• 제목/요약/키워드: Yielding curve

검색결과 113건 처리시간 0.028초

비등방 압축의 선행재하를 받은 다짐풍화화강토의 항복거동 (Yielding Behavior of Compacted Decomposed Granitic Soil under Anisotropic Compression Previous Loading)

  • 정상국;강권수;양재혁
    • 한국구조물진단유지관리공학회 논문집
    • /
    • 제5권3호
    • /
    • pp.233-244
    • /
    • 2001
  • Stress-strain behaviour of soil varies based on stress path and stress history. There has been few study on the characteristics of yielding curve which has anisotropic compression stress history in decomposed granite soil. During this study, various stress path tests in previous anisotropic compression stress history are performed on compacted decomposed granite soil sampled at Iksan, Chonbuk. Yielding points are determined from various stress-strain curves (${\eta}-{\varepsilon}$, ${\eta}$-v, and ${\eta}$-k, ${\eta}$-W curves). Stress-strain curve is certified which shows yielding point very clearly. The shape and characteristics of anisotropic compression yielding curves are examined. The main results are summarized as follows : 1) p' constant and compressive direction in stress paths, which has experienced previous anisotropic compression stress history, shows relatively dear yielding points. 2) Yielding curves defined from ${\eta}$-k and ${\eta}$-W curve show almost perfect ellipse. 3) Directions of plastic strain incremental vector($dv^p/d{\varepsilon}^p$) are not perpendicular to yielding curve.

  • PDF

등방 및 비등방 압밀된 다짐풍화화강토의 항복곡선 (Yielding Curve of Isotropic and Anisotropic Consolidated Compacted Weathered Granite Soil)

  • 정진섭;양재혁
    • 한국농공학회지
    • /
    • 제44권1호
    • /
    • pp.103-115
    • /
    • 2002
  • During this study, various stress path tests in previous isotropic and anisotropic (compression and tension) stress histories are performed on weathered granite soil sampled at Iksan, Jeonbuk. Yielding points are determined from various stress-strain curves(stress ratio-shear strain, volumetric strain, normalized energy and dissipated total energy curves). The shape and characteristics of isotropic and anisotropic yielding curves are examined. The main results are summarized as follows . 1) Yielding curries defined from stress ratio - normarized energy and dissipated total energy curves show almost perfect ellipse. 2) Directions of plastic strain incremental vector are not perpendicular to yielding curve. 3) Normarized energy and dissipated total energy spread with similar tendency with respect to yielding currie in stress space.

비등방 압밀된 다짐화강풍화토의 응력-변형률 거동 예측 (Prediction of Stress-strain Behavior for Anisotropic Consolidated Compacted Decomposed Granite Soil)

  • 정진섭;양재혁
    • 한국농공학회지
    • /
    • 제45권2호
    • /
    • pp.86-95
    • /
    • 2003
  • During this study, constant stress ratio tests with previous compression anisotropic stress history are performed on compacted decomposed granite soil sampled at Iksan, Jeonbuk. Yielding points are determined from stress-strain curves. The shape and characteristics of compression anisotropic yield curves is examined. In addition, the measured value of yielding curve and stress-strain behavior is predicted by Yasufuku's anisotropic constitutive model based on non-associated flow rule. The main results are summarized as follows : 1) Shape of yielding curves shows almost ellipse but asymmetry with respect to stress path during previous consolidation stress. 2) Yasufuku's anisotropic constitutive model is suitable in evaluation of yielding curves on anisotropic consolidated decomposed granite soil. 3) The predicted stress-strain curve shows reasonable agreement to measured behaviours.

장흥해성토의 항복특성 연구 (A study on the yielding characteristics for Jangheung marine clay)

  • 장병욱;이경호;우철웅
    • 한국농공학회:학술대회논문집
    • /
    • 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
    • /
    • pp.575-581
    • /
    • 1999
  • Yielding is an important feature of the stress-strain behavior of clays. This study was performed to estabilish the yielding curves and properties for a marine caly from Jangheung. Chonnam Province . A series of tests was done by means of the various stress path tests. Results of the tests are as follows ; 1) The laboratory -determined Ko is very similar to that applied to the Jaky equation. 2) The shape of yielding curve is nealry symmetrical about the p' axis like other natural clays. 3) The critical state parameters, Mc and Me are the same for compression and extension tests which contrasts with the results of the isotropically consolidated soils. 4) The state boundary suface using the critical state paratmers can resresent the normalized yielding curve obtained by various stress path experiments.

  • PDF

원공결함을 갖는 SM45C 인장시험편의 강도해석과 음향방출에 관한 사례연구 (Case Study on the Load-Deflection and Acoustic Emission Analysis of SM45C Coupons with a Circular Hole Defect under Tensile Loading)

  • 우창기;이장규
    • 한국공작기계학회논문집
    • /
    • 제17권1호
    • /
    • pp.50-58
    • /
    • 2008
  • The SM45C metallic coupons have been tested under static tensile loading with acoustic emission (AE) as the load-deflection curve mainly. In this study, we used AE to detect the yielding of material and AE techniques was applied to rapidly estimate the mechanical characteristics of a material. First, coupons without an artificial defect were tested at different cross-head speed. For all cases in this analysis, yielding point of SM45C coupons did not appear definitely compared to mild steel, whereas coupons start to generate AE counts upon yielding. So all cases are normalized to know the possibility of accelerated life test of a material. And next, coupons with different from sizes of circular hole defects were tested at the same cross-head speed of 5 mm/min. Results were classified into 3 classes and analyzed by AE amplitude & signal strength as a function of time. Summarizing the specific conclusions, we need to additional research considering plate with width-ratio in order to estimate the fracture mechanism.

강 압축 부재의 잔류응력에 따른 기둥강도곡선의 비탄성영역에 대한 해석적 고찰 (An Analytical Review on the Inelastic Region of Column Strength Curve Associated with Residual Stress of Steel Member under Axial Force)

  • 시상광
    • 한국구조물진단유지관리공학회 논문집
    • /
    • 제22권2호
    • /
    • pp.161-168
    • /
    • 2018
  • 이 연구는 CRC기둥강도곡선의 비탄성영역에 대한 해석적 고찰이다. CRC기둥강도곡선의 비탄성영역은 최대 잔류응력 크기 $0.5{\sigma}_y$와 Bleich이론을 기초로 하고 있다. 이는 실제로 알려진 최대 압축 잔류응력의 크기가 $0.3{\sigma}_y$인 경우 보다 다소 보수적이다. 본 연구는 열압연강재의 최대 압축 잔류응력의 크기를 $0.3{\sigma}_y$으로 고려하여 그에 따른 기둥강도곡선과 접선탄성계수 Et를 제안하고 이를 CRC에서 제안하고 있는 값들과 각각 비교 고찰한다. 축 압축력을 받는 비탄성 기둥의 응력은 기둥에 작용하는 하중이 좌굴을 일으키기 전에 재료의 비례한도를 넘어 항복점에 도달할 것이다. 따라서 점차적인 단면의 항복 상태에 따른 기둥강도곡선을 검토할 필요가 있다. 본 연구는 최대 압축 잔류응력 ${\sigma}_r=0.5{\sigma}_y$을 사용하여 재료의 항복에 따른 임계하중 곡선식을 유도하고 이를 CRC기둥강도곡선과 비교 고찰한다.

A numerical investigation of the tensile behavior of the thread-fixed one-side bolted T-stubs at high temperature

  • You, Yang;Liu, Le;Jin, Xiao;Wang, Peijun;Liu, Fangzhou
    • Steel and Composite Structures
    • /
    • 제45권4호
    • /
    • pp.605-619
    • /
    • 2022
  • The tensile behavior of the Thread-fixed One-side Bolt (TOB) at high temperatures was studied using the Finite Element Modeling (FEM) to explore the structural responses that could not be measured in tests. The accuracy of the FEM was verified using the test results from the failure mode, load-displacement curve as well as yielding load. Three typical failure modes of TOB connected T-stubs were observed, which were the Flange Yielding (FY), the Bolt Failure (BF) and the Coupling Failure mode (CF). The influence of the flange thickness tb and the temperature θ on the tensile behavior of the T-stub were discussed. The initial stiffness and the yielding load decreased with the increase of the temperature. The T-stubs almost lost their resistance when the temperature exceeded 700℃. The failure modes of T-stubs were mainly decided by the flange thickness, which relates to the anchorage of the hole threads and the bending resistance of flange. The failure mode could also be changed by the high temperature. Design equations in EN 1993-1-8 were modified and verified by the FEM results. The results showed that these equations could predict the failure mode and the yielding load at different temperatures with satisfactory accuracy.

A simplified evaluation method of skeleton curve for RC frame with URM infill

  • Jin, Kiwoong;Choi, Ho
    • Earthquakes and Structures
    • /
    • 제13권3호
    • /
    • pp.309-322
    • /
    • 2017
  • In this paper, a simplified evaluation method of the skeleton curve for reinforced concrete (RC) frame with unreinforced masonry (URM) infill is proposed in a practical form, based on the previous studies. The backbone curve for RC boundary frame was modeled by a tri-linear envelope with cracking and yielding points. On the other hand, that of URM infill was modeled by representative characteristic points of cracking, maximum, and residual strength; also, the interaction effect between RC boundary frame and the infill was taken into account. The overall force-displacement envelopes by the sum of RC boundary frame and URM infill, where the backbone curves of the infill from other studies were also considered, were then compared with the previous experimental results. The simplified estimation results from this study were found to almost approximate the overall experimental results with conservative evaluations, and they showed much better agreement than the cases employing the infill envelopes from other studies.

Seismic performance of mixed column composed of square CFST column and circular RC column in Chinese archaized buildings

  • Xue, Jianyang;Zhou, Chaofeng;Lin, Jianpeng
    • Steel and Composite Structures
    • /
    • 제29권4호
    • /
    • pp.451-464
    • /
    • 2018
  • This paper presents some quasi-static tests for 4 mixed columns composed of CFST column and RC column. The seismic performance and failure mode were studied under low-cyclic revised loading. The failure mode was observed under different axial compression ratios. The hysteretic curve and skeleton curve were obtained. The effects of axial compression ratio on yield mechanism, displacement ductility, energy dissipation, stiffness and strength attenuation were analyzed. The results indicate that the failure behavior of CFST-RC mixed column with archaized style is mainly caused by bending failure and accompanied by some shear failure. The axial compression ratio performs a control function on the yielding order of the upper and lower columns. The yielding mechanism has a great influence on the ductility and energy dissipation capacity of specimens. Based on the experiment, finite element analysis was made to further research the seismic performance by ABAQUS software. The variable parameters were stiffness ratio of upper and lower columns, axial compression ratio, yielding strength of steel tube, concrete strength and rebar ratio. The simulation results show that with the increase of stiffness ratio of the upper and lower columns, the bearing capacity and ductility of specimens can correspondingly increase. As the axial compression ratio increases, the ductility of the specimen decreases gradually. The other three parameters both have positive effect on the bearing capacity but have negative effect on the ductility. The results can provide reference for the design and engineering application of mixed column consisted of CFST-RC in Chinese archaized buildings.