An integrated expansion segment preform and method of making the same

Abstract

The application discloses an integrated expansion section preform and a preparation method thereof. The preparation method comprises the following steps: making a forming die; dividing the preform into N unit layers with different areas according to function requirements; laying different kinds of unit layers on the forming die according to the function requirements of each part of the preform, and fixing the unit layers layer by layer by using a needle punching process; fixing and suturing the unit layers after being punched for several layers by using a blind seam process; and performing needle punching and blind seam on all the unit layers, so that each unit layer forms an entirety, the forming preform is taken out of the die, and the preparation of the preform is completed. The preparation method of the application is used for making the preform by layer stacking thickness, the fibers of the layer are continuous, the integrated expansion section is formed, the overall structural strength is improved, the interlaminar performance and comprehensive performance of the composite material are enhanced, the fiber volume content of the preform is improved, and the expansion section with complex structure, large curvature and various sizes can be prepared.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of an interlaminar reinforced preform for composite materials, in particular to an integrated expansion section preform and a preparation method thereof. BACKGROUND

[0002] The expansion section is an important anti-ablation component in a solid rocket engine nozzle. The expansion section needs to have high normal strength to resist ablation and scouring of high-temperature and high-speed gas flow. At present, the preform of the expansion section of the solid rocket engine is prepared by using a cloth tape winding process, and the finally formed composite material has poor mechanical properties, poor ablation performance, and poor interlaminar performance. The outstanding problem is that the interlaminar shear performance is low. The comprehensive performance is not high, and in particular, the interlaminar shear performance is low. The characteristics are not suitable for the development trend of modern weapons with high supersonic speed, high penetration and high precision. SUMMARY

[0003] The application aims at the shortcomings of the prior art, such as poor mechanical properties, poor ablation performance and poor interlaminar performance, and provides an integrated expansion section preform and a preparation method thereof.

[0004] Technical scheme: In order to solve the above problems, the application adopts a preparation method of an integrated expansion section preform, which comprises the following steps:

[0005] Step 1, forming a forming die; according to the inner profile of the preform, a corresponding preform forming die is processed;

[0006] Step 2, the preform is divided into N unit layers with different areas according to the functional requirements, and N is greater than or equal to 1;

[0007] Step 3, according to the functional requirements of each part of the preform, different types of unit layers are laid on the forming die, and are fixed layer by layer by using a needle punching process;

[0008] Step 4, the unit layers after needle punching for several layers are fixed and sutured by using a blind seam process;

[0009] Step 5, the needle punching and blind seam are performed on all the unit layers, so that the unit layers form an integral whole, and the formed preform is taken out of the die, and the preparation of the preform is completed.

[0010] Further, the forming die in step 1 comprises a small end die and a large end die, the small end die is a large cylinder with a center through hole, one end of the large end die is a small cylinder, the radius of the small cylinder is equal to the radius of the center through hole of the small end die, the length of the small cylinder is greater than the length of the small end die, the small cylinder is inserted into the through hole of the small end die, and the front end face of the small cylinder is flush with the front end face of the small end die; the other end of the large end die is a circular truncated cone, the upper bottom area of the circular truncated cone is equal to the bottom area of the small cylinder, and the small cylinder and the circular truncated cone are coaxially connected to form an integral whole and have a through hole in the center.

[0011] Further, the preform parts in step 3 include a front section of the expansion section, a middle section of the expansion section, a flange plate and a tail section of the expansion section, the middle section of the expansion section is prepared by laying unit layers horizontally on a large end mold and fixing by needle punching layer by layer, the front section of the expansion section is prepared by laying unit layers horizontally on a small end mold and fixing by needle punching layer by layer, the flange plate is prepared by laying unit layers horizontally on the middle section of the expansion section near the small cylinder and fixing by needle punching layer by layer, and the tail section of the expansion section is prepared by laying unit layers parallel to the side of the circular truncated cone and fixing by needle punching layer by layer.

[0012] Further, the different kinds of unit layers in step 3 are as follows: the first unit layer composed of a quartz mesh tire and a high-silica fiber cloth is used in the front section of the expansion section; and the second unit layer composed of a carbon fiber mesh tire and a carbon fiber cloth is used in the middle section of the expansion section, the flange plate and the tail section of the expansion section.

[0013] Further, in the first unit layer, the quartz mesh tire is arranged above the high-silica fiber cloth; and in the second unit layer, the carbon fiber mesh tire is arranged above the carbon fiber cloth.

[0014] Further, the number of monofilaments in the carbon fiber cloth bundle is 3000 or less, and the carbon fiber cloth is plain weave, twill weave or satin weave carbon fiber cloth.

[0015] Further, the blind seam process in step 3 is as follows: a suture needle with a single suture line is passed through several layers of unit layers, and then moved a distance and passed through the unit layers again, and returned along the original path, in the process of returning, the friction between the suture line and the unit layers accumulates to form a loop, and the loop is retained by a loop catcher; the suture needle continues to pass through the loop formed last time, and then moves a distance and returns along the original path, to form a new loop, under the action of the loop catcher and the suture needle, the loop is locked, and a blind seam cycle is completed.

[0016] Further, the suture needle passes through ten layers of unit layers.

[0017] Further, the suture needle is crescent-shaped, and has a through hole at the needle head.

[0018] The application also provides an integrated expansion section preform prepared by the above preparation method.

[0019] Beneficial effects: Compared with the prior art, the significant advantages of this invention are (1) the design scheme of combined molds is adopted to disperse complex structures into simple structures; (2) the preform is made by laying and needle-punching stitching process, which can enhance the interlayer performance and comprehensive performance of composite materials, increase the fiber volume content of the preform, and reduce the internal pore size; (3) it can prepare expansion sections with complex structures, large curvature and various sizes; (4) the preform is made by layering thickness, the layered fibers are continuous, and the integrated forming expansion section is realized, which improves the overall structural strength; (5) the layup direction is mainly horizontal, which can improve the ablation resistance and erosion resistance of the material. Attached Figure Description

[0020] Figure 1 This is a flowchart of the method for preparing the integrated expansion section preform of the present invention;

[0021] Figure 2 This is a schematic diagram showing the fit between the large-end mold and the small-end mold of the preform forming mold of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of the large end mold of the preform forming mold of the present invention;

[0023] Figure 4 This is a schematic diagram of the cross-section of the prefabricated expansion section of the present invention;

[0024] Figure 5 This is a schematic diagram of the prefabricated body layup direction of the present invention. Detailed Implementation

[0025] like Figure 1 As shown, the preparation method of an integrated expanded section preform in this embodiment includes the following steps:

[0026] Step 1: Make the molding mold. For example... Figure 2 As shown, the forming mold in this embodiment includes a small-end mold 1 and a large-end mold 2. The small-end mold 1 is a large cylinder with a central through hole. Figure 2 and Figure 3 As shown, one end of the large end mold 2 is a small cylinder 3. The radius of the small cylinder 3 is equal to the radius of the central through hole of the small end mold 1. The length of the small cylinder 3 is greater than the length of the small end mold 1. The small cylinder 3 is inserted into the through hole of the small end mold 1. The front end face of the small cylinder 3 is flush with the front end face of the small end mold 1. The other end of the large end mold 2 is a frustum 4. The area of ​​the upper base of the frustum 4 is equal to the area of ​​the lower base of the small cylinder 3. The small cylinder 3 and the frustum 4 are coaxially connected as a whole and have a through hole in the center.

[0027] Step 2: Divide the precast structure into four unit layers of different areas according to functional requirements, such as... Figure 4 As shown, each unit layer consists of the front section 5 of the expansion section, the middle section 6 of the expansion section, the flange 7, and the tail section 8 of the expansion section.

[0028] Step 3, according to the functional requirements of each part of the preform, two kinds of unit layers are laid on the forming mold, and are fixed layer by layer by using needle punching process. Among them, the first unit layer is composed of a first unit layer of quartz mesh tire and high silica fiber cloth, and the quartz mesh tire in the first unit layer is placed above the high silica fiber cloth; the second unit layer is composed of carbon fiber mesh tire and carbon fiber cloth, and in the second unit layer, the carbon fiber mesh tire is placed above the carbon fiber cloth.

[0029] Step 4, the unit layer after needle punching several layers is fixed and stitched by using blind seam process. The needle punching depth of this embodiment is 10mm, the needle punching density is 30 stitches / cm 2 , and the blind seam density is stitched with a fiber spacing of 10mm×10mm.

[0030] Place the forming mold horizontally along the central axis, and lay a layer of high-density sponge board with a thickness of 5mm on the surface of the mold. First, start laying the first unit layer horizontally along the surface of the small cylindrical body 3 which is not inserted into the through hole of the small end mold 1, and lay it until it contacts the side surface of the circular truncated cone 4 in the horizontal direction. The unit layer is fixed layer by layer by needle punching, and blind seam is performed once every ten unit layers. After laying the unit layer to a certain thickness, start laying the unit layer of the tail section 8 of the expansion section at the same time; continue to lay the unit layer horizontally, and after the unit layer contacts the side surface of the circular truncated cone 4, continue to lay along the side surface of the circular truncated cone 4 until the entire side surface of the circular truncated cone 4 is covered, repeat the above laying steps, and after the unit layer reaches a certain thickness, stop laying the unit layer, and complete the manufacture of the middle section 6 and the tail section 8 of the expansion section.

[0031] Lay the second unit layer horizontally along the side edge of the small end mold 1, and the unit layer covers the entire side surface. The unit layer is fixed layer by layer by needle punching, and blind seam is performed once every ten unit layers. Stop laying the unit layer after accumulating to a position where the horizontal thickness is flush with the already manufactured middle section 6 of the expansion section, and complete the manufacture of the front section 5 of the expansion section.

[0032] The front section 5 of the expansion section and the already manufactured part of the middle section 6 of the expansion section are stitched together by using blind seam process. Start laying the first unit layer horizontally along the common horizontal height of the front section 5 of the expansion section and the already manufactured part of the middle section 6 of the expansion section from a position a small distance away from the front end of the front section 5 of the expansion section, and extend the laying to the tail section 8 of the expansion section. The unit layer is fixed layer by layer by needle punching, and blind seam is performed once every ten unit layers. Stop laying after reaching the required thickness, complete the manufacture of the middle section 6 and the tail section 8 of the expansion section. The inner surface of the middle section 6 of the expansion section withstands the erosion of high-speed airflow and resists ablation. Laying the unit layer horizontally at a certain angle with the side surface of the circular truncated cone 4 can improve the ablation resistance of the expansion section. The unit layer of the tail section 8 of the expansion section is formed by extending the unit layer outside the middle section 6 of the expansion section, which improves the connection strength between the tail section 8 of the expansion section and the middle section 6 of the expansion section.

[0033] The unit layer is laid horizontally from a position a small distance from the front end of the middle section 6 of the expansion section, the unit layer is narrow in width, the unit layers are fixed by needle punching layer by layer, and every ten unit layers are blind sewn once, after reaching the required thickness, the laying is stopped, and the production of the flange plate 7 is completed. The flange plate 7 and the produced part of the middle section 6 of the expansion section are sewn together by the blind sewing process.

[0034] Step 5, after the production of all unit layers is completed, the upper end face and the lower end face of the tail section 8 of the expansion section are trimmed in the horizontal direction, and finally the second unit layer expansion section 9 and the first unit layer expansion section 10 are formed, as shown in Figure 5 The formed preform is taken out of the mold, and the preparation of the preform is completed. The obtained preform has a maximum length of 290 mm and a maximum diameter of 202 mm.

Claims

1. A method for preparing an integrated expanded section preform, characterized in that, Includes the following steps: Step 1: Make the forming mold; process the corresponding preform forming mold according to the inner shape of the preform; the forming mold includes a small end mold (1) and a large end mold (2), the small end mold (1) is a large cylinder with a central through hole, one end of the large end mold (2) is a small cylinder (3), the radius of the small cylinder (3) is equal to the radius of the central through hole of the small end mold (1), the length of the small cylinder (3) is greater than the length of the small end mold (1), the small cylinder (3) is inserted into the through hole of the small end mold (1), and the front end face of the small cylinder (3) is flush with the front end face of the small end mold (1); the other end of the large end mold (2) is a frustum (4), the upper base area of ​​the frustum (4) is equal to the base area of ​​the small cylinder (3), the small cylinder (3) and the frustum (4) are coaxially connected as a whole and have a central through hole; Step 2: Divide the precast body into N unit layers of different areas according to functional requirements, where N≥1; Step 3: Based on the functional requirements of each part of the precast body, different types of unit layers are laid on the forming mold, and the layers are fixed one by one using a needle punching process; Step 4: Use blind suture technique to fix and suture the unit layer after several layers of needle punching; Step 5: Punch and blind-sew all unit layers to form a whole. Remove the preform from the mold to complete the preparation of the preform.

2. The preparation method according to claim 1, characterized in that, The prefabricated body in step 3 includes the front section (5), the middle section (6), the flange (7), and the tail section (8). The middle section (6) is made by horizontally laying unit layers on the large end mold (2) and fixing them layer by layer by needle. The front section (5) is made by horizontally laying unit layers on the small end mold (1) and fixing them layer by layer by needle. The flange (7) is made by horizontally laying unit layers on the side of the middle section (6) near the small cylinder (3) and fixing them layer by layer by needle. The tail section (8) is made by horizontally laying unit layers on the side of the frustum (4) and fixing them layer by layer by needle.

3. The preparation method according to claim 2, characterized in that, The different types of unit layers mentioned in step 3 are as follows: the front section (5) of the expansion section adopts a second unit layer composed of carbon fiber mesh and carbon fiber cloth; the middle section (6), flange (7) and tail section (8) of the expansion section adopt a first unit layer composed of quartz mesh and high silica fiber cloth.

4. The preparation method according to claim 3, characterized in that, In the first unit layer, the quartz mesh is placed on top of the high silica fiber cloth; in the second unit layer, the carbon fiber mesh is placed on top of the carbon fiber cloth.

5. The preparation method according to claim 4, characterized in that, The number of monofilaments in the carbon fiber cloth bundle must be 3,000 or less, and the carbon fiber cloth shall be plain weave, twill weave or satin weave carbon fiber cloth.

6. The preparation method according to claim 5, characterized in that, The blind stitching process described in step 4 is as follows: A suture needle with a single suture thread passes through several unit layers and continues to move a certain distance before passing through the unit layers again and returning along the original path. During the return process, friction between the suture thread and the unit layers accumulates to form a coil, which is held in place by a coil catcher. The suture needle continues to pass through the previously formed coil and continues to move a certain distance before returning along the original path to form a new coil. Under the action of the coil catcher and the suture needle, the coil is locked, completing one blind stitching cycle.

7. The preparation method according to claim 6, characterized in that, The suture needle passes through several unit layers, specifically ten layers.

8. The preparation method according to claim 7, characterized in that, The suture needle is crescent-shaped and has a through hole at the tip.

9. An integrated expansion segment prefabricated body, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

Images