CN-121997472-A - Combined material blade and design method thereof

CN121997472ACN 121997472 ACN121997472 ACN 121997472ACN-121997472-A

Abstract

The invention provides a combined material blade and a design method thereof, the design method comprises the steps of S 1 , carrying out blade vibration characteristic analysis to determine the natural frequency order and the vibration mode which possibly generate dangerous resonance, S 2 , determining the direction of the frequency to be adjusted, S 3 , analyzing the geometric position of the material to be replaced locally and the trend of the change of the blade frequency possibly caused by the replacement of the material according to the characteristics of the available material, determining the blade material for replacement, S 4 , carrying out the detailed check of the natural frequency on the structure of the combined material blade formed by the determined replacement material, and S 5 , designing a material combination scheme and a blade structure scheme which meet the frequency requirement. Under the condition that the pneumatic wing profile is unchanged, the structural frequency adjustment can be realized, so that the pneumatic performance design is guaranteed to be optimal, and the working efficiency of the component is improved.

Inventors

LIU XIAOLI
Yu Xueran
ZHOU XUAN
WANG DANDAN
Si Wulin

Assignees

中国航发商用航空发动机有限责任公司

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (12)

1. A method of designing a composite material blade, the method comprising the steps of: S 1 , carrying out blade vibration characteristic analysis, and determining the natural frequency order and vibration mode of dangerous resonance possibly occurring; S 2 , determining the direction of the frequency to be adjusted; S 3 , analyzing the geometric position of the material to be replaced locally and the trend of the blade frequency change possibly caused by the replacement of the material according to the characteristics of the available material, and determining the blade material for replacement; S 4 , carrying out natural frequency detailed checking on the structure of the combined material blade formed by adopting the determined replacement material; S 5 , designing a material combination scheme and a blade structure scheme which meet the frequency requirement.
2. The method of designing a composite material blade according to claim 1, wherein the blade mode includes a bending mode, a torsional mode, a chordwise mode, and a composite mode.
3. The method of designing a composite blade according to claim 1, wherein the relationship between the natural frequency of the blade structure and the elastic modulus and density of the blade material is: wherein ω is the natural frequency, E is the elastic modulus of the blade material, ρ is the density of the blade material, and k is the coefficient; in the step S 3 , a is set as an original blade material, b is set as a replacement blade material, E a is set as an elastic modulus of the original blade material, ρ a is set as a density of the original blade material, E b is set as an elastic modulus of the replacement blade material, and ρ b is set as a density of the replacement blade material; If the blade frequency needs to be increased, then If the blade frequency needs to be reduced, then
4. A composite blade, characterized in that it is designed by the method according to any one of claims 1-3, and that the composite comprises at least two different materials, the blade structures of which are interconnected to form the whole of the blade, the joints of which have transition areas, and in which the different materials are mutually permeable.
5. The composite blade of claim 4 wherein the composite material comprises a first material and a second material, the blade structure of the first material and the blade structure of the second material being interconnected to form the entirety of the blade, the junction of the first material and the second material having a transition region in which the first material and the second material are interpenetrating.
6. The composite blade of claim 5 wherein the material of the upper structure of the composite blade body is a first material and the material of the lower and dovetail structures of the composite blade body is a second material.
7. The composite blade of claim 5 wherein the material to the left in the axial direction of the composite blade is a first material and the material to the right in the axial direction of the composite blade is a second material.
8. The composite blade of claim 5 wherein the material at the blade root bending mode pitch line location of the composite blade is a first material and the material at the remaining locations of the composite blade is a second material.
9. The composite blade of claim 5 wherein the material at the axial mid-section line position of the composite blade is a first material and the material at the remaining positions of the composite blade is a second material.
10. The composite blade of claim 5, wherein the composite blade is a guide blade, the upper blade body structure and the upper outer ring structure of the guide blade are made of a first material, and the lower blade body and the lower inner ring structure of the guide blade are made of a second material.
11. The composite blade of claim 5 wherein the composite material comprises three different materials, further comprising a third material; The upper part of the blade body of the combined material blade is made of a first material, the middle part of the blade body of the combined material blade is made of a second material, and the lower part of the blade body and the tenon structure of the combined material blade are made of a third material.
12. The composite blade of claim 5 wherein the composite blade is manufactured using additive manufacturing or welding.

Description

Combined material blade and design method thereof Technical Field The invention relates to the technical field of aeroengines, in particular to a combined material blade and a design method thereof. Background Aeroengine blades are the main working parts of an aeroengine, and are usually parts which are uniformly arranged along the circumference in the main flow channel of the impeller machine and are provided with a certain airfoil shape for converting the energy of the air or guiding the direction of the air flow. Aero-engine blades are subjected to complex vibratory alternating stresses in use. If the magnitude of the vibration stress born by the blade exceeds the corresponding fatigue limit, fatigue cracks appear in the blade within the design life, and the fatigue cracks often occur in a short time, so that the safety of the aeroengine is seriously affected. Therefore, in the product design stage, the dangerous resonance point is required to avoid the main working rotation speed interval through frequency modulation design, so that the blade is prevented from being subjected to the risk of overrun of vibration stress caused by resonance, and the blade is prevented from being broken due to high-cycle fatigue. Most of the blades of the aero-engine are solid blade types except for the blades with inner cavities, the frequency modulation design of the blades is generally realized by adjusting the size, the mass distribution and the like of the blades, the initial airfoil shape of the blades is designed according to the optimal aerodynamic performance, for example, the frequency modulation is carried out only from the structural optimization, the aerodynamic airfoil shape is inevitably deviated from the optimal scheme, thus the performance loss is caused, and the contradiction between the performance and the safety requirement is often encountered in the design. In view of the above, the present inventors have devised a blade made of composite material and a method for designing the same, in order to overcome the above-mentioned problems Disclosure of Invention The invention aims to solve the technical problem that the performance and safety requirements of the prior art are difficult to meet in the design of the aeroengine blade, and provides a combined material blade and a design method thereof. The invention solves the technical problems by the following technical proposal: The invention provides a combined material blade design method which is characterized by comprising the following steps of S 1, carrying out blade vibration characteristic analysis, determining the natural frequency order and vibration mode which possibly generate dangerous resonance, S 2, determining the direction in which frequency needs to be adjusted, S 3, analyzing the geometric position of a material which needs to be partially replaced and the trend possibly causing blade frequency change after replacing the material according to the characteristics of available materials, determining a blade material for replacement, S 4, carrying out detailed checking on the natural frequency of a combined material blade structure formed by adopting the determined replacement material, and S 5, designing a material combination scheme and a blade structure scheme which meet the frequency requirement. According to one or more embodiments of the invention, the modes of the blade include bending mode, torsional mode, chordwise mode, and composite mode. According to one or more embodiments of the present invention, the relationship between the natural frequency of the blade structure and the elastic modulus and density of the blade material is: Wherein ω is natural frequency, E is elastic modulus of the blade material, k is coefficient, in the step S 3, a is the original blade material, b is the replacement blade material, E a is elastic modulus of the original blade material, ρ a is the density of the original blade material, E b is elastic modulus of the replacement blade material, ρ b is the density of the replacement blade material, and if the blade frequency is required to be increased If the blade frequency needs to be reduced, then The invention also provides a combined material blade which is characterized in that the combined material blade is designed by adopting the combined material blade design method, the combined material comprises at least two different materials, the blade structures of the different materials are mutually connected to form the whole blade, the connection parts of the different materials are provided with transition areas, and the different materials are mutually penetrated in the transition areas. According to one or more embodiments of the invention, the combined material comprises a first material and a second material, the blade structures of the first material and the second material being interconnected to form a whole of the blade, the junction of the first material and the second material having a transiti