Bag type isostatic pressing generation structure for composite material pressure forming
Through the bladder isostatic pressure generating structure composed of fiber reinforced bodies and sealed elastomers, the problems of high cost of composite pressure forming equipment and uneven pressure distribution are solved, and low-cost and efficient hydrostatic pressure forming is achieved.
Patent Information
- Application Number
- CN202422594618.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-25
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2034-10-25
AI Technical Summary
Existing composite pressure forming equipment is costly and unevenly distributed, requiring simple and low-cost alternatives.
A bladder structure composed of a fiber reinforced body and a sealed elastomer is mechanically weaved to form a hollow cylindrical fiber reinforced body. After injection of the sealed elastomer, a bladder isostatic pressure generation structure is formed. Pressure is applied at both ends using a pressure working fluid to apply hydrostatic pressure to the mold.
It improves the strength and sealing of the capsule structure, improves the uniformity of pressure distribution, reduces the purchase cost of equipment, and provides a reliable hydrostatic pressure forming solution.
Smart Images
Figure CN223252384U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of composite materials, in particular to a bladder-type isostatic pressing production structure for pressure molding of composite materials. Background Art
[0002] In industry and aerospace, pressure-assisted molding of composite materials typically involves applying pressure to a solid mold using a press, or using a tank filled with high-pressure fluid to apply pressure to a flexible or solid mold. These molding methods typically require specialized equipment.
[0003] If a simple isostatic pressing structure is provided to replace the above-mentioned special equipment, the cost required for pressure forming of the composite material can be effectively reduced. Utility Model Content
[0004] The content of this disclosure is intended to briefly introduce concepts that will be described in detail in the detailed description of the embodiments below. The content of this disclosure is not intended to identify key features or essential features of the claimed technical solution, nor is it intended to limit the scope of the claimed technical solution.
[0005] The utility model provides a bladder-type isostatic pressing structure for pressure forming of composite materials, so as to solve the technical problems mentioned in the above background technology part.
[0006] The composite material pressure forming bladder isostatic pressing production structure comprises a fiber reinforcement and a bladder structure composed of a sealing elastic body wrapping the fiber reinforcement, and a pressure working fluid, wherein:
[0007] The fiber reinforcement is formed by mechanical weaving and includes a warp fiber reinforcement structure and a weft fiber reinforcement structure that are evenly arranged; the fiber reinforcement is in the shape of a hollow cylinder with an opening at one or both ends;
[0008] The sealing elastomer is formed by injecting slurry into the fiber reinforcement using the RTM process;
[0009] The pressure working fluid is injected into the bladder structure, and after the opening is sealed, a bladder-type isostatic pressure generating structure is formed;
[0010] In a working state, pressure is applied to both ends of the bladder-type isostatic pressure generating structure, thereby applying hydrostatic pressure to the mold in composite material molding.
[0011] Optionally, the weft-fiber reinforced structure needs to be loosely woven with a tensile strain reserve of 10% to 50%.
[0012] Optionally, the fiber in the fiber reinforcement is selected from one of the following: nylon fiber, aramid fiber, glass fiber, high silica fiber, quartz fiber, carbon fiber.
[0013] Optionally, the fiber volume content of the fiber reinforcement is 10% to 20%.
[0014] Optionally, the tensile strain rate of the sealing elastomer is 100% to 300%, and the high temperature resistance is not less than 250°C.
[0015] Optionally, the slurry includes one of the following: rubber, silicone rubber, and resin.
[0016] Optionally, the bladder structure has a thickness of 0.5 mm to 4 mm, and a cross-sectional circumference strain rate of 10% to 50%.
[0017] Optionally, the pressure working fluid includes one of the following: water, ethylene glycol, and oil radiator.
[0018] Optionally, the operating temperature of the pressure working fluid is not higher than 0.8 times the melting point of the pressure working fluid.
[0019] Optionally, the opening is tied with multiple straps or ropes.
[0020] The above embodiment of the present invention has the following beneficial effects: the bladder structure formed by wrapping the fiber reinforcement with a sealing elastomer has elasticity and sealing properties. The fiber reinforcement is evenly provided with a warp fiber reinforcement structure and a weft fiber reinforcement structure, thereby enhancing the overall strength of the bladder structure.
[0021] In this way, when the bladder structure is injected with pressure working fluid and completed with packaging, that is, after the bladder-type isostatic pressure generating structure is formed, when subjected to pressure, the bladder-type structure can provide the required elasticity, strength and sealing, thereby improving the reliability of the bladder-type isostatic pressure generating structure.
[0022] Finally, by applying pressure at both ends of the bladder-type isostatic pressure generating structure, hydrostatic pressure is generated around it, exerting hydrostatic pressure on the mold used in composite molding. This bladder-type isostatic pressure generating structure can improve the uneven pressure distribution often associated with traditional ejector-type pressure transmission devices. It also avoids the cost of using dedicated pressure tanks / pressure boxes and other hydrostatic equipment, making it simple, easy to use, and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0024] Figure 1 A schematic structural diagram of an embodiment of a simple bladder isostatic pressing structure for composite material pressure molding according to the present invention;
[0025] Figure 2 The present invention is a schematic structural diagram of an embodiment of a fiber reinforcement in a structure produced by simple bladder isostatic pressing for pressure forming of a composite material.
[0026] Description of reference numerals:
[0027] 1. Sealing elastomer; 2. Fiber reinforcement; 21. Weft fiber reinforcement structure; 22. Warp fiber reinforcement structure. DETAILED DESCRIPTION
[0028] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.
[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.
[0031] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.
[0032] See also Figure 1 and Figure 2 , Figure 1 A schematic structural diagram of an embodiment of a simple bladder isostatic pressing structure for composite material pressure molding according to the present invention; Figure 2 This is a schematic structural diagram of an embodiment of a fiber reinforcement in a simple bladder isostatic pressing structure for composite material pressure molding according to the present invention. Figure 1 and Figure 2 As shown, the composite material pressure forming bladder isostatic pressing production structure includes a fiber reinforcement 2 and a sealing elastomer 1 and a pressure working fluid.
[0033] The sealing elastomer 1 wraps around the fiber reinforcement 2 to form a bladder-like structure. After the pressure working fluid is injected into the bladder structure and the bladder structure is encapsulated, the bladder-like isostatic pressure generating structure is formed. During actual use, pressure is applied to both ends of the bladder-like isostatic pressure generating structure, thereby applying hydrostatic pressure to the mold used to form the composite material. This improves the uneven pressure distribution often associated with conventional ejector-type pressure transmission devices and avoids the cost associated with using dedicated pressure tanks / boxes and other static pressure equipment.
[0034] The fiber reinforcement 2 can be formed by mechanical weaving and specifically includes a uniformly arranged warp fiber reinforcement structure 22 and weft fiber reinforcement structure 21. This can improve the overall strength of the fiber reinforcement 2 and the bladder structure. The fiber reinforcement 2 can be a hollow cylindrical structure with an opening at one or both ends.
[0035] The fibers in the fiber reinforcement 2 can be selected from any of the following: nylon fiber, aramid fiber, glass fiber, high-silica fiber, quartz fiber, or carbon fiber. The fiber volume fraction of the fiber reinforcement 2 is 10% to 20%. Because the bladder-type isostatic pressing structure is subject to pressure at both ends, the weft-oriented fiber reinforcement structure 21 requires a loose weave with a strain reserve of 10% to 50%.
[0036] The above-mentioned sealing elastomer 1 can be injected into the fiber reinforcement 2 through the RTM process (Resin Transfer Molding) using slurry such as rubber, silicone rubber, and resin, and a sac-like structure is formed after vulcanization and demolding. Specifically, the woven fiber reinforcement 2 can be inserted into the inner membrane, and the outer mold is closed and vacuumed. The slurry is then injected simultaneously through different injection ports, and the sac-like structure is formed after room temperature vulcanization. Therefore, the sealing elastomer 1 can provide good elasticity and sealing for the sac-like structure.
[0037] The thickness of the bladder structure may be 0.5 mm to 4 mm, and the cross-sectional circumference strain rate may be 10% to 50%.
[0038] The pressure working fluid can be injected into the bladder structure. The pressure working fluid can be water, ethylene glycol, oil radiator, etc. The working temperature of the pressure working fluid is not higher than 0.8 times the melting point of the pressure working fluid.
[0039] After the pressure working fluid is injected, the opening is tied with multiple layers of ropes such as cable ties, nylon ropes or cotton ropes to complete the encapsulation of the pressure working fluid. This forms the bladder isostatic pressing structure for pressure forming of the composite material. In other words, Figure 1 and Figure 2 The structure shown is a schematic diagram of the structure produced by bladder isostatic pressing and fiber reinforcement after encapsulating the pressure working fluid for pressure molding of the composite material.
[0040] It should be noted that the above description is based on an example in which one end of the fiber reinforcement 2 is opened. That is, fibers are also woven into the bottom of the fiber reinforcement 2, and the sealing elastomer can wrap the bottom of the fiber reinforcement 2. Therefore, the bottom of the bladder structure is closed, and pressurized working fluid can be directly injected.
[0041] However, when the fiber reinforcement 2 is too long, uneven wrapping can easily occur during the RTM process when the slurry is injected into the fiber reinforcement 2 to form the sealing elastomer 1. Therefore, the fiber reinforcement 2 can be woven to have openings at both ends. Thus, the bladder-like structure has both ends open. One end can be sealed first, and then the pressurized working fluid can be injected, and finally the other opening can be sealed to form a bladder-like isostatic pressure generating structure.
[0042] By applying pressure at both ends of a bladder-type isostatic pressure generating structure, hydrostatic pressure is generated around the structure, applying hydrostatic pressure to the mold during composite molding. This bladder-type isostatic pressure generating structure improves the uneven pressure distribution often associated with traditional ejector-type pressure transmission devices. It also avoids the cost of specialized pressure tanks / boxes and other isostatic pressure equipment, making it simple, easy to use, and low-cost.
[0043] Finally, the forming process of the bladder-type isostatic pressing structure is described in a specific implementation method.
[0044] Fiber reinforcement 2 is mechanically woven from a blend of T300 carbon fiber and polyester. The weft-direction fiber reinforcement structure 21 has an elastic reserve of 70%. The warp-to-weft fiber volume ratio is 1:2, and a single layer is 1.5 mm thick with a fiber volume content of 20%. Fiber reinforcement 2 is constructed by stacking three layers.
[0045] The slurry forming the sealing elastomer is room temperature vulcanized silicone rubber.
[0046] The bladder structure molding process: Using the RTM process, the fiber reinforcement 2 is placed into the inner mold. After the outer mold is closed, the vacuum is evacuated to -0.8atm. The configured room temperature vulcanized silicone rubber is injected simultaneously through different injection ports. After room temperature vulcanization for 24 hours, the mold is removed to complete the bladder structure molding.
[0047] Next, the bladder structure was filled with 22.7 kg of ethylene glycol, with a volume of approximately 20,356 cm 3 .
[0048] Finally, the opening of the bladder structure filled with ethylene glycol is knotted and sealed using a self-tightening knot, ultimately forming a bladder-type isostatic pressure generating structure.
[0049] After performance testing, the above-mentioned bladder-type isostatic pressure generating structure can generate a hydrostatic pressure of about 3 MPa on the wall surface of a metal mold with an inner diameter of Φ300 mm.
[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A bladder isostatic pressing structure for composite material pressure forming, characterized in that: The invention comprises a bladder structure composed of a fiber reinforcement, a sealing elastic body wrapping the fiber reinforcement, and a pressure working fluid, wherein: The fiber reinforcement is formed by mechanical weaving and includes a warp fiber reinforcement structure and a weft fiber reinforcement structure that are evenly arranged; the fiber reinforcement is in the shape of a hollow cylinder with an opening at one or both ends; The sealing elastomer is formed by injecting slurry into the fiber reinforcement using the RTM process; The pressure working fluid is injected into the bladder structure, and after the opening is sealed, a bladder-type isostatic pressure generating structure is formed; In a working state, pressure is applied to both ends of the bladder-type isostatic pressure generating structure, thereby applying hydrostatic pressure to the mold in composite material molding.
2. The bladder isostatic pressing structure for composite material pressure molding according to claim 1, characterized in that: The weft-fiber reinforced structure needs to be loosely woven and have a tensile strain reserve of 10% to 50%.
3. The bladder isostatic pressing structure for composite material pressure molding according to claim 2, characterized in that: The fiber in the fiber reinforcement is selected from one of the following: nylon fiber, aramid fiber, glass fiber, high silica fiber, quartz fiber, carbon fiber.
4. The bladder isostatic pressing structure for composite material pressure molding according to claim 3, characterized in that: The fiber volume content of the fiber reinforcement is 10% to 20%.
5. The bladder isostatic pressing structure for composite material pressure molding according to claim 1, characterized in that: The tensile strain rate of the sealing elastic body is 100% to 300%, and the high temperature resistance is not less than 250°C.
6. The bladder isostatic pressing structure for composite material pressure molding according to claim 1, characterized in that: The slurry comprises one of the following: rubber, silicone rubber, and resin.
7. The bladder isostatic pressing structure for composite material pressure molding according to claim 1, characterized in that: The thickness of the bladder structure is 0.5 mm to 4 mm, and the cross-sectional perimeter strain rate is 10% to 50%.
8. The bladder isostatic pressing structure for composite material pressure molding according to claim 1, characterized in that: The pressure working fluid includes one of the following: water, ethylene glycol, and oil radiator.
9. The bladder isostatic pressing structure for composite material pressure molding according to claim 1, characterized in that: The operating temperature of the pressure working fluid is not higher than 0.8 times the melting point of the pressure working fluid.
10. The bladder isostatic pressing structure for composite material pressure molding according to claim 1, characterized in that: The opening is tied with multiple straps or ropes.