Bonding forming method for fiber winding shell skirt

Abstract

The invention discloses a fiber winding shell skirt bonding forming method which comprises the following steps: after a winding core mold is formed, machining is carried out according to the molded surface of an inner heat insulation layer of a fiber winding shell, the inner heat insulation layer is adhered to the winding core mold and polished, skirt inner winding is carried out on the surface of the inner heat insulation layer in a spiral winding and annular winding alternating winding mode, and an uncured shell is obtained; the method comprises the following steps: processing a stress release groove, bonding a rubber buffer layer on the inner surface and the outer surface of a skirt and curing, installing the skirt to a skirt bonding area of an uncured shell, binding the skirt on the buffer layer on the outer surface of the skirt and annularly winding, and hoisting into a curing oven for rotary curing after the annular winding is finished. According to the bonding forming method, the bonding quality of the upper skirt is improved, the process reliability is high, and the method is suitable for a wet-process upper skirt fiber winding shell.

Description

Technical Field

[0001] The invention belongs to the technical field of solid rocket engine casing molding, and in particular relates to a fiber-wound casing skirt bonding molding method. Background Art

[0002] The composite shell connection skirt is mainly used to connect the engine with the interstage or other parts of the rocket. During the flight of the solid rocket engine, the huge thrust generated by the engine is transmitted to the missile body through the connection skirt to drive the entire missile to fly. The connection skirt is an important load-bearing component of the rocket. During the flight of the rocket, it must withstand the combined effects of multiple loads such as axial pressure and bending moment, and the stress conditions are complex. How to improve the structural efficiency of the connection skirt is of great significance to the improvement of the overall performance of the engine and even the rocket. A large number of studies have been conducted on the parameter research, performance analysis, and failure analysis of the connection parts of the composite shell skirt of the solid rocket engine, but none of them indicate what kind of process methods can be adopted to improve the bonding quality of the skirt part. Summary of the invention

[0003] The purpose of the present invention is to solve the above technical problems and provide a fiber winding shell skirt bonding molding method which improves the skirt bonding quality.

[0004] To achieve the above object, the present invention provides a fiber winding shell skirt bonding molding method comprising the following steps:

[0005] S1) selecting a winding core mold according to the aspect ratio of the fiber winding shell, and machining the winding core mold according to the inner profile of the thermal insulation layer in the fiber winding shell after the winding core mold is formed;

[0006] S2) pasting the inner insulation layer onto the winding core mold, and grinding the skirt bonding area on the surface of the inner insulation layer with an automatic grinder;

[0007] S3) performing inner skirt winding on the surface of the inner insulation layer in a winding manner of alternating spiral winding and hoop winding to obtain an uncured shell;

[0008] S4) machining a stress relief groove on the skirt at a bonding area with the uncured shell;

[0009] S5) using nitrile phenolic adhesive to evenly apply on the inner and outer surfaces of the skirt and each bonding surface of the rubber buffer layer, and bonding the rubber buffer layer to the inner and outer surfaces of the skirt, and then vacuuming and curing;

[0010] S6) evenly applying nitrile phenolic adhesive on the buffer layer surface of the inner surface of the skirt, and installing the skirt to the skirt bonding area of ​​the uncured shell;

[0011] S7) evenly brushing nitrile phenolic adhesive on the buffer layer surface of the skirt outer surface, then tying the skirt and winding it in a hoop direction;

[0012] S8) laying a layer of adhesive tape on the surface of the uncured shell after the circumferential winding is completed, and then using glass fiber yarn to circumferentially wrap the surface of the uncured shell. After the circumferential winding is completed, it is hoisted into a curing furnace for rotational curing.

[0013] Furthermore, the winding core mold shown is a gypsum core mold or a sand core mold.

[0014] Furthermore, in the step S3), the shell interference is controlled during the circumferential winding before the last spiral winding, and then the last spiral winding is performed; the specific method of the interference control is:

[0015] First, confirm the theoretical required dimensions: set the skirt bonding starting point to (0, (D1-d-2h-0.5) / 2) and the skirt tip to (L, (D2-d-2h+2) / 2), where D1 is the inner diameter of the skirt bonding starting point, d is the increment of the diameter of a spirally wound uncured shell, D2 is the inner diameter of the skirt tip, h is the thickness of the rubber buffer layer, and L is the axial length from the skirt bonding starting point to the skirt tip; then substitute the two points of the skirt bonding starting point and the skirt tip into the equation Y=kX+b to calculate the values ​​of k and b, and then take a diameter value Y every 20 to 40 mm from the skirt bonding starting point n As the measurement point, that is, X n =20~40n, n=1,2,3……,until LX n ≤20mm, each diameter Y n Tolerance is ±0.3mm;

[0016] Measure the outer diameter of the uncured shell before the last spiral winding for the first time, and confirm the thickness a required for each measuring point by comparing the actual measured value with the theoretical required size; then divide the thickness a by the single-layer circumferential winding thickness increment b, and round down to get the number of circumferential layers c1 required for each measuring point, and start from the position of the maximum number of circumferential layers 10 to 20 mm on one side of the barrel section to carry out circumferential winding in the direction of the skirt bonding starting point, until it is 10 to 20 mm past the position of the minimum number of circumferential layers on this side, and then run the reverse circumferential winding to 10 to 20 mm past the position of the minimum number of circumferential layers on the other side; if the maximum number of circumferential layers is at the skirt tip, then go over the skirt The tip is 10 to 20 mm, and then starting from this point, continue to perform rewinding according to the above requirements, so that the actual number of circumferential layers of rewinding at each position for the first time meets c1 or c1-1; after the first rewinding is completed, measure the outer diameter of the uncured shell for the second time, and adopt the above-mentioned method for calculating the number of circumferential layers of rewinding to obtain the number of circumferential layers c2 for the second rewinding, and perform the above-mentioned rewinding operation so that the actual number of circumferential layers of rewinding for the second time meets c2 or c2-1; finally, measure the outer diameter of the uncured shell for the third time, and adopt the above-mentioned method for calculating the number of circumferential layers of rewinding to obtain the number of circumferential layers c3 for the third rewinding, and only need to perform circumferential winding on the rewinding position with the corresponding number of circumferential layers c3.

[0017] Furthermore, in the step S4), the length of the stress release groove extends from the skirt bonding starting point to the skirt tip.

[0018] Furthermore, in the step S4), the number of the stress release grooves is 24 to 48, and the width is 2 to 5 mm.

[0019] Furthermore, in the step S5), curing is performed at 60 to 70° C. for 2 to 6 hours, and the vacuum degree is -90 to -110 KPa.

[0020] Furthermore, the specific process of step S7) skirt binding and circumferential winding is: starting from the front equatorial position, 5 to 7 layers of skirt binding layers are circumferentially wound back and forth toward the front skirt tip; after the skirt is tied, the yarn is continuously wound to the surface of the unsolidified shell and the triangle area of ​​the skirt tip is leveled, and then the rear skirt is also circumferentially wound, and finally the circumferential winding of the skirt outer side is completed.

[0021] Furthermore, in the step S7), the skirt binding starting point is wound back and forth from the equator line to the skirt tip, and the tension of the single yarn is 50-70N.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) The present invention adopts a shell outer diameter required dimension calculation scheme and a shell outer diameter winding method, which not only ensures that the interference fit in the upper skirt area transitions from negative to positive from the equator to the skirt tip, increases the angle of the upper skirt area, and improves the bonding strength between the skirt and the shell, but also effectively ensures the straightness of the upper skirt area, which can effectively improve the bonding quality between the skirt and the shell and prevent debonding at the interface between the skirt and the shell.

[0024] 2) The bonding molding method of the present invention improves the bonding quality of the upper skirt, has strong process reliability, and is suitable for wet-process upper skirt fiber winding shells. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with specific embodiments.

[0026] The fiber winding shell skirt bonding molding method of the present invention comprises the following steps:

[0027] S1) A winding core mold is selected according to the aspect ratio of the fiber winding shell, and after the winding core mold is formed, machining is performed according to the inner profile of the thermal insulation layer in the fiber winding shell; the winding core mold can be a gypsum core mold or a sand core mold.

[0028] S2) The inner insulation layer is pasted on the winding core mold, and the skirt bonding area on the surface of the inner insulation layer is polished with an automatic grinder to ensure the roundness and straightness of the skirt bonding area, effectively avoiding quality problems such as uneven skirt force caused by the shell being out of roundness and the skirt bonding area being suspended in the subsequent winding process.

[0029] S3) Performing skirt winding on the surface of the inner insulation layer in an alternating winding manner of spiral winding and hoop winding to obtain an uncured shell, and performing hoop winding before the last spiral winding to control the shell interference, and then performing the last spiral winding.

[0030] The specific method of interference control is as follows: First, confirm the theoretical required dimensions: set the skirt bonding starting point to (0, (D1-d-2h-0.5) / 2), and the skirt tip to (L, (D2-d-2h+2) / 2), where D1 is the inner diameter of the skirt bonding starting point, d is the increment of the diameter of a spirally wound uncured shell, D2 is the inner diameter of the skirt tip, h is the thickness of the rubber buffer layer, and L is the axial length from the skirt bonding starting point to the skirt tip; then substitute the two points of the skirt bonding starting point and the skirt tip into the equation Y=kX+b to calculate the values ​​of k and b, and then take a diameter value Y every 20 to 40 mm from the skirt bonding starting point. n As the measurement point, that is, X n =20~40n, n=1,2,3……,until LX n ≤20mm, each diameter Y n The tolerance is ±0.3mm.

[0031] Measure the outer diameter of the uncured shell before the last spiral winding for the first time, and confirm the thickness a required for each measuring point by comparing the actual measured value with the theoretical required size; then divide the thickness a by the single-layer circumferential winding thickness increment b, and round down to get the number of circumferential layers c1 required for each measuring point, and start from the position of the maximum number of circumferential layers 10 to 20 mm on one side of the barrel section to carry out circumferential winding in the direction of the skirt bonding starting point, until it is 10 to 20 mm past the position of the minimum number of circumferential layers on this side, and then run the reverse circumferential winding to 10 to 20 mm past the position of the minimum number of circumferential layers on the other side; if the maximum number of circumferential layers is at the skirt tip, then go over the skirt The tip is 10 to 20 mm, and then starting from this point, continue to perform rewinding according to the above requirements, so that the actual number of circumferential layers of rewinding at each position for the first time meets c1 or c1-1; after the first rewinding is completed, measure the outer diameter of the uncured shell for the second time, and adopt the above-mentioned method for calculating the number of circumferential layers of rewinding to obtain the number of circumferential layers c2 for the second rewinding, and perform the above-mentioned rewinding operation so that the actual number of circumferential layers of rewinding for the second time meets c2 or c2-1; finally, measure the outer diameter of the uncured shell for the third time, and adopt the above-mentioned method for calculating the number of circumferential layers of rewinding to obtain the number of circumferential layers c3 for the third rewinding, and only need to perform circumferential winding on the rewinding position with the corresponding number of circumferential layers c3.

[0032] Compared with the traditional fiber-wound shell, this theoretical shell outer diameter requirement dimension calculation scheme and shell outer diameter filling winding method adopt a universal calculation method to obtain the required outer diameter dimension before the last spiral winding before the shell upper skirt, which ensures that the interference in the upper skirt area transitions from negative to positive, and ensures the straightness of the upper skirt area; continuous circumferential winding is used for filling winding, which ensures the roundness of the outer surface of the upper skirt area and avoids the occurrence of high and low points in the upper skirt area. The above method effectively improves the bonding quality between the skirt and the shell and prevents debonding at the interface between the skirt and the shell.

[0033] S4) Processing stress relief grooves on the skirt and in the bonding area where the skirt is bonded to the uncured shell. The length of the stress relief grooves extends from the skirt bonding starting point to the skirt tip, which can effectively prevent debonding at the starting point of the bonding area. The number of stress relief grooves is 24 to 48, and the width is 2 to 5 mm.

[0034] S5) Use nitrile phenolic adhesive to evenly apply on the inner and outer surfaces of the skirt and the bonding surfaces of the rubber buffer layer, and bond the rubber buffer layer to the inner and outer surfaces of the skirt, and then vacuum cure at 60-70°C for 2-6 hours, with a vacuum degree of -90 to -110KPa. Bonding the rubber buffer layer to the inner and outer surfaces of the skirt in advance effectively avoids the slippage of the rubber buffer layer caused by friction during the skirt application process, and effectively ensures the bonding strength between the skirt and the rubber buffer layer.

[0035] S6) Evenly apply nitrile phenolic adhesive on the buffer layer surface of the inner surface of the skirt, install the skirt to the skirt bonding area of ​​the uncured shell, and ensure the front and rear skirt spacing and quadrant deviation.

[0036] S7) Evenly apply nitrile phenolic adhesive on the buffer layer surface of the skirt outer surface, and then start from the front equator position to the front skirt tip to wrap 5 to 7 layers of skirt binding back and forth; after the skirt is tied, the yarn is continuously wrapped to the uncured shell surface and the skirt tip triangle area is leveled, and then the rear skirt is also wrapped in the same way, and finally the skirt outer ring is wrapped; the skirt binding starting point is wrapped back and forth from the equator to the skirt tip, and the single yarn tension is 50 to 70N.

[0037] S8) laying a layer of adhesive tape on the surface of the uncured shell after the circumferential winding is completed, and then using glass fiber yarn to circumferentially wrap the surface of the uncured shell. After the circumferential winding is completed, it is hoisted into a curing furnace for rotational curing.

[0038] The bonding molding method of the invention improves the bonding quality of the upper skirt, has strong process reliability, and is suitable for wet-process upper skirt fiber winding shells.

Claims

1. A fiber winding shell skirt bonding molding method, characterized in that: The bonding molding method comprises the following steps: S1) selecting a winding core mold according to the aspect ratio of the fiber winding shell, and machining the winding core mold according to the inner profile of the thermal insulation layer in the fiber winding shell after the winding core mold is formed; S2) pasting the inner insulation layer onto the winding core mold, and grinding the skirt bonding area on the surface of the inner insulation layer with an automatic grinder; S3) performing inner skirt winding on the surface of the inner insulation layer in a winding manner of alternating spiral winding and hoop winding to obtain an uncured shell; S4) machining a stress relief groove on the skirt at a bonding area with the uncured shell; S5) using nitrile phenolic adhesive to evenly apply on the inner and outer surfaces of the skirt and each bonding surface of the rubber buffer layer, and bonding the rubber buffer layer to the inner and outer surfaces of the skirt, and then vacuuming and curing; S6) evenly applying nitrile phenolic adhesive on the buffer layer surface of the inner surface of the skirt, and installing the skirt to the skirt bonding area of ​​the uncured shell; S7) evenly brushing nitrile phenolic adhesive on the buffer layer surface of the skirt outer surface, then tying the skirt and winding it in a hoop direction; S8) laying a layer of adhesive tape on the surface of the uncured shell after the circumferential winding is completed, and then using glass fiber yarn to circumferentially wrap the surface of the uncured shell. After the circumferential winding is completed, it is hoisted into a curing furnace for rotational curing.

2. The fiber winding shell skirt bonding molding method according to claim 1 is characterized in that: The winding core mold shown is a gypsum core mold or a sand core mold.

3. The fiber winding shell skirt bonding molding method according to claim 1, characterized in that: In the step S3), the shell interference is controlled during the circumferential winding before the last spiral winding, and then the last spiral winding is performed; the specific method of the interference control is: First, confirm the theoretical required dimensions: set the skirt bonding starting point to (0, (D1-d-2h-0.5) / 2) and the skirt tip to (L, (D2-d-2h+2) / 2), where D1 is the inner diameter of the skirt bonding starting point, d is the increment of the diameter of a spirally wound uncured shell, D2 is the inner diameter of the skirt tip, h is the thickness of the rubber buffer layer, and L is the axial length from the skirt bonding starting point to the skirt tip; then substitute the two points of the skirt bonding starting point and the skirt tip into the equation Y=kX+b to calculate the values ​​of k and b, and then take a diameter value Y every 20 to 40 mm from the skirt bonding starting point n As the measurement point, that is, X n =20~40n, n=1,2,3……,until LX n ≤20mm, each diameter Y n Tolerance is ±0.3mm; Measure the outer diameter of the uncured shell before the last spiral winding for the first time, and confirm the thickness a required for each measuring point by comparing the actual measured value with the theoretical required size; then divide the thickness a by the single-layer circumferential winding thickness increment b, and round down to get the number of circumferential layers c1 required for each measuring point, and start from the position of the maximum number of circumferential layers 10 to 20 mm on one side of the barrel section to carry out circumferential winding in the direction of the skirt bonding starting point, until it is 10 to 20 mm past the position of the minimum number of circumferential layers on this side, and then run the reverse circumferential winding to 10 to 20 mm past the position of the minimum number of circumferential layers on the other side; if the maximum number of circumferential layers is at the skirt tip, then go over the skirt The tip is 10 to 20 mm, and then starting from this point, continue to perform rewinding according to the above requirements, so that the actual number of circumferential layers of rewinding at each position for the first time meets c1 or c1-1; after the first rewinding is completed, measure the outer diameter of the uncured shell for the second time, and adopt the above-mentioned method for calculating the number of circumferential layers of rewinding to obtain the number of circumferential layers c2 for the second rewinding, and perform the above-mentioned rewinding operation so that the actual number of circumferential layers of rewinding for the second time meets c2 or c2-1; finally, measure the outer diameter of the uncured shell for the third time, and adopt the above-mentioned method for calculating the number of circumferential layers of rewinding to obtain the number of circumferential layers c3 for the third rewinding, and only need to perform circumferential winding on the rewinding position with the corresponding number of circumferential layers c3.

4. The fiber winding shell skirt bonding molding method according to claim 1, characterized in that: In the step S4), the length of the stress release groove extends from the skirt bonding starting point to the skirt tip.

5. The fiber winding shell skirt bonding molding method according to claim 1, characterized in that: In the step S4), the number of the stress release grooves is 24 to 48, and the width is 2 to 5 mm.

6. The fiber winding shell skirt bonding molding method according to claim 1, characterized in that: In the step S5), curing is carried out at 60-70° C. for 2-6 hours, and the vacuum degree is -90--110 KPa.

7. The fiber winding shell skirt bonding molding method according to claim 1, characterized in that: The specific process of step S7) skirt binding and circumferential winding is: starting from the front equator position to the front skirt tip, 5 to 7 layers of skirt binding layers are circumferentially wound back and forth; after the skirt is tied, the yarn is continuously wound to the surface of the unsolidified shell and the triangle area of ​​the skirt tip is leveled, and then the rear skirt is also circumferentially wound, and finally the outer circumferential winding of the skirt is completed.

8. The fiber winding shell skirt bonding molding method according to claim 7, characterized in that: In the step S7), the skirt binding starting point is wound back and forth from the equator line to the skirt tip, and the tension of the single yarn is 50-70N.