Method for detecting rigidity of composite material blade

Abstract

The invention belongs to the technical field of rigidity detection, and particularly relates to a composite material blade rigidity detection method which comprises the following steps: step 1, protecting a test blade; 2, determining a loading point of the test blade; 3, mounting the test blade on the test device; step 4, performing test loading on the test blade; 5, calculating the rigidity value of the test blade; step 6, dismounting the test blade; the method can meet the actual use requirements of a production field, and is simple to operate, short in test period and suitable for batch detection of the production field; meanwhile, a test result judgment method is simple, rapid and accurate, the quality control requirement is met, and the large-batch detection requirement of a factory is met.

Description

Technical Field

[0001] The invention belongs to the technical field of stiffness detection, and in particular relates to a method for detecting stiffness of a composite material blade. Background Art

[0002] Blade stiffness is a property that characterizes the blade's ability to resist elastic deformation under external forces. By measuring the deformation of the blade under the test load, it is verified whether the blade stiffness meets the design requirements. The test specimens for aviation gas turbine engine blade stiffness tests are generally original engine blades or simulated parts.

[0003] Composite blades are a new type of blades. There is currently no good way to measure their stiffness due to the different material properties. Therefore, developing an efficient and accurate composite blade stiffness detection method is of great significance for aircraft engines. Summary of the invention

[0004] In view of the deficiencies of the prior art, the object of the present invention is to provide a method for detecting the stiffness of a composite material blade, by measuring the deformation of the blade under a test load to verify whether the stiffness of the blade meets the design requirements.

[0005] A method for detecting the stiffness of a composite blade comprises the following steps:

[0006] Step 1: Test blade protection;

[0007] Step 2: Determine the loading point of the test blade;

[0008] Step 3: The test blade is installed on the test device;

[0009] Step 4: Perform test loading on the test blade;

[0010] Step 5: Calculate the stiffness value of the test blade;

[0011] Step 6: Test blade disassembly.

[0012] In step 1, in order to prevent the test blade from being bumped, paper tape is used to protect the area where the test blade contacts the test device and the torque wrench.

[0013] In step 2, the loading point is determined according to the test loading position requirements, marked, and the test number is recorded.

[0014] In step 3, the test device includes a column, a fixing plate, a blade root fixing plate, a blade tip fixing plate, a top screw, a weight, a micrometer, and a clamp. The root of the test blade is fixed to the blade root fixing plate by bolts, and the blade root fixing plate is fixed to the column through the fixing plate; the tip of the test blade is overlapped above the tip fixing plate, one end of the tip fixing plate is directly fixed to the column, and the other end is fixed to the column by a top screw, and the top screw adjusts the height of the tip fixing plate so that the tip of the test blade is parallel to the root of the test blade; the clamp is installed on the loading point of the test blade, and the clamp is in soft contact with the loading point of the test blade; a weight is connected to the bottom of the clamp, and the direction of the weight is perpendicular to the reference surface of the plate basin side of the upper edge of the root of the test blade, and a micrometer is provided on the clamp.

[0015] The tightening torque of the bolts fixing the test blade root and the blade root fixing plate is 12.5 N·m to 13.5 N·m.

[0016] In step 4, the test blade is loaded with a weight, and the displacement is measured using a micrometer 9; the loading is performed at three levels of 5kg, 10kg, and 15kg, and the displacement of the test blade after each loading is measured using a micrometer, and the displacement value is recorded, and the measurement point is located at the back of the blade corresponding to the loading point.

[0017] In step 6, after the test is completed, first remove the weight and the micrometer, then disassemble the bolts between the root of the test blade and the root fixing plate, then disassemble the test blade and the fixture, remove the paper tape on the test blade, and visually check whether the test blade has any bumps. If any bumps occur, they must be recorded truthfully, and finally the test blade is placed in a parts box for storage.

[0018] In step 5, the SLOPE function is used with loading loads of 5kg, 10kg, and 15kg as independent variables, and the displacement value under the corresponding loading load measured in step 4 is used as the dependent variable to obtain the slope of the fitted linear regression line. The slope value of the regression line is the stiffness value. The test is repeated twice, and the average value of the three test results is taken as the stiffness value of the test piece.

[0019] The beneficial effects of the present invention are:

[0020] The invention provides a test method for the stiffness of a composite material blade. First, the loading point of the test blade is determined. Then, the test blade is installed on a test device, and the deformation is measured by graded loading. The stiffness value is obtained by using a SLOPE function. After taking an average value of multiple experiments, the final stiffness value is obtained. The method can meet the actual use requirements of the production site. The method is simple to operate and has a short test cycle, and is suitable for batch detection at the production site. At the same time, the test result judgment method is concise, fast and accurate, which meets the quality control requirements and meets the large-scale detection needs of the factory.

[0021] The test device of the present application simulates the stress characteristics of the blade installed on the engine. The root of the blade is tightened and the tip of the blade overlaps. At the same time, the tip and root of the blade can be adjusted to be completely parallel through the top screw, ensuring that there is no gap between the tip and root of the blade and ensuring that the test blade does not deform. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of a test blade clamping in a method for detecting the stiffness of a composite blade according to the present invention;

[0023] Figure 2 A schematic diagram of load loading points of a method for detecting the stiffness of a composite material blade according to the present invention;

[0024] In the attached figure: 1. column; 2. fixing plate; 3. blade root fixing plate; 4. test blade; 5. blade tip fixing plate; 6. top screw; 7. weight; 8. micrometer; 9. clamp; 10. reference surface on the side of the upper edge plate basin. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below with reference to the accompanying drawings.

[0026] like Figures 1-2 As shown, a method for detecting the stiffness of a composite blade comprises the following steps:

[0027] Step 1: Test blade protection;

[0028] Before the test, the test blade 4 was visually inspected to confirm whether the test blade 4 was intact; to prevent the test blade 4 from being bumped, a 25 mm wide 3M paper tape was used to protect the area of ​​the test blade 4 that might contact the test device and the torque wrench;

[0029] Step 2: Determine the loading point of the test blade;

[0030] Determine the loading point according to the test loading position requirements, mark it, and record the test number; the loading point is generally the position that best reflects the force on the test blade 4. In this embodiment, the loading point is 30 cm away from the air inlet edge of the test blade 4 and 166 cm away from the root of the test blade.

[0031] Step 3: The test blade is installed on the test device;

[0032] Simulating the engine installation method, the test device includes a column 1, a fixing plate 2, a blade root fixing plate 3, a blade tip fixing plate 5, a top screw 6, a weight 7, a micrometer 8, and a clamp 9. The root of the test blade 4 is fixed to the blade root fixing plate 3 by bolts, and the tightening torque of the bolts is maintained between 12.5N·m and 13.5N·m by a torque wrench, and the root of the test blade 4 is tightened; the blade root fixing plate 3 is fixed to the column 1 through the fixing plate 2; the tip of the test blade 4 is overlapped above the tip fixing plate 5, one end of the tip fixing plate 5 is directly fixed to the column 1, and the other end is fixed to the column 1 through the top screw 6, and the top screw 6 adjusts the height of the tip fixing plate 5 so that the tip of the test blade 4 is parallel to the root of the test blade 4; through the overlap of the tip of the test blade 4 and the adjustment of the top screw 6, the gap between the tip of the test blade 4 and the tip fixing plate 5 is eliminated, and it is ensured that the test blade 4 does not produce obvious deformation;

[0033] Install the clamp 9 on the loading point of the test blade 4, and the clamp 9 and the loading point of the test blade 4 are in soft contact; pay attention to controlling the tightness of the clamp 9 to avoid damaging the test piece. The bottom of the clamp 9 is connected to a weight 7, which is applied to the blade basin side of the test blade, and the direction is from the blade basin to the blade back. The direction of the weight 7 is perpendicular to the reference surface 10 on the plate basin side of the upper edge of the root of the test blade. The clamp 9 is provided with a micrometer 8.

[0034] Step 4: Perform test loading on the test blade;

[0035] The test blade 4 is loaded by a weight 7, and the displacement is measured by a micrometer 8; in order to prevent damage to the test blade 4, the total mass loaded after the tooling should not exceed 18kg; the load is loaded at three levels of 5kg, 10kg, and 15kg, and the displacement of the test blade 4 after each loading is measured by a micrometer 8, and the displacement value is recorded, and the measurement point is at the back of the blade corresponding to the loading point;

[0036] Step 5: Calculate the stiffness value of the test blade;

[0037] Calculate the stiffness according to the displacement data under a load of 5-15kg; use the SLOPE function with loading loads of 5kg, 10kg, and 15kg as independent variables, and the displacement value under the corresponding loading load measured in step 4 as the dependent variable, and obtain the slope of the fitted linear regression line. The slope value of the regression line is the stiffness value. Repeat the loading test in step 4 three times, and take the average value of the three test results as the stiffness value of the test piece. The first pre-load displacement data can be not used as the basis for stiffness calculation.

[0038] Step 6: Test blade disassembly;

[0039] After the test is completed, first remove the weight 7 and the micrometer 8, then disassemble the bolts between the root of the test blade 4 and the root fixing plate 3, then disassemble the test blade 4 and the clamp 9, remove the paper tape on the test blade 4, and visually check whether the test piece has any bumps. If any bumps occur, record them truthfully. Finally, put the test blade 4 into the parts box for storage.

[0040] The present invention provides a test method for composite blade stiffness, which can meet the actual use requirements of the production site, is simple to operate, has a short test cycle, and is suitable for batch testing at the production site; at the same time, the test result judgment method is concise, fast, and accurate, which meets the quality control requirements and meets the large-scale testing needs of the factory.

[0041] The test device of the present application simulates the stress characteristics of the blade installed on the engine. The root of the blade is tightened and the tip of the blade overlaps. At the same time, the tip and root of the blade can be adjusted to be completely parallel through the top screw, ensuring that there is no gap between the tip and root of the blade and ensuring that the test blade does not deform.

Claims

1. A method for detecting the stiffness of a composite material blade, characterized in that: The specific steps include: Step 1: Test blade protection; Step 2: Determine the loading point of the test blade; Step 3: The test blade is installed on the test device; Step 4: Perform test loading on the test blade; Step 5: Calculate the stiffness value of the test blade; Step 6: Test blade disassembly.

2. A composite material blade stiffness detection method according to claim 1, characterized in that: In step 1, in order to prevent the test blade from being bumped, paper tape is used to protect the area where the test blade contacts the test device and the torque wrench.

3. The method for detecting the stiffness of a composite material blade according to claim 1, characterized in that: In step 2, the loading point is determined according to the test loading position requirements, marked, and the test number is recorded.

4. The method for detecting the stiffness of a composite material blade according to claim 1, characterized in that: In step 3, the test device includes a column, a fixing plate, a blade root fixing plate, a blade tip fixing plate, a top screw, a weight, a micrometer, and a clamp. The root of the test blade is fixed to the blade root fixing plate by bolts, and the blade root fixing plate is fixed to the column through the fixing plate; the tip of the test blade is overlapped above the tip fixing plate, one end of the tip fixing plate is directly fixed to the column, and the other end is fixed to the column by a top screw, and the top screw adjusts the height of the tip fixing plate so that the tip of the test blade is parallel to the root of the test blade; the clamp is installed on the loading point of the test blade, and the clamp is in soft contact with the loading point of the test blade; a weight is connected to the bottom of the clamp, and the direction of the weight is perpendicular to the reference surface of the plate basin side of the upper edge of the root of the test blade, and a micrometer is provided on the clamp.

5. A composite material blade stiffness detection method according to claim 4, characterized in that: The tightening torque of the bolts fixing the test blade root and the blade root fixing plate is 12.5 N·m to 13.5 N·m.

6. The method for detecting the stiffness of a composite material blade according to claim 1, characterized in that: In step 4, the test blade is loaded with a weight, and the displacement is measured using a micrometer 9; the loading is performed at three levels of 5kg, 10kg, and 15kg, and the displacement of the test blade after each loading is measured using a micrometer, and the displacement value is recorded, and the measurement point is located at the back of the blade corresponding to the loading point.

7. A composite material blade stiffness detection method according to claim 6, characterized in that: In step 5, the SLOPE function is used with loading loads of 5kg, 10kg, and 15kg as independent variables, and the displacement value under the corresponding loading load measured in step 4 is used as the dependent variable to obtain the slope of the fitted linear regression line. The slope value of the regression line is the stiffness value. The test is repeated twice, and the average value of the three test results is taken as the stiffness value of the test piece.

8. The method for detecting the stiffness of a composite material blade according to claim 1, characterized in that: In step 6, after the test is completed, first remove the weight and the micrometer, then disassemble the bolts between the root of the test blade and the root fixing plate, then disassemble the test blade and the fixture, remove the paper tape on the test blade, and visually check whether the test blade has any bumps. If any bumps occur, they must be recorded truthfully, and finally the test blade is placed in a parts box for storage.

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