improve the structural stiffness.

[0011] (3) Based on finite element calculations, force-transmitting diagonal braces are installed at the points where plastic deformation occurs in the end frame, and connected to the side wall skin to form a triangular support area;

[0012] (4) Multiple shear pins are set in the 90° region where the radial deformation of the shell is the largest to realize shear force transmission;

[0013] (5) Load tests are conducted on the designed structure according to the load requirements to measure the structural displacement and strain and verify the strengthening effect.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) This invention effectively reduces structural deformation caused by large concentrated forces and large cross-section loads by using a multi-dimensional variable cross-section distributed force transmission strengthening structural design, thereby increasing the structural stiffness by more than double. At the same time, for the segment connection structure, the transmission of axial force and shear force is separated, reducing the load on the connecting bolts and improving the reliability of the structure.

[0016] (2) The variable cross-section design of this invention greatly expands the design freedom and effectively improves the utilization rate of materials.

[0017] (3) This invention conducts structural design from multiple design dimensions and simultaneously conducts force transmission path design, making full use of materials through variable cross-section design; the essence of variable cross-section structure is to improve the load-bearing efficiency of the structure, improve the utilization rate of materials, and achieve equal strength design. Equal strength design is one of the important ideas in structural design. It adaptively changes the cross-sectional shape or structural layout according to the load conditions of the structure to make the stress equal at all points; thereby achieving the purpose of dispersing force transmission, improving structural stiffness, and reducing structural weight. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure.

[0019] Figure 2 This is a schematic diagram of the design process of the present invention.

[0020] Figure 3 Schematic diagram of overall structural optimization scheme.

[0021] Figure 4 This is a schematic diagram of a force-distributing reinforcement frame.

[0022] Figure 5 This is a schematic diagram of the diagonal bracing for force transmission in the end frame. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0024] A multi-dimensional variable cross-section distributed force transmission reinforcement structure includes a front shell section, a rear shell section, a force transmission structure, a distributed force transmission reinforcement frame, shear pins, and butt screws, etc., for details. Figure 1The overall structure consists of a front shell section and a rear shell section, connected by butt bolts and transmitting shear force through shear pins. A force-transmitting structure is installed on the front shell section to transfer concentrated forces, and a force-distributing reinforcing frame is installed on the front shell section to distribute the concentrated forces onto the front shell skin. Shear pins are installed at the end frames connecting the front and rear shell sections. The rear shell section is reinforced by a variable cross-section diagonal bracing structure, such as... Figure 5 As shown.

[0025] A design method for a multidimensional variable cross-section distributed force transmission reinforcement structure is proposed. This method involves variable cross-section optimization design from multiple dimensions, including the overall structural scheme, the distributed force transmission reinforcement frame, end frame braces, and shear pins. Finite element simulation analysis is primarily used for quantification during the optimization process. The final structural scheme is verified through experiments. The flowchart is shown below. Figure 2 The specific details are as follows:

[0026] (1) Overall structural scheme optimization

[0027] The overall structural design is crucial for structural force transmission. Once the location of a large concentrated force is determined, the stress on each section of the structure is also largely determined. For cantilever structures, the cumulative mass force has a cumulative effect, resulting in large section forces. The overall deformation of the circular shell can be calculated using finite element analysis, and this can be achieved by rationally allocating section lengths and designing the mating surfaces (…). Figure 3 It can fully utilize the load-bearing characteristics of structural elements to diffuse and concentrate forces.

[0028] (2) Distributed force transmission reinforcement frame

[0029] The reinforcing frame can disperse large concentrated forces into shear flow that is transferred to the segment skin, while also improving structural stiffness. Further optimization of the reinforcing frame's cross-sectional shape and dimensions can further enhance its stiffness. Figure 4 The cross-sectional shapes include both "I" and "π" shapes. Finite element analysis results show that the stiffness of the "I" shaped frame is superior to that of the "π" shaped frame. After determining the "I" shaped cross-section, a variable cross-section design was carried out. The "I" shape has the highest height at the location of the concentrated force, gradually decreasing towards both sides. The lower semi-circular shell section of the front shell deforms less and can be modified into a "T" shaped structure. The reinforcing frame is approximately crescent-shaped on the side where the concentrated force is applied. This variable cross-section structure is beneficial for improving structural stiffness.

[0030] (3) End frame force transmission diagonal brace

[0031] High concentrated forces can easily cause rotation at the end face of the segment connection, resulting in significant bending moments on the connecting bolts. To reduce end frame deformation and optimize the stress on the segment connecting bolts, force-transmitting diagonal braces were installed at the points of plastic deformation in the end frame, connected to the sidewall skin to form a triangular support zone, based on finite element analysis. The hypotenuse of the triangular support zone was parameterized as a spline curve, and the thickness of the force-transmitting diagonal braces was optimized using finite element analysis. This resulted in a cross-sectional change in the end frame area, ultimately reducing the load on the connecting bolts by 10%.

[0032] (4) Shear pin force transmission design

[0033] The large concentrated force causes significant radial deformation of the shell, and bolt connections alone are insufficient to meet the load-bearing requirements at the joint surfaces of the sections. Therefore, multiple shear pins are installed in the 90° area where the deformation is greatest to transfer shear force, thus optimizing the number of shear pins.

[0034] (5) Experimental verification

[0035] The designed structure was subjected to loading tests according to the load requirements, and the structural displacement and strain were measured. The results showed that the structure was intact, and the test data matched the simulation data.

[0036] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0037] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A multidimensional variable cross-section distributed force transmission reinforcement structure, characterized in that, Includes front shell section, rear shell section, force transmission structure, force-dispersing reinforcement frame, and shear pin; A force transmission structure is installed on the front shell section to transmit concentrated force, and a force-dispersing reinforcement frame is installed on the front shell section to disperse the concentrated force and apply it to the front shell section skin. The front and rear shell sections are connected by butt bolts, and shear pins are installed at the end frame where the front and rear shell sections connect to transmit shear force. The rear shell section is reinforced by a variable cross-section diagonal bracing structure.

2. The multidimensional variable cross-section distributed force transmission reinforcement structure according to claim 1, characterized in that, The distributed force transmission reinforcement frame adopts an "I" shaped cross section.

3. The multidimensional variable cross-section distributed force transmission reinforcement structure according to claim 1, characterized in that, The lower semi-circular shell section of the front shell has a T-shaped cross-section for dispersing force transmission.

4. The multidimensional variable cross-section distributed force transmission reinforcement structure according to claim 1, characterized in that, Multiple shear pins are installed in the 90° region where the radial deformation is greatest in the front and rear shell sections to achieve shear force transfer.

5. A multidimensional variable cross-section distributed force transmission enhancement method, characterized in that, include: (1) Once the location of the concentrated force is determined, determine the forces acting on each section of the structure; Based on the overall deformation of the circular shell obtained from finite element calculations, the concentrated force is diffused by allocating segment lengths and designing mating surfaces, utilizing the load-bearing characteristics of structural elements. (2) The reinforced frame disperses the concentrated force into shear flow and transmits it to the segment skin. At the same time, the reinforced frame can improve the structural stiffness. (3) Based on finite element calculations, force-transmitting diagonal braces are installed at the points where plastic deformation occurs in the end frame, and connected to the side wall skin to form a triangular support area; (4) Multiple shear pins are set in the 90° region where the radial deformation of the shell is the largest to realize shear force transmission; (5) Load tests are conducted on the designed structure according to the load requirements to measure the structural displacement and strain and verify the strengthening effect.

6. The multidimensional variable cross-section distributed force transmission reinforcement structure according to claim 5, characterized in that, In step (1), for cantilever structures, the accumulated mass force will have a cumulative effect, resulting in a large cross-sectional force.

7. The multidimensional variable cross-section distributed force transmission reinforcement structure according to claim 5, characterized in that, In step (2), the stiffness of the reinforcing frame is improved by optimizing the cross-sectional shape and size of the reinforcing frame; an "I" shaped cross-section is used at the location where the concentrated force is applied, and a "T" shaped cross-section is used for the lower semi-circular shell part of the front shell section.

8. The multidimensional variable cross-section distributed force transmission reinforcement structure according to claim 5, characterized in that, In step (3), the hypotenuse of the triangular support area is parameterized as a spline curve, and the thickness of the force transmission brace is optimized using finite element calculation, resulting in cross-sectional changes in the end frame area.

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