• Title, Summary, Keyword: 비선형 거동

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A Study on Behavior of Anisotrpic Circular Cylingdrical Shell including Large Deformation Effects (대변형 효과를 고려한 비등방성 원통형 쉘의 거동에 관한 연구)

  • Chun, Kyoung Sik;Son, Byung Jik;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.14 no.4
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    • pp.489-497
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    • 2002
  • Nonlinear behavior and large deformation cannot be analyzed using techniques based on linear theory. Nonetheless, they are emerging as gradually huge and complex structures. In addition, the optimum design of structure is necessary in the development of high-performance computation and numerical methods. as well as stricter design-criterion. Therefore, the structural problems in engineering that are limited to the linear region must be extended to the nonlinear region. Likewise, structural behavior must be accurately analyzed. In turn, this requires considering the expected problems beforehand. Only then can an efficient, economical, and optimized structure be designed. This paper presents the solution of the geometrical nonlinear problem of anisotropic cylindrical shell. The characteristics of the geometrical nonlinear behavior of anisotropic circular cylindrical shells may vary according to several causes. e.g., change of fibers, curvature in the circumferential direction, subtended angle, aspect, etc. Parametric studies were conducted to determine the effect of factors on the large deflection behavior of laminated shells, with interesting observations.

A Behavior Analysis in the Circular Hybrid Subminiture Energy Harvesting Device (순환형 하이브리드 초소형 에너지 수확장치에서의 거동 해석)

  • Bae, Young-Chul
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.11
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    • pp.1691-1696
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    • 2013
  • In this paper, an analysis of behavior is performed in the circular hybrid energy harvesting device. This analysis of behavior is to confirm with or without an existence of nonlinear system because its system is required to produce the more energy. To do this, first of all the phase portrait is reconstructed through Taken's embedding method, and then Poincare map is organized by using phase portrait and finally Lyapunov exponent is analyzed.

A Computational Platform for Nonlinear Analysis of Prestressed Concrete Deep Beams (프리스트레스트 콘크리트 깊은 보의 비선형해석을 위한 전산플랫폼)

  • Kim, Tae-Hoon;Kim, Young-Jin;Shin, Hyun-Mock
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.734-737
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    • 2010
  • 이 연구에서는 프리스트레스트 콘크리트 깊은 보의 비선형해석을 위한 전산플랫폼을 개발하였다. 프리스트레스트 콘크리트 깊은 보의 전단거동을 정확하게 파악하고 합리적이면서 경제적인 설계기준의 개발을 위한 자료를 제공하는데 그 목적이 있다. 재료적 비선형성에 대해서는 균열콘크리트에 대한 인장, 압축, 전단모델과 콘크리트 속에 있는 철근모델을 조합하여 고려하였다. 사용된 부착 또는 비부착 텐던요소는 유한요소법에 근거하며 프리스트레스트 콘크리트 부재의 콘크리트와 텐던의 상호작용을 구현할 수 있다. 이 연구에서는 프리스트레스트 콘크리트 깊은 보의 전단거동을 파악하기 위해 제안한 해석기법을 신뢰성 있는 연구자의 실험 결과와 비교하여 그 타당성을 검증하였다.

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Modified Earthquake resistant design for a concrete bridge in the Low to moderated seismic Region (중약진지역에 위치한 콘크리트교량의 수정내진 설계)

  • 국승규
    • Journal of the Earthquake Engineering Society of Korea
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    • v.4 no.3
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    • pp.11-21
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    • 2000
  • 구조물에 내진설계를 적용하는 목적은 지진에 노출되는 구조물에 안전성과 경제성을 고려한 파괴메카니즘을 부여하는 것이다. 내진설계에 보편적으로 적용하고 있는 응답스펙트럼해석법은 선형해석법으로 구조물의 비선형 동적거동에 의한 영향은 특정 계수로 반영한다. 그러나 기존의 내진설계시방서들이 강진지역에 있는 나라들에 의해 제정 및 개정되어 왔기 때문에 응답스펙트럼 해석법 뿐만 아니라 기타의 적용규정이 강진지역에 위치한 구조물의 상황만을 고려하여 제시되었다. 따라서 중약진지역에 위치한 구조물의 내진설계에 대한 별도의 연구가 요구되고 있다. 이 연구에서는 중약진지역에 위치한 콘크리트 교량을 선정하여 비선형 동적거동을 반영하는 계수를 결정하고 응답스펙트럼 해석법을 적용하였다. 연구 결과 바탕으로 중약진지역의 교량에 대해 내진설계의 목적을 만족하는 개선된 내진설계 절차를 제시하였다.

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Dynamic Analysis of Geometric Nonlinear Behavior of Suspension Bridges under Random Wind Loads (랜덤풍하중에 대한 현수교의 기하학적 비선형 거동의 동적해석)

  • Yun, Chung Bang;Hyun, Chang Hun;Yoo, Je Nam
    • Journal of The Korean Society of Civil Engineers
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    • v.8 no.2
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    • pp.185-196
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    • 1988
  • In this study, a method of nonlinear dynamic analysis of suspension bridges subjected to random wind loads is pre.sented. The nonlinearity considered is the one due to the interaction between the motion of the bridge girder and the tertsion variation of the main cables. The equation of motion is formulated using a continuum approach. The coupling between the vertical and torsional motions are included in the analysis. The equation of motion is solved by using the mode superposition method. The analysis is carried out in the frequency domain utilizing the stochastic linearization technique on to the modal equations. In the linearization procedure, the nonlinear terms are approximated as linear ones with constant terms. The verification of the method has been performed on a case with four modal degrees of freedom. Example analyses are carried out on two suspension bridges for various wind speeds and wind force parameters. Numerical results indicate that, by including the nonlinearity into the analysis, the dynamic responses of the bridges, particularly in the vertical direction, change considerably.

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Analysis of Behavior of Metal Plate Connection by Nonlinear Finite Element Method (비선형 유한요소법을 이용한 메탈 플레이트 접합부의 거동해석)

  • Hyun, Jae-Hyuk;Kun, Gwang-Chul;Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.27 no.3
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    • pp.23-30
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    • 1999
  • have been many studies to analyze the behavior of metal plate connector that most widely used to connect light frame wood trusses. Finite element method{FEM) was one of the methods for those studies. FEM using linear model may well be applicable to predict the initial slope of load-displacement curve for metal plate connection. However, displacement may be overestimated above experimental results with the increase of load. Therefore, linear model cannot be used for the nonlinear behavior part. To predict real behavior more exactly, nonlinear term was included to FEM model in this study. It was found out that EA and AA mode showed the high agreement between predicted results and experimental ones. However, EE and AE mode showed a little difference between predicted results and experimental ones in nonlinear part. This results might be caused by insufficient reflection of the slip effect. Consequently, the effect of slip shall be considered to approve the accuracy of nonlinear analysis for the behavior of metal plate connection.

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Papers : Snap - through Phenomena on Nonlinear Thermopiezoelastic Behavior of Piezolaminated Plates (논문 : 압전적층판의 비선형 열압전탄성 거동에서의 스냅 - 스루 현상)

  • O,Il-Gwon;Sin,Won-Ho;Lee,In
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.1
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    • pp.36-43
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    • 2002
  • Thermopiezoelastic snap-through phenomena of piezolaminated plates are investigated by applying an are-length scheme to Newton-Raphson method. Based on the layerwise displacement theory and von Karman strain-displacement relationships, nonlinear finite element formulations are derived for the thermopiezoelastic composite plates. From the static and dynamic viewpoint, nonlinear thermopierzoelastic behavior and vibration characteristicx are stuied for symmetric and eccentric structural models with various piezoelestric actuation modes. Present results show the possibility to enhance the performance, namely thermopiezoelastic snapping, induced by the excessive piezoelectric actuation in the active suppression of thermally buckled large deflection piezolaminated paltes.

거시적 방법(Marcroscopic Approach)을 이용한 전단벽체의 비선형 해석모델

  • 이영욱
    • Computational Structural Engineering
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    • v.6 no.1
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    • pp.44-49
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    • 1993
  • 이 글에서는 거시적 모델을 사용하여 전단벽체를 수치모델하는 방법에는 여러가지의 방법이 있으며 각기 그 모델들에는 장점과 단점을 지니고 있음을 보았다. 거시적 모델로 구조물을 해석하는 경우에는 전단벽체의 모델과 그에 맞는 반복이력모델의 선정에 주의하여야 한다. 이는 전단벽체의 파괴양상과 비선형거동 등의 복잡한 거동을 한개의 모델을 가지고 일률적으로 적용하지 못한다는 거시적 모델의 한계점 때문이다. 그러나 아직까지 계산기의 발전과 미시적 모델의 한계점을 고려한다면 구조물 비선형해석시 최선의 선택은 미시적 방법보다는 거시적 방법이라하겠다. 거시적 모델을 사용하여 구조물의 3차원 해석 프로그램을 개발한 예를 보았듯이, 3차원 비선형거동까지 고려한다면 거시적방법이 적당하리라고 판단된다.

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Finite Element Simulation of Hysteretic Behavior of Structural Stainless Steel under Cyclic Loading (반복하중을 받는 스테인리스강의 이력거동 해석모델 개발)

  • Jeon, Jun-Tai
    • Journal of the Society of Disaster Information
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    • v.15 no.2
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    • pp.186-197
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    • 2019
  • Purpose: This study intends to develop a nonlinear cyclic plasticity damage model in the framework of finite element formulation, which is capable of taking large deformation effects into account, in order to accurately predict the hysteretic behavior of stainless steel structures. Method: The new cyclic constitutive equations that utilize the combined isotropic-kinematic hardening rule for plastic deformation is incorporated into the damage mechanic model in conjunction with the large strain formulation. The damage growth law is based on the experimental observations that the evolution of microvoids yields nonlinear damage accumulation with plastic deformation. The damage model parameters and the procedure for their identification are presented. Results and Conclusion: The proposed nonlinear damage model has been verified by simulating uniaxial strain-controlled monotonic and cyclic loading tests, and successfully applied to a thin-walled stainless steel pipe subjected to constant and alternating strain-controlled cyclic loadings.

Seismic analysis of tunnel considering the strain-dependent shear modulus and damping ratio of a Jointed rock mass (절리암반의 변형률 의존적 전단탄성계수 및 감쇠비 특성을 고려한 터널의 내진 해석)

  • Song, Ki-Il;Jung, Sung-Hoon;Cho, Gye-Chun;Lee, Jeong-Hark
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.12 no.4
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    • pp.295-306
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    • 2010
  • Contrary to an intact rock, the jointed rock mass shows strain-dependent deformation characteristics (elastic modulus and damping ratio). The maximum elastic modulus of a rock mass can be obtained from an elastic wave-based exploration in a small strain level and applied to seismic analyses. However, the assessment and application of the non-linear characteristics of rock masses in a small to medium strain level ($10^{-4}{\sim}0.5%$) have not been carried out yet. A non-linear dynamic analysis module is newly developed for FLAC3D to simulate strain-dependent shear modulus degradation and damping ratio amplification characteristics. The developed module is verified by analyzing the change of the Ricker wave propagation. Strain-dependent non-linear characteristics are obtained from disks of cored samples using a rock mass dynamic testing apparatus which can evaluate wave propagation characteristics in a jointed rock column. Using the experimental results and the developed non-linear dynamic module, seismic analyses are performed for the intersection of a shaft and an inclined tunnel. The numerical results show that vertical and horizontal displacements of non-linear analyses are larger than those of linear analyses. Also, non-linear analyses induce bigger bending compressive stresses acting on the lining. The bending compressive stress concentrates at the intersection part. The fundamental understanding of a strain-dependent jointed rock mass behavior is achieved in this study and the analytical procedure suggested can be effectively applied to field designs and analyses.