• 한국강구조학회 논문집
• /
• 제8권3호통권28호
• /
• pp.151-160
• /
• 1996

The fatigue test under the constant amplitude repeated loading is performed to investigate the fatigue behavior of the Torque Shear type high tension bolted joint which is able to manage the axial force uniformly. From the test results, it's known that the reduction of the axial force of T/S bolt followed by the elasped time is similar to that of the high tension bolts. The difference of relaxation is not occurred according to the position of bolts, the size of the introduced axial force but the effect of the variation of temperature is large. In the reduction of the axial force followed by the cumulation of the fatigue load, the outer bolt is larger than the inner bolt. This result depends on the difference in the distribution of the non-slip zone. The variation of the surface roughness affects the slip and the reduction of the anal force.

• 자동차안전학회지
• /
• 제7권1호
• /
• pp.20-26
• /
• 2015

In vehicle development process, durability test should be carried out in field condition. Nowadays there are many customer live there multiple conditions. It makes change of the car's material. Such change causes to lose a bolt. Diversifications of climatic conditions are also a matter of loosening the bolt. To avoid this problem, to identify the cause of the problem, and the solution should be applied. To avoid problems during the durability development test should be measured by the clamping force. Ultrasonic instruments clamping force without affecting the torque can be measured. This instrument is part of the problem by monitoring the clamping force required to obtain objective data.

• 한국강구조학회 논문집
• /
• 제20권3호
• /
• pp.399-407
• /
• 2008

건축공사 표준시방서에서 규정하는 TS고력볼트는 KS B 2819에 따라 토크관리법에 의한 체결한다. TS고력볼트는 핀 테일이 파단되면 적정축력이 도입되는 것으로 알려져 있지만, 실제로는 온도조건에 따라 토크계수가 변하고 도입축력도 설계기준에 미치지 못하는 경우가 발생한다. 본 논문에서는 현장 온도조건이 볼트의 토크계수 및 도입축력의 영향을 평가하기 위해 ${-10^{\circ}C{\sim}50^{\circ}C}$ 범위에서 3 종류의 고력 볼트에 대해 도입축력, 토크계수, 너트회전각을 실험적으로 비교 분석하였다. 실험결과 TS고력볼트의 경우 핀 테일이 파단될 때 모든 온도조건에서 설계볼트장력과 표준볼트장력을 상회하는 도입축력을 나타냈으며 ${-10^{\circ}C}$에서 ${50^{\circ}C}$까지 온도 상승함에 따라 핀 테일 파단시점의 볼트에 도입되는 평균축력은 20kN 증가되었다. 아연피막 처리한 일반육각형 고력볼트의 경우, $0^{\circ}C$, $20^{\circ}C$, $50^{\circ}C$조건, 토크계수 0.13과 토크 ${462N{\cdot}m} $에서 표준볼트축력을 상회하였지만, 도입축력의 일정한 경향을 찾을 수 없었으며 온도변수 별 평균 도입축력 차는 최대 50kN이었다. 일반 육각고력볼트의 경우, 온도상승에 따라 평균 도입축력도 상승되는 추세였으며 토크 ${462N{\cdot}m} $ 일때 온도변수별 볼트의 도입축력은 최대 33kN 차이를 보였다. 또한, TS볼트를 제외한 육각볼트 종류 군에 대해서는 너트회전각 ${90^{\circ}}$ 경우의 도입축력은 설계볼트장력에 미치지 못했다. 따라서, 기존 너트회전각 ${120^{\circ}{\pm}30^{\circ}}$의 하한치 ${-30^{\circ}}$에 대한 재평가를 고려해 볼 필요가 있다.

• 한국자동차공학회논문집
• /
• 제18권3호
• /
• pp.37-42
• /
• 2010

Plastic region tightening is widely used in critical bolted joints in internal combustion engines in order to reduce the engine weight by maximizing the use of load-carrying capacity of bolt. Mechanical behavior of bolt tightened in plastic region under external axial tensile load is investigated for various friction conditions using three dimensional finite element analysis. The behavior of bolt tightened in elastic region as well as that in tensile test are investigated for comparison. Tightening process is simulated by rotating the bolt in order to examine the friction effect realistically. It is revealed that the bolt tightened in plastic region can carry more external load until the joint is opened, and yields at lower bolt load than the bolt tightened in elastic region. The friction coefficient has effect on the yield load, but not on the load-carrying capacity. Moreover, the scatter in the bolt preload due to friction begins with plastic deformation of bolt in the angle tightening control, whereas it begins with the onset of tightening in the torque tightening control. The observations are interpreted with the residual torsional stress in the bolt generated during the tightening.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제53권3호
• /
• pp.123-127
• /
• 2004

Mode conversion type ultrasonic rotary motor using bolt tightened Langevin type vibrator was studied. Driving frequency of the motor, displacements and elliptical trajectories at tip of the coupler were simulated by finite element analysis program (ANSYS). Speed and torque of the fabricated motor were measured as functions of input voltage and load. As results, from FEA the driving frequency of 40.8[kHz] and useful elliptical trajectories were found. Fabricated motor rotated clockwise at frequency of 38.2[kHz]. Speed and torque of the motor were increased when the input voltage was increased. Maximum speed, torque and efficiency were 75[rpm], 0.14[Nm] and 6.28[％], respectively.

• 한국위성정보통신학회논문지
• /
• 제7권3호
• /
• pp.94-98
• /
• 2012

정확한 토크 체결력을 제공하기 위하여 토크 측정기는 최소자승이 적용된 커브피팅 알고리즘을 사용한다. 본 논문에서 제안하는 보정 최소자승 커브피팅 알고리즘은 토크 정밀 측정을 사용하는 다양한 산업분야에서 볼트와 너트에 향상된 체결력을 제공할 수 있다. 먼저, 제안한 알고리즘에 대한 수학적 모델을 소개하고, 제안한 알고리즘을 시뮬레이션하여 기존 알고리즘과 그 결과를 비교하였다. 보정된 최소자승 알고리즘은 기존의 토크 측정에 사용되었던 알고리즘보다 낮은 표준 오차 값을 보임으로써 제안한 보정된 최소자승 알고리즘의 성능의 정확성을 증명한다. 따라서, 본 알고리즘을 토크 계측에 적용함으로써 정밀 산업기계 및 전자부품 그리고 기타 항공기, 우주선등 나사의 조임 체결력이 적용되는 산업분야에 적용함으로써 비용 및 안전성 향상에 기여될 것을 예상한다.

• 복합신소재구조학회 논문집
• /
• 제6권3호
• /
• pp.32-40
• /
• 2015

The torque shear high strength bolt is clamped normally at the break of pin-tail specified. However, the clamping forces on slip critical connections do not often meet the required tension, as it considerably fluctuates due to torque coefficient dependent on lubricant affected temperature. In this study, the clamping tests of torque shear bolts were conducted independently at indoor conditions and at construction site conditions. During last six years, temperature of candidated site conditions was recorded from $-11^{\circ}C$ to $34^{\circ}C$. The indoor temperature condition was ranged from $-10^{\circ}C$ to $50^{\circ}C$ at each $10^{\circ}C$ interval. As for site conditions, the clamping force was reached in the range from 159 to 210 kN and the torque value was from 405 to $556 N{\cdot}m$. The range of torque coefficient at indoor conditions was analyzed from 0.126 to 0.158 while tensions were indicated from 179 to 192 kN. The torque coefficient at site conditions was ranged from 0.118 to 0.152. Based on this test, the variable trends of torque coefficient, tension subjected temperature can be taken by statistic regressive analysis. The variable of torque coefficient under the indoor conditions is $0.13%/^{\circ}C$ while it reaches $2.73%/^{\circ}C$ at actual site conditions. When the indoor trends and site conditions is combined, the modified variable of torque coefficient can be expected as $0.2%/^{\circ}C$. and the modified variable of tension can be determined as $0.18%/^{\circ}C$.

• 한국구조물진단유지관리공학회 논문집
• /
• 제14권6호
• /
• pp.162-170
• /
• 2010

토크쉬어볼트의 토크계수는 환경요인에 의해 영향을 받는다. 습기, 녹, 시공중의 작업성 등. 토크쉬어볼트의 토크계수의 변동에 기인하여 볼트에 도입된 축력을 예측하는 매우 어렵다. 이런 이유로 시공중인 볼트 축력을 측정하고, 체결력을 검증하는 것은 필수적이다. 이 연구에서, 볼트에 도입된 하중을 확인하기 위해 시작품 제작이 계획되었다. 시작품의 알고리즘은 토크쉬어 전동렌치에서 얻은 전기에너지와 유압축력기에서 얻은 축력과의 상관관계를 구성한 것이다. 직접축력을 계측하는 회귀분석식은 미니탭 프로그램을 이용한 통계학적인 분석방법에서 구한 것이다. 이 시작품은 상용 토크렌치에 견줄만한 인장력을 평가하는 신뢰성이 있는 도구라고 판단된다.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제1권2호
• /
• pp.95-108
• /
• 2001

To enhance the corrosion resistance of a bolt by surface treatment, dacrotization was considered as a substitute for phosphate coating which is widely used for general applications. In this study, comparisons were made among 5 different kinds of surface treatments including dacrotization and phosphate coating with respect to corrosion resistance, adhesion property with painting, and preload when tightened. The result shows that the dacrotized and surface-stabilized bolt is much superior in every aspects studied herein to others. An excellent corrosion resistance and a fairly good adhesion property with painting were achieved in the dacrotized and surface-stabilized bolt. When tightened at the same torque, the amount of preload and its deviation of dacrotized and surface-stabilized bolt were comparable with those of phosphate coated bolt.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 추계학술대회 논문집
• /
• pp.1000-1004
• /
• 1995

In the case of the external cylindrical grinding machine, the grinding mechanism can cause a wheel to vibrate due to a wheel cutter. This phenomena will bring about the unsymmetric wear up to high frequency without any relation of rotational speed. So far, when the grinding spindle is analyzed, it is assumed that a wheel is considered as lumped mass at the endof a beam. Nowadays, there is a tendency to use the wheel with a lsrge diameter or CBN wheel to achieve the high speed and accuracy grinding performance. Therefore, this kind of assumption is no longer valid. At the analysis of the grinding spindle, the parameter which dapends on the dynamic characteristics is a combination force between each part. For example, there is the tightness torque of a bolt and taper element in the grindle. In addition, the material property of the wheel can contribute the dynamic characteristics. This paper shows the mode participation of the shell mode of the wheel in the grindle and the dynamic characteristics according to the parameters which are the configuration of the flange and tightness torque of a bolt and taper. Modal parameter of the wheel, flange and the spindle can be extracted through frequency response function obtained by modal test. After that, by changing the tightness torque and kinds of wheel, we could accomplish the test in the whole combined grinding spindle. To perform modal analysis of vibration characteristics in the grinding spindle, we could develop the model of finite element method.