Mooring fragile cover and preparation method thereof

Abstract

The invention discloses a tethered fragile cover and a preparation method thereof, the tethered fragile cover comprises a cover body and a flange, the cover body is connected with the flange, and the cover body is provided with a stress groove. The preparation method of the tethered fragile cover comprises the following steps: using a fragile cover mold, obtaining a foaming piece through high-pressure foaming forming, and preparing the fragile cover through polyurea forming. Materials are configured according to different performance requirements of a cover body, a stress groove and a flange of the tethered fragile cover, the light weight, heat preservation and heat insulation functions of the tethered fragile cover are achieved through a two-step compression molding preparation method, a storage and transportation box channel is broken and opened along the stress groove under a certain combustion gas flow condition, and the stability of the tethered fragile cover is improved. Fragments of the moored fragile cover are left on the storage and transportation box pressing frame and the pressing frame, potential safety hazards cannot be caused to ground equipment, and therefore the safety and reliability of a launching system are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft storage, transportation and launching systems, and in particular relates to a tethered fragile cover and a preparation method thereof. Background Art

[0002] The fragile cover and the storage box (cylinder) form a complete closed body, isolating the aircraft from the external environment, and has the functions of heat preservation, heat insulation and sealing for aircraft storage, providing a better storage environment for the aircraft. When the aircraft is launched, under the action of the shock wave of the gas flow, the fragile cover breaks and falls off along the stress groove of the fragile cover and splashes out of the storage box, opening a channel for the aircraft launch. However, the splashing fragile cover fragments pose a safety hazard to ground equipment. Therefore, in recent years, the development of tethered fragile covers has been favored.

[0003] In recent years, the research and development of moored fragile covers mainly focuses on resin-based fiber-reinforced fiber composite materials, and adopts a machined moored fragile cover structure. Due to the material characteristics and machining costs, the quality stability of the moored fragile cover is poor, and the weight is relatively heavy. However, there are no reports on lightweight, heat-insulating, and heat-insulating multifunctional moored fragile covers. Therefore, it is necessary to develop a new type of lightweight, heat-insulating, and heat-insulating moored fragile cover to meet the needs of this technical field.

[0004] The patent document with announcement number CN117682218A discloses a fragile cover with auxiliary support function and its preparation method. The fragile cover is composed of a flange, a stress groove, a cover body and an auxiliary support. The flange is used to connect to the metal bottom frame and the pressure frame and then to the storage and transportation box, but its flange and cover body are made of polyurethane foam fragile materials.

[0005] The patent document with announcement number CN117567858A discloses an electromagnetic protection coating material for a foam fragile cover and a preparation method thereof, including a fragile cover, the fragile cover material is polyurethane foam, and a six-layer coating structure is applied to the concave and convex surfaces of the polyurethane foam fragile cover, wherein the concave surface of the fragile cover includes a five-layer coating structure, and the convex surface of the fragile cover includes a one-layer coating structure. The polyurethane foam fragile cover substrate is subjected to heat treatment, curing post-treatment and other processes, which effectively improves the polymerization degree of the polyurethane, removes the moisture adsorbed in the substrate, and avoids problems such as blistering and bulging during coating curing and high temperature testing. However, the patent requires the scraping of absorbing putty, the preparation of a closed varnish layer and a primer layer, etc. to improve the electromagnetic shielding effectiveness of the foam fragile cover, which will lead to an increase in the preparation cost. The fragile cover of this patent is mainly used for electromagnetic shielding and is not suitable for use in non-military scenarios. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a tethered frangible cover and a preparation method thereof.

[0007] The present invention is achieved through the following technical solutions.

[0008] The present invention provides a captive fragile cover, which comprises a cover body and a flange. The cover body and the flange are connected, and a stress groove is arranged on the cover body.

[0009] Preferably, the cover body and the flange both include an outer layer and a middle layer, the two sides of the middle layer are respectively connected to the outer layer, the cover body is arc-shaped, and the stress grooves are cross-arranged at two locations on the cover body.

[0010] Preferably, the material of the stress groove is polyurethane foam, the material of the outer layer is polyurea, the polyurea is aromatic polyurea or aliphatic polyurea, and the material of the middle layer is a foam-based fiber-reinforced composite material.

[0011] Preferably, the polyurea comprises prepolymer A, prepolymer B and flame retardant, in parts by mass, the prepolymer A is 80-120 parts, the prepolymer B is 80-120 parts, and the flame retardant is 9-14 parts, and the flame retardant is made of dimethyl methyl phosphate.

[0012] Preferably, the foam material in the foam-based fiber-reinforced composite material is a polyurethane foam material, and the base fiber is one of aramid fiber and carbon fiber.

[0013] Preferably, the polyurethane foam material has a density of 0.15-0.40 g / cm 3 .

[0014] Preferably, the polyurethane foam comprises white material and isocyanate. In parts by weight, the white material component comprises: 80-130 parts of combined polyether, 1-6 parts of silicone oil stabilizer, 1-5 parts of amine combined curing agent, 1-4 parts of combined anti-aging agent, 12-18 parts of hydrofluoroalkane foaming agent, and 9-20 parts of dimethyl methyl phosphate flame retardant.

[0015] A method for preparing a tethered fragile cover includes a process of using a fragile cover mold and obtaining a foamed part through high-pressure foaming molding, and then preparing the fragile cover through a two-step compression molding method of polyurea molding.

[0016] Preferably, the high pressure foaming molding comprises the following steps:

[0017] S1: Control the temperature of the operating site at 23±5℃, the relative humidity below 65%, and prepare the white material;

[0018] S2: Pump the evenly mixed white material into the white material storage tank of the high-pressure foaming machine, and at the same time pump the isocyanate into the black material storage tank;

[0019] S3: Cut the fiber cloth and make pre-made holes in the fiber cloth, but ensure that the fibers are continuous;

[0020] S4: laying fiber cloth on the lower mold, the fiber cloth laying position is the mold position corresponding to the non-stress groove of the tethered fragile cover, and the fiber cloth is prevented from being carried on the stress groove position;

[0021] S5: Pour the mixed white material and cyanate ester into the fragile cover forming mold, close the mold, lock the fragile cover forming mold, push it into the oven, heat it to 100±5℃ and keep it warm for 70-100min to cure. After the curing is completed, push it out of the oven and air cool it to room temperature to demold and obtain the foamed part.

[0022] Preferably, the polyurea molding comprises the following steps:

[0023] S1: Control the temperature of the operating site at 23±5℃ and the relative humidity below 65%, prepare polyurea and mix and stir evenly;

[0024] S2: grinding the surface of the foamed part and drilling holes at positions other than the stress grooves on the foamed part;

[0025] S3: Place the punched foamed part on the lower mold of the fragile cover molding mold, pour the evenly mixed polyurea onto the punched foamed part and close the mold, remove the bubbles and close the mold and lock the fragile cover molding mold, and let it stand for 10-26 minutes;

[0026] S4: Push the forming mold into the oven, heat it to 100±5℃ and keep it warm for 50-70min. After the insulation is completed, air cool it to room temperature and remove the mold to obtain a tethered fragile cover.

[0027] The beneficial effects of the present invention are:

[0028] The invention configures materials according to the different performance requirements of the cover body, stress groove and flange of the tethered fragile cover, and realizes the lightweight, heat preservation and heat insulation functions of the tethered fragile cover through a two-step compression molding preparation method. Under certain gas flow conditions, the cover breaks along the stress groove to open the storage box passage, while fragments of the tethered fragile cover remain on the pressure frame and the pressure frame of the storage box, which will not cause safety hazards to ground equipment, thereby improving the safety and reliability of the launch system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a main structural schematic diagram of the present invention;

[0030] Figure 2 It is a side structural schematic diagram of the present invention;

[0031] Figure 3 is a cross-sectional view of the cover body of the present invention;

[0032] Figure 4 is a cross-sectional view of the stress groove of the present invention;

[0033] In the figure: 1-cover body, 2-stress groove, 3-flange, 4-outer layer, 5-middle layer. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0035] Embodiment 1:

[0036] like Figures 1 to 4 As shown, a captive fragile cover comprises a cover body 1 and a flange 3, wherein the cover body 1 and the flange 3 are connected, and a stress groove 2 is arranged on the cover body 1.

[0037] The cover body 1 and the flange 3 both include an outer layer 4 and an intermediate layer 5 , the two sides of the intermediate layer 5 are respectively connected to the outer layer 4 , the cover body 1 is arc-shaped, and the stress grooves 2 are cross-arranged at two locations on the cover body 1 .

[0038] The stress groove 2 is V-shaped and made of polyurethane foam. The outer layer 4 is made of polyurea with a thickness of 2-3 mm. The polyurea is aromatic polyurea or aliphatic polyurea. The middle layer 5 is made of foam-based fiber-reinforced composite material.

[0039] The polyurea comprises prepolymer A, prepolymer B and flame retardant. Prepolymer A and prepolymer B constitute a two-component polyether polyurethane. In units of parts by mass, the prepolymer A comprises 80 parts, the prepolymer B comprises 80 parts, and the flame retardant comprises 9 parts. The material of the flame retardant is dimethyl methyl phosphate.

[0040] The foam material in the foam-based fiber-reinforced composite material is a polyurethane foam material, and the base fiber is one of aramid fiber and carbon fiber.

[0041] The polyurethane foam material has a density of 0.15 g / cm 3 .

[0042] The polyurethane foam comprises white material and isocyanate, and the white material component comprises, in parts by weight: 80 parts of combined polyether, 1 part of silicone oil stabilizer, 1 part of amine combined curing agent, 1 part of combined anti-aging agent, 12 parts of hydrofluoroalkane foaming agent, and 9 parts of dimethyl methyl phosphate flame retardant. The combined anti-aging agent has anti-oxidation and ultraviolet absorption functions.

[0043] A method for preparing a tethered fragile cover includes using a fragile cover mold and obtaining a foamed part through high-pressure foaming, and then preparing the fragile cover through polyurea molding. The actual required tethered fragile cover molding mold is set, one set of molding molds is used for molding a foam-based fiber-reinforced composite material part, and one set of molding molds is used for molding a polyurea layer.

[0044] The high pressure foaming molding comprises the following steps:

[0045] S1: Control the temperature of the operating site at 23±5℃ and the relative humidity below 65%, prepare the white material, and the white material can be used after circulating and stirring for 4 hours;

[0046] S2: Pump the evenly mixed white material into the white material storage tank of the high-pressure foaming machine, and at the same time pump the isocyanate into the black material storage tank;

[0047] S3: Cut the fiber cloth and make prefabricated holes on the fiber cloth. The prefabricated holes have a diameter of 5 mm, which is convenient for the fiber cloth to be soaked during foaming, but ensures that the fibers are continuous. The fiber cloth can be replaced with fiber yarn as needed;

[0048] S4: laying fiber cloth on the lower mold, the fiber cloth laying position is the mold position corresponding to the non-stress groove 2 of the tethered fragile cover, and cutting off excess fiber cloth with scissors to prevent the fiber cloth from being carried on the stress groove 2 position;

[0049] S5: Pour the mixed white material and cyanate ester into the fragile cover forming mold, close the mold, lock the fragile cover forming mold, push it into the oven, heat it to 95°C and keep it warm for 70 minutes to cure. After the curing is completed, push it out of the oven and air cool it to room temperature to demold and obtain the foamed part.

[0050] The polyurea molding comprises the following steps:

[0051] S1: Control the temperature of the operating site to 18°C ​​and the relative humidity to below 65%, prepare polyurea and mix and stir evenly;

[0052] S2: Grind the surface of the foamed part, and punch holes on the foamed part except for the stress groove 2, with a hole diameter of 4-5 mm;

[0053] S3: Place the punched foamed part on the lower mold of the fragile cover molding mold, pour the evenly mixed polyurea onto the punched foamed part and close the mold, remove the bubbles and close the mold and lock the fragile cover molding mold, and let it stand for 10 minutes;

[0054] S4: Push the forming mold into an oven, slowly heat it to 95°C and keep it warm for 50 minutes. After the insulation is completed, air cool it to room temperature and remove the mold to obtain a tethered fragile cover.

[0055] Embodiment 2:

[0056] like Figures 1 to 4 As shown, a captive fragile cover comprises a cover body 1 and a flange 3, wherein the cover body 1 and the flange 3 are connected, and a stress groove 2 is arranged on the cover body 1.

[0057] The cover body 1 and the flange 3 both include an outer layer 4 and an intermediate layer 5 , the two sides of the intermediate layer 5 are respectively connected to the outer layer 4 , the cover body 1 is arc-shaped, and the stress grooves 2 are cross-arranged at two locations on the cover body 1 .

[0058] The stress groove 2 is V-shaped and made of polyurethane foam. The outer layer 4 is made of polyurea with a thickness of 2-3 mm. The polyurea is aromatic polyurea or aliphatic polyurea. The middle layer 5 is made of foam-based fiber-reinforced composite material.

[0059] The polyurea comprises prepolymer A, prepolymer B and flame retardant. Prepolymer A and prepolymer B constitute a two-component polyether polyurethane. In parts by mass, the prepolymer A comprises 120 parts, the prepolymer B comprises 120 parts, and the flame retardant comprises 14 parts. The material of the flame retardant is dimethyl methyl phosphate.

[0060] The foam material in the foam-based fiber-reinforced composite material is a polyurethane foam material, and the base fiber is one of aramid fiber and carbon fiber.

[0061] The polyurethane foam material has a density of 0.40 g / cm 3 .

[0062] The polyurethane foam comprises white material and isocyanate, and the white material component comprises, in parts by weight: 130 parts of combined polyether, 6 parts of silicone oil stabilizer, 5 parts of amine combined curing agent, 4 parts of combined anti-aging agent, 18 parts of hydrofluoroalkane foaming agent, and 20 parts of dimethyl methyl phosphate flame retardant. The combined anti-aging agent has anti-oxidation and ultraviolet absorption functions.

[0063] A method for preparing a tethered fragile cover includes using a fragile cover mold and obtaining a foamed part through high-pressure foaming, and then preparing the fragile cover through polyurea molding. The actual required tethered fragile cover molding mold is set, one set of molding molds is used for molding a foam-based fiber-reinforced composite material part, and one set of molding molds is used for molding a polyurea layer.

[0064] The high pressure foaming molding comprises the following steps:

[0065] S1: Control the temperature of the operating site at 23±5℃ and the relative humidity below 65%, prepare the white material, and the white material can be used after circulating and stirring for 4 hours;

[0066] S2: Pump the evenly mixed white material into the white material storage tank of the high-pressure foaming machine, and at the same time pump the isocyanate into the black material storage tank;

[0067] S3: Cut the fiber cloth and make prefabricated holes on the fiber cloth. The prefabricated holes have a diameter of 5 mm, which is convenient for the fiber cloth to be soaked during foaming, but ensures that the fibers are continuous. The fiber cloth can be replaced with fiber yarn as needed;

[0068] S4: laying fiber cloth on the lower mold, the fiber cloth laying position is the mold position corresponding to the non-stress groove 2 of the tethered fragile cover, and cutting off excess fiber cloth with scissors to prevent the fiber cloth from being carried on the stress groove 2 position;

[0069] S5: Pour the mixed white material and cyanate ester into the fragile cover forming mold, close the mold, lock the fragile cover forming mold, push it into the oven, heat it to 105°C and keep it warm for 100 minutes to cure. After the curing is completed, push it out of the oven and air cool it to room temperature to demold and obtain the foamed part.

[0070] The polyurea molding comprises the following steps:

[0071] S1: Control the temperature of the operating site at 23±5℃ and the relative humidity below 65%, prepare polyurea and mix and stir evenly;

[0072] S2: Grind the surface of the foamed part, and punch holes on the foamed part except for the stress groove 2, with a hole diameter of 4-5 mm;

[0073] S3: Place the punched foamed part on the lower mold of the fragile cover molding mold, pour the evenly mixed polyurea onto the punched foamed part and close the mold, remove the bubbles and close the mold and lock the fragile cover molding mold, and let it stand for 26 minutes;

[0074] S4: Push the forming mold into an oven, slowly heat it to 105°C and keep it warm for 70 minutes. After the insulation is completed, air cool it to room temperature and remove the mold to obtain a tethered fragile cover.

[0075] Embodiment 3:

[0076] like Figures 1 to 4 As shown, a captive fragile cover comprises a cover body 1 and a flange 3, wherein the cover body 1 and the flange 3 are connected, and a stress groove 2 is arranged on the cover body 1.

[0077] The cover body 1 and the flange 3 both include an outer layer 4 and an intermediate layer 5 , the two sides of the intermediate layer 5 are respectively connected to the outer layer 4 , the cover body 1 is arc-shaped, and the stress grooves 2 are cross-arranged at two locations on the cover body 1 .

[0078] The stress groove 2 is V-shaped and made of polyurethane foam. The outer layer 4 is made of polyurea with a thickness of 2-3 mm. The polyurea is aromatic polyurea or aliphatic polyurea. The middle layer 5 is made of foam-based fiber-reinforced composite material.

[0079] The polyurea comprises prepolymer A, prepolymer B and flame retardant. Prepolymer A and prepolymer B constitute a two-component polyether polyurethane. In units of parts by mass, the prepolymer A is 100 parts, the prepolymer B is 100 parts, and the flame retardant is 12 parts. The material of the flame retardant is dimethyl methyl phosphate.

[0080] The foam material in the foam-based fiber-reinforced composite material is a polyurethane foam material, and the base fiber is one of aramid fiber and carbon fiber.

[0081] The polyurethane foam material has a density of 0.22 g / cm 3 .

[0082] The polyurethane foam comprises white material and isocyanate, and the white material component comprises, in parts by weight: 100 parts of combined polyether, 3 parts of silicone oil stabilizer, 3 parts of amine combined curing agent, 2 parts of combined anti-aging agent, 14 parts of hydrofluoroalkane foaming agent, and 13 parts of dimethyl methyl phosphate flame retardant. The combined anti-aging agent has anti-oxidation and ultraviolet absorption functions.

[0083] A method for preparing a tethered fragile cover includes using a fragile cover mold and obtaining a foamed part through high-pressure foaming, and then preparing the fragile cover through polyurea molding. The actual required tethered fragile cover molding mold is set, one set of molding molds is used for molding a foam-based fiber-reinforced composite material part, and one set of molding molds is used for molding a polyurea layer.

[0084] The high pressure foaming molding comprises the following steps:

[0085] S1: Control the temperature of the operating site at 23±5℃ and the relative humidity below 65%, prepare the white material, and the white material can be used after circulating and stirring for 4 hours;

[0086] S2: Pump the evenly mixed white material into the white material storage tank of the high-pressure foaming machine, and at the same time pump the isocyanate into the black material storage tank;

[0087] S3: Cut the fiber cloth and make prefabricated holes on the fiber cloth. The prefabricated holes have a diameter of 5 mm, which is convenient for the fiber cloth to be soaked during foaming, but ensures that the fibers are continuous. The fiber cloth can be replaced with fiber yarn as needed;

[0088] S4: laying fiber cloth on the lower mold, the fiber cloth laying position is the mold position corresponding to the non-stress groove 2 of the tethered fragile cover, and cutting off excess fiber cloth with scissors to prevent the fiber cloth from being carried on the stress groove 2 position;

[0089] S5: Pour the mixed white material and cyanate ester into the fragile cover forming mold, close the mold, lock the fragile cover forming mold, push it into the oven, heat it to 100°C and keep it warm for 90 minutes to cure. After the curing is completed, push it out of the oven and air cool it to room temperature to demold and obtain the foamed part.

[0090] The polyurea molding comprises the following steps:

[0091] S1: Control the temperature of the operating site at 23±5℃ and the relative humidity below 65%, prepare polyurea and mix and stir evenly;

[0092] S2: Grind the surface of the foamed part, and punch holes on the foamed part except for the stress groove 2, with a hole diameter of 4-5 mm;

[0093] S3: Place the punched foamed part on the lower mold of the fragile cover molding mold, pour the evenly mixed polyurea onto the punched foamed part and close the mold, remove the bubbles and close the mold and lock the fragile cover molding mold, and let it stand for 15 minutes;

[0094] S4: Push the forming mold into an oven, slowly heat it to 100°C and keep it warm for 60 minutes. After the insulation is completed, air cool it to room temperature and remove the mold to obtain a tethered fragile cover.

[0095] The tethered fragile covers prepared in Examples 1-3 were subjected to a static pressure explosion test. The tethered fragile covers were assembled on a special test fixture. When the air pressure was pressurized to 180 kPa, the stress grooves 2 of the tethered fragile covers prepared in Examples 1-3 were all able to rupture, meeting the technical requirements for tethered fragile covers.

Claims

1. A tethered frangible cover, characterized in that: It comprises a cover body (1) and a flange (3), wherein the cover body (1) and the flange (3) are connected, and a stress groove (2) is arranged on the cover body (1).

2. A tethered frangible cover as claimed in claim 1, characterized in that: The cover body (1) and the flange (3) both comprise an outer layer (4) and an intermediate layer (5), the two sides of the intermediate layer (5) are respectively connected to the outer layer (4), the cover body (1) is arc-shaped, and the stress grooves (2) are cross-arranged at two locations on the cover body (1).

3. A tethered frangible cover as claimed in claim 2, characterized in that: The material of the stress groove (2) is polyurethane foam, the material of the outer layer (4) is polyurea, the polyurea is aromatic polyurea or aliphatic polyurea, and the material of the middle layer (5) is a foam-based fiber-reinforced composite material.

4. A tethered frangible cover as claimed in claim 2, characterized in that: The polyurea comprises prepolymer A, prepolymer B and flame retardant. In units of parts by mass, the prepolymer A is 80-120 parts, the prepolymer B is 80-120 parts, and the flame retardant is 9-14 parts. The material of the flame retardant is dimethyl methyl phosphate.

5. A tethered frangible cover as claimed in claim 2, characterized in that: The foam material in the foam-based fiber-reinforced composite material is a polyurethane foam material, and the base fiber is one of aramid fiber and carbon fiber.

6. A tethered frangible cover as claimed in claim 5, characterized in that: The polyurethane foam material has a density of 0.15-0.40 g / cm 3 .

7. A tethered frangible cover as claimed in claim 5, characterized in that: The polyurethane foam comprises white material and isocyanate. In units of parts by weight, the white material components comprise: 80-130 parts of combined polyether, 1-6 parts of silicone oil stabilizer, 1-5 parts of amine combined curing agent, 1-4 parts of combined anti-aging agent, 12-18 parts of hydrofluoroalkane foaming agent, and 9-20 parts of dimethyl methyl phosphate flame retardant.

8. A method for preparing a tethered frangible cover as claimed in any one of claims 1 to 7, characterized in that: The invention comprises a process of using a fragile cover mold, obtaining a foamed part by high-pressure foaming molding, and then preparing the fragile cover by polyurea molding.

9. A method for preparing a tethered frangible cover as claimed in claim 8, characterized in that: The high pressure foaming molding comprises the following steps: S1: Control the temperature of the operating site at 23±5℃, the relative humidity below 65%, and prepare the white material; S2: Pump the evenly mixed white material into the white material storage tank of the high-pressure foaming machine, and at the same time pump the isocyanate into the black material storage tank; S3: Cut the fiber cloth and make pre-made holes in the fiber cloth, but ensure that the fibers are continuous; S4: laying the fiber cloth on the lower mold, the fiber cloth laying position is the mold position corresponding to the non-stress groove (2) of the tethered fragile cover, and avoiding the fiber cloth from being carried by the stress groove (2); S5: Pour the mixed white material and cyanate ester into the fragile cover forming mold, close the mold, lock the fragile cover forming mold, push it into the oven, heat it to 100±5℃ and keep it warm for 70-100min to cure. After the curing is completed, push it out of the oven and air cool it to room temperature to demold and obtain the foamed part.

10. A method for preparing a tethered frangible cover as claimed in claim 8, characterized in that: The polyurea molding comprises the following steps: S1: Control the temperature of the operating site at 23±5℃ and the relative humidity below 65%, prepare polyurea and mix and stir evenly; S2: grinding the surface of the foamed part and drilling holes at positions other than the stress groove (2) on the foamed part; S3: Place the punched foamed part on the lower mold of the fragile cover molding mold, pour the evenly mixed polyurea onto the punched foamed part and close the mold, remove the bubbles and close the mold and lock the fragile cover molding mold, and let it stand for 10-26 minutes; S4: Push the forming mold into the oven, heat it to 100±5℃ and keep it warm for 50-70min. After the insulation is completed, air cool it to room temperature and remove the mold to obtain a tethered fragile cover.

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