• Title, Summary, Keyword: Damage behavior

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Global Behavior Analyses of Rock Mass Structures with Defects Using Damage Tensor (Damage Tensor를 이용한 손상된 암반구조체의 거동해석)

  • 이상호;이형기;허용학;김재철
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.133-140
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    • 2000
  • The objective of this study is to develop a damage model based on damage mechanics that can be used to analyze the mechanical behavior of structures with defects and the global behavior of damaged structures. A modified second order damage tensor that can be applied to finite element analysis is used to reflect the effect of damage. The damage stress computed from the effective stress is considered as an additional loading term acting on nodes and can represent the effect of crack surface. The accuracy of the proposed algorithm is verified by comparing the analysis results with the experimental data from other studies and the analysis results based on transverse isotropic theory. The developed damage model is applied to the analyses of structures with cracks under linear elastic condition. Numerical results show that the developed model can effectively analyze the global behavior of damaged structures.

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Sensitivity analysis of mechanical behaviors for bridge damage assessment

  • Miyamoto, Ayaho;Isoda, Satoshi
    • Structural Engineering and Mechanics
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    • v.41 no.4
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    • pp.539-558
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    • 2012
  • The diagnosis of bridge serviceability is carried out by a combination of in-situ visual inspection, static and dynamic loading tests and analyses. Structural health monitoring (SHM) using information technology and sensors is increasingly being used for providing a better estimate of structural performance characteristics rather than above traditional methods. Because the mechanical behavior of bridges with various kinds of damage can not be made clear, it is very difficult to estimate both the damage mode and degree of damage of existing bridges. In this paper, the sensitivity of both static and dynamic behaviors of bridges are studied as a measure of damage assessment through experiments on model bridges induced with some specified artificial damages. And, a method of damage assessment of bridges based on those behaviors is discussed in detail. Finally, based on the results, a possible application for structural health monitoring systems for existing bridges is also discussed.

Global Behavior Analyses of Structures with Damages Using a Modified Second Order Damage Tensor (수정된 2차손상텐서를 이용한 손상된 구조체의 거동해석)

  • 이상호;이형기;허용학
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.13 no.2
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    • pp.257-270
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    • 2000
  • The objective of this study is to develop a damage model based on damage mechanics that can be used to analyze the mechanical behavior of structures with defects and the global behavior of damaged structures. A modified second order damage tensor that can be applied to finite element analysis is used to reflect the effect of damage. The damage stress computed from the effective stress is considered as an additional loading term acting on nodes and can represent the effect of crack surface. The accuracy of the proposed algorithm is verified by comparing the analysis results with the experimental data from other studies and the analysis results based on transverse isotropic theory. The developed damage model is applied to the analyses of structures with cracks under linear elastic condition. The comparisons confirmed that the quantitative analysis of the structural behavior due to crack orientation and multiple sets of cracks is possible. Also, the damage caused by rock excavation and fault zone is analyzed. The results also showed that the developed model can effectively analyze the global behavior of damaged structures.

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Transient dynamic analysis of impact damage behavior for concrete (콘크리트의 순간동역학적 충돌손상 거동해석)

  • Park, Tae-Hyo;Noh, Myung-Hyun
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.857-860
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    • 2006
  • In the present study, the method and procedure for analysis of impact damage behavior for concrete under penetration and perforation of projectile is investigated. Conservation law, equation of motion, initial and boundary conditions, and FEM formulation are introduced and derived respectively. Specially, the constitutive equation which rate-dependent damage combined with rate-dependent plasticity within the appropriate framework of theory of thermodynamics is examined. This paper aimed at the review with respect to impact damage models for concrete to develop that model. This paper is a basis research for the development of impact damage model for concrete.

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Elastoplastic Behavior and Progressive Damage of Circular Fiber-Reinforced Composites (원형섬유강화 복합재료의 탄소성거동 및 점진적 손상)

  • Lee, Haeng Ki;Kim, Bong Rae
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.1A
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    • pp.115-123
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    • 2008
  • The performance prediction of fiber-reinforced composites has attracted engineer's attention in many fields, and the various theoretical and numerical methods have been proposed to predict the behavior of the fiber-reinforced composites. An evolutionary damage model for progressive interfacial debonding between circular fibers and the matrix is newly incorporated into the micromechanics-based elastoplastic model proposed by Ju and Zhang (2001) in this framework. Using the proposed model, a series of numerical simulations are conducted to illustrate the elastoplastic behavior and evolutionary damage of the framework. Furthermore, the influence of the evolutionary interfacial debonding on the behavior of the composites is investigated by comparing it with the result of a stationary damage model.

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Rate-dependent Viscoplastic-Damage Model of Concrete under Cyclic Loading (반복하중을 받는 콘크리트의 재하속도 의존 점소성-손상 모델)

  • 송하원;임현우;김인순
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.468-473
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    • 1998
  • The objective of this paper is to develop a consistent algorithm for the finite element analysis for behavior of concrete under cyclic loading using viscoplastic-damage model. For modeling the behavior of concrete under cyclic loading, consistent algorithms of rate-dependent viscoplastic-damage are employed with a Willam-Warnke 5-parameter failure criterion which can consider the softening behavior of concrete and consistent tangent moduli are derived. Using finite element program implemented with the developed algorithms, the algorithms are verified and the behaviors of concrete under cylic loading are simulated and compared with experimental data.

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A Study on the Impact Behavior and Damage of Laminated Composite Plates Subjected to the Low-Velocity Impact (저속 충격을 받는 적층판의 충격거동과 손상에 관한 연구)

  • Ahn, Kook-Chan;Kim, Kyu-Su;Park, Seung-Bum;Hwang, Byung-Sun
    • Journal of the Korean Society of Safety
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    • v.17 no.1
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    • pp.6-10
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    • 2002
  • This paper presents the impact behavior and damage of laminated composite plates subjected to low-velocity impact. For this purpose, a pendulum impact test for impact behavior and C-scan for impact damage are done. Test materials are carbon/epoxy laminated composite plates and stacking sequences $[0/90_4\;[0/45_2/-45]_s,\;[0/45/-45/90]_s$ and [0/26/51/77/-77/-51/-26/0].

Effects of tendon damage on static and dynamic behavior of CFTA girder

  • Vu, Thuy Dung;Lee, Sang Yoon;Chaudhary, Sandeep;Kim, Dookie
    • Steel and Composite Structures
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    • v.15 no.5
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    • pp.567-583
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    • 2013
  • Experimental studies and finite element analyses have been carried out to establish the effect of tendon damage on the structural behavior of concrete filled tubular tied arch girder (CFTA girder). The damage of tendon is considered in different stages by varying the number of damaged cables in the tendon. Static and dynamic structural parameters are observed at each stage. The results obtained from the experiments and numerical studies have been compared to validate the studies. The tendons whose damage can significantly affect the stiffness of the CFTA girder are identified by performing the sensitivity analysis. The locations in the girder which are sensitive to the tendon damage are also identified.

Seismic Margin Analysis of Reinforced Concrete Pier Using Damage Model Proceedings (손상모형을 이용한 철근 콘크리트 교각의 지진여유도 해석)

  • 고현무;이지호;정우영;조호현
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.220-227
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    • 2002
  • This study introduces the fragility analysis method for the safety evaluation of reinforced concrete pier subject to earthquake. Damage probability is calculated instead of the failure probability from definition of the damage state in the fragility curve. Not only the damage model determined by the response of structure subject to earthquake, but also the plastic-damage model which can represent the local damage is applied to fragility analysis. The evaluation method of damage state by damage variable in global structure is defined by this procedure. This study introduces the fragility analysis method considering the features of nonlinear time history behavior of reinforced concrete element and the plastic behavior of materials. At last, This study gives one of the approach method for seismic margin evaluation with the result of fragility analysis to design seismic load.

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Fatigue Damage Assessment for Steel Structures Subjected to Earthquake (지진에 대한 강구조물의 피로손상도 추정법)

  • Song, Jong Keol;Yun, Chung Bang;Lee, Dong Guen
    • Journal of Korean Society of Steel Construction
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    • v.9 no.1
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    • pp.95-105
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    • 1997
  • Structures subjected to strong seismic excitation may undergo inelastic deformation cycles. The resulting cumulative fatigue damage process reduces the ability of structures and components to withstand seismic loads. Yet, the present earthquake resistance design methods focus mainly on the maximum displacement ductility, ignoring the effect of the cyclic responses. The damage parameters closely related to the cumulative damage need to be properly reflected on the aseismic design methods. In this study, two cumulative damage assessment methods derived from the plastic fatigue theory are investigated. The one is based on the hysteretic ductility amplitude, and the other is based on the dissipated hysteretic energy. Both methods can consider the maximum ductility and the cyclic behavior of structural response. The validity of two damage methods has been examined for single degree of freedom structures with various natural frequencies against two different earthquake excitations.

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