• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.459-463
• /
• 2008

Induction hardening has been used to improve torsional strength and characteristics of wear for axle shaft which is a part of automobile to transmit driving torque from differential to wheel. After rapidly heating and cooling process of induction hardening, the shaft has residual stress and material properties change which affect allowable transmit torque. The objective of this study is to predict the distribution of residual stress and estimate the torsional strength of induction hardened axle shafts which has been residual stress using finite element analysis considered thermo mechanical behavior of material and experiments. Results indicate that the torsional strength of axle shaft depends on the surface hardening depth and distribution of residual stress.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2003년도 추계학술발표대회 논문집
• /
• pp.183-186
• /
• 2003

Long shafts for power transmission should transmit torsional load with vibrational stability. Hybrid shafts made of unidirectional fiber-reinforced composite and metal have high fundamental bending natural frequency as well as high torque transmission capability. However, thermal residual stresses due to the coefficient difference of thermal expansion of the composite and metal are developed so that the high residual stresses decrease fatigue resistance of the hybrid shafts, especially at low operating temperatures. In this work, axial compressive preload was given to the shaft in order to change the residual stresses. Static and fatigue torsional tests were performed and correlated with stress analyses with respect to the preload and service temperature.

• 대한기계학회논문집A
• /
• 제34권5호
• /
• pp.645-649
• /
• 2010

고주파열처리(induction hardening)는 엔진의 구동력을 차동장치에서 바퀴까지 전달해주는 부품인 액슬축(axle shaft)의 비틀림 강도를 증가시키기 위해 적용되는 열처리 방법이다. 고주파 열처리 과정의 급속가열과 급속냉각은 소재에 잔류응력과 물성치를 변화시켜 액슬축의 허용 전달토크를 변화시킨다. 본 연구에서는 고주파 열처리한 액슬축의 잔류응력의 분포와 열처리 깊이에 따른 비틀림 강도 변화를 열물성 및 상변태를 고려한 유한요소 해석을 통해 예측하였으며 이를 시험과 비교하였다.

• 한국생산제조학회지
• /
• 제7권6호
• /
• pp.126-131
• /
• 1998

The influence of shot peening on the fatigue strength of SCM22 steel is investigated in this work. The shot peening process is applied to the heat treated specimens. Then, basic material properties and residual stresses are evaluated for specimens. Rotate bending and torsional fatigue tests are accomplished to investigate the effects of shot peening on the fatigue strength. experimental results show that the fatigue life was increased tremendously by shot peening. The compressive residual stress, which is induced by shot peening process, seems to be an important factor of increasing the fatigue strength.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.196-201
• /
• 2004

Adhesive joints have been widely used for fastening thin adherends because they can distribute the load over a larger area than mechanical joints, require no hole, add very little weight to the structure and have superior fatigue resistance. However, the fatigue characteristics of adhesive joints are much affected by applied pressure during curing operation because actual curing temperature is changed by applied pressure and the adhesion characteristics of adhesives are very sensitive to manufacturing conditions. In this study, cure monitoring and torsional fatigue tests of adhesive joints with an epoxy adhesive were performed in order to investigate the effects of the applied pressure during curing operation. From the experiments, it was found that the actual curing temperature increased as the applied pressure increased, which increased residual thermal stress in the adhesive layer. Therefore, the fatigue life decreased as the applied pressure increased because the mean stress during fatigue tests increased due to the residual thermal stress.

• Structural Engineering and Mechanics
• /
• 제23권4호
• /
• pp.339-352
• /
• 2006

Observing the unique stress-strain curves of the superelastic shape memory alloy (SMA) in tension and compression, the primary intention of this study is to investigate the behavior of the shafts made of the same material, under torsional loading-unloading cycles for large angle of twist. Experiments have been performed for the superelastic SMA shafts with different unsupported lengths and angles of twist and the results are compared with those of stainless steel (SUS304) shafts under similar test conditions. As expected for the superelastic SMA, the residual strains are small enough after each cycle and consequently, the hysteresis under loading-reverse loading is much narrower than that for the SUS304. For large angle of twists, the torsional strength of the superelastic SMA increases nonlinearly and exceeds that of SUS304. Most interestingly, the slender solid superelastic SMA shafts are found to buckle when acted upon torsion for large angle of twist.

• 한국강구조학회 논문집
• /
• 제16권2호통권69호
• /
• pp.215-224
• /
• 2004

에너지법을 이용하여 보-기둥 및 기둥의 비탄성 좌굴거동을 해석하였다. 미국에서 생산되는 I 형강에 적용되는 단순형 잔류응력 모델을 우리나라에서 생산되는 I 형강에 적용하였다. 먼저, 집중 압축 축하중과 균등 휨을 동시에 받는 I 형강에 대하여 비탄성 횡-비틀림 좌굴거동을 알아보고 보-기둥에서의 잔류응력의 영향을 해석하였다. 또한 기둥의 경우에 대하여 해석하였으며 얻어진 결과를 강구조편람에 의한 설계 시의 값과 비교하였다. 결론적으로 강구조편람에 의한 설계는 과설계가 됨을 알 수 있었다.

• 대한기계학회논문집A
• /
• 제24권2호
• /
• pp.403-410
• /
• 2000

The effects of various factors were studied on the process of a steel cord by twisting wires. To remove residual twisting moment after the steel cord process, the twisting angles of residual elasti c twisting and overtwisting were measured and compared with finite element results. The agreement between experimental data and finite element calculations was good for the angles of residual elastic twisting and over-twisting. The stress distributions in a steel cord under complex loading conditions were also obtained by using the finite element analysis.

• 한국강구조학회 논문집
• /
• 제16권1호통권68호
• /
• pp.155-167
• /
• 2004

각각 집중하중과 등분포하중을 받는 단순보의 비탄성 횡-비틀림 좌굴에 대하여 연구하였다. 잔류응력을 단순형과 다항식형으로 하여 line-type 유한요소법으로 해석하였다. 잔류응력의 형태는 플랜지에서는 4차 곡선으로 웨브에서는 2차 곡선으로 가정하였다. 우리나라에서 생산되는 4종류의 I형강에 대하여 비탄성 횡-비틀림 좌굴에 대하여 해석한 후 결과를 강구조편람의 내용과 비교하였다. 해석결과로부터 강구조 편람에 의한 설계는 주보에 보조보가 있는 경우나 없는 경우 모두 전반적으로 과설계임을 알 수 있었다.

• 한국강구조학회 논문집
• /
• 제16권1호통권68호
• /
• pp.61-72
• /
• 2004

우리나라에서는 생산되는 I형강을 대상으로 비탄성 휨-뒤틀림 좌굴에 대하여 연구하였으며 잔류응력은 다항식형과 단순형으로 고려하였다. 또한 웨브의 면의 뒤틀림이 구속된 보의 비탄성 휨-비틀림 좌굴에 대해서도 알아보았다. 해석결과를 강구조편람의 허용 휨응력과 비교하였다. 균일한 휨을 받는 보의 경우는 비탄성 휨-비틀림 좌굴이 중요한 큰 영향을 미치지 않았으나, 중간 브레이싱이 없는 단지간 및 중지간보의 경우 강구조편람에 의한 설계는 과설계가 됨을 알 수 있었다.