Demolding device and demolding method for a thin-walled composite material pipe with guide ribs

Abstract

The present invention provides a demoulding device and a demoulding method for a thin-walled composite material pipe with guide ribs, belonging to the field of demoulding of composite material pipe bodies. It solves the problem that it is difficult to demould a composite material pipe fitting with a large length-diameter ratio and an internal guide rib in a thin wall. It includes a hydraulic pressure perfusion cylinder, a first ground-connected positioning plate, a second ground-connected positioning plate, a core shaft with rib grooves, and an oil cylinder mechanism. The outside of the core shaft with rib grooves is the product to be demoulded. The product to be demoulded is horizontally arranged between the first ground-connected positioning plate and the second ground-connected positioning plate. The hydraulic pressure perfusion cylinder is connected to the first ground-connected positioning plate by threads. The core shaft with rib grooves penetrates through the middle openings of the first ground-connected positioning plate and the second ground-connected positioning plate. The core shaft with rib grooves is connected to the oil cylinder mechanism on the traction direction side, and the other side is located inside the hydraulic pressure perfusion cylinder. It is mainly used for demoulding a thin-walled composite material pipe with guide ribs.

Description

Technical Field

[0001] The invention belongs to the field of demolding of composite material pipe bodies, and particularly relates to a demolding device and a demolding method for a thin-walled composite material pipe with guide ribs. Background Art

[0002] Composite materials have the characteristics of high specific strength and specific modulus, designable properties, excellent thermophysical properties, etc., and are widely used in the fields of aviation, aerospace, etc. The development of modern aviation and aerospace technologies has proven that composite materials can improve the performance and competitiveness of aircraft, while reducing the mass without sacrificing their reliability and service life.

[0003] In particular, carbon fiber reinforced resin matrix composite pipe fittings are widely used in products such as large telescopic arms, space deployable antennas, solar wing connectors, and strut mechanisms. In order to meet the functions of large capacity, multi-spectrum, high power, etc., the size of space deployable antennas is getting larger and larger. However, restricted by the load mass requirements, the basic unit carbon fiber pipe fittings tend to be longer, thinner, and lighter. Thin-walled composite pipe fittings are more sensitive to defects caused by production, and defects and damages need to be avoided throughout the manufacturing process. Therefore, it is crucial to complete each step of the forming, demolding, and non-destructive testing of carbon fiber pipe fittings according to the design requirements.

[0004] The main reasons for the difficulty in demolding composite materials mainly include: grooves in the mold, insufficient mold taper, and low mold finish, etc. The self-structural characteristics of large aspect ratio composite pipe fittings with thin walls and internal guide ribs determine that their demolding has a certain degree of difficulty. For composite pipe fittings with straightness requirements, such slender structures are not suitable for preparing by splitting the mandrel, and how to safely remove the mandrel has always been the content of people's research. Summary of the Invention

[0005] In order to solve the problems in the prior art, the invention provides a demolding device and a demolding method for a thin-walled composite material pipe with guide ribs.

[0006] To achieve the above object, the invention adopts the following technical solutions: A demolding device for a thin-walled composite material pipe with guide ribs, which includes a water pressure perfusion cylinder, a first ground connection positioning plate, a second ground connection positioning plate, a ribbed groove mandrel, and an oil cylinder mechanism. The outside of the ribbed groove mandrel is the product to be demolded. The product to be demolded is horizontally arranged between the first ground connection positioning plate and the second ground connection positioning plate. The water pressure perfusion cylinder and the first ground connection positioning plate are connected by threads. The ribbed groove mandrel penetrates through the middle openings of the first ground connection positioning plate and the second ground connection positioning plate. The ribbed groove mandrel is connected to the oil cylinder mechanism on the traction direction side, and the other side is located inside the water pressure perfusion cylinder.

[0007] Furthermore, the first ground connection positioning plate and the second ground connection positioning plate are connected by matching a connecting screw and a fastening nut.

[0008] Furthermore, the connecting screw is formed by splicing a plurality of screws and connecting sleeves, and the number of the connecting screws is 3-6.

[0009] Furthermore, the first ground-connected positioning plate and the second ground-connected positioning plate are both connected to the ground feet through a bottom plate.

[0010] Furthermore, an opening auxiliary tooling is connected to the middle opening position of the first ground connection positioning plate and the second ground connection positioning plate.

[0011] Furthermore, a sealant filling groove A is provided at the position where the first ground-connected positioning plate is connected to the water pressure injection cylinder, and the sealant filling groove A is filled with a 1-3 mm thick rubber ring for sealing.

[0012] Furthermore, a 3-10 mm thick rubber waterproof baffle is arranged between the first ground positioning plate and the product to be demolded, the outer diameter of the rubber waterproof baffle is larger than the outer diameter of the product to be demolded, and the inner diameter of the rubber waterproof baffle is larger than the minimum outer diameter of the ribbed groove core shaft.

[0013] Furthermore, the oil cylinder mechanism is a plurality of oil cylinders connected in series.

[0014] Furthermore, a force sensor is arranged in front of the oil cylinder mechanism.

[0015] The present invention also includes a demoulding method for a thin-walled composite material pipe with guide rail ribs, which comprises the following steps:

[0016] Step 1: The product to be demoulded is a thin-walled composite pipe with guide ribs. The water pressure tolerance is calculated according to the composite layer angle ratio and the selected material property values, and the water injection pressure is controlled not to exceed 70% of the composite pipe's water pressure tolerance;

[0017] Step 2: Fix the product to be demoulded, connect the demoulding device, fix the ribbed groove mandrel as a whole horizontally, tighten the fastening nut and connect and fix it with the foot;

[0018] Step 3: The hydraulic injection cylinder is connected to the hydraulic device, and water is injected according to the water injection pressure obtained in step 1. The core shaft with ribbed grooves is pulled along the pulling direction through the cylinder mechanism to achieve demoulding.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention solves the problem that it is difficult to demold large aspect ratio composite pipe fittings with internal guide ribs in thin-walled belts. Combining with mechanical analysis software and using simple and common parts for assembly, the present invention manufactures a set of demolding tooling, which reduces the demolding cost, is convenient to use, and the products are verified to be intact and undamaged through ultrasonic testing. This method is not limited to the demolding of composite pipe fittings with guide ribs, but also applicable to large aspect ratio thin-walled pipe fittings that are difficult to demold, breaking through multiple demolding difficulties such as thin-walled pipes, integrally formed internal strengthening guide ribs, and large aspect ratio, and realizing a demolding method with uniform force without damaging the products. The present invention is assembled with simple and common parts, which reduces the demolding cost, is convenient to use, and the products are verified to be intact and undamaged, without problems such as delamination, cracking, and debonding through ultrasonic testing. It has wide application applicability for thin-walled and slender pipe fittings. The core shaft traction direction is connected to a short oil cylinder, and the short oil cylinders are connected in series. Selecting a long oil cylinder is likely to cause instability, and traction force design and evaluation can be carried out through series connection. Through actual testing, the traction force can reach more than 12t for stable demolding. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of a demolding device for a thin-walled composite pipe with guide ribs according to the present invention;

[0021] Figure 2 is a schematic structural diagram of the water pressure perfusion cylinder according to the present invention;

[0022] Figure 3 is a schematic structural diagram of the first ground connection positioning plate according to the present invention;

[0023] Figure 4 is a schematic structural diagram of the second ground connection positioning plate according to the present invention.

[0024] 1 - water pressure perfusion cylinder, 2 - first ground connection positioning plate, 3 - rubber water baffle, 4 - connecting screw, 5 - second ground connection positioning plate, 6 - fastening nut, 7 - ribbed groove core shaft, 8 - product to be demolded, 9 - oil cylinder mechanism. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention.

[0026] See Figures 1-4Description of this embodiment, a demolding device for a thin-walled composite pipe with guide rail ribs, which includes a water pressure perfusion cylinder 1, a first ground connection positioning plate 2, a second ground connection positioning plate 5, a ribbed groove mandrel 7 and an oil cylinder mechanism 9. The outside of the ribbed groove mandrel 7 is the product 8 to be demolded. The product 8 to be demolded is horizontally arranged between the first ground connection positioning plate 2 and the second ground connection positioning plate 5. The water pressure perfusion cylinder 1 and the first ground connection positioning plate 2 are connected by threads. The ribbed groove mandrel 7 passes through the middle openings of the first ground connection positioning plate 2 and the second ground connection positioning plate 5. The side of the ribbed groove mandrel 7 in the traction direction is connected to the oil cylinder mechanism 9, and the other side is located inside the water pressure perfusion cylinder 1.

[0027] In this embodiment, the product 8 to be demolded is a thin-walled composite pipe with guide rail ribs. The composite pipe fitting is a thin-walled and slender pipe fitting prepared by winding and laying composite resin matrices such as carbon fiber, glass fiber, and aramid fiber. Except for the middle openings of the first ground connection positioning plate 2 and the second ground connection positioning plate 5 being limited by the size of the ribbed groove mandrel 7, other components are universal.

[0028] The first ground connection positioning plate 2 and the second ground connection positioning plate 5 are connected by matching a connecting screw 4 and a fastening nut 6, and the product 8 to be demolded is horizontally clamped and fixed through the first ground connection positioning plate 2 and the second ground connection positioning plate 5. For an ultra-long mandrel, the connecting screw 4 is formed by splicing multiple screws and connecting sleeves, and can be spliced to adapt to the demolding of pipe fittings with different lengths. The number of connecting screws 4 is 3 - 6. Both the first ground connection positioning plate 2 and the second ground connection positioning plate 5 are connected to the ground through the bottom plate, and the ground can move according to the mandrel to be demolded. The middle opening positions of the first ground connection positioning plate 2 and the second ground connection positioning plate 5 can be connected with opening auxiliary tools of different diameters by screws to adapt to mandrel molds of different sizes. The first ground connection positioning plate 2 is provided with a sealant filling groove A at the position where it is butted against the water pressure perfusion cylinder 1. During use, a rubber ring with a thickness of 1 - 3 mm is filled in the sealant filling groove A for sealing. The internal thread depth of the water pressure perfusion cylinder 1 is longer than the external thread length of the first ground connection positioning plate 2. A rubber water isolation baffle 3 with a thickness of 3 - 10 mm is arranged between the first ground connection positioning plate 2 and the product 8 to be demolded. The outer diameter of the rubber water isolation baffle 3 is larger than the outer diameter of the product 8 to be demolded, and the inner diameter of the rubber water isolation baffle 3 is larger than the minimum outer diameter of the ribbed groove mandrel 7. The oil cylinder mechanism 9 is connected in series by multiple oil cylinders, and multiple oil cylinders are all short oil cylinders to ensure stable thrust. A force measuring sensor is arranged in front of the oil cylinder mechanism 9 for real-time monitoring.

[0029] This embodiment is a demolding method for a thin-walled composite pipe with guide rail ribs, which includes the following steps:

[0030] Step 1: The product 8 to be demolded is a thin-walled composite pipe with guide rail ribs. Calculate the water pressure tolerance according to the composite material layup angle ratio and the material characteristic values, and control the water injection pressure not to exceed 70% of the water pressure tolerance of the composite pipe.

[0031] Step 2: Fix the product 8 to be demolded, connect the demolding device, horizontally support and fix the ribbed groove mandrel 7 as a whole, tighten the fastening nut 6 and connect and fix it to the floor

[0032] Step 3: Connect the water pressure perfusion cylinder 1 to the water pressure device, inject water according to the water injection pressure obtained in Step 1, and use the oil cylinder mechanism 9 to pull the ribbed groove mandrel 7 along the traction direction to achieve demolding.

[0033] In this embodiment, taking the demolding of a carbon fiber composite pipe fitting as an example, the wall thickness of the composite material pipe is 1.4 mm, the length is 5000 mm, the outer diameter is 130 mm, it has internal guide rails, and the guide rails and the pipe wall are integrally formed, both of which are composite materials. The recessed grooves of the special ribbed groove mandrel 7 are evenly distributed along the whole length, and the ribbed groove mandrel 7 has an equal diameter and no demolding angle.

[0034] The specific usage steps are as follows:

[0035] 1. Calculate the pressure tolerance of the pipe fitting: According to the ply angle ratio of the composite material and the characteristic values of the selected material, its pressure tolerance can be calculated to be 2.6 MPa, and the applied water pressure does not exceed 1.82 MPa;

[0036] 2. Fix the product to be demolded: Horizontally support and fix the ribbed groove mandrel 7 to be demolded as a whole, connect the demolding device, tighten the screws, and fix the floor.

[0037] 3. Install the demolding device in sequence: Connect the demolding tooling as required, and place the product 8 to be demolded with the ribbed groove mandrel 7 in the middle.

[0038] 4. Place the sealing ring: The water pressure perfusion cylinder 1 and the first ground connection positioning plate 2 are connected by threads. The docking position of the first ground connection positioning plate 2 is provided with a sealing glue filling groove A, and a 2-mm-thick rubber ring is filled for sealing during use.

[0039] 5. Place the rubber water baffle: A 10-mm rubber water baffle 3 is clamped between the first ground connection positioning plate 2 and the product 8 to be demolded.

[0040] 6. Tighten the screws: The first ground connection positioning plate 2 and the ground connection positioning plate are fixed by connecting screws and fastening nuts. Six 900-mm-long screws are assembled and spliced through internal thread connecting sleeves, and there are 4 groups of connecting screws in total.

[0041] 7. Connect the floor: The ground connection positioning plate 1 and the second ground connection positioning plate 5 are connected by the bottom plate and the floor, and the distance between the two bottom plates connecting the floor is 5000 mm.

[0042] 8. Connect the oil cylinder traction: Four series-connected short oil cylinders are connected in the traction direction of the ribbed groove mandrel 7, and a force measuring sensor is placed in front of the short oil cylinders for real-time monitoring.

[0043] After demoulding, upon visual inspection, there are no visible damage defects on the product. After ultrasonic non-destructive testing, there are no problems such as delamination, cracking, and debonding.

[0044] The above has introduced in detail a demoulding device and a demoulding method for a thin-walled composite material pipe with guide ribs provided by the present invention. Specific examples are used in this article to expound the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A demoulding device for a thin-walled composite material pipe with guide ribs, characterized in that: It includes a hydraulic perfusion cylinder (1), a first ground-connected positioning plate (2), a second ground-connected positioning plate (5), a ribbed groove mandrel (7) and an oil cylinder mechanism (9). The outside of the ribbed groove mandrel (7) is the product to be demolded (8). The product to be demolded (8) is horizontally arranged between the first ground-connected positioning plate (2) and the second ground-connected positioning plate (5). The hydraulic perfusion cylinder (1) and the first ground-connected positioning plate (2) are connected by threads. The ribbed groove mandrel (7) passes through the middle openings of the first ground-connected positioning plate (2) and the second ground-connected positioning plate (5). The side in the traction direction of the ribbed groove mandrel (7) is connected to the oil cylinder mechanism (9), and the other side is located inside the hydraulic perfusion cylinder (1). The first ground-connected positioning plate (2) and the second ground-connected positioning plate (5) are connected by matching a connecting screw (4) and a fastening nut (6). Both the first ground-connected positioning plate (2) and the second ground-connected positioning plate (5) are connected to the ground feet through the bottom plates. The connecting screw (4) is formed by splicing a plurality of screws and connecting sleeves. The number of the connecting screws (4) is 3 - 6. The oil cylinder mechanism (9) is connected in the form of a series connection of a plurality of oil cylinders. A force measuring sensor is arranged in front of the oil cylinder mechanism (9).

2. The demoulding device of a thin-walled composite material pipe with guide ribs according to claim 1, characterized in that: An opening auxiliary tooling is connected to the middle opening positions of the first ground-connected positioning plate (2) and the second ground-connected positioning plate (5).

3. The demolding device for a thin-walled composite pipe with guide ribs according to claim 1, characterized in that: The first ground-connected positioning plate (2) is provided with a sealant filling groove A at the position where it is butted against the hydraulic perfusion cylinder (1). A rubber seal ring with a thickness of 1 - 3 mm is filled in the sealant filling groove A for sealing.

4. The demoulding device for a thin-walled composite material pipe with guide ribs according to claim 1, characterized in that: A rubber water isolation baffle (3) with a thickness of 3 - 10 mm is arranged between the first ground-connected positioning plate (2) and the product to be demolded (8). The outer diameter of the rubber water isolation baffle (3) is larger than the outer diameter of the product to be demolded (8), and the inner diameter of the rubber water isolation baffle (3) is larger than the minimum outer diameter of the ribbed groove mandrel (7).

5. A demolding method for a demolding device of a thin-walled composite material pipe with guide ribs as described in claim 1, characterized in that: It includes the following steps: Step 1: The product to be demolded (8) is a thin-walled composite material pipe with guide ribs. Calculate the water pressure tolerance according to the composite material layup angle ratio and the selected material characteristic values, and control the water injection pressure not to exceed 70% of the water pressure tolerance of the composite material pipe. Step 2: Fix the product to be demolded (8), connect the demolding device, horizontally support and fix the whole ribbed groove mandrel (7), tighten the fastening nut (6) and connect and fix it to the ground feet; Step 3: Connect the hydraulic perfusion cylinder (1) to the hydraulic device, inject water according to the water injection pressure obtained in Step 1, and traction the ribbed groove mandrel (7) in the traction direction through the oil cylinder mechanism (9) to realize demolding.

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