Method and device for transmitting and acquiring pressure intensity of T-shaped stringer mold

Abstract

The invention discloses a method and a device for transmitting and acquiring pressure intensity of a T-shaped stringer mold. The parameters comprise tank pressure P, downward pressure P1, oblique pressure P2, leftward pressure P3, pressure P4 transmitted by the movable mold on a T stringer web, height H of the movable mold, width W of the movable mold, paving height h of the T stringer web, sliding friction force of the movable mold, friction coefficient mu, oblique angle theta of the movable mold, supporting force of the movable mold, and pressure transmission rules among all the parameters. The pressure transmission calculation method for the T-shaped stringer mold is found by combining theories with practice.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft composite material manufacturing, and in particular to a method and device for obtaining pressure transmission of a T-shaped long stringer mold. Background Art

[0002] Composite material T-shaped long stringers are generally used in aircraft wing panels. Composite material T-shaped long stringers are long in size and large in number, and the length of T-shaped long stringers can reach 30 meters. The mold of composite material T-shaped long stringers is made of Invar steel, which is very expensive. A medium-sized aircraft often costs billions of RMB to manufacture the mold of composite material T-shaped long stringers. Therefore, the stability of the design performance of the T-shaped long stringer mold is very important.

[0003] The molding of T-type long stringer parts generally adopts a structure in which the movable mold and the fixed mold are placed on a flat frame. After the carbon fiber is laid on the movable mold and the fixed mold respectively, the movable mold and the fixed mold are closed. After closing the mold, a vacuum bag is made on the flat frame. The pressure on the web surface of the T-type long stringer is transmitted by the movable mold moving toward the fixed mold under the tank pressure. The current situation is that the calculation principle of pressure transmission is not clear, and the T-type long stringer mold is designed only based on past experience. Accidents of too little or too much pressure transmission have occurred, causing the Aogui composite material T-type long stringer and mold to be scrapped.

[0004] There is an urgent need for a T-type long stringer mold pressure transfer calculation method to accurately calculate the size of the movable and fixed molds so that the movable mold can transfer the correct pressure to the web surface of the T-type long stringer. Summary of the invention

[0005] The present invention provides a method and device for obtaining pressure transmission of a T-shaped long stringer mold, which can accurately calculate the size of a movable mold and a fixed mold, so that the movable mold can transmit correct pressure to the web surface of the T-shaped long stringer.

[0006] A first aspect of the present invention provides a method for obtaining pressure transmission of a T-shaped long stringer mold, comprising:

[0007] Obtain the relationship between tank pressure P, movable mold height H, movable mold width W, T long stringer web laying height h, movable mold sliding friction coefficient μ, and all the above parameters;

[0008] The formula P4 = (P*HP*W*μ) / h is used to obtain the pressure P4 transmitted by the dynamic mold to the web of the T-stringer.

[0009] Optionally, the web laying height of the T-stringer is h = (H-μW) / 1.3.

[0010] Optionally, the T-shaped long stringer mold includes: a bottom plate, a movable mold, and a fixed mold;

[0011] The bottom plate and the fixed mold are welded as one body, and the movable mold is slidably arranged on the bottom plate.

[0012] Optionally, the movable mold is rectangular.

[0013] Optionally, the movable mold is a rectangle with beveled edges.

[0014] Optionally, μ is the friction coefficient with a maximum value of 0.2.

[0015] A second aspect of the present invention provides a T-shaped long stringer mold pressure transfer acquisition device for executing the method as described in any one of the first aspects.

[0016] A third aspect of the present invention provides a computer program for executing the method as described in any one of the first aspects.

[0017] The present invention provides a method and device for obtaining pressure transmission of a T-type long stringer mold. By combining theory with practice, a simple formula is found, which not only provides a theoretical basis for the design of the T-type long stringer mold, but also can accurately transmit pressure to the manufactured mold by controlling the web surface paving length. T-type long stringers are widely used in the aviation industry, and the invar steel material mold occupies a large proportion of the cost. The present invention can improve the mold structure efficiency, improve the product qualification rate, and greatly reduce the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the T-shaped long stringer mold structure;

[0019] Figure 2 This is a schematic diagram of the T-shaped long stringer mold being subjected to tank pressure;

[0020] Figure 3 This is a schematic diagram of the key dimensions of the T-shaped long stringer mold;

[0021] Description of reference numerals:

[0022] 1- Bottom plate;

[0023] 2-Fixed mold;

[0024] 3- Moving mold;

[0025] 4-T-type long stringer;

[0026] 5- Vacuum chamber;

[0027] 6- Vacuum bag making area;

[0028] P-autoclave pressure;

[0029] H-moving mold height;

[0030] W-moving mold width;

[0031] h-height of the web of the long stringer. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0033] See attached Figure 1-3 The present invention mainly controls the width, height and paving size of the web surface of the T-shaped long truss mold to control the pressure transmission of the mold, so that the solidification thickness and losslessness of the web surface of the T-shaped long truss are qualified.

[0034] The T-shaped long girder mold mainly comprises a bottom plate 1 , a fixed mold 2 , and a movable mold 3 . The bottom plate 1 and the fixed mold 2 are welded as one, and the movable mold 3 can slide on the bottom plate 1 .

[0035] The process of using the mold is as follows: first, the movable mold 2 and the fixed mold 3 are separated, and the carbon fiber is laid separately. After the laying is completed, the movable mold 3 is moved to close the movable and fixed molds. After closing the molds, a sealing strip is attached to the vacuum bag making area 6 of the bottom plate 1 to make a vacuum bag. The vacuum bag wraps the fixed mold 2, the movable mold 3 and the T-shaped long stringer 4. After the vacuum bag is made, it is sent into the autoclave. In the autoclave, the mold is subjected to pressure P, such as Figure 2 shown.

[0036] The pressure P acts on the upper and side parts of the movable and fixed molds. Since the fixed mold 2 and the bottom plate 1 are welded and fixed, the fixed mold does not transmit pressure to the web of the long stringer, and only the movable mold 3 transmits pressure to the web of the long stringer. The present invention aims to calculate the pressure transmission of the movable mold 3.

[0037] The present invention provides a method for calculating pressure transfer of a T-shaped long stringer mold, comprising the following steps:

[0038] Step 1: The movable mold 3 is subjected to gravity, downward pressure P1, oblique pressure P2, leftward pressure P3, bottom friction, and the support force of the web surface of the T-beam. (P1, P2, and P3 have the same value, which is the tank pressure P).

[0039] Step 2: The oblique pressure is P2*m*L (L is the length of the movable mold, m and θ are shown in Figure 2 ), the downward force component is P2*m*L*cosθ, and the leftward force component is P2*m*L*sinθ. It can be seen that the force transmitted when the movable mold has a hypotenuse with an angle of θ is the same as that of the rectangular movable mold.

[0040] Step 3: The curing tank pressure of the carbon fiber T-shaped long stringer is generally 0.5-0.8MPa. The weight of a one-meter-long dynamic mold is about 100Kg, so the friction generated by the weight of the dynamic mold can be ignored.

[0041] Step 4: Figure 3 Where h is the laying height of the web of the T-beam. The ultimate purpose of the present invention is that the pressure P4 of the web of the T-beam subjected to the moving mold is greater than or equal to the tank pressure P, and μ is the friction coefficient with a maximum value of 0.2.

[0042] P4=(P*H*LP*W*L*μ) / h*L

[0043] P4=(P*HP*W*μ) / h

[0044] The web surface pressure P4 is the same as the tank pressure P, and the relationship between the dynamic mold width W and height H is obtained:

[0045] h=H-μW

[0046] h includes the web surface of the stringer and the laying allowance, so when H and W are fixed, the laying allowance can be changed to control the pressure on the web surface.

[0047] Step 5: Through the analysis of a large number of successful cases and theoretical calculations in the past, when P4 = 1.3P, the quality of the long stringer reaches the best and most stable. At this time:

[0048] 1.3h=H-μW

[0049] The present invention combines theory with practice to find a simple formula, which not only provides a theoretical basis for the design of T-long stringer molds, but also can accurately transmit pressure to the manufactured molds by controlling the web surface paving length. T-type long stringers are widely used in the aviation industry, and the invar steel molds occupy a large proportion of the cost. The present invention can improve the mold structure efficiency, improve the product qualification rate, and greatly reduce the production cost.

[0050] The above description is only a partial specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for obtaining pressure transmission of a T-shaped long stringer mold, characterized in that ,include: Obtain the relationship between tank pressure P, movable mold height H, movable mold width W, T long stringer web laying height h, movable mold sliding friction coefficient μ, and all the above parameters; The formula P4 = (P*HP*W*μ) / h is used to obtain the pressure P4 transmitted by the dynamic mold to the web of the T-stringer.

2. A method for obtaining pressure transmission of a T-shaped long stringer mold according to claim 1, characterized in that ,T long girder web laying height h=(H-μW) / 1.

3.

3. A method for obtaining pressure transmission of a T-shaped long stringer mold according to claim 1, characterized in that ,T-type long truss mold includes: bottom plate, movable mold and fixed mold; The bottom plate and the fixed mold are welded as one body, and the movable mold is slidably arranged on the bottom plate.

4. A method for obtaining pressure transmission of a T-shaped long stringer mold according to claim 3, characterized in that , the moving mold is rectangular.

5. A method for obtaining pressure transmission of a T-shaped long stringer mold according to claim 4, characterized in that , the moving mold is a rectangle with beveled edges.

6. A method for obtaining pressure transmission of a T-shaped long stringer mold according to claim 1, characterized in that , μ is the friction coefficient and its maximum value is 0.

2.

7. A T-shaped long stringer mold pressure transmission acquisition device, characterized in that , used to perform the method as described in any one of claims 1-6.

8. A computer-readable storage medium, characterized in that: include: Memory and processor; The memory is configured to store executable instructions; The processor is configured to implement the method according to any one of claims 1 to 6 when executing the executable instructions stored in the memory.

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