• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1997년도 추계학술대회 논문집
• /
• pp.786-789
• /
• 1997

Ti-6Al-4V has been used widely in biomedical field. But because of its toxicity, the ${\beta}$ stabilizing element, V, in Ti-6Al-4V has been replaced by Nb, Ta. Ti-10Ta-10Nb has been developed for biomedical applications. The fatigue crack propagation behavior of Ti-alloy(Ti-10Ta-10Nb) was investigated, in comparison with that of pure Ti. In order to better understand the fundamental fatigue behavior of Ti-10Ta-10Nb, rotating bending fatigue tests have been carried out. Ti-10Ta-10Nb has a better fatigue strength than pure Ti. In this paper, fatigue life has been predicted with Nisitani's equation of the fatigue crack propagation that can be established by measuring fatigue crack growth rates.

• 한국산학기술학회논문지
• /
• 제13권6호
• /
• pp.2589-2599
• /
• 2012

일부 종합병원에 근무하는 간호사들의 A형 행동유형과 피로자각증상과의 관련성을 검토하고자 일부 종합병원에서 근무하는 간호사 306명을 대상으로 2011년 5월 1일부터 6월 30일까지의 기간 동안에 구조화된 무기명 자기기입식 설문지(self-administered questionnaire)를 이용한 설문조사를 하였다. 연구결과, 조사대상자의 A형 행동유형의 분포는 A형 행동유형군이 50.7%, B형 행동유형군이 49.3%이었으며, 피로자각증상의 분포는 정상군이 76.8%, 고위험피로군이 23.2%이었다. A형 행동유형에 따른 피로자각증상의 분포를 보면, 피로자각증상이 정상인군은 B형 행동유형군이 높은 반면, 고위험피로군은 A형 행동유형군이 유의하게 높았으며, A형 행동유형은 피로자각증상과 유의한 양의 상관관계를 보였다. 또한 B형 행동유형군보다 A형 행동유형군에서 고위험피로군에 속할 위험비가 유의하게 상승하였다. 위와 같은 결과를 볼 때 A형 행동유형군은 B형 행동유형군보다 피로자각증상이 유의하게 높은 것을 알 수 있었다. 향후 다양한 연구대상에 대한 A형 행동유형과 피로자각증상과의 관련성에 대한 지속적인 연구가 필요할 것으로 생각된다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.359-364
• /
• 2004

In this study, experiments were tried on the mixed-mode I+II single overloading model which changes the loading mode of overload and fatigue load. Aspects of deformation field in front of the crack which is formed by mixed-mode I+II single overloading were experimentally studied. Then the shape and size of mixed-mode plastic zone were approximately calculated. The propagation behavior of fatigue crack was examined under the test conditions combined by changing the loading mode. The behavior of fatigue cracks were greatly affected by shapes of plastic deformation field and applying mode of fatigue load. Accuracy of prediction and evaluation for fatigue life may be improved by considering all aspects of deformation and behavior of fatigue cracks.

• 한국정밀공학회지
• /
• 제18권5호
• /
• pp.74-83
• /
• 2001

In this study, internal fatigue crack initiation and propagation behavior were investigated by triple piece spot welded specimen. To estimate fatigue life of the specimen varied with shape and thickness, Crack tip opening angle(CTOA) correlated with stress intensity factor was used as the stiffness parameter. The relation between fatigue life and CTOA can be arranged by the quantitative equation for each specimen by experiment. In addition, the variation of stress distribution was solved and the effect on fatigue crack behavior was examined by finite element method(FEM).

• 대한기계학회논문집
• /
• 제7권4호
• /
• pp.355-360
• /
• 1983

This paper deals with fatigue behavior of ion-nitrided coil spring. It is found that fatigue limit can be significantly increased by ion-nitriding. Ion-nitribed specimen which is treated at 550.deg. C for 5 hours improves in the fatigue limit by 30 percent in comparison with that of non-nitrided specimen. On the other hand, the value of spring constant K has nothing to do with nitriding time and temperature in this experimental range. Besides fatigue behavior, the following effects are discussed such as compound layer, diffusion layer, hardness distribution and their relations.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2002년도 춘계학술대회 논문집
• /
• pp.64-69
• /
• 2002

The purpose of this paper was to investigate the welding characteristics and the fatigue crack propagation behavior of titanium commonly using power station, aircraft and ship. The experimented material was TIG welded in order to look over the characteristics according to the notch position and compare with other materials. We compared and reviewed the fatigue crack propagation behavior of nontch base metal and welded specimens having different notch position to evaluate the fatigue crack propagation behavior by welding condition.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
• /
• pp.1161-1166
• /
• 2001

Fatigue behavior of reinforced concrete(RC) elements has been experimentally and analytical investigated. Fatigue behavior influenced by longitudinal reinforcement ratio, strength of concrete and load ratio $P_{u}$/ $P_{o}$. The purpose of these studies is to propose an empirical formula for fatigue behavior on basis of experimental results. Also an analytical method to predict the crack propagation of RC beams has been developed based on the relationships between bond stress and slip.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2001년도 춘계학술대회 논문집
• /
• pp.443-452
• /
• 2001

Fatigue behavior of reinforced concrete(RC) and steel fiber reinforced concrete(SFRC) beams has been experimentally investigated. Fatigue behavior influenced by longitudinal reinforcement ratio, volume and type of steel fiber, strength of concrete and load ratio $P_{u}/P_{o}$. It can be observed from experimental results that addition of steel fiber to reinforced concrete beam reduces crack widths and increases stiffness, and thus enhances the behavior in serviceability limit states also for high cyclic fatigue loading.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
• /
• pp.431-438
• /
• 2001

Fatigue behavior of reinforced concrete(RC) and steel fiber reinforced concrete(SFRC) elements has been experimentally investigated. Fatigue behavior influenced by longitudinal reinforcement ratio, volume and type of steel fiber, strength of concrete and load ratio $P_{u}$ $P_{o}$. It can be observed from experimental results that addition of steel fiber to reinforced concrete beam reduces crack widths and increases stiffness, and thus enhances the behavior in serviceability limit states also for high cyclic fatigue loadingngng

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.499-503
• /
• 2001

Fatigue behavior of reinforced concrete (RC) elements has been experimentally and analytical investigated. Fatigue behavior influenced by longitudinal reinforcement ratio, strength of concrete and load ratio P／sub u／／P／sub o／. The purpose of these studies is to propose an empirical formula for fatigue behavior on basis of experimental results. Also an analytical method to predict the crack propagation of RC beams has been developed based on the relationships between bond stress and slip.