• Title, Summary, Keyword: failure mechanism

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A study on fatigue life of Al 7075/CFRP multilayered hybrid composite materials (Al 7075/CFRP 다적층 하이브리드 복합재료의 피로수명에 대한 연구)

  • 윤한기;김연겸;박준수;이경봉
    • Journal of Ocean Engineering and Technology
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    • v.10 no.4
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    • pp.92-102
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    • 1996
  • In this research, to develope the A1 7075/CFRP multilayered hybrid composites, CRALL(Carbon Reinforced aluminum lamiate) specimens were processed by autoclavecuring system that curing temperature, time, surface pretreatment condition of aluminum were constant. Andthe fatigye life and failure mechanism on CFRP volume fraction and fiber orientation of CRALLspecimens were investigated. A fatigue life was greatly influenced by effect of CFRP fiber volume fraction but it was less effected than those of fiber orientation. The fatigue failure arised from interface delamination of CFRP and aluminum sheet after shear fracture of aluminum layer. The failure mechanism is assumed that the aluminum laminates which divide the CFRP into many thim layers tend to arrest the failure propagation.

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Investigation of the thyristor failure mechanism induced by stress (Thyristor 소자의 스트레스에 따른 소자파괴 메커니즘 연구)

  • Kim, Hyoung-Woo;Seo, Kil-Soo;Kim, Sang-Cheol;Kang, In-Ho;Kim, Nam-Kyun;Kim, Ein-Dong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.129-130
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    • 2005
  • The electrical stress has a major effect on the long-term reliability of the thyristor. Therefore, it is needed to analyze the relationship between reliability and stress. In this paper, we investigate the device failure mechanism which induced by the stress. And also investigate the effect of the thermal stress on the device failure and relationship between electrical and thermal stress. Two-dimensional process simulator ATHENA and device simulator ATLAS are used to analyze the failure mechanism of the device.

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An Overview on Performamce Control and Efficient Design of Lateral Resisting Moment Frames

  • Grigorian, Mark;Grigorian, Carl E.
    • International Journal of High-Rise Buildings
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    • v.2 no.2
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    • pp.141-152
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    • 2013
  • This paper presents a brief overview of the recently developed performance-control method of moment frame design subjected to monotonously increasing lateral loading. The final product of any elastic-plastic analysis is a nonlinear loaddisplacement diagram associated with a progressive failure mechanism, which may or may not be as desirable as expected. Analytically derived failure mechanisms may include such undesirable features as soft story failure, partial failure modes, overcollapse, etc. The problem is compounded if any kind of performance control, e.g., drift optimization, material savings or integrity assessment is also involved. However, there is no reason why the process can not be reversed by first selecting a desirable collapse mechanism, then working backwards to select members that would lead to the desired outcome. This article provides an overview of the newly developed Performance control methodology of design for lateral resisting frameworks with a view towards integrity control and prevention of premature failure due to propagation of plasticity and progressive P-delta effects.

The effect of compression load and rock bridge geometry on the shear mechanism of weak plane

  • Sarfarazi, Vahab;Haeri, Hadi;Shemirani, Alireza Bagher
    • Geomechanics and Engineering
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    • v.13 no.3
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    • pp.431-446
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    • 2017
  • Rock bridges in rock masses would increase the bearing capacity of Non-persistent discontinuities. In this paper the effect of ratio of rock bridge surface to joint surface, rock bridge shape and normal load on failure behaviour of intermittent rock joint were investigated. A total of 42 various models with dimensions of $15cm{\times}15cm{\times}15cm$ of plaster specimens were fabricated simulating the open joints possessing rock bridge. The introduced rock bridges have various continuities in shear surface. The area of the rock bridge was $45cm^2$ and $90cm^2$ out of the total fixed area of $225cm^2$ respectively. The fabricated specimens were subjected to shear tests under normal loads of 0.5 MPa, 2 MPa and 4 MPa in order to investigate the shear mechanism of rock bridge. The results indicated that the failure pattern and the failure mechanism were affected by two parameters; i.e., the ratio of joint surface to rock bridge surface and normal load. So that increasing in joint area in front of the rock bridge changes the shear failure mode to tensile failure mode. Also the tensile failure change to shear failure by increasing the normal load.

Investigation on Failure Mechanism of Back-to-Back Geosynthethic Reinforced Wall Using Discrete Element Analysis (불연속체 해석을 이용한 Back-to-Back 보강토 옹벽의 파괴 메커니즘에 관한 연구)

  • Yoo, Chung-Sik;Woo, Seung-Je;Jeon, Hun-Min;Shin, Bu-Nam
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.2
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    • pp.55-66
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    • 2011
  • This paper presents the results of an investigation on the failure mechanism of geosynthetic reinforced soil walls in back-to-back configuration using 1-g reduced-scale model tests as well as discrete element method-based numerical investigation. In the 1-g reduced scale model tests, 1/10 scale back-to-back walls were constructed so that the wall can be brought to failure by its own weight and the effect of reinforcement length on the failure mechanism was investigated. In addition, a validated discrete element method-based numerical model was used to further investigate the failure mechanism of back-to-back walls with different boundary conditions. The results were then compared with the failure mechanisms defined in the FHWA design guideline.

Numerical Analysis on Progressive Failure of Plane Slopes (평면 사면의 점진적 파괴에 관한 수치해석)

  • 송원경;권광수
    • Tunnel and Underground Space
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    • v.7 no.1
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    • pp.31-38
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    • 1997
  • Residual shear strength should be taken into consideration as well as peak one when analysing stability of slopes constituted by weathered rock or overconsolidated soils since such materials could be subjected to progressive failure mechanism. When landslide of a slope is related to progressive failure phenomenon, the failure might occur even though shear strength of the slope materials does not reach their residual shear strength over the whole slip surface. Therefore, stability of the slope concerned may be overstimated or underestimated when using only its peak or residual shear srength parameters. Mechanical description for progressive failure phenomenon is given by Bjerrum(1967). In parameters. Mechanical description for progressive failure phenomenon is given by Bjerrum(1967). In this study, his theory has been extended to estimate the distance of failed zone for a plane slope and the results calculated by this extended equatio has been compared with that obtained by numerical modelling using FLAC. In addition, stress state on the slip surface has been, in detail, analysed to understand failure mechanism when a limited progressive failure occurs. Effects of mechanical and hydraulic factors on progressive failure have also been analysed.

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Investigation on the failure mechanism of steel-concrete steel composite beam

  • Zou, Guang P.;Xia, Pei X.;Shen, Xin H.;Wang, Peng
    • Steel and Composite Structures
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    • v.20 no.6
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    • pp.1183-1191
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    • 2016
  • The internal crack propagation, the failure mode and ultimate load bearing capacity of the steel-concrete-steel composite beam under the four-point-bend loading is investigated by the numerical simulation. The results of load - displacement curve and failure mode are in good agreement with experiment. In order to study the failure mechanism, the composite beam has been modeled, which part interface interaction between steel and concrete is considered. The results indicate that there are two failure modes: (a) When the strength of the interface is lower than that of the concrete, failure happens at the interface of steel and concrete; (b) When the strength of the interface is higher than that of the concrete, the failure modes is cohesion failure, i.e., and concrete are stripped because of the shear cracks at concrete edge.

Comparison on the Failure Mechanism of Punching Shear in the Reinforced Concrete (철근 콘크리트의 뚫림전단 파괴메카니즘에 과한 비교)

  • 이주나;연규원;이호준;박찬수
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.533-538
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    • 2000
  • In R.C. flat slab system, a brittle punching failure is a very fatal problem. But there is no generally well-defined answer to the problem and there are wide differences in current practical design codes. therefore, in this study, the factors affecting to punching failure mechanism have been studied to find out the punching shear behavior in R.C. flat slabs by comparing other investigations and practical design codes. Therefore, In this study, the factors affecting to punching failure mechanism have been studied to find out the punching shear behavior in R.C. flat slabs by comparing other investigations and practical design codes. The conclusions in this study are summarized as follows; 1) The factors affecting to punching shear are concrete strength ($f_\alpha$), ratio of column side length to slab depth (c/d), ratio of distance from column center to radial contraflexure (l/d), yield strength of steel ($f_y$), flexural reinforcement ratio ($\rho$) and size effects. 2) It is shown that th use of $\surd{f_{ck}}$in applying($f_\alpha$ to punching shear strength estimation may be more sensitive in high concrete strength. 3) The effects of l/d, ($f_y$, size are no clear in the punching failure mechanism, so in the future, it should be investigated with the effects of various composed load.

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