초록 ▼

Disclosed are a method for ultrasonic fatigue testing at high temperature and a testing device without needing preliminary Young's modulus measurement, and a method for ultrasonic fatigue testing at high temperature and a testing device capable of securing heat insulation for protecting a vibrator w

Disclosed are a method for ultrasonic fatigue testing at high temperature and a testing device without needing preliminary Young's modulus measurement, and a method for ultrasonic fatigue testing at high temperature and a testing device capable of securing heat insulation for protecting a vibrator without water cooling of a horn, measuring end surface displacement of a test specimen in a noncontact manner, and solving problems of a noncontact temperature measurement of a test specimen and temperature control. Young's modulus is calculated by inverse calculation, a rod and a horn having heat resistance, heat insulation, and temperature symmetry of a test specimen are used, laser light is irradiated and received from an oblique direction to measure end surface displacement, and a noncontact temperature measurement of a test specimen by a black-body coating and a two-color radiation thermometer and temperature control by a high-frequency coil having a special shape are performed.

대표청구항 ▼

1. A method for ultrasonic fatigue testing at high temperature, wherein Young's modulus corresponding to temperature is calculated from a measurement result of a resonance frequency by inverse calculation, and a fatigue load condition is controlled, the method comprising: (a) calculating a shoulder

1. A method for ultrasonic fatigue testing at high temperature, wherein Young's modulus corresponding to temperature is calculated from a measurement result of a resonance frequency by inverse calculation, and a fatigue load condition is controlled, the method comprising: (a) calculating a shoulder part length (L2) by expressions (1) to (5), as follows: U″⁡(x)+P⁡(x)⁢U′⁡(x)+k2⁢U⁡(x)=0;(1)P⁡(x)=S′⁡(x)S⁡(x);(2)k=2⁢⁢π⁢⁢f⁢ρE;(3)S⁡(x)=π4⁢d⁢⁢12⁢cos⁢⁢h2⁡(α⁢⁢x)⁢α=1L⁢⁢1⁢cos⁢⁢h-1⁡(d⁢⁢2d⁢⁢1),0≤x≤L⁢⁢1;and(4)S⁡(x)=π4⁢d⁢⁢22⁢L⁢⁢1≤x≤L⁢⁢1+L⁢⁢2;(5)(b) measuring the shoulder part length (L2) using an ultrasonic fatigue testing device; and(c) searching Young's modulus when the shoulder part length (L2) calculated in step (a) and the shoulder part length (L2) measured in step (b) are identical. 2. The method for ultrasonic fatigue testing at high temperature according to claim 1, wherein rods and horns are attached to both ends of a test specimen to secure temperature symmetry of the test specimen. 3. The method for ultrasonic fatigue testing at high temperature according to claim 2, wherein laser light is irradiated in an oblique direction using a laser displacement meter, and laser light reflected in the same direction is received to measure end surface displacement of the test specimen. 4. The method for ultrasonic fatigue testing at high temperature according to claim 3, wherein a black-body coating is coated on the test specimen using a two-color radiation thermometer to measure and control a temperature at a center of the test specimen. 5. The method for ultrasonic fatigue testing at high temperature according to claim 4, wherein high-frequency heating is performed using a double-wound coil with a coil interval equal to or smaller than 20 mm. 6. The method for ultrasonic fatigue testing at high temperature according to claim 3, wherein high-frequency heating is performed using a double-wound coil with a coil interval equal to or smaller than 20 mm. 7. The ultrasonic fatigue testing device which performs the method for ultrasonic fatigue testing at high temperature according to claim 3, the ultrasonic fatigue testing device comprising: the rods; andthe horns which are provided at ends of the rods opposite to the test specimen. 8. The method for ultrasonic fatigue testing at high temperature according to claim 2, wherein a black-body coating is coated on the test specimen using a two-color radiation thermometer to measure and control a temperature at a center of the test specimen. 9. The method for ultrasonic fatigue testing at high temperature according to claim 8, wherein high-frequency heating is performed using a double-wound coil with a coil interval equal to or smaller than 20 mm. 10. The method for ultrasonic fatigue testing at high temperature according to claim 2, wherein high-frequency heating is performed using a double-wound coil with a coil interval equal to or smaller than 20 mm. 11. The ultrasonic fatigue testing device which performs the method for ultrasonic fatigue testing at high temperature according to claim 2, the ultrasonic fatigue testing device comprising: the rods; andthe horns which are provided at ends of the rods opposite to the test specimen. 12. The method for ultrasonic fatigue testing at high temperature according to claim 1, wherein laser light is irradiated in an oblique direction using a laser displacement meter, and laser light reflected in the same direction is received to measure end surface displacement of a test specimen. 13. The method for ultrasonic fatigue testing at high temperature according to claim 12, wherein a black-body coating is coated on the test specimen using a two-color radiation thermometer to measure and control a temperature at a center of the test specimen. 14. The method for ultrasonic fatigue testing at high temperature according to claim 13, wherein high-frequency heating is performed using a double-wound coil with a coil interval equal to or smaller than 20 mm. 15. The method for ultrasonic fatigue testing at high temperature according to claim 12, wherein high-frequency heating is performed using a double-wound coil with a coil interval equal to or smaller than 20 mm. 16. The ultrasonic fatigue testing device which performs the method for ultrasonic fatigue testing at high temperature according to claim 12, the ultrasonic fatigue testing device comprising: rods which are attached to both ends of the test specimen; andhorns which are provided at ends of the rods opposite to the test specimen. 17. The method for ultrasonic fatigue testing at high temperature according to claim 1, wherein a black-body coating is coated on a test specimen using a two-color radiation thermometer to measure and control a temperature at a center of the test specimen. 18. The method for ultrasonic fatigue testing at high temperature according to claim 17, wherein high-frequency heating is performed using a double-wound coil with a coil interval equal to or smaller than 20 mm. 19. The method for ultrasonic fatigue testing at high temperature according to claim 1, wherein high-frequency heating is performed using a double-wound coil with a coil interval equal to or smaller than 20 mm. 20. The ultrasonic fatigue testing device which performs the method for ultrasonic fatigue testing at high temperature according to claim 1, the ultrasonic fatigue testing device comprising: rods which are attached to both ends of a test specimen; andhorns which are provided at ends of the rods opposite to the test specimen.