Wheel disc cutting method

Abstract

The invention relates to the technical field of aviation auxiliary power device tests, and discloses a wheel disc cutting method, which comprises the following steps of: cutting three notches in a meridian section at trisection positions of a wheel disc in advance by taking the centroid of the meridian section as a starting end and extending outwards along the radial direction of the wheel disc; the wheel disc is applied to a hub containment test. The notches are cut in the trisection positions of the wheel disc in advance, so that in the hub containing test, the translational kinetic energy of hub fragments is the maximum, the technical standard regulation of CTSO-C77b is met, and the hub containing test in the auxiliary power device is successfully achieved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of aviation auxiliary power device testing, in particular to a wheel disc cutting method. BACKGROUND

[0002] The turboshaft engine is internally provided with a power turbine, the power turbine is provided with blades, the power turbine outputs power axially through a power worm gear shaft, and the power worm gear shaft is exposed to the outside. A general process for realizing the blade containment test is as follows: connecting a power absorption device and the power turbine shaft of the turboshaft engine; after the turboshaft engine works at a rated state for a preset time, cutting the power turbine shaft by using a cutter or other cutting device, so that the turboshaft engine instantaneously loses load, the rotating speed rapidly rises, when the rotating speed rises to a certain range, the blades break due to the centrifugal force, and the blades impact the casing, so that the purpose of the containment test is achieved.

[0003] For the wheel hub in the auxiliary power device, the wheel hub containment airworthiness test needs to verify that the casing contains the maximum kinetic energy fragments generated by the wheel hub failure. According to the technical standard of CTSO-C77b, the rotating speed of the wheel hub containment test is the highest rotating speed caused by the single-point failure of the control system, and the wheel hub needs to break in a way that generates the maximum translational kinetic energy within the specified rotating speed. In the wheel hub containment test, a wheel disc is generally used for the containment test. SUMMARY

[0004] Therefore, the application provides a wheel disc cutting method applied to the wheel hub containment test to expand the range of the containment test.

[0005] The application provides a wheel disc cutting method, which comprises the following steps:

[0006] Three notches are cut on the meridian section at the three-equal-position of the wheel disc, the notches are cut from the center of the meridian section as a starting end and extend outward along the radial direction of the wheel disc, and the wheel disc is applied to the wheel hub containment test. Advantageous effects: the application adopts the above technical scheme, the notches are cut at the three-equal-position of the wheel disc, so that the translational kinetic energy of the wheel hub fragments is the maximum in the wheel hub containment test, the technical standard of CTSO-C77b is met, the wheel hub containment test of the auxiliary power device is successfully realized, and the range of the containment test is expanded.

[0007] Optionally, the notches are cut in a wire cutting manner. Advantageous effects: the application adopts the above technical scheme, and energy loss caused by cutting is minimized.

[0008] Optionally, the wire cutting speed at the end of the notch cutting position is lower than the wire cutting speed at the other positions of the notch. Advantageous effects: the application adopts the above technical scheme, and energy loss caused by cutting is further minimized.

[0009] Optionally, a rounding structure is arranged at the end of the notch cut. Advantage: the above technical solution reduces the stress concentration of the wire cutting end, preventing the effect of affecting the hub containment test.

[0010] Optionally, the radius of the rounding structure is 2 mm.

[0011] Optionally, the notch avoids the end tooth structure and the vent hole structure. Advantage: the above technical solution avoids the premature failure of the wheel disc due to special structures such as the end tooth structure and the vent hole structure.

[0012] Optionally, the notch avoids the tenon groove structure and the blade structure provided on the rim of the wheel disc. Advantage: the above technical solution avoids the premature failure of the wheel disc due to special structures such as the tenon groove structure and the blade structure.

[0013] Optionally, determining the depth of the notch comprises:

[0014] Suppose the solid part section between the beginning of the notch and the inner edge of the meridian section is a first section, the solid part section between the end of the notch and the outer edge of the meridian section is a second section; the section between the inner edge and the outer edge of the meridian section is a third section; the hollow section between the beginning of the notch and the end of the notch is a fourth section; the area of the first section is A1, the area of the second section is A2, the area of the third section is A3; the area of the fourth section is A4;

[0015] The centrifugal force F is calculated by formula (3) 离心力 ;

[0016] F 离心力 =MR C ω 2 (3)

[0017] Wherein, M is the mass of 1 / 3 wheel disc, unit is kg; R C is the centroid radius of 1 / 3 wheel disc, unit is m; ω is the angular velocity of wheel disc rotation, unit is rad / s;

[0018] A1+A2 is calculated by formula (4);

[0019]

[0020] Wherein, σ b实测 is the measured tensile ultimate stress, unit is MPa;

[0021] A4 is calculated by formula (5);

[0022] A4=A3-(A1+A2) (5)

[0023] The depth of the notch is obtained by A4 and the shape of the hollow part between the beginning end of the notch and the end of the notch. Advantage: the present application accurately determines the depth of the notch, and ensures the smooth progress of the hub containment test.

[0024] Optionally, a reserve coefficient E is introduced, and the E is greater than 1;

[0025] A2 is calculated according to formula (6);

[0026]

[0027] A4 is calculated according to formula (3) again;

[0028] The depth of the notch is obtained by A4 and the shape of the hollow part between the beginning end of the notch and the end of the notch. Advantage: the present application further considers the actual test condition, accurately determines the depth of the notch, and ensures the smooth progress of the hub containment test.

[0029] Optionally, the E is 1.05. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0031] Figure 1 A schematic diagram of a partial top view structure of a wheel disc provided in an embodiment of the present application Figure 1 ;

[0032] Figure 2 A curve intended to show the relationship between the average kinetic energy of a fragment of a wheel disc and a wheel disc equi-partition cutting mode provided in an embodiment of the present application

[0033] Figure 3 A schematic diagram of a meridian cross-section range of a wheel disc provided in an embodiment of the present application

[0034] Figure 4 A schematic diagram of a partial top view structure of a wheel disc provided in an embodiment of the present application Figure 2 ;

[0035] Figure 5 A schematic diagram of a top view structure of a wheel disc provided in an embodiment of the present application

[0036] Figure 6This is a partial cross-sectional view of the wheel provided in an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the force acting on the meridional section of the 1 / 3 disk provided in an embodiment of the present invention;

[0038] Figure 8 This is a photograph of the wheel disc before the hub containment test provided in the embodiment of the present invention;

[0039] Figure 9 This is a physical image of the wheel disc provided in an embodiment of the present invention after a hub containment test.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Meridian section; 2. Notch. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] As required by the customer, the hub of the auxiliary power unit needs to have containment capacity. In addition, the existing containment test of the turbine blade is a containment test that achieves blade fracture by over-rotation. Compared with the hub containment test, it belongs to a different failure mode, and the existing containment test method cannot be used. Therefore, it is necessary to study how to conduct the hub containment test to fill the gap in hub containment test.

[0044] like Figures 1 to 9 One specific implementation of the illustrated wheel cutting method includes:

[0045] Three notches 2 are pre-cut on the meridian section 1 at the trisection position of the disc, starting from the centroid of the meridian section 1 and extending radially outward along the disc, as follows: Figure 1 and Figure 4 As shown; the wheel disc is used in the hub containment test. The notch 2 is also called a slot. The wheel disc cutting method described in this application achieves the wheel disc breaking at a specified speed and impacting the casing by pre-grooving a slot in the meridional section 1 of the wheel disc, thereby completing the hub containment test. The range of the meridional section 1 of the wheel disc is shown in the diagram. Figure 3The wheel disc is cut from the center of the wheel disc meridian section 1. If the wheel disc is cut from outside to inside, the blade structure will fall off. If the wheel disc is cut from inside to outside, the structural integrity of the wheel disc will be damaged.

[0046] The technical standard of CTSO-C77b stipulates that the translational kinetic energy of the wheel hub fragment for containment test is required to be maximum.

[0047] The translational kinetic energy E of the fragment k is calculated by formula (1).

[0048]

[0049] wherein m 碎 is the mass of the fragment, in kg; n is the angular velocity of the fragment, in rad / s; and r is the radius of rotation at the center of mass of the fragment, in m.

[0050] The relationship between the equal division cutting mode of the wheel disc and the average kinetic energy of the fragment when the wheel disc fails is analyzed comprehensively, as shown in Figure 2 only when the wheel disc is cut into three equal parts, the translational kinetic energy of the fragment after failure is maximum. Therefore, the notch 2 of the wheel disc for the wheel hub containment test is pre-set in the circumferential direction.

[0051] Specifically, the notch 2 is cut by wire cutting.

[0052] Further, the wire cutting speed at the end of the cutting of the notch 2 is lower than the wire cutting speed at other positions of the cutting of the notch 2. That is, slow wire cutting is required at the end of the notch 2. That is, the wire cutting mode is hybrid wire cutting.

[0053] Further, a rounding structure is provided at the end of the cutting of the notch 2.

[0054] Specifically, the radius of the rounding structure is 2 mm.

[0055] The size of the notch 2 is shown in Figure 5 The notch 2 is also called a cutting groove or a cutting slot. The depth of the cutting slot is defined as the maximum distance of the cutting groove, marked as D. The depth of the cutting slot is also called the depth of the notch 2. The shortest distance of the cutting groove to the center of the wheel disc is marked as L, and the shortest distance of the cutting groove to the center of the wheel disc is marked as R. In Figure 5 only one notch 2 is shown.

[0056] Further, the notch 2 avoids the end tooth structure and the air hole structure. That is, when there are special structures such as end tooth structure and air hole structure at the inner diameter of the wheel disc, in order to avoid the special structures such as end tooth structure and air hole structure causing the wheel disc to fail prematurely, L should be greater than the radial dimension of the special structure.

[0057] Further, the notch 2 avoids the tenon groove structure and the blade structure provided on the rim of the wheel disc. That is, when there are special structures such as tenon groove structure and blade structure on the outer diameter of the wheel disc, in order to avoid the wheel disc being damaged due to the special structures such as tenon groove structure and blade structure, R should be less than the outer diameter of the meridian section 1.

[0058] Specifically, the depth of the notch 2 includes the following steps:

[0059] S1, assuming that the solid part section between the beginning of the notch 2 and the inner edge of the meridian section 1 is the first section, the solid part section between the end of the notch 2 and the outer edge of the meridian section 1 is the second section, the section between the inner edge and the outer edge of the meridian section 1 is the third section, and the hollow part section between the beginning of the notch 2 and the end of the notch 2 is the fourth section; the area of the first section is A1, the area of the second section is A2, the area of the third section is A3, and the area of the fourth section is A4; as shown in Figure 6 .

[0060] As shown in Figure 7 , the angle between the three notches 2 is 120°, and in the working process of the wheel disc, the tangential load generated by the centrifugal force F 离心力 is borne by the meridian section 1 as the bearing section, and the bearing section after the preset notch 2 is reduced to A1+A2 as shown in Figure 6 , and the force acting on the meridian section 1 is shown in Figure 7 , wherein F1 is 1 / 3 of the total force acting on the wheel disc, and the relationship between F1 and F 离心力 is shown in formula (2).

[0061]

[0062] Wherein, σ1 is the stress of the bearing section, and the unit is MPa.

[0063] S2, the centrifugal force F 离心力 is calculated by formula (3).

[0064] F 离心力 =MR C ω 2 (3)

[0065] Wherein, M is the mass of 1 / 3 of the wheel disc, and the unit is kg; R C is the centroid radius of 1 / 3 of the wheel disc, and the unit is m; ω is the angular velocity of the wheel disc, and the unit is rad / s.

[0066] S3, A1+A2 is calculated by formula (4).

[0067]

[0068] wherein σ b实测 is the measured tensile ultimate stress, in MPa. When σ1 reaches the measured tensile ultimate stress σ b实测 at the wheel disc test temperature, the wheel disc breaks into three equal parts.

[0069] S4, calculating A4 by using formula (5);

[0070] A4 = A3 - (A1 + A2) (5)

[0071] S5, obtaining the depth of the notch 2 by A4 and the shape of the hollow part between the beginning of the notch 2 and the end of the notch 2.

[0072] Further, a reserve coefficient E is introduced, which is greater than 1;

[0073] calculating A2 according to formula (6);

[0074]

[0075] calculating A4 according to formula (5) again;

[0076] obtaining the depth of the notch 2 by A4 and the shape of the hollow part between the beginning of the notch 2 and the end of the notch 2.

[0077] Specifically, the E is 1.05.

[0078] When the wheel disc breaks into three equal parts during the premenstrual inclusion test, there is a tendency for the outer part of the second cross section of the wheel disc to break prematurely. For safety, a reserve coefficient of 1.05 is considered for the area A2 of the second cross section when cutting during the hub inclusion test. That is, when the size of the remaining meridian cross section 1 meets formula (7), it meets the breaking requirements of the wheel disc used in the hub inclusion test.

[0079]

[0080] As shown in Figure 8 and Figure 9 , it has been verified in practice that, after the wheel disc cutting method described in the present application is performed, Figure 8 the wheel disc breaks into three equal parts at the predetermined notch 2 at the specified speed, that is, the breaking form of the wheel disc is the three equal parts along the meridian cross section 1 as shown in Figure 9 , and the hub inclusion test is successfully completed.

[0081] Although embodiments of the present application have been described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A method of cutting a wheel disc, characterized in that, The application relates to a wheel disc cutting method. Three notches (2) are cut on a meridian section (1) of the wheel disc at three equal intervals, and the notches (2) are cut from the center of the meridian section (1) to the outside of the wheel disc.

2. The wheel disc cutting method according to claim 1, characterized in that, The notches (2) are cut by wire cutting.

3. The wheel disc cutting method according to claim 2, characterized in that, The wire cutting speed at the end of the notches (2) is lower than that at other positions of the notches (2).

4. The wheel disc cutting method according to any one of claims 1-3, characterized in that, The end of the notches (2) is provided with a rounding structure.

5. The wheel disc cutting method according to claim 4, characterized in that, The radius of the rounding structure is 2 mm.

6. The wheel disc cutting method according to any one of claims 1 to 3, characterized in that, The notches (2) avoid the end tooth structure and the air hole structure.

7. The wheel disc cutting method according to any one of claims 1 to 3, characterized in that, The notches (2) avoid the tenon groove structure and the blade structure provided on the rim of the wheel disc.

8. The wheel disc cutting method according to any one of claims 1-3, characterized in that, The depth of the notches (2) is determined by the following steps: Supposing that the solid section between the start end of the notches (2) and the inner edge of the meridian section (1) is a first section, the solid section between the end of the notches (2) and the outer edge of the meridian section (1) is a second section, the section between the inner edge and the outer edge of the meridian section (1) is a third section, and the hollow section between the start end of the notches (2) and the end of the notches (2) is a fourth section, the area of the first section is A1, the area of the second section is A2, the area of the third section is A3, and the area of the fourth section is A4; The centrifugal force F is calculated using formula (3) 离心力 ; F 离心力 = MR C ω 2 (3) where M is the mass of the 1 / 3 wheel, in kg; R C is the radius of the center of mass of the 1 / 3 wheel, in m; and ω is the angular velocity of the wheel, in rad / s; A1+A2 is calculated by formula (4); wherein σ b实测 is the measured tensile ultimate stress in MPa; A4 is calculated by formula (5); A4=A3-(A1+A2) (5) The depth of the notches (2) is obtained by A4 and the shape of the hollow section between the start end of the notches (2) and the end of the notches (2).

9. The wheel disc cutting method according to claim 8, characterized in that, a reserve coefficient E is introduced, and the E is greater than 1; A2 is calculated by formula (6); A4 is calculated by formula (5); The depth of the notches (2) is obtained by A4 and the shape of the hollow section between the start end of the notches (2) and the end of the notches (2).

10. The wheel disc cutting method according to claim 9, characterized in that, The E is 1.05.

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