A method for establishing constitutive model of polycrystalline turbine disk under optimal partition radius

Abstract

The present invention provides a constitutive model establishment method under the optimal partition radius of a polycrystalline turbine disk, comprising the following steps: S1, initial partitioning of the polycrystalline turbine disk; S2: establishing an initial constitutive model of the polycrystalline turbine disk material taking into account the partition coefficient; S3: obtaining the optimal partition radius of each area and making a rationality judgment; S4: establishing the final constitutive model; S5: correcting the final constitutive model after verifying and analyzing the residual deformation. The method determines the optimal partition radius of the typical grain structure through the optimized iterative design of the disk rupture speed reserve and the rim creep deformation and the grain structure partition position. The constitutive model of the polycrystalline turbine disk created based on the optimal partition radius can be used for the elastic-plastic stress-strain simulation analysis of the polycrystalline turbine disk, thereby improving the rupture speed and residual deformation analysis accuracy of the polycrystalline turbine disk.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft engine disks, and in particular relates to a method for establishing a constitutive model of a polycrystalline turbine disk under an optimal partition radius. Background Art

[0002] As a key hot end component of an aircraft engine, the turbine disk is subjected to high speed and high temperature. Based on the working characteristics of the turbine disk, its hub part needs to have high fatigue strength, while the rim part needs to have better creep performance. Therefore, a polycrystalline turbine disk with different microstructures in the rim and hub parts is more suitable for aircraft engines. It obtains fine-grained structure in the hub part of the disk to ensure high fatigue strength, and coarse-grained structure in the rim part to ensure good creep performance. The grain structure in the transition zone (spoke plate position) between the rim and hub parts should be smoothly transitioned. This polycrystalline turbine disk avoids the potential safety hazards caused by the use of dissimilar metal connections and is more in line with the use requirements of high thrust-to-weight ratio engines.

[0003] However, the traditional strength design method of turbine disk does not take into account the performance differences caused by the organizational partitioning of polycrystalline turbine disks, and cannot quantitatively analyze the benefits of the organizational partitioning of polycrystalline turbine disks. For polycrystalline turbine disks, the larger the coarse-grained organizational area, the better the creep performance of the turbine disk; the larger the fine-grained organizational area, the higher the fatigue strength of the turbine disk. How to design the grain organizational partition position is directly related to whether the material and structural capacity of the turbine disk can be maximized. It is urgent to establish an elastic-plastic stress-strain constitutive model and strength design method for polycrystalline turbine disks that take into account the performance differences of the partitions. Summary of the invention

[0004] In order to solve the above problems, the object of the present invention is to provide a method for establishing a constitutive model of a polycrystalline turbine disk under an optimal partition radius, the method comprising the following steps:

[0005] S1. Initially partition the polycrystalline turbine disk according to the material properties of different grain sizes;

[0006] S2: Establishing the initial constitutive model of the polycrystalline turbine disk material taking into account the partition coefficient according to the material properties of the initial partitioned tissue;

[0007] S3: According to the strength design index of the polycrystalline turbine disk and the initial constitutive model, the optimal partition radius of each area is obtained and the rationality is judged;

[0008] S4: Establish the final constitutive model according to the optimal partition radius obtained in S3;

[0009] S5: The final constitutive model is modified after verification analysis of the residual deformation of the polycrystalline turbine disk.

[0010] The constitutive model establishment method of the polycrystalline turbine disk under the optimal partition radius provided by the present invention also has the following characteristics: the material properties of different grain sizes in S1 include tensile limit and yield strength; the initial partition is divided into a fine grain zone, a transition zone and a coarse grain zone,

[0011] Among them, the radius of the center hole of the polycrystalline turbine disk is r0, and the radius of the rim is r n The partition radius between the fine grain zone and the transition zone is r a , the partition radius between the transition zone and the coarse grain zone is r b , then, r0﹤r a ﹤r b ﹤r n .

[0012] The constitutive model establishment method of the polycrystalline turbine disk under the optimal partition radius provided by the present invention also has the following characteristics: S2 comprises the following steps:

[0013] S2.1: Normalize the material properties of different grain sizes and correspond them to the material properties of each initial partition;

[0014] S2.2: Establish the initial constitutive model of the polycrystalline turbine disk material taking into account the partition coefficient;

[0015] S2.3: Obtain the partition coefficient of the polycrystalline turbine disk at any radius based on the material properties of each initial partition in S2.1.

[0016] The constitutive model establishment method of the polycrystalline turbine disk under the optimal partition radius provided by the present invention also has the following characteristics: the initial constitutive model in S2.2 is:

[0017]

[0018] Among them, σ is stress, ε is strain, σ s0 is the yield strength, ε s0 =σ s0 / E is the elastic strain; σ b0 is the tensile limit, ε b0 is the strain corresponding to the material reaching its tensile limit; ε p is the plastic strain, ε p =ε-σ / E, n is the strain hardening exponent, E is the elastic modulus, k is the slope, C1(r) is the plastic partition coefficient, and C2(r) is the elastic partition coefficient.

[0019] The constitutive model establishment method of the polycrystalline turbine disk under the optimal partition radius provided by the present invention also has the following characteristics: the partition coefficient in S2.3 is divided into a plastic partition coefficient C1(r) and an elastic partition coefficient C2(r), then

[0020]

[0021]

[0022] Where r is the arbitrary radius of the polycrystalline turbine disk, r i =(r a +r b ) / 2, r0 is the radius of the center hole of the disk, r n is the rim radius, n is the number of rim grain size grades, b i For r i The normalized tensile limit at b n For r n The normalized tensile limit at s i For r i The normalized yield strength at s n For r n The normalized yield strength at .

[0023] The constitutive model establishment method of the polycrystalline turbine disk under the optimal partition radius provided by the present invention also has the following characteristics: S3 comprises the following steps:

[0024] S3.1: Determine the lower limit of the circumferential fracture speed reserve of the polycrystalline turbine disk as k min The upper limit of the creep deformation of the wheel rim is l max ;

[0025] S3.2: According to the initial constitutive model of the polycrystalline turbine disk obtained in S2, the relationship curve between the circumferential rupture speed reserve of the polycrystalline turbine disk and the tissue partition radius is established, and then the optimal partition radius r of the fine grain zone and the transition zone is obtained according to the lower limit of the circumferential rupture speed reserve of the polycrystalline turbine disk. a1 ;

[0026] S3.3: According to the initial constitutive model of the polycrystalline turbine disk obtained in S2, the relationship curve between the creep deformation of the rim of the polycrystalline turbine disk and the tissue partition radius is established, and then the optimal partition radius r of the transition zone and the coarse grain zone is obtained according to the upper limit value of the creep deformation of the rim of the polycrystalline turbine disk. b1 ;

[0027] S3.4: When r a1 <r b1 When r a1 ≥r b1 When the circumferential rupture speed reserve lower limit value k is reduced, return to S3.1. min Or increase the upper limit of wheel rim creep deformation l max .

[0028] The constitutive model establishment method of the polycrystalline turbine disk under the optimal partition radius provided by the present invention also has the following characteristics: S5 comprises the following steps:

[0029] S5.1: Based on the final constitutive model obtained in S4, analyze the residual deformation of the polycrystalline turbine and draw the relationship curve between the residual deformation and the speed;

[0030] S5.2: Trial production of a polycrystalline turbine disk is carried out according to the optimal partition radius obtained in S3, and then an over-speed test of the turbine disk is carried out to obtain a curve of the relationship between residual deformation and speed;

[0031] S5.3: Obtain the material correction factor U according to the relationship curves obtained in S5.1 and S5,2 respectively. After correcting the partition coefficient by the material correction factor U, the final constitutive model is obtained again.

[0032] The constitutive model establishment method for the polycrystalline turbine disk under the optimal partition radius provided by the present invention also has the following characteristics: in S5.3, the final constitutive model re-obtained is:

[0033]

[0034] Among them, σ is stress, ε is strain, σ s0 is the yield strength, ε s0 =σ s0 / E is the elastic strain; σ b0 is the tensile limit, ε b0 is the strain corresponding to the material reaching its tensile limit; ε p is the plastic strain, ε p =ε-σ / E, n is the strain hardening exponent, E is the elastic modulus, k is the slope, C1(r) is the plastic partition coefficient, and C2(r) is the elastic partition coefficient.

[0035] Beneficial Effects

[0036] The constitutive model establishment method of a polycrystalline turbine disk under the optimal partition radius provided by the present invention obtains the relationship curves and change laws of the disk rupture speed reserve, rim creep deformation and tissue partition radius through the optimized iterative design of the disk rupture speed reserve and the rim creep deformation and the grain tissue partition position, determines the optimal partition radius of the typical grain structure, and the constitutive model of the polycrystalline turbine disk created based on the optimal partition radius can be used for the elastic-plastic stress-strain simulation analysis of the polycrystalline turbine disk, thereby improving the rupture speed and residual deformation analysis accuracy of the polycrystalline turbine disk. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1The invention provides an optimal partition radius determination process in a constitutive model establishment method for a polycrystalline turbine disk under an optimal partition radius.

[0038] Figure 2 Schematic diagram of the initial partitioning of a polycrystalline turbine disk.

[0039] Figure 3 A schematic diagram of the optimal partition determined by the method provided in an embodiment of the present invention.

[0040] Figure 4 This is the variation rule of the partition coefficient with the radius in the method provided by the embodiment of the present invention.

[0041] Figure 5 The circumferential rupture speed reserve k and the tissue partition radius r in the method provided in the embodiment of the present invention a relationship curve.

[0042] Figure 6 The rim creep deformation l and the tissue partition radius r in the method provided by the embodiment of the present invention b relationship curve. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with the accompanying drawings and examples, but it should be noted that these implementation modes are not limitations of the present invention, and equivalent changes or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these implementation modes are all within the scope of protection of the present invention.

[0044] In the description of the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the invention.

[0045] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0046] The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0047] like Figure 1-6 As shown, this embodiment provides a method for establishing a constitutive model of a polycrystalline turbine disk under an optimal partition radius, and the method comprises the following steps:

[0048] S1. Initial partitioning of the polycrystalline turbine disk according to the material properties of different grain sizes:

[0049] The material properties of different grain sizes include tensile limit and yield strength. The grain size grades from large to small should cover the A0, A i (i=1,…,n-1)…A n The physical and mechanical properties (including at least tensile properties) of at least three grain size grades should be measured, and the three grain sizes should include A0, A n and A i At least one of A0, A i , A n The tensile limits of the three grain size samples are σ b0 , σ bi , σ bn , the yield strengths are σ s0 , σ si , σ sn ;

[0050] S2: Establishing the initial constitutive model of the polycrystalline turbine disk material taking into account the partition coefficient according to the material properties of the initial partitioned tissue;

[0051] S3: According to the strength design index of the polycrystalline turbine disk and the initial constitutive model, the optimal partition radius of each area is obtained and the rationality is judged;

[0052] S4: according to the optimal partition radius obtained in S3, the partition coefficient of the final constitutive model is obtained according to the optimal partition radius, and the final constitutive model of the polycrystalline turbine disk under the optimal partition radius is established;

[0053] S5: The final constitutive model is modified after verification analysis of the residual deformation of the polycrystalline turbine disk.

[0054] In some embodiments, the initial partition in S1 is preliminarily divided into a fine grain zone, a transition zone and a coarse grain zone, wherein the radius of the center hole of the polycrystalline turbine disk is r0 and the radius of the wheel rim is r n The partition radius between the fine grain zone and the transition zone is r a , the partition radius between the transition zone and the coarse grain zone is r b , then, if Figure 2 As shown, r0﹤r a ﹤r b ﹤r n .

[0055] In some embodiments, S2 comprises the following steps:

[0056] S2.1: Normalize the material properties of different grain sizes and correspond them to the material properties of each initial partition, as shown in Table 1;

[0057] Table 1 Normalized mechanical properties of polycrystalline turbine disk partitions

[0058]

[0059] S2.2: Establish the initial constitutive model of the polycrystalline turbine disk material taking into account the partition coefficient;

[0060] S2.3: Obtain the partition coefficient of the polycrystalline turbine disk at any radius based on the material properties of each initial partition in S2.1.

[0061] In some embodiments, the initial constitutive model in S2.2 is:

[0062]

[0063] Among them, σ is stress, ε is strain, σ s0 is the yield strength, ε s0 =σ s0 / E is the elastic strain; σ b0 is the tensile limit, ε b0 is the strain corresponding to the material reaching its tensile limit; ε p is the plastic strain, ε p =ε-σ / E, n is the strain hardening exponent, E is the elastic modulus, k is the slope, C1(r) is the plastic partition coefficient, and C2(r) is the elastic partition coefficient. Among them, the partition coefficient is introduced to consider the material properties differences in different tissue regions.

[0064] In some embodiments, the partition coefficient in S2.3 is divided into a plastic partition coefficient C1(r) and an elastic partition coefficient C2(r), then

[0065]

[0066]

[0067] Where r is the arbitrary radius of the polycrystalline turbine disk, r i =(r a +r b ) / 2, r0 is the radius of the center hole of the disk, r n is the rim radius, n is the number of rim grain size grades, b i For r i The normalized tensile limit at b n For r n The normalized tensile limit at s i For r i The normalized yield strength at s n For r n The normalized yield strength at . The relationship between the partition coefficient and the turbine disk radius is shown in Figure 4 shown.

[0068] In some embodiments, S3 includes the following steps:

[0069] S3.1: Determine the lower limit of the circumferential fracture speed reserve of the polycrystalline turbine disk as k min The upper limit of the creep deformation of the wheel rim is l max ;

[0070] S3.2: Based on the initial constitutive model and corresponding partition coefficient of the polycrystalline turbine disk obtained in S2, the circumferential rupture speed reserve k and the tissue partition radius r of the polycrystalline turbine disk are established through numerical analysis. a The relationship curve k=f1(r a ),like Figure 5 As shown in the figure, the radius value range is determined according to the requirements of the circumferential rupture speed reserve of the polycrystalline turbine disk, corresponding to the minimum design circumferential rupture speed reserve k≥k min The radius r is determined by a The value range corresponds to the minimum design circumferential rupture speed reserve k min The radius r a1 That is the optimal partition radius between the fine grain zone and the transition zone;

[0071] S3.3: Based on the initial constitutive model and corresponding partition coefficient of the polycrystalline turbine disk obtained in S2, the creep deformation l of the polycrystalline turbine disk rim and the tissue partition radius r are established through numerical analysis. b The relationship curve l=f2(r b ),like Figure 6 As shown, according to the creep deformation l <l max The radius r is determined by b The value range corresponds to the maximum creep deformation lmax The radius r b1 That is the optimal partition radius between the transition zone and the coarse grain zone;

[0072] S3.4: When r a1 <r b1 When r a1 ≥r b1 When the circumferential rupture speed reserve lower limit value k is reduced, return to S3.1. min Or increase the upper limit of wheel rim creep deformation l max .

[0073] In some embodiments, S5 includes the following steps:

[0074] S5.1: Analyze the residual deformation δ of the polycrystalline turbine according to the final constitutive model obtained in S4 c , and draw the relationship curve between residual deformation and rotation speed;

[0075] S5.2: According to the optimal partition radius obtained in S3, a multi-crystalline turbine disk is trial-produced, and then a super-rotation test of the turbine disk is performed. Through the super-rotation test of the turbine disk, the residual deformation δ of the multi-crystalline turbine disk is measured. e , obtain the relationship curve between residual deformation test value and rotation speed;

[0076] S5.3: Obtain the material correction factor U according to the relationship curves obtained in S5.1 and S5,2 respectively. After correcting the partition coefficient by the material correction factor U, the final constitutive model is obtained again.

[0077] Among them, the final constitutive model of the aforementioned polycrystalline turbine disk is based on the mechanical properties of the sample, which is different from the mechanical properties of the polycrystalline turbine disk components. The material correction coefficient U is introduced to correct the constitutive model constructed for the polycrystalline turbine disk.

[0078] In some embodiments, in S5.3, the final constitutive model retrieved is:

[0079]

[0080] Among them, σ is stress, ε is strain, σ s0 is the yield strength, ε s0 =σ s0 / E is the elastic strain; σ b0 is the tensile limit, ε b0 is the strain corresponding to the material reaching its tensile limit; ε p is the plastic strain, ε p =ε-σ / E, n is the strain hardening exponent, E is the elastic modulus, k is the slope, C1(r) is the plastic partition coefficient, and C2(r) is the elastic partition coefficient.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A method for establishing a constitutive model of a polycrystalline turbine disk under an optimal partition radius, characterized in that: The method comprises the following steps: S1. Initially partition the polycrystalline turbine disk according to the material properties of different grain sizes; S2: Establishing the initial constitutive model of the polycrystalline turbine disk material taking into account the partition coefficient according to the material properties of the initial partitioned tissue; S3: According to the strength design index of the polycrystalline turbine disk and the initial constitutive model, the optimal partition radius of each area is obtained and the rationality is judged; S4: Establish the final constitutive model according to the optimal partition radius obtained in S3; S5: After verifying and analyzing the residual deformation of the polycrystalline turbine disk, the final constitutive model is modified. The initial zoning is divided into fine-grained zone, transition zone and coarse-grained zone. The S3 comprises the following steps: S3.1: Determine the lower limit of the circumferential fracture speed reserve of the polycrystalline turbine disk as k min The upper limit of the creep deformation of the wheel rim is l max ; S3.2: According to the initial constitutive model of the polycrystalline turbine disk obtained in S2, the relationship curve between the circumferential rupture speed reserve of the polycrystalline turbine disk and the tissue partition radius is established, and then the optimal partition radius r of the fine grain zone and the transition zone is obtained according to the lower limit of the circumferential rupture speed reserve of the polycrystalline turbine disk. a1 ; S3.3: According to the initial constitutive model of the polycrystalline turbine disk obtained in S2, the relationship curve between the creep deformation of the rim of the polycrystalline turbine disk and the tissue partition radius is established, and then the optimal partition radius r of the transition zone and the coarse grain zone is obtained according to the upper limit value of the creep deformation of the rim of the polycrystalline turbine disk. b1 ; S3.4: When r a1 <r b1 When r a1 ≥r b1 When the circumferential rupture speed reserve lower limit value k is reduced, return to S3.

1. min Or increase the upper limit of wheel rim creep deformation l max .

2. The constitutive model establishment method of a polycrystalline turbine disk under an optimal partition radius according to claim 1 is characterized in that: The material properties of different grain sizes in S1 include tensile limit and yield strength; Among them, the radius of the center hole of the polycrystalline turbine disk is r0, and the radius of the rim is r n The partition radius between the fine grain zone and the transition zone is r a , the partition radius between the transition zone and the coarse grain zone is r b , then, r0﹤r a ﹤r b ﹤r n .

3. The constitutive model establishment method of a polycrystalline turbine disk under an optimal partition radius according to claim 2 is characterized in that: The S2 comprises the following steps: S2.1: Normalize the material properties of different grain sizes and correspond them to the material properties of each initial partition; S2.2: Establish the initial constitutive model of the polycrystalline turbine disk material taking into account the partition coefficient; S2.3: Obtain the partition coefficient of the polycrystalline turbine disk at any radius based on the material properties of each initial partition in S2.

1.

4. The constitutive model establishment method of a polycrystalline turbine disk under an optimal partition radius according to claim 3 is characterized in that: The initial constitutive model in S2.2 is: Among them, σ is stress, ε is strain, σ s0 is the yield strength, ε s0 =σ s0 / E is the elastic strain; σ b0 is the tensile limit, ε b0 is the strain corresponding to the material reaching its tensile limit; ε p is the plastic strain, ε p =ε-σ / E, n is the strain hardening exponent, E is the elastic modulus, k is the slope, C1(r) is the plastic partition coefficient, and C2(r) is the elastic partition coefficient.

5. The constitutive model establishment method of a polycrystalline turbine disk under an optimal partition radius according to claim 3, characterized in that: The partition coefficient in S2.3 is divided into the plastic partition coefficient C1(r) and the elastic partition coefficient C2(r), then Where r is the arbitrary radius of the polycrystalline turbine disk, r i =(r a +r b ) / 2, r0 is the radius of the center hole of the disk, r n is the rim radius, n is the number of rim grain size grades, b i For r i The normalized tensile limit at b n For r n The normalized tensile limit at s i For r i The normalized yield strength at s n For r n The normalized yield strength at .

6. The constitutive model establishment method of a polycrystalline turbine disk under an optimal partition radius according to claim 1, characterized in that: The S5 comprises the following steps: S5.1: Based on the final constitutive model obtained in S4, analyze the residual deformation of the polycrystalline turbine disk and draw the relationship curve between the residual deformation and the rotation speed; S5.2: Trial production of a polycrystalline turbine disk is carried out according to the optimal partition radius obtained in S3, and then an over-speed test of the turbine disk is carried out to obtain a curve of the relationship between residual deformation and speed; S5.3: Obtain the material correction factor U according to the relationship curves obtained in S5.1 and S5.2 respectively. After correcting the partition coefficient by the material correction factor U, the final constitutive model is obtained again.

7. The constitutive model establishment method of a polycrystalline turbine disk under an optimal partition radius according to claim 6, characterized in that: In S5.3, the final constitutive model retrieved is: Among them, σ is stress, ε is strain, σ s0 is the yield strength, ε s0 =σ s0 / E is the elastic strain; σ b0 is the tensile limit, ε b0 is the strain corresponding to the material reaching its tensile limit; ε p is the plastic strain, ε p =ε-σ / E, n is the strain hardening exponent, E is the elastic modulus, k is the slope, C1(r) is the plastic partition coefficient, and C2(r) is the elastic partition coefficient.

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