Dynamic evolution measurement method for internal damage of material in high-temperature service environment

Abstract

The invention provides a dynamic evolution measurement method for internal damage of a material in a high-temperature service environment, and mainly aims to solve the problem that the dynamic evolution process of micro defects such as micro holes and micro cracks in an engineering material in a high-temperature, high-pressure and closed environment is difficult to measure and the engineering problem that the life is not accurately predicted due to the holes. According to the technical scheme, a phased array nondestructive testing technology and a high-temperature testing machine are combined, the whole dynamic evolution process of the diameter of the micro-hole is actually measured, the function mapping relation between the micro-hole growth and displacement and the stress level is established, and the micro-hole diameter is accurately measured on the basis of the rigidity equivalence principle of a mechanical loading system of the testing machine. Therefore, the dynamic evolution measurement method for the internal damage of the material in the high-temperature service environment is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of fatigue damage monitoring of engineering materials, and in particular relates to a method for measuring the dynamic evolution of internal damage of a material in a high-temperature service environment. Background Art

[0002] Engineering structures serving in high temperature, high pressure, and closed environments have micro defects such as micro holes and micro cracks inside their materials due to fatigue and vibration loads, which affect the constitutive behavior of the materials and shorten their actual service life. Due to the extreme nature of the service environment and the operability of limited space, it is difficult to measure the dynamic evolution of micro defects inside the materials. The numerical simulation and theoretical modeling based on the traditional constitutive model in the existing life analysis technology of engineering structures either ignore micro holes or assume that micro holes grow, which is still far from its actual dynamic evolution. This directly affects the accuracy of life calculation and is related to the safety, reliability, maintenance strategy and overhaul cost of the service structure.

[0003] Phased array ultrasonic testing is an advanced non-destructive testing technology with the advantages of high efficiency, flexibility, accuracy and advanced data processing capabilities. It is widely used in aerospace, petrochemical, automobile manufacturing and other fields. High temperature fatigue testing machine is a key equipment for material performance testing. It has the advantages of being able to simulate real working conditions, a wide range of material applications, a wide variety of loading conditions, high test data accuracy, strong data acquisition capabilities, and high engineering application value. It has important engineering application value in material research and development, structural design, quality control and other aspects. The combination of phased array ultrasonic testing technology and high temperature fatigue testing machine is the first case of measuring the dynamic evolution of internal damage of engineering materials in extreme service environments such as high temperature. It can be used to improve the problem of inaccurate stress-strain response caused by ignoring micropores or assuming micropores in traditional constitutive models, which is conducive to improving the accuracy of engineering structure life analysis, improving safety and reliability, and reducing maintenance costs. Summary of the invention

[0004] The purpose of the present invention is to provide a method for measuring the dynamic evolution of internal damage of materials in a high-temperature service environment. This method provides a new idea for the problem of the difficulty in measuring the dynamic evolution of internal defects of engineering materials in high-temperature service environments. It can measure in real time the entire process of the dynamic size evolution of micropores inside the material under high-temperature cyclic loads, and provide high-accuracy data support for the constitutive modeling of the material, thereby improving the accuracy of stress-strain response and the precision of life analysis.

[0005] The technical solution of the present invention:

[0006] A method for measuring the dynamic evolution of internal damage of a material in a high-temperature service environment, wherein a hole is punched in the middle of a smooth sample 19, the hole diameter is Φ=0.5 mm, and a hole sample 17 is prepared; the maximum temperature of the high-temperature furnace 2 can be adjusted in the range of 400 to 1200°C; the minimum size of a defect that can be measured by a phased array damage probe 18 is 0.3 mm;

[0007] Based on the high temperature fatigue testing machine platform, the upper end surface of the high temperature furnace 2 is adjusted down to about 30 mm from the upper end surface of the lower fixture, and its main function is to complete the room temperature fatigue test of the hole sample 17;

[0008] The hole sample 17 is fixed by the lower clamp 10 at about 2 / 3 of the distance from the clamping ends on both sides, and the lower clamp 10 is ensured to be aligned with the axis of the hole sample 17. Its main function is to complete the centering clamping of the lower end of the hole sample 17;

[0009] At about 2 / 3 of the distance from the clamping ends on both sides of the hole sample 17, the control hydraulic cylinder 5 is fixed through the upper clamp 9, and the upper clamp 9 is ensured to be aligned with the axis of the hole sample 17. Its main function is to complete the centering clamping of the upper end of the hole sample 17;

[0010] A phased array damage probe 18 is placed in the middle of the hole sample 17. The upper surface of the phased array damage probe 18 and the plane formed by the axis of the hole 16 and the axis of the hole sample 17 are kept parallel. Its main function is to make the defect imaging position standard.

[0011] A phased array damage probe 18 is placed in the middle of the hole sample 17, and a coupling agent is applied at the contact point between the phased array damage probe 18 and the hole sample 17, the main function of which is to make the defect imaging clearer;

[0012] The lower clamp 10 is used to fix the smooth sample 19 at about 2 / 3 of the distance from the clamping ends on both sides, and ensure that the lower clamp 10 is aligned with the axis of the smooth sample 19. Its main function is to complete the centering clamping of the lower end of the smooth sample 19;

[0013] At about 2 / 3 of the distance from the clamping ends on both sides of the smooth sample 19, the control hydraulic cylinder 5 is fixed through the upper clamp 9, and the upper clamp 9 is ensured to be aligned with the axis of the smooth sample 19. Its main function is to complete the centering clamping of the upper end of the smooth sample 19;

[0014] Based on the high temperature fatigue testing machine platform, the high temperature furnace 2 is adjusted to the middle position of the smooth sample 19 , and its main function is to complete the high temperature fatigue test of the smooth sample 19 .

[0015] Beneficial effects of the invention: The above technical solution of the invention has the following advantages: The invention provides important technical support and solutions for the problem of the difficulty in measuring the dynamic evolution of internal defects of engineering materials under high temperature, high pressure and closed environment, and also provides high-accuracy data support for the accurate construction of material constitutive model, thereby improving the accuracy of stress-strain response and the accuracy of life analysis. At the same time, the method of combining phased array nondestructive testing technology at room temperature with a high-temperature testing machine is also the first time to be applied to the measurement of the dynamic evolution of internal damage of engineering materials under high temperature environment, which has certain innovation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a front view schematic diagram of a high temperature fatigue testing machine provided by an example of the present invention;

[0017] Figure 2 is a top view schematic diagram of a high temperature fatigue testing machine provided by an example of the present invention;

[0018] Figure 3 is a bottom view schematic diagram of a high temperature fatigue testing machine provided by an example of the present invention;

[0019] Figure 4 It is a schematic diagram of clamping a hole sample with a damage probe provided by an example of the present invention;

[0020] Figure 5 It is a schematic diagram of a smooth sample clamping provided by an example of the present invention;

[0021] Figure 6 It is a schematic diagram of the structure of a damage probe provided by an example of the present invention;

[0022] Figure 7 It is a schematic diagram of a hole sample provided by an example of the present invention;

[0023] Figure 8 is a schematic diagram of a smooth sample provided by an example of the present invention;

[0024] In the figure: 1-high temperature furnace slip ring, 2-high temperature furnace, 3-high temperature furnace slide rod, 4-front left pillar, 5-hydraulic cylinder, 6-front right pillar, 7-upper chassis, 8-pin, 9-upper clamp, 10-lower clamp, 11-lower chassis, 12-rear left pillar, 13-rear right pillar, 14-threaded hole of lower clamp, 15-threaded hole of high temperature furnace slide rod, 16-Φ0.5mm micropore, 17-hole sample, 18-damage probe, 19-smooth sample. DETAILED DESCRIPTION

[0025] In order to make the purpose and technical solution of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be further described below in conjunction with the accompanying drawings in the embodiment of the present invention;

[0026] like Figure 1As shown, before the room temperature fatigue test of the hole sample 17, the upper end surface of the high temperature furnace 2 is moved to a position 30 mm away from the upper end surface of the lower fixture 10 through the high temperature furnace slip ring 1 and the high temperature furnace slide rod 3; by controlling the hydraulic cylinder 5, based on the threaded connection between the lower fixture 10 and the upper fixture 9 and the 2 / 3 of the clamping end of the hole sample 17, the centering and clamping of the hole sample 17 in the room temperature fatigue test are completed; in the middle position of the hole sample 17, the phased array damage probe 18 is placed to ensure that the upper surface of the phased array damage probe 18 and the plane formed by the axis of the hole 16 and the axis of the hole sample 17 are parallel, and the coupling agent is applied to the contact between the phased array damage probe 18 and the hole sample 17.

[0027] During the room temperature fatigue test of the hole specimen 17, different stress levels σ were applied through the mechanical loading system of the high temperature fatigue testing machine. i The micro-hole diameter Φ and displacement peak d are recorded every 50 cycles by phased array ultrasonic nondestructive testing technology until the hole sample breaks, and the functional mapping relationship between the dynamic evolution of the hole diameter and the displacement peak d is constructed. i =f i (Φ i ,σ i ).

[0028] Before the high-temperature fatigue test of the smooth specimen 19, the upper end surface of the high-temperature furnace 2 is moved to the middle position of the smooth specimen 19 through the high-temperature furnace slip ring 1 and the high-temperature furnace slide rod 3; by controlling the hydraulic cylinder 5, based on the threaded connection between the lower clamp 10 and the upper clamp 9 and the 2 / 3 of the clamping end of the smooth specimen 19, the centering and clamping of the smooth specimen 19 in the high-temperature fatigue test are completed.

[0029] During the high temperature fatigue test of the smooth specimen 19, the temperature is raised to the required temperature by the high temperature furnace 2 and the required load level σ is applied based on the mechanical loading system of the high temperature fatigue testing machine. h , respectively record the displacement peak value d h , based on d i =f i (Φ i ,σ i ) and then obtain the micropore diameter Φ h =f h (d h ,σ h ), that is, given any stress level σ and displacement peak d in a high-temperature service environment, the diameter of the micropores inside the material can be obtained.

Claims

1. A method for measuring the dynamic evolution of internal damage of a material in a high-temperature service environment, wherein a hole sample (17) and a smooth sample (19) are respectively clamped between an upper clamp (9) and a lower clamp (10); characterized in that: The hole specimen (17) is subjected to a normal temperature fatigue test, and the smooth specimen (19) is subjected to a high temperature fatigue test.

2. The method for measuring the dynamic evolution of internal damage of materials in a high-temperature service environment according to claim 1, characterized in that: A hole is punched in the middle of the smooth sample (19) with a hole diameter of Φ=0.5 mm, thereby completing the preparation of the hole sample (17); the adjustable range of the maximum temperature of the high-temperature furnace (2) is 400-1200° C.; and the minimum size of the defect that can be measured by the phased array damage probe (18) is 0.3 mm.

3. The method for measuring the dynamic evolution of internal damage of materials in a high-temperature service environment according to claim 1, characterized in that: The hole sample (17) is fixed by a lower clamp (10) at a distance of about 2 / 3 of the clamping ends on both sides, and the axis of the lower clamp (10) and the hole sample (17) are aligned. Its main function is to complete the centering clamping of the lower end of the hole sample (17).

4. The method for measuring the dynamic evolution of internal damage of materials in a high-temperature service environment according to claim 1, characterized in that: A phased array damage probe (18) is placed in the middle of the hole sample (17). The upper surface of the phased array damage probe (18) and the plane formed by the axis of the hole (16) and the axis of the hole sample (17) are kept parallel. Its main function is to make the defect imaging position standard.

5. The method for measuring the dynamic evolution of internal damage of materials in a high-temperature service environment according to claim 1, characterized in that: A phased array damage probe (18) is placed in the middle of the hole sample (17), and a coupling agent is applied at the contact point between the phased array damage probe (18) and the hole sample (17), the main function of which is to make the defect imaging clearer.

6. The method for measuring the dynamic evolution of internal damage of materials in a high-temperature service environment according to claim 1, characterized in that: The lower clamp (10) is fixed at about 2 / 3 of the distance from the clamping ends on both sides of the smooth sample (19), and the axis of the lower clamp (10) and the smooth sample (19) are ensured to be aligned. Its main function is to complete the centering clamping of the lower end of the smooth sample (19).

7. The method for measuring the dynamic evolution of internal damage of materials in a high-temperature service environment according to claim 1, characterized in that: At about 2 / 3 of the distance from the clamping ends on both sides of the smooth sample (19), the control hydraulic cylinder (5) is fixed through the upper clamp (9) and ensures that the axis of the upper clamp (9) and the smooth sample (19) are aligned. Its main function is to complete the centering clamping of the upper end of the smooth sample (19).

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