Heterogeneous corrugated sandwich composite variable cross-section box girder structure and forming process thereof

Abstract

The present application relates to box girder structure technical field, especially to a kind of heterogeneous corrugated sandwich composite variable cross-section box girder structure, including structure ontology, the structure ontology is the stereoscopic structure of two ends narrow middle wide, the transition area of two ends and middle part of the structure ontology is inclined plane, two ends of the structure ontology are support section, and middle part is pure bending section, the transition area between support section and the pure bending section is shear section, the structure ontology includes inner tube and outer tube that is sleeved in outer tube of inner tube, hollow cavity is equipped between the inner tube and the outer tube, variable cross-section rigid foam core is filled in the cavity.The structure is superior in bending resistance, shear resistance, high material utilization rate, and has the function design that can be used for laying line, ventilation etc..The present application also provides a kind of heterogeneous corrugated sandwich composite variable cross-section box girder structure forming process.

Description

Technical Field

[0001] This invention relates to the field of box girder structure technology, and in particular to a heterogeneous corrugated sandwich composite material variable cross-section box girder structure and its molding process. Background Technology

[0002] Box girders subjected to four-point bending are a widely used structure in engineering, such as train axles and vehicle floor beams. Composite materials have lightweight advantages such as high specific strength and high specific modulus, and have been widely used in aerospace, automotive manufacturing, and civil engineering. However, existing composite box girder structures have poor performance and limited functionality. There is no box girder structure that simultaneously possesses superior bending and shear resistance and can perform multiple functions. Therefore, this invention designs a heterogeneous corrugated sandwich composite variable cross-section box girder structure and its molding process. Summary of the Invention

[0003] The purpose of this invention is to provide a heterogeneous corrugated sandwich composite material variable cross-section box girder structure. This structure exhibits superior bending and shear resistance, high material utilization, and is designed for applications such as wiring and ventilation. This invention also provides a molding process for the heterogeneous corrugated sandwich composite material variable cross-section box girder structure.

[0004] This invention provides a heterogeneous corrugated sandwich composite material variable cross-section box girder structure, including a structural body. The structural body is a three-dimensional structure that is narrow at both ends and wide in the middle. The transition area between the two ends and the middle of the structural body is an inclined plane. The two ends of the structural body are support sections, and the middle is a pure bending section. The transition area between the support section and the pure bending section is a shear section. The structural body includes an inner tube and an outer tube sleeved outside the inner tube. A hollow cavity is provided between the inner tube and the outer tube, and the cavity is filled with a variable cross-section rigid corrugated sandwich core.

[0005] Preferably, the upper part of the cavity is filled with an upper flange core, the lower part of the cavity is filled with a lower flange core, and the left and right sides of the cavity are filled with a left web core and a right web core, respectively.

[0006] Preferably, the upper flange core, lower flange core, left web core, and right web core are all composed of continuous trapezoidal corrugated cores.

[0007] Preferably, both the left web core and the right web core are made of horizontally longitudinally continuous corrugated cores.

[0008] Preferably, the upper flange core is composed of a transversely periodically arranged vertical longitudinal continuous corrugated structure and rigid foam, wherein the vertical longitudinal continuous corrugated structure is inserted into the rigid foam.

[0009] Preferably, the lower flange core is composed of a longitudinally periodically arranged vertical and transverse continuous corrugated structure interspersed with longitudinally continuous reinforcing ribs.

[0010] Preferably, the trapezoidal cells in the upper flange core, lower flange core, left web core, and right web core have the same inclination angle, horizontal segment length, height, and wall thickness.

[0011] Preferably, the structural body is made of resin-based carbon fiber reinforced composite material.

[0012] A molding process for the above-mentioned heterogeneous corrugated sandwich composite variable cross-section box girder structure includes the following steps:

[0013] Step 1: Prepare horizontal longitudinal continuous corrugated structures, vertical longitudinal continuous corrugated structures and rigid foam, vertical transverse continuous corrugated structures and longitudinal continuous reinforcing ribs for the web core, upper flange core and lower flange core; prepare long strip-shaped horizontal longitudinal continuous corrugated structures by compression molding process, and cut them into the same external dimensions as the web core using a CNC machine tool.

[0014] Cut the corrugated structure along the direction perpendicular to the horizontal longitudinal continuous corrugated structure, and bond them in pairs to form a hexagonal honeycomb shape. Then cut rigid foam and fill the gaps to complete the upper flange core composed of the vertical longitudinal continuous corrugated structure and rigid foam.

[0015] The long strip-shaped horizontal longitudinal continuous corrugated structure is cut laterally, placed vertically and bonded in pairs to form a vertical horizontal continuous corrugated structure. Grooves for assembly are cut on each period cell. Then, longitudinal continuous reinforcing ribs consistent with the lower flange contour line are prepared and cut by molding method and combined with the former.

[0016] Step 2: Processing rigid foam core mold and inner tube wall forming. The rigid foam core mold is processed by CNC machine tool and longitudinal through holes are opened. Carbon fiber prepreg is wrapped around the rigid foam core mold layer by layer and formed in a hot autoclave to prepare the inner tube. The rigid foam core mold is not removed after forming, so there is no demolding problem.

[0017] Step 3 involves attaching the four types of cores from Step 1 to the outer surface of the inner tube wall, then rolling up carbon fiber prepreg layer by layer, and finally placing it in a hot autoclave to form the outer tube, thus completing the fabrication of the entire structure.

[0018] Preferably, the inner and outer tubes are continuously ply-laid. Based on the continuous ply-laid structure, a ±45-degree shear ply is added to the inner and outer walls of the web in the shear section, and a 90 / 0 / 90 compressive ply is added to the inner and outer walls of the web in the pure bending section and the support section.

[0019] Beneficial effects:

[0020] This invention rationally selects the corrugated core layup and the cutting and placement direction of the corrugated core based on the stress state of the upper and lower flanges and the left and right webs, designing a heterogeneous corrugated sandwich composite variable cross-section box girder structure. This structure exhibits superior bending and shear resistance, high material utilization, and its longitudinally continuous internal cavity and the gaps between the corrugated cores in the two side webs can be used for functions such as wiring and ventilation. This invention also employs a molding process for fabricating this structure using resin-based carbon fiber reinforced composite materials, resulting in a structure with significant lightweight advantages. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall invention;

[0023] Figure 2 This is an enlarged cross-sectional schematic diagram of the present invention;

[0024] Figure 3 This is a schematic diagram showing the positional relationship of the four types of cores in this invention;

[0025] Figure 4 This is a schematic diagram of the vertical longitudinal continuous corrugated structure of the upper flange core in this invention;

[0026] Figure 5 This is a schematic diagram of the overall structure of the upper flange core in this invention;

[0027] Figure 6 This is a schematic diagram of the overall structure of the lower flange core in this invention;

[0028] Figure 7 This is a flowchart illustrating the preparation process of the upper flange core in the molding process of this invention.

[0029] Figure 8 This is a flowchart illustrating the preparation process of the lower flange core in the molding process of this invention.

[0030] Explanation of reference numerals in the attached drawings: 1-Structural body, 101-Outer tube, 102-Inner tube, 2-Support section, 3-Pure bending section, 4-Shear section, 5-Upper flange core, 501-Vertical longitudinal continuous corrugated structure, 502-Rigid foam, 6-Lower flange core, 601-Vertical transverse continuous corrugated structure, 602-Strengthening rib, 7-Left web core, 8-Right web core, 9-Horizontal longitudinal continuous corrugated structure. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 invention.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] Example 1

[0035] A heterogeneous corrugated sandwich composite material variable cross-section box girder structure, such as Figure 1-8 As shown, the structure includes a structural body 1, which is a three-dimensional structure that is narrow at both ends and wide in the middle. The transition area between the two ends and the middle of the structural body is an inclined plane. The two ends of the structural body are support sections 2, and the middle is a pure bending section 3. The transition area between the support section 2 and the pure bending section 3 is a shear section 4. The structural body 1 includes an inner tube 102 and an outer tube 101 sleeved outside the inner tube 102. A hollow cavity is provided between the inner tube 102 and the outer tube 101, and the cavity is filled with a variable cross-section rigid corrugated core.

[0036] The upper part of the cavity is filled with an upper flange core 5, the lower part of the cavity is filled with a lower flange core 6, and the left and right sides of the cavity are filled with a left web core 7 and a right web core 8. The upper flange core 5, the lower flange core 6, the left web core 7, and the right web core 8 are all composed of continuous trapezoidal corrugated cores.

[0037] like Figure 2 and Figure 3 As shown, both the left web core 7 and the right web core 8 adopt a horizontally longitudinally continuous corrugated core.

[0038] like Figure 4 and Figure 5 As shown, the upper flange core 5 is composed of a transversely periodically arranged vertical longitudinal continuous corrugated structure 501 and rigid foam 502, with the vertical longitudinal continuous corrugated structure 501 inserted into the rigid foam 502.

[0039] like Figure 6 As shown, the lower flange core 6 is composed of a longitudinally periodically arranged vertical and transverse continuous corrugated structure 601 interspersed with longitudinally continuous reinforcing ribs 602.

[0040] The left and right webs are the main contributors to the bending moment of inertia of the cross section, and use horizontally continuous longitudinal corrugated cores. The upper flange mainly bears in-plane bending compressive stress and compressive stress caused by out-of-plane concentrated loads, so it uses a core composed of transversely periodically arranged vertical longitudinal continuous corrugations and rigid foam. The lower flange mainly bears in-plane bending tensile stress, and its geometry is complex, making longitudinal continuity impossible. Therefore, it uses a core composed of longitudinally periodically arranged vertical transverse continuous corrugations interspersed with longitudinally continuous reinforcing ribs. The trapezoidal cells in the upper flange core 5, lower flange core 6, left web core 7, and right web core 8 have the same inclination angle, horizontal segment length, height, and wall thickness. All trapezoidal corrugated cores are prepared using the same set of molds through a molding method, which greatly reduces mold costs. The structural body 1 is made of resin-based carbon fiber reinforced composite material.

[0041] Based on the stress state of the upper and lower flanges and the left and right webs, a heterogeneous corrugated sandwich composite variable cross-section box girder structure was designed by rationally selecting the corrugated core layup and the cutting and placement direction of the corrugated core. This structure exhibits superior bending and shear resistance, high material utilization, and its longitudinally continuous internal cavity and the gaps between the corrugated cores in the two side webs can be used for functions such as wiring and ventilation. This invention also introduces the molding process for preparing this structure using resin-based carbon fiber reinforced composite materials. This composite material structure offers significant lightweight benefits.

[0042] A molding process for the above-mentioned heterogeneous corrugated sandwich composite variable cross-section box girder structure includes the following steps:

[0043] Step 1: Prepare the horizontal longitudinal continuous corrugated structure 9, the vertical longitudinal continuous corrugated structure 501 and rigid foam 502, the vertical transverse continuous corrugated structure 601 and the longitudinal continuous reinforcing rib 602 for the web core, the upper flange core and the lower flange core; prepare the long strip horizontal longitudinal continuous corrugated structure 9 by compression molding process, and cut it into the same external dimensions as the web core by CNC machine tool;

[0044] like Figure 7 As shown, the corrugated structure is cut along the direction of the continuous corrugated structure 9 perpendicular to the horizontal longitudinal direction, and then bonded in pairs to form a hexagonal honeycomb shape. Then, rigid foam 502 is cut and filled into the gaps to complete the upper flange core 5 composed of the vertical longitudinal continuous corrugated structure 501 and rigid foam 502.

[0045] like Figure 8 As shown, the long strip-shaped horizontal longitudinal continuous corrugated structure 9 is cut laterally, placed vertically and bonded in pairs to form a vertical and horizontal continuous corrugated structure 601. An assembly groove is cut on each period cell. Then, longitudinal continuous reinforcing ribs 602 that are consistent with the lower flange contour line are prepared and cut by molding method and combined with the former.

[0046] Step 2: Processing rigid foam core mold and inner tube wall forming. The rigid foam core mold is processed by CNC machine tool and longitudinal through holes are opened. Carbon fiber prepreg is wrapped around the rigid foam core mold layer by layer and formed in a hot autoclave to prepare the inner tube. The rigid foam core mold is not removed after forming, so there is no demolding problem.

[0047] Step 3 involves attaching the four types of cores from Step 1 to the outer surface of the inner tube wall, then rolling up carbon fiber prepreg layer by layer, and finally placing it in a hot autoclave to form the outer tube, thus completing the fabrication of the entire structure.

[0048] The inner and outer tubes are continuously ply-laid. On the basis of continuous ply-laid, ±45-degree shear ply-laid is added to the inner and outer walls of the web of the shear section, and 90 / 0 / 90 compressive ply-laid is added to the inner and outer walls of the web of the pure bending section and the support section.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heterogeneous corrugated sandwich composite material variable cross-section box girder structure, characterized in that, The structure includes a main body, which is a three-dimensional structure narrow at both ends and wide in the middle. The transition area between the two ends and the middle of the main body is an inclined plane. The two ends of the main body are support sections, and the middle is a pure bending section. The transition area between the support sections and the pure bending section is a shear section. The main body includes an inner tube and an outer tube sleeved outside the inner tube. A hollow cavity is provided between the inner tube and the outer tube. The cavity is filled with a variable cross-section rigid corrugated core. The upper part of the cavity is filled with an upper flange core, and the lower part of the cavity is filled with a lower flange core. The left side of the cavity... Both the upper and lower flange cores are filled with left and right web cores. The upper flange core, lower flange core, left web core, and right web core are all composed of continuous trapezoidal corrugated cores. The left and right web cores are both horizontally longitudinally continuous corrugated cores. The upper flange core is composed of a transversely periodically arranged vertical longitudinally continuous corrugated structure and rigid foam. The vertical longitudinally continuous corrugated structure is inserted into the rigid foam. The lower flange core is composed of a longitudinally periodically arranged vertical transversely continuous corrugated structure interspersed with longitudinally continuous reinforcing ribs.

2. The heterogeneous corrugated sandwich composite variable cross-section box girder structure according to claim 1, characterized in that, The trapezoidal cells in the upper flange core, lower flange core, left web core, and right web core all have the same tilt angle, horizontal segment length, height, and wall thickness.

3. The heterogeneous corrugated sandwich composite variable cross-section box girder structure according to claim 2, characterized in that, The main body of the structure is made of resin-based carbon fiber reinforced composite material.

4. A molding process for a heterogeneous corrugated sandwich composite variable cross-section box girder structure according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Prepare horizontal longitudinal continuous corrugated structures, vertical longitudinal continuous corrugated structures and rigid foam, vertical transverse continuous corrugated structures and longitudinal continuous reinforcing ribs for the web core, upper flange core and lower flange core; prepare long strip-shaped horizontal longitudinal continuous corrugated structures by compression molding process, and cut them into the same external dimensions as the web core using a CNC machine tool. Cut the corrugated structure along the direction perpendicular to the horizontal longitudinal continuous corrugated structure, and bond them in pairs to form a hexagonal honeycomb shape. Then cut rigid foam and fill the gaps to complete the upper flange core composed of the vertical longitudinal continuous corrugated structure and rigid foam. The long strip-shaped horizontal longitudinal continuous corrugated structure is cut laterally, placed vertically and bonded in pairs to form a vertical horizontal continuous corrugated structure. Grooves for assembly are cut on each period cell. Then, longitudinal continuous reinforcing ribs consistent with the lower flange contour line are prepared and cut by molding method and combined with the former. Step 2: Processing rigid foam core mold and inner tube wall forming. The rigid foam core mold is processed by CNC machine tool and longitudinal through holes are opened. Carbon fiber prepreg is wrapped around the rigid foam core mold layer by layer and formed in a hot autoclave to prepare the inner tube. The rigid foam core mold is not removed after forming, so there is no demolding problem. Step 3 involves attaching the four types of cores from Step 1 to the outer surface of the inner tube wall, then rolling up carbon fiber prepreg layer by layer, and finally placing it in a hot autoclave to form the outer tube, thus completing the fabrication of the entire structure.

5. The molding process of the heterogeneous corrugated sandwich composite variable cross-section box girder structure according to claim 4, characterized in that, The inner and outer tubes are continuously ply-laid. On the basis of the continuous ply-laid, ±45-degree shear ply-laid is added to the inner and outer walls of the web of the shear section, and 90 / 0 / 90 compressive ply-laid is added to the inner and outer walls of the web of the pure bending section and the support section.

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