• Journal of Korean Society of Steel Construction
• /
• v.8 no.3 s.28
• /
• 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.

• Journal of Auto-vehicle Safety Association
• /
• v.7 no.1
• /
• 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.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.3
• /
• pp.399-407
• /
• 2008

The clamping of torque shear bolt is based on KS B 2819. It was misunderstood that the tension force of the TS bolt was induced generally at the break of pin-tail specified. However, the clamping forces on slip critical connections do not often meet the intended tension, as it considerably varies due to torque coefficient dependent on temperature variables despite the break of the pin tail. In this study, the tension of torque shear bolts were compared with two types of high-strength hexagon bolts by temperature parameters from ${-10^{\circ}C}$ to ${50^{\circ}C}$. Torque shear bolts showed that the average clamping force increased to 20kN as the temperature increased. In case of galvanized high-strength hexagon bolts, the average clamping forces at $0^{\circ}C$, $20^{\circ}C$, $50^{\circ}C$ were recorded over standard bolt tension, 178kN, and the worst standard deviation was 50kN. In case of high-strength hexagon bolts, ave rage clamping forces increased as the temperature went up, and the worst standard deviation was 33kN lower than that of galvanized high-strength hexagon bolts. As for the turn-of-the-nut method, at nut rotation of ${90^{\circ}}$, two types of high-strength hexagon bolts did not met the intended design bolt in tension, 162kN.it is neccessary to re-evaluate the range of turn of nut, ${120^{\circ}{\pm}30^{\circ}}$.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.3
• /
• 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.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.3
• /
• 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.

• Journal of Satellite, Information and Communications
• /
• v.7 no.3
• /
• pp.94-98
• /
• 2012

In order to serve the exact torque clamping force, the torque measurement system use the curve fitting algorithm by the least square. The corrected least square curve fitting algorithm which suggested in this paper can surpport more exact clamping force for fastner in variable industry field using the torque. At first, This paper introduces mathematical modeling for curve fitting algorithm, and simulate it. As a result, the corrected least square algorithm have shown lower standard error value than that of the used algoritm with torque, and so this corrected least square algorithm prove high accuracy than nomal least square algorithm. The suggested algorithm will contribute to improvement of cost and safety on industry field with bolt clamping force for precision industry parts, electronics parts, aircraft, aerospace, etc.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.6 no.3
• /
• 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 $0.18%/^{\circ}C$.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.6
• /
• pp.162-170
• /
• 2010

The torque-coefficient of torque-shear type high-strength bolts is affected by the environmental factors, such as 'wet', 'rust', 'exposure to air' and workability during tightening high strength bolts. It is difficult to assume the direct tension induced into the bolt due to variation of torque-coefficient for torque-shear type high-strength bolts. Therefore, it is essential to measure tension loads of bolts and to verify the clamping force under construction. In this study, the manufacture of trial product was planned to identify the induced force into the bolts. The algorithm for a trial product was composed of the relation between electricity energy taken from torque shear wrench and tension force from hydraulic tension meter. The regression analysis equation to measure the direct tension was derived by statistical analysis using Minitab program. It is considered that the trial product is reliable tool to evaluate the tension force comparable to a commercial torque wrench.

• Journal of Applied Reliability
• /
• v.1 no.2
• /
• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• 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.