• Structural Engineering and Mechanics
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• 제4권1호
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• pp.9-23
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• 1996

The behaviour of elasto-plastic planar arches subjected to dynamic loads in presented. The governing equations are formulated through the dynamic equations and compatibility conditions. The latter is established by applying the generalized conjugate segment analogy. Bending moments at the nodes and axial forces in the members are considered as primary variables in the elastic regime. They are supplemented by the rotations at the nodes and dislocations in the elements when plastic hinges occur. Newmark-${\beta}$ method is adopted in the time marching process. The interaction diagram of each element is treated as the yield surface for the element and the associated flow rule is enforced as plastic flow occurs. The method provides good prediction of dynamic response of elasto-plastic arches while requiring small core storage and short computer time.

• Earthquakes and Structures
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• 제7권3호
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• pp.333-347
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• 2014

Multi-scale model can take both computational efficiency and accuracy into consideration when it is used to conduct elasto-plastic seismic response analysis for complex steel bridges. This paper proposed a method based on pushover analysis of member sharing the same section pattern to verify the accuracy of multi-scale model. A deck-through type steel arch bridge with a span length of 200m was employed for seismic response analysis using multi-scale model and fiber model respectively, the validity and necessity of elasto-plastic seismic analysis for steel bridge by multi-scale model was then verified. The results show that the convergence of load-displacement curves obtained from pushover analysis for members having the same section pattern can be used as a proof of the accuracy of multi-scale model. It is noted that the computational precision of multi-scale model can be guaranteed when length of shell element segment is 1.40 times longer than the width of section where was in compression status. Fiber model can only be used for the predictions of the global deformations and the approximate positions of plastic areas on steel structures. However, it cannot give exact prediction on the distribution of plastic areas and the degree of the plasticity.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.169-172
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• 2015

This paper presents a numerical investigation on kerosene-air mixture detonation and behaviors of thermal elasto-plstic thin metal tube under detonation loading based on multi-material analysis. The detonation loading is modeled by the kerosene-air mixture detonation which is compared with CJ condition and experimental cell size. And the thermal softening effect on elasto-plstic model of metal tube is indicated by different dynamic response of detonation loaded tube in various temperature and tube thickness.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.507-512
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• 1997

The objective of present paper is to provide the fundamental data of earthquake-resistance design such as estimating the resistance capacity and evaluating the design seismic load. With one bending failed building, it is checked and compared between real damaged result and analysis value by means of static and dynamic analysis using multi-degree of freedom system. In this analysis, four kinds of the earthquake waves are used. Through elasto-plastic seismic response analysis of reinforced concrete building, we could estimate dynamic behaviour of building.

• Structural Engineering and Mechanics
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• 제32권1호
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• pp.21-36
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• 2009

An importance sampling method is presented for computing the first passage probability of elasto-plastic structures under stochastic excitations. The importance sampling distribution corresponds to shifting the mean of the excitation to an 'adapted' stochastic process whose future is determined based on information only up to the present. A stochastic control approach is adopted for designing the adapted process. The optimal control law is determined by a control potential, which satisfies the Bellman's equation, a nonlinear partial differential equation on the response state-space. Numerical results for a single-degree-of freedom elasto-plastic structure shows that the proposed method leads to significant improvement in variance reduction over importance sampling using design points reported recently.

• Structural Engineering and Mechanics
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• 제14권4호
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• pp.455-472
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• 2002

The paper involves the study on the elastic and elasto-plastic stress wave propagation in the 1-D and 2-D solid media. The Smooth Particle Hydrodynamics equations governing the elastic and elasto-plastic large deformation dynamic response of solid structures are presented. The proposed additional stress points are introduced in the formulation to mitigate the tensile instability inherent in the SPH approach. Both incremental rate approach and leap-frog algorithm for time integration are introduced and the new solution algorithm is developed and implemented. Two examples on stress wave propagation in aluminium bar and 2-D elasto-plastic steel plate are included. Results from the proposed SPH approach are compared with available analytical values and finite element solutions. The comparison illustrates that the stress wave propagation problems can be effectively solved by the proposed SPH method. The study shows that the SPH simulation is a reliable and robust tool and can be used with confidence to treat transient dynamics such as linear and non-linear transient stress wave propagation problems.

• Journal of Hydrospace Technology
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• 제1권1호
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• pp.111-124
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• 1995

An improved analysis model for material nonlinearity induced by elasto-plastic deformation and damage including a large strain response was proposed. The elasto-plastic-damage constitutive model based on the continuum damage mechanics approach was adopted to overcome limitations of the conventional plastic analysis theory. It can manage the anisotropic tonsorial damage evolved during the time-independent plastic deformation process of materials. Updated Lagrangian finite element formulation for elasto-plastic damage coupling problems including large deformation, large rotation and large strain problems was completed to develop a numerical model which can predict all kinds of structural nonlinearities and damage rationally. Finally a finite element analysis code for two-dimensional plane problems was developed and the applicability and validity of the numerical model was investigated through some numerical examples. Calculations showed reasonable results in both geometrical nonlinear problems due to large deformation and material nonlinearity including the damage effect.

• 한국지반공학회지:지반
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• 제13권4호
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• pp.85-94
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• 1997

지하공간에 대한 설계 및 시공시에는 필연적으로 많온 불확정성이 내포되어 있다. 가장 중요 한 요소로는 설계단계 에서 입력 값으로 사용하는 지반계수이며, 이의 정 확한 산정 에는 많은 어려 움이 따른다. 특히, 지하공동의 굴착으로 인해 소성영역이 발생하게 되면, 지반거동은 항복규준 을 결정짓는 강도정수에 민감한 반응을 나타내므로 탄성해석법에만 근거한 역 해석기법의 적용 으로는 신뢰성 있는 지반계수를 추정할 수 없게 된다. 본 논문에서는 지하공간의 설계와 시공의 유기적인 결합으로 터널의 소성상태까지 고려할 수 있는 최적의 지반계수를 산정하기 위하여, 초기예측치와 계측치로부터 예측된 값을 합리적으로 조합할 수 있는 확장 Bayesian방법(Extended Bayesian Method:EBM)을 적용하였다. 지반 조합 거동 예측은 Mohr-Coulomb 항복규준에 근거한 탄.소성 유한요소해석법을 사용하였다. 개발된 피드백 시스템의 효용성을 검증하기 위하여 소성 거동을 나타내는 단면에 대해 예제해석을 수행하였다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.91-97
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• 2002

Total stress analysis method and nonlinear constitutive models have been used to analyze a dynamic performance of Dams but, there is some limitation in analysis, for example, effects of build up of pore pressure and generations of permanent deformations. Therefore considering these limitations, which is mentioned before, dynamic behavior characteristics of dams and response acceleration characteristics was analyzed in time domain, applying an elasto-plastic constitutive model and effective analysis method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.746-752
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• 2001

Design sensitivity analysis for nonlinear structural problems has been emerged in the last decade as a glowing area of engineering research. As a result, theoretical formulations and computational algorithms have already developed for design sensitivity of nonlinear structural problems. There is not enough research for practical nonlinear problems using multi-element, due to difficulties of implementation into FEA. Therefore, nonlinear response analysis for stiffened shell which consists of Mindlin plate and Timoshenko beam, was considered. Specially, it presents the backward-Euler method which is adopted to describe an exact yield state in the stress computation procedure. Then, design sensitivity analysis of nonlinear structures, particularly elasto-perfectly-plastic structure, is developed using direct differentiation method. The accuracy of the developed sensitivity analysis was compared with the central finite difference method. Finally, on the basis of above results, design improvement for stiffened shell is suggested.