초음파 피로시험시 시험편의 유한요소 동적 해석

국문 초록 (Abstract)

본 논문에서는 초고주기피로영역의 가속시험 방법인 초음파 피로시험에 대해 20 kHz 근처에서 시험편 게이지부의 동적거동을 유한요소해석으로 검토하였다. 실제 실험에서 시험편에 작용하는 응력은 시험편의 형상과 변위를 통해 식으로 계산되는데 여기서 가정하는 시험편의 형상과 실제 시험편의 형상에 차이가 발생한다. 실험으로 구해진 응력과 유한요소 동적 해석의 결과를 비교하고 형상차이에 따른 응력분포를 확인하였다. 또한, 이론적으로 생각하는 초음파 피로시험기의 동적 거동을 가시적으로 확인하여 초음파 피로시험의 정확성을 확보하였다.

다국어 초록 (Multilingual Abstract)

An accelerated ultrasonic fatigue test (UFT) was used for analyzing very high cycle fatigue (VHCF, Nf > 107) behaviors of a specimen with a test resonance of 20 kHz. Using the finite element method (FEM), the dynamic behaviors of the specimen was studied by calculating the stresses along its gauge portion, with displacement. The shape of gauge portion profile was assumed to be a hyperbolic according to the stress equation of the UFT. However, as the specimen used in the test had a circular arc profile, the FEM was used for studying the local stresses for two cases of the gauge profile. The results were compared with those obtain from the stress equation of the UFT. The dynamic behavior of the gauge portion could be understood for further comparison with the actual results.

목차 (Table of Contents)

• 초록
• Abstract
• 1. 서론
• 2. 초음파 피로시험 이론
• 3. 실험
• 4. 유한요소 해석
• 5. 결론
• 참고문헌(References)

참고문헌 (Reference)

1 명노준, "초음파 피로시험편 결정법의 연구동향" 대한기계학회 37 (37): 967-973, 2013

2 Pyttel, B, "Very High Cycle Fatigue – Is There a Fatigue Limit?" 33 : 49-58, 2011

3 "Ultrasonic Fatigue Testing" 8 :

4 Green, C. H., "The Ultrasonic Stress Distribution in a Specimen with a Circular Gauge Profile" 9 (9): 1063-1069, 1976

5 Batias, C, "Gigacycle Fatigue in MECHANICAL PRACTICE" Marcel Dekker 2005

6 Bruchhausen, M., "Device for Carrying out Environmental very High Cycle Fatigue Tests with Ultrasonic Excitation in Asymmetric Push-Pull Mode" 52 : 11-19, 2013

7 Bajons, P, "Determination of Magnification and Resonance Length of Samples Used in Ultrasonic Fatigue Test" 16 (16): 213-217, 1978

8 Matikas, T. E., "A High-Cycle Fatigue Apparatus at 20 kHz for low-cycle Fatigue/High-Cycle Fatigue Interaction Testing" 24 (24): 687-697, 2008