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하중 비전달형 면외 거셋판이 부착된 강교량 부재의 피로강도
우상익,정경섭,Woo, Sang Ik,Jung, Kyoung Sup 한국강구조학회 1998 韓國鋼構造學會 論文集 Vol.10 No.4
본 논문은 강교량 부재에 번번하게 사용되는 용접상세로 비교적 낮은 피로강도를 보이는 부재에 대해 실험과 해석적 연구를 수행하였다. 측정응력을 고려해보면, 피로균열은 복부에 연결되는 거셋판의 필렛용접 지단부에서 시작하였으며, 용접단면의 기하학적 조건과 불연속성으로 인하여 집중응력이 발생하는 것으로 나타났다. 비드단면의 기하학적 형상을 고려한 FEM 모델의 해석결과와 동일한 위치에서 게이지에 의한 측정응력은 둘다 비슷한 수준의 응력집중이 용접지단부에서 발생하고 있음을 보여주고 있다. 피로실험 결과를 AASHTO와 JSSC의 피로설계기준과 비교한 결과, 80mm와 150mm 부착 시험편 모두에서 AASHTO의 D와 E등급, JSSC의 F와 G등급을 만족하거나 상회하는 것으로 나타났다. 또한, WG1와 WG3 시험편은 AASHTO와 JSSC의 S-N선도 보다 완만한 -0.3의 기울기를 갖는 것으로 나타났다. This paper presents the results of the experimental and analytical investigation for the fatigue strength of welded details frequently used in steel bridges, especially for the details with relatively lower fatigue strength. Considering the measured stress fatigue cracking initiated at toe of the transverse fillet weld joining the gusset plates to the web because of the stress concentration that developed as a result of the geometric conditions and the greater probability of microscopic discontinuities at the fillet weld toe A comparison was made of the stress calculated by considering geometric aspect of bead and measured at same position. They indicate that the geometric conditions of the weld toe result in similar stress concentration on both FEM models and test results. The test results were compared with the fatigue criteria of AASHTO, JSSC specifications. Specimens of 80 and 150mm gusset plate configuration tested either respectively equaled or exceeded the fatigue resistance provided by category D and E of the AASHTO specification. It also satisfied the category F and G of JSSC. Both WG1 and WG3 specimen tend to provide S-N curves with a store near -0.3 less than AASHTO and JSSC.
김현성,우상익,정경섭,Kim, Hyun Sung,Woo, Sang Ik,Jung, Kyoung Sup 한국강구조학회 2000 韓國鋼構造學會 論文集 Vol.12 No.2
본 연구는 유한요소법을 이용해서 시간이력 열전도해석과 열탄성해석을 통해 필렛용접 이음부에서의 잔류응력분포를 측정하였다. 필렛용접은 1패스 용접이며, 경계조건으로는 표면유속조건과 온도에 의존하는 재료의 특성치를 고려하여 잔류응력을 평가하였다. 여기서, 용접입열양을 변수로 하였다. 그리고, 열탄성해석에 의해 잔류응력 평가할 때 중요한 문제로 언급되고 있는 cut-off 온도 설정에 대해 조사하였다. 또한, 시험체에서 구멍뚫기 방법에 의해 잔류응력분포를 측정하여 유한요소법에 의한 잔류응력분포와 비교하였다. 그 결과, 용접부에서는 재료의 항복강도 수준에 해당하는 인장잔류응력이 측정되었으며, 유한요소해석에 의한 수치해석 결과는 구멍뚫기 방법에 의한 측정치 및 다른 연구자의 측정치와 비교적 일치하는 것으로 나타났다. 그리고, Cut-off 온도는 재료의 항복강도가 나타나는 온도로 설정하는 것이 효과적임을 알 수 있었다. A transient heat transfer analysis and thermo-elastic analysis have been performed for the residual stress distribution on the fillet weldment used by finite element method. Specimen is fabricated single-pass fillet welding. This computation was performed for conditions including surface heat flux and temperature dependent thermo-physical properties using by heat input as parameter. Also, cut-off temperature of residual stress estimation by thermo-elastic analysis is determined. The fillet weldment were measured to determined their residual stress distributions for using hole-drilling method. As result, it was found that large tensile residual stress is about material yield strength, and the numerical simulation results for finite element method similar to residual stresses by hole-drilling method and other exiting research. Also, cut-off temperature is effectively determined by temperature which calculated maximum thermal stress equal to material yield strength.
배수갑문 테인터 게이트(Tainter Gate)의 진동현상에 관한 모형실험(Ⅱ)- 문비 안에서 밖으로의 흐름 -
이성행,우상익,Lee , Seong-Haeng,Woo , Sang-Ik 한국농공학회 2004 한국농공학회논문집 Vol.46 No.2
A model test is carried out to investigate flow-induced vibration of a Tainter gate in estuary sulices. The gate model scaled with the ratio of 1:25 is made of acryl panel dimensioned 0.66 m in width, 0.5 m in height in the concrete test flume. Firstly, natural frequencies of the model gate are measured and the results are compared with the numerical results in order to verify the model. In the flow from the gate inside to the gate outside, the amplitudes of the vibration are measured under the different gate opening and downstream water level conditions. Also revised gate models with 20 mm bottom width are tested under the different gate openings and water levels. The results are analyzed to study the characteristics of the Tainter gate vibration in the sea ward flow. These test results are assessed in comparison with the results in the lake ward flow, as a result, presents the dynamic characteristics of the Tainter gate and a basic data for the guide manuals of gate management.
전제상,우상익,이성행,정경섭,JUN, Je Sang,WOO, Sang Ik,LEE, Seong Heang,JUNG, Kyoung Sup 한국강구조학회 1996 韓國鋼構造學會 論文集 Vol.8 No.3
H/T(High Tension) bolt is generally being used in joining the members of steel structure. It has some difficulties in management such as an adequate fastening force and a selection of proper instrument for fastening. T/S(Torque Shear Type High Tension) bolt which is more convenient and easier than H/T bolt in quality control has recently been developed. T/S bolts are produced and widely used these days in domestic, but those have not a detail regulation for their on. Those are only being used according to the specification for the H/T bolts. In this study, we tried to confirm the soundness of T/S bolts by the fatigue test of the modified specimens. First, we measured the reduction rate of the initial axial force with time at bolts. Second, we investigated the slip forces of bolts when the test specimen is loaded in tension. Third, we implemented the fatigue tests. During the test, we measured the variation of the axial forces of bolts under the cyclic loading. Finally, we compared and analyzed the fatigue behavior of H/T and T/S bolt, by S-N curve diagrams that are obtained in this study.
전제상(Je Sang Jun),우상익(Sang Ik Woo),이성행(Seong Heang Lee),정경섭(Kyoung Sup Jung) 한국강구조학회 1996 韓國鋼構造學會誌 Vol.8 No.2
H/T(High Tension) bolt is generally being used in joining of members of steel structure. But it has some difficulties in management such a adequate fastening force, a selection of proper instrument for fastening. T/S (Torque Shear type) bolt which is more convenient and easier in quality control has recently been developed. As H/T bolts, T/S bolts are also producted and widely used in the country. But those are now being used only according to the specification for the H/T bolts without a detail regulation. In this study, we attempted to confirm the soundness of T/S bolts by the fatigue test of the modified specimens. First, measured the reduction rate of the initial axial force in bolts with time, second, we investigated the slip forces of bolts when the test specimen is loaded in tension. In the last step, we implemented the fatigue tests, and during the testing, also measured the variation of the axial forces of bolts at the cyclic loading. Finally, we compared and analyzed successfully the fatigue behavior of H/T and T /S bolt by S-N curve diagram.