CN116901481A - Modularized cylindrical shell structure, combined die and preparation method - Google Patents
Modularized cylindrical shell structure, combined die and preparation method Download PDFInfo
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- CN116901481A CN116901481A CN202310968079.6A CN202310968079A CN116901481A CN 116901481 A CN116901481 A CN 116901481A CN 202310968079 A CN202310968079 A CN 202310968079A CN 116901481 A CN116901481 A CN 116901481A
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- 238000000034 method Methods 0.000 claims description 31
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- 238000004519 manufacturing process Methods 0.000 claims description 21
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
- B29C70/32—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core on a rotating mould, former or core
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/30—Mounting, exchanging or centering
- B29C33/306—Exchangeable mould parts, e.g. cassette moulds, mould inserts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
- B29L2031/3097—Cosmonautical vehicles; Rockets
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/40—Weight reduction
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- Engineering & Computer Science (AREA)
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- Chemical & Material Sciences (AREA)
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Abstract
The application belongs to the field of modular carrier design, and particularly relates to a modular cylindrical shell structure, a combined die and a preparation method. The application aims to solve the problem of load change of a modularized aerospace carrier under a multitasking condition. The modularized cylindrical shell structure integrally adopts a composite material thin-wall structure, comprises a plurality of detachable reinforcing ribs and an orthogonal grid reinforcing rib structure, is of a multi-layer and multi-gradient reinforcing rib structure, has overall rigidity and strength which can be adjusted by adjusting the number and the size of the detachable reinforcing ribs, so that the structure meets the design requirement under a multi-task load, and compared with the traditional design concept aiming at the model, the modularized cylindrical shell structure avoids the embarrassment of redesigning and processing the bearing structure, reduces the cost, can realize the quick assembly of a carrier, and simultaneously, greatly reduces the structural weight compared with a metal structure.
Description
Technical Field
The application belongs to the field of modular carrier design, and particularly relates to a modular cylindrical shell structure, a combined die and a preparation method.
Background
Modular aerospace vehicles are one of the main directions of development of the aerospace industry because of their suitability for many types of tasks, complex space environments, and high economic benefits. The replacement of sub-modules provides flexibility to the modular structure, but at the same time, as the task type changes, the replacement of sub-modules also brings about changes in load conditions. If the load demand is reduced, the original main bearing structure inevitably reduces the bearing efficiency, and the waste of the carrying weight is caused; if the load demand increases, the original main bearing structure faces the embarrassment of redesign and manufacture. The redesign and the manufacture inevitably bring about the waste of resources and the extension of the design period, and the low-efficiency and model-oriented design concept is contrary to the development concept of high efficiency and rapidness in the aerospace industry, so that a modularized main bearing structure with adjustable rigidity can be realized within a certain range according to task requirements is quite necessary.
The grid reinforcement structure is one of the main load bearing structures of the aerospace vehicle, and the load bearing capacity and the load bearing efficiency directly affect the carrying capacity. The traditional composite material grid reinforcement structure is often a single-layer reinforcement structure, and lacks more material protection in a stress concentration area, so that the traditional composite material grid reinforcement structure is influenced by local buckling, and the bearing capacity of the shell structure is influenced. Inspired by dragonfly wing lines in nature, gradient stiffening structures are proposed, zhang et al propose gradient stiffening plates and apply the gradient stiffening plates to explosion vents, and the structure effectively inhibits local buckling behaviors under explosion load. Because of the process limitation, the design and the processing of the gradient reinforced cylindrical shell are less. In addition, the grid reinforced cylindrical shell structure often adopts a rubber mold, and in the curing and heating process, the high thermal expansion coefficient of the rubber mold enables the mold to excessively expand at high temperature, so that the structure to be molded is excessively extruded, and the size is distorted. Therefore, it is necessary to use a high-precision, low-cost manufacturing method that can be applied to a gradient ribbed cylindrical shell structure.
Disclosure of Invention
The application aims to solve the problem of load change caused by the replacement of a submodule of a modularized aerospace carrier and simultaneously solve the problem of preparation of a complex composite material structure. The application adopts a modularized scheme, provides a modularized cylindrical shell structure, a combined die and a preparation method, adopts a split structure and a multi-stage reinforcement idea, realizes the adjustment of the rigidity and strength of the gradient multi-stage reinforcement cylindrical shell structure in a certain range, and adopts a process method of combining a hard die with a hot die pressing process, thereby realizing the low-cost manufacture of the modularized cylindrical shell structure. The whole modularized cylindrical shell structure is a gradient reinforced thin-wall structure and consists of a plurality of detachable reinforcing ribs and an orthogonal grid reinforced structure. In this example 4 removable stiffeners are used. The gradient reinforcing ribs can obviously limit the local buckling behavior of the grid reinforcing cylindrical shell structure, and improve the bearing capacity and the bearing efficiency of the structure. The orthogonal grid reinforcement structure consists of orthogonal base reinforcement ribs and an outer skin. The detachable reinforcing rib is of a T-shaped strip-like structure, the height of the detachable reinforcing rib is consistent with that of the cylindrical shell, the detachable reinforcing rib comprises a web plate, wing plates and bottom pins, the bottom pins enclose a bottom groove, the size of the detachable reinforcing rib is slightly smaller than that of the orthogonal base reinforcing rib, and interference fit can be formed during insertion. In order to solve the problems of difficult molding and molding dimension errors of a complex composite material structure, the application combines the structural characteristics of the modularized cylindrical shell structure, and provides combined die equipment aiming at the orthogonal grating reinforced cylindrical shell structure and the detachable reinforcing ribs respectively.
The aim of the application is achieved by the following technical scheme.
The application provides a modularized cylindrical shell structure, which is integrally of a gradient reinforced thin-wall structure and consists of a plurality of detachable reinforcing ribs and an orthogonal grid reinforced structure. In this example, 4 removable stiffeners of the same size are used. The gradient reinforcing ribs can obviously limit the local buckling behavior of the grid reinforcing cylindrical shell structure, and improve the bearing capacity and the bearing efficiency of the structure.
Further, the orthogonal grid reinforcement structure comprises orthogonal base reinforcement ribs and an outer skin, due to the characteristic of continuous fibers, the transverse reinforcement ribs and the longitudinal reinforcement ribs are inevitably accumulated at the intersections to form intersections, the fibers are bent by fiber stacking, the mechanical property at the intersections is seriously affected, and the root of the intersections is weaker, so that the intersection fillet of the orthogonal base reinforcement ribs is arranged at the intersections, the stress concentration of the intersections is reduced, the strength of the intersections is improved, and the bearing capacity of the cylindrical shell is further improved.
Further, the detachable reinforcing rib is of a T-shaped strip-like structure, the height of the detachable reinforcing rib is consistent with the height of the cylindrical shell, the detachable reinforcing rib is composed of a web plate, wing plates and bottom pins, two side picking parts are the wing plates, the middle protruding part is the web plate, the bottom pins enclose a bottom groove which is identical to the orthogonal grid reinforcing rib structure, and the detachable reinforcing rib is convenient to insert.
Further, the whole modularized cylindrical shell structure is made of a continuous fiber reinforced resin matrix composite material. The continuous reinforced resin matrix composite material has the characteristics of small density, high strength and high rigidity, and can obviously reduce the structural weight under the condition of ensuring the structural strength.
A modular cylindrical shell structure manufacturing mold assembly apparatus, characterized by: the mold equipment is divided into a mold equipment for manufacturing the orthogonal grid reinforcement structure combination and a mold equipment for manufacturing the detachable reinforcement structure combination.
Further, the orthogonal grid reinforcement structure assembling die equipment comprises an outer skin clamp, a winding auxiliary disc, a fixing nut, a central shaft, a winding support and an inner core module, wherein a round hole is formed in the center of the fixing disc, the inner core is fixed on two sides of the central shaft through connecting keys, left and right ends of the inner core can be fixed to the fixing disc through screws, the inner core is alternately laid until the fixing disc is covered for a circle, the center of the winding auxiliary disc is also provided with the round hole for facilitating winding, the fixing nut is fixed on the outer side of the fixing disc under the action of the fixing nut, the central shaft with the fixing disc, the winding auxiliary disc, the fixing nut and the inner core module is placed on the winding support, the outer skin clamp is covered on the outer side of the fixing disc, and a through hole is formed in the flanging of the outer skin clamp for facilitating the application of pressure by the bolts.
Further, the inner core mold component is a female mold and a male mold, the female mold is not provided with a flanging, the male mold is provided with a flanging, and the flanging size is the same as that of the orthogonal base reinforcing rib. The female die and the male die can be fixed to the fixed disc in an alternative seamless manner, the core die set adopts a modularized design, and can be assembled according to the design requirement, similar to a 'type printing' method, the repeated use of the die and the rapid forming of the orthogonal grid reinforcement structures with different reinforcement sizes are realized; the convex parts of the female die and the male die are provided with round corners so as to form round corners at the crossing points of the products.
Further, the detachable reinforcing rib structure combined die equipment comprises a pressurized stringer, an upper die set, a middle die and a bottom die, wherein the upper die set is a pair of symmetrical dies, grooves are dug on the surface of the upper die set to fill prepreg, the middle die is positioned below the upper die set, through holes are formed in the middle die set to fill prepreg, the bottom die set comprises bosses, the bosses can be seamlessly inserted into the through holes of the middle die set, and the heights of the bosses are lower than the depths of the through holes of the middle die set.
Furthermore, the materials of the two sets of die equipment are high-strength die steel. The adoption of the high-strength die steel can avoid the deformation of the die structure of the combined die structure in the hot die pressing process, so that the die structure is difficult to reuse. In a preferred embodiment of the present application, the high strength H13 die steel is machined.
A process method of a modularized cylindrical shell structure comprises the following steps:
1) And determining the size and the number of the detachable reinforcing ribs based on a finite element simulation method according to the product load and the design requirement. In the application, the modularized cylindrical shell structure can control the structural rigidity by selecting the detachable reinforcing ribs with proper size and number so as to meet the design requirement, and the orthogonal grid reinforcing rib structure is not required to be redesigned and processed, and only the original mold and process are required to be adopted.
2) The number of prepregs required was calculated from the design results in 1. For the orthogonal grid reinforcement structure, selecting a prepreg tape with a proper size according to the size of the orthogonal substrate reinforcement; aiming at the layering angles and layering sequences of the prepregs required by the detachable reinforcing ribs, in the embodiment, a quasi-isotropic layering sequence is adopted, an automatic cloth cutting machine is adopted to cut the prepregs, a two-dimensional CAD model is drawn according to the design requirement in step 1, the two-dimensional CAD model is led into a numerical control cloth cutting machine tool, cloth cutting operation is carried out according to the number of the prepregs for each layer, and in a preferred mode provided by the application, an Aike BKL2516 cloth cutting machine is adopted.
3) And (5) processing and selecting combined die equipment. And if the available die is available, assembling the die by adopting a die formed by the previous machining, and if the existing die is not available, cutting the die by adopting a high-precision numerical control machine tool to obtain the die meeting the design requirement.
4) Using alcohol or acetone to clean all surfaces of the die, and coating a release agent on the surfaces of the combined die for not less than 3-5 times; the mold can be cleaned by using alcohol or acetone to effectively wipe off dust on the surface of the mold and resin remained on the mold in the former several molding processes, and if the resin remained on the surface is liable to influence the molding quality of the beam structure to be molded, the surface is rough, and the defects such as impurities are caused. The surface is coated with the release agent, so that the beam structure is convenient to be released after being cured and molded, and if the release agent is not wiped in place, the release process is difficult, the beam structure cannot be released or the surface quality is poor after being released.
5) The grating reinforced cylindrical shell structure is wound. And paving the cut prepreg tape in the groove of the die, rotating the die mandrel to lay the circumferential prepreg tape, transversely paving the prepreg tape along the groove after a layer of the prepreg tape is paved, and circularly reciprocating until the groove is filled. Prepreg sheets cut to a predetermined size are laid on the ribs to form an outer skin. And after the paving is finished, the upper outer skin clamp and the lower outer skin clamp are installed and pre-clamped to be attached to the surface of the outer skin.
6) And (5) solidifying the grating reinforced cylindrical shell structure. Placing the assembled grid reinforced cylindrical shell structure in an oven for heating and curing, wherein in a preferred mode provided by the application, the curing process comprises the following steps: the temperature is kept at 80 ℃ for 1 hour and 120 ℃ for 1.5 hours. And when the surface temperature of the die reaches 80 ℃ for the first time, applying pressure to the outer skin clamp through bolts on the outer skin clamp until the upper and lower outer skin clamps are tightly attached. After solidification, cooling to room temperature, firstly taking down the upper and lower clamps of the outer skin, taking out the connecting key along the axis direction of the central shaft, further dismantling the central shaft and fixing the disc to obtain a core mould assembly consisting of the core mould and the orthogonal grid reinforcement structure, taking out the female mould without the flanging along the inner normal direction easily according to the characteristics of the core mould, and taking down the male mould naturally after the female mould is completely taken down to obtain the orthogonal grid reinforcement structure.
7) And (5) laying detachable reinforcing ribs. And paving the prepreg in the groove of the upper die until the groove is completely filled, filling the prepreg lamination into the groove of the middle die, assembling the paved die, and pre-fixing the die through bolts.
8) And (5) curing the detachable reinforcing ribs. The assembled mould is placed in an oven for heating and curing, in a preferred scheme provided by the application, the curing process parameters which are the same as those of the orthogonal grid reinforcement structure are adopted, and the bolts are screwed down and pressure is applied until all the moulds are completely attached at 80 ℃. And after the solidification is finished, air cooling is carried out to room temperature, and the detachable reinforcing rib can be obtained after all bolts are unscrewed.
9) And aligning the prepared grooves at the bottoms of the detachable reinforcing ribs with the orthogonal grid reinforcing rib structure, and inserting the designed number of detachable reinforcing ribs along the normal direction of the curved surface to obtain the modularized cylindrical shell structure.
Advantageous effects
1. Through detachable gradient strengthening rib design and modularized design theory, regard as submodule with detachable strengthening rib, through adjusting detachable strengthening rib quantity and size, realized that aerospace vehicle main load-carrying structure's rigidity is adjustable, make it be applicable to the design of modularized structure.
2. The problem of bearing caused by sub-module replacement is avoided, meanwhile, the orthogonal grid reinforcement structure which is suitable for batch production of the detachable reinforcing ribs can be selected according to the load requirement, the carrier can be quickly assembled, meanwhile, the detachable reinforcing ribs and the orthogonal grid reinforcement structure can be independently produced without intervention, and the production period is greatly shortened due to the parallel production scheme.
3. The metal mold is combined with the hot molding process to prepare the structure, so that the high-precision manufacturing of the structure is realized, the metal mold has the advantage of high cycle period, the production cost is reduced, the characteristic of the metal mold suitable for the hot molding process is also free from the dependence of the autoclave process, and the production cost is greatly reduced.
Drawings
FIG. 1 is a schematic view of a modular cylindrical shell structure;
FIG. 2 is a schematic view of a removable stiffener;
FIG. 3 is a schematic diagram of a mold for an orthogonal grid ribbed cylindrical shell structure;
FIG. 4 is a cross-sectional view of a mold of an orthogonal grid ribbed cylindrical shell structure;
FIG. 5 is a schematic diagram of a mandrel-male mold of an orthogonal grid ribbed cylindrical shell structure;
FIG. 6 is a schematic diagram of a mandrel-negative mold of an orthogonal grid ribbed cylindrical shell structure;
FIG. 7 is a schematic view of a removable stiffener mold;
FIG. 8 is a schematic view of a removable stiffener mold upper mold;
FIG. 9 is a schematic view of a middle layer mold of a removable stiffener mold;
fig. 10 is a schematic view of a bottom mold of a removable stiffener mold.
The device comprises a 1-detachable reinforcing rib, a 2-outer skin, a 3-orthogonal base reinforcing rib, a 4-orthogonal base reinforcing rib intersection point, a 5-orthogonal base reinforcing rib intersection point fillet, a 6-web plate, a 7-wing plate, an 8-bottomable pin, a 9-bottoming groove, a 10-outer skin upper clamp, an 11-left winding auxiliary disc, a 12-left fixing disc, a 13-left fixing nut, a 14-central shaft, a 15-winding bracket, a 16-right winding auxiliary disc, a 17-right fixing disc, an 18-right fixing nut, a 19-outer skin lower clamp, a 20-male die, a 21-female die, a 22-connecting key, a 23-first upper die, a 24-second upper die, a 25-middle die, a 26-bottom die, a 27-pressing stringer, a 28-second pressing stringer, a 29-third pressing stringer and a 30-fourth pressing stringer.
Detailed Description
The application will now be described in detail by way of example with reference to the accompanying drawings.
Example 1
The present application provides a modular cylindrical shell structure as shown in fig. 1. The whole modularized cylindrical shell structure is of a gradient reinforced thin-wall structure and is composed of a plurality of detachable reinforcing ribs 1 and an orthogonal grid reinforced structure. In this example 4 removable stiffeners are used. The gradient reinforcing ribs can obviously limit the local buckling behavior of the grid reinforcing cylindrical shell structure, and improve the bearing capacity and the bearing efficiency of the structure.
Further, the orthogonal grid reinforcement structure comprises the orthogonal base reinforcement 3 and the outer skin 2, due to the characteristic of continuous fibers, the transverse reinforcement and the longitudinal reinforcement are inevitably accumulated at the intersections to form the intersections 4, the fibers are bent by fiber stacking, the mechanical property at the intersections is seriously affected, and the roots of the intersections are weaker, so that the intersection fillet of the orthogonal base reinforcement is arranged at the intersections, the stress concentration of the intersections 4 is reduced, the strength of the intersections is improved, and the bearing capacity of the cylindrical shell is further improved.
The detachable reinforcing rib is of a T-shaped strip-like structure, the height of the detachable reinforcing rib is identical to that of the cylindrical shell, as shown in fig. 2, the detachable reinforcing rib consists of a web plate 6, wing plates 7 and bottom pins 8, two side picking parts are wing plates, the middle protruding part is the web plate, and the bottom pins enclose a bottom groove which is identical to the orthogonal grid reinforcing rib structure, so that the detachable reinforcing rib is convenient to insert.
Further, the whole modularized cylindrical shell structure is made of a continuous fiber reinforced resin matrix composite material. The continuous reinforced resin matrix composite material has the characteristics of small density, high strength and high rigidity, and can obviously reduce the structural weight under the condition of ensuring the structural strength.
A modular cylindrical shell structure manufacturing mold assembly apparatus, characterized by: the mold equipment is divided into a mold equipment for manufacturing the orthogonal grid reinforcement structure combination and a mold equipment for manufacturing the detachable reinforcement structure combination.
Further, the orthogonal grid reinforcement structure assembling die apparatus, as shown in fig. 3, includes: an upper outer skin jig 10, a lower outer skin jig 19, a left winding auxiliary disc 11, a right winding auxiliary disc 16, a left fixing disc 12, a right fixing disc 17, a left fixing nut 13, a right fixing nut 18, a center shaft 14, a winding bracket 15, and an inner core module. To facilitate demolding, the inner mandrel assembly is divided into a male die 20 with a flange of the same size as the orthogonal base web and a female die 21 without a flange. Rounded corners are processed at the intersecting positions of grooves of the female die and the male die so as to form rounded corners at the intersecting points of products. The male die 20 and the female die 21 are fixed on the left fixed disk 12 and the right fixed disk 17 in an annular array in a staggered way, and the fixed disks are connected with the central shaft 14 through connecting keys 22. After connection, a left winding auxiliary disc 11 and a right winding auxiliary disc 16 are respectively arranged on the left side and the right side, and are respectively fixed by a left fixing nut 13 and a right fixing nut 18. After the assembly is completed, the outer skin clamp is placed on the winding bracket 15 so as to be convenient for winding fiber or prepreg, after the winding is completed, the upper outer skin clamp 10 and the lower outer skin clamp 19 are used for clamping, the outer skin clamp can apply pressure through bolts, so that air bubbles can be conveniently discharged in the curing process, structural defects are reduced, and structural quality is improved.
Further, the detachable reinforcing rib structure assembling die apparatus includes: left side upper die 23, right side upper die 24, middle die 25 and bottom die 26, first pressurized stringer 27, second pressurized stringer 28, third pressurized stringer 29, fourth pressurized stringer 30. The left side upper die 23 and the right side upper die 24 are symmetrically placed, and grooves are formed according to the size characteristics of the product to be formed so as to fill the prepreg. The middle layer mould 25 is provided with holes for filling prepreg, the protruding size of the bottom layer mould 26 is the same as the opening size of the middle layer mould 25, and when the mould is assembled, the bottom layer mould is inserted into the middle layer mould 25 along the protruding normal direction of the bottom layer mould. After the assembly is completed, the first pressurized stringer 27, the second pressurized stringer 28, the third pressurized stringer 29 and the fourth pressurized stringer 30 are used for applying pressure to the mold, and the pressure is transmitted to a product to be molded through the lower mold, so that the molding quality is improved.
Furthermore, the materials of the two sets of die equipment are high-strength die steel. The adoption of the high-strength die steel can avoid the deformation of the die structure of the combined die structure in the hot die pressing process, so that the die structure is difficult to reuse. In a preferred embodiment of the present application, the high strength H13 die steel is machined.
A process method of a modularized cylindrical shell structure comprises the following steps:
1) According to the load of the product and the design requirement, selecting an orthogonal grid reinforcement structure with a proper size and determining the size parameters and the number of the detachable reinforcement ribs; in the application, the modularized cylindrical shell structure can control the structural rigidity by selecting the detachable reinforcing ribs with proper size and number so as to meet the design requirement, the orthogonal grid reinforcing rib structure is not required to be redesigned and processed generally, and the orthogonal grid reinforcing rib cylindrical shell structure without proper size is required to be processed according to the step 5.
2) Calculating the number of the required prepregs according to the design parameters obtained in step 1; the method comprises the steps of determining the number of required prepregs by means of a CATIA three-dimensional CAD design fillet composite material module, and cutting the prepregs into the required shape by adopting an automatic cloth cutting machine, wherein in a preferred mode provided by the application, an Aike BKL2516 cloth cutting machine is adopted.
3) Selecting combined die equipment; and selecting modularized die equipment in the die library, and cutting the die by adopting a high-precision numerical control machine tool if the die library does not have proper die equipment.
4) Preparing before layering and winding; using alcohol or acetone to clean all surfaces of the die, and coating a release agent on the surfaces of the combined die for not less than 3-5 times; the mold can be cleaned by using alcohol or acetone to effectively wipe off dust on the surface of the mold and resin remained on the mold in the former several molding processes, and if the resin remained on the surface is liable to influence the molding quality of the beam structure to be molded, the surface is rough, and the defects such as impurities are caused. The surface is coated with the release agent, so that the beam structure is convenient to be released after being cured and molded, and if the release agent is not wiped in place, the release process is difficult, the beam structure cannot be released or the surface quality is poor after being released.
5) Preparing an orthogonal grating reinforced cylindrical shell structure; and paving the cut prepreg tape in the groove of the die, rotating the die mandrel to lay the circumferential prepreg tape, transversely paving the prepreg tape along the groove after a layer of the prepreg tape is paved, and circularly reciprocating until the groove is filled. Prepreg sheets cut to a predetermined size are laid on the ribs to form an outer skin. And after the paving is finished, the upper outer skin clamp and the lower outer skin clamp are installed and pre-clamped to be attached to the surface of the outer skin.
6) Curing the orthogonal grid reinforced cylindrical shell structure; placing the assembled grid reinforced cylindrical shell structure in an oven for heating and curing, wherein in a preferred mode provided by the application, the curing process comprises the following steps: the temperature is kept at 80 ℃ for 1 hour and 120 ℃ for 1.5 hours. And when the surface temperature of the die reaches 80 ℃ for the first time, applying pressure to the outer skin clamp through bolts on the outer skin clamp until the upper and lower outer skin clamps are tightly attached. After solidification, cooling to room temperature, firstly taking down the upper and lower clamps of the outer skin, taking out the connecting key along the axis direction of the central shaft, further dismantling the central shaft and fixing the disc to obtain a core mould assembly consisting of the core mould and the orthogonal grid reinforcement structure, taking out the female mould without the flanging along the inner normal direction easily according to the characteristics of the core mould, and taking down the male mould naturally after the female mould is completely taken down to obtain the orthogonal grid reinforcement structure.
7) Laying detachable reinforcing ribs; and paving the prepreg in the groove of the upper die until the groove is completely filled, filling the prepreg lamination into the groove of the middle die, assembling the paved die, and pre-fixing the die through bolts.
8) And (5) curing the detachable reinforcing ribs. The assembled mould is placed in an oven for heating and curing, in a preferred scheme provided by the application, the curing process parameters which are the same as those of the orthogonal grid reinforcement structure are adopted, and the bolts are screwed down and pressure is applied until all the moulds are completely attached at 80 ℃. And after the solidification is finished, air cooling is carried out to room temperature, and the detachable reinforcing rib can be obtained after all bolts are unscrewed.
9) Assembling a modularized cylindrical shell structure; and aligning the prepared grooves at the bottoms of the detachable reinforcing ribs with the orthogonal grid reinforcing rib structure, and inserting the designed number of detachable reinforcing ribs along the normal direction of the curved surface to obtain the modularized cylindrical shell structure.
The modularized cylindrical shell structure obtained through the die equipment and the process method can obviously reduce the structural quality on the premise of ensuring the bearing capacity, compared with a metal structure, the weight is effectively reduced by about 42 percent, and the specific compression strength (bearing efficiency) of the cylindrical shell structure is in an ascending trend along with the increase of the number of the reinforcing ribs because the local buckling behavior of the cylindrical shell structure is limited by the gradient reinforcing rib design. Meanwhile, the application provides a low-cost and high-precision preparation method of the modularized cylindrical shell structure. The application provides a modularized cylindrical shell structure which adopts a modularized design thought to effectively solve the problem of load change under the multitasking of the modularized structure, avoids the waste and inefficiency of model design, realizes the rapid assembly of products, and greatly increases the design and production efficiency. The die has the advantages of simple processing technology, low manufacturing cost, easy maintenance and simple operation, and can realize efficient molding.
Example 2
This example is substantially the same as the first example described above, except that: adopt detachable strengthening rib of different quantity and not unidimensional detachable strengthening rib, form multistage reinforcement structure.
Example 3
This example is substantially the same as the first example described above, except that: and a glue layer is smeared at the joint of the detachable reinforcing rib and the orthogonal grid reinforcing rib structure so as to increase the connection strength, so that the joint is suitable for the high-strength service environment.
Example 4
This example is substantially the same as the first example described above, except that: the detachable reinforcing rib web is not rectangular, triangular, sinusoidal or wavy.
In summary, the above embodiments are only preferred embodiments of the present application, and are not intended to limit the scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (10)
1. A modular cylindrical shell structure, characterized in that: the integral composite material is a multi-stage reinforcing rib cylindrical shell structure and comprises a detachable reinforcing rib and an orthogonal grid reinforcing rib structure, wherein the detachable reinforcing rib is fixed on the inner side of the orthogonal grid reinforcing rib structure in an interference fit mode or a glue layer adding mode to form a modularized cylindrical shell structure.
2. The modular cylindrical shell structure of claim 1, wherein: the orthogonal grid reinforcement structure comprises orthogonal base reinforcing ribs and an outer skin, and the orthogonal base reinforcing ribs and the outer skin are integrally formed by adopting a co-curing forming process.
3. The modular cylindrical shell structure of claim 2, wherein: and round corners are arranged at the crossing points of the transverse and longitudinal ribs of the orthogonal base reinforcing ribs.
4. The modular cylindrical shell structure of claim 1, wherein: the section of the detachable reinforcing rib is of a T-shaped strip-like structure, the height of the detachable reinforcing rib is consistent with that of the cylindrical shell, the detachable reinforcing rib consists of a web plate, wing plates and bottom pins, two side picking parts are the wing plates, the middle protruding part is the web plate, and the bottom pins enclose a bottom groove which is identical with the orthogonal grid reinforcing rib structure.
5. The modular cylindrical shell structure of claim 4, wherein: the removable stiffener web contains a variety of forms including, but not limited to: rectangular, triangular, sinusoidal, zigzag.
6. A modular cylindrical shell structure manufacturing mold assembly apparatus, characterized by: the mold equipment is divided into a mold equipment for manufacturing the orthogonal grid reinforcement structure combination and a mold equipment for manufacturing the detachable reinforcement structure combination.
7. The modular cylindrical shell structure modular mold apparatus of claim 6, wherein: the utility model provides an orthogonal grid adds muscle structure assembling die equipment contains outer skin anchor clamps, winding auxiliary disc, fixed disc, fixation nut, the center pin, winding support and inside core module, open at fixed disc center has the round hole, be fixed in the center pin both sides through the connecting key, both ends accessible screw fixation is to fixed disc about the inside mandrel, inside mandrel is laid in turn until covering fixed disc a week, for the winding of being convenient for, open equally at winding auxiliary disc center has the round hole, be fixed in the fixed disc outside under fixation nut effect, the center pin that has fixed disc, winding auxiliary disc, fixation nut and inside core module is placed on the winding support, cover outer skin anchor clamps at its outside, outer skin anchor clamps turn-ups is opened and is convenient for the bolt to exert pressure with the through-hole.
8. The modular cylindrical shell structure modular mold apparatus of claim 7, wherein: the core mold component comprises a female mold and a male mold; the female die is not provided with a flanging, the male die is provided with a flanging, and the flanging size is the same as that of the orthogonal base reinforcing rib; the female die and the male die are alternately and seamlessly fixed to the fixed disc.
9. The modular cylindrical shell structure modular mold apparatus of claim 6, wherein: the detachable reinforcing rib structure combined die equipment comprises a pressurized stringer, an upper die set, a middle die and a bottom die, wherein the upper die set is a pair of symmetrical dies, a groove is dug on the surface of the upper die set, the middle die is positioned below the upper die, a through hole is formed in the middle die set, the bottom die set comprises a boss, the height of the boss is lower than the depth of the through hole of the middle die set, and in the assembling process, the boss is seamlessly inserted into the through hole of the middle die set along the normal direction.
10. A method of making a modular cylindrical shell structure according to claim 1, characterized by: the method comprises the following steps:
1) According to the load of the product and the design requirement, selecting an orthogonal grid reinforcement structure with a proper size and determining the size parameters and the number of the detachable reinforcement ribs; if the orthogonal grid reinforcement structure with the proper size is not provided, the preparation is carried out according to the step 5;
2) Determining the quantity of the needed prepreg by means of the CATIA composite material module according to the design parameters obtained in the step 1, and cutting the prepreg into the needed shape by adopting an automatic cloth cutting machine;
3) Selecting combined die equipment; selecting modularized die equipment in a die library, and cutting the die by adopting a high-precision numerical control machine tool if the die library does not have proper die equipment;
4) Preparing before layering and winding, including cleaning a die and soaking a die surface with a release agent;
5) Preparing an orthogonal grating reinforced cylindrical shell structure; laying the cut prepreg tape in a groove of a die, sequentially winding the prepreg tape along the circumferential direction and the longitudinal direction until the groove is filled, then laying prepreg sheets on ribs to form an outer skin, and after the laying is completed, installing and pre-clamping an upper outer skin clamp and a lower outer skin clamp until the upper outer skin clamp and the lower outer skin clamp are attached to the surface of the outer skin;
6) Curing the orthogonal grid reinforced cylindrical shell structure; placing the assembled grating reinforced cylindrical shell structure in an oven for heating and curing, cooling to room temperature after curing is completed, and taking out the orthogonal grating reinforced cylindrical shell structure;
7) Laying detachable reinforcing ribs; laying the prepreg in the groove of the upper die until the groove is completely filled, filling the prepreg lamination into the groove of the middle die, assembling the laid die, and pre-fixing the laid die through bolts;
8) Curing the detachable reinforcing ribs; placing the assembled mold in an oven for heating and curing, after curing is completed, cooling to room temperature by air, completely unscrewing bolts, and taking out the detachable reinforcing ribs;
9) Assembling a modularized cylindrical shell structure; and aligning the prepared grooves at the bottoms of the detachable reinforcing ribs with the orthogonal grid reinforcing rib structure, and inserting the designed number of detachable reinforcing ribs along the normal direction of the curved surface to form the modularized cylindrical shell structure.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117445260A (en) * | 2023-12-26 | 2024-01-26 | 天津轻快未来科技有限公司 | Forming die and forming process for net-size composite material of dense-cell product |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117445260A (en) * | 2023-12-26 | 2024-01-26 | 天津轻快未来科技有限公司 | Forming die and forming process for net-size composite material of dense-cell product |
| CN117445260B (en) * | 2023-12-26 | 2024-04-19 | 天津轻快未来科技有限公司 | Forming die and forming process for net-size composite material of dense-cell product |
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