• Title, Summary, Keyword: Progressive Failure

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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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Development of Progressive Failure Analysis Method for Composite Laminates based on Puck's Failure Criterion-Damage Mechanics Coupling Theories (Puck 파손기준-손상역학 연계이론을 활용한 적층 복합재료의 점진적 파손해석기법 개발)

  • Lee, Chi-Seung;Lee, Jae-Myung
    • Journal of the Society of Naval Architects of Korea
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    • v.52 no.1
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    • pp.52-60
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    • 2015
  • In the present study, an evaluation method for progressive failure of composite laminates has been proposed based on Puck's failure criterion and damage mechanics. The initial failure (or initiation of crack/delamination) has been assessed using Puck's failure criterion, and the progressive failure (or growth of crack/delamination) has been evaluated using fiber- and matrix-dependent damage variables. Based on Puck's failure criterion-damage mechanics coupling theories, the ABAQUS user-defined subroutine UMAT has been developed in order to analyze the progressive failure of glass/carbon fiber-reinforced composite laminates efficiently. In addition, the developed subroutine has been applied to progressive failure problem of industrial composite laminates, and the analysis results has been compared to experimental results which have been already reported in publications. It was confirmed that the simulation results were coincided well with the reported composite failure results.

Multi-scale Progressive Failure Analysis of Triaxially Braided Textile Composites

  • Geleta, Tsinuel N.;Woo, Kyeongsik
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.3
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    • pp.436-449
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    • 2017
  • In this paper, the damage and failure behavior of triaxially braided textile composites was studied using progressive failure analysis. The analysis was performed at both micro and meso-scales through iterative cycles. Stress based failure criteria were used to define the failure states at both micro- and meso-scale models. The stress-strain curve under uniaxial tensile loading was drawn based on the load-displacement curve from the progressive failure analysis and compared to those by test and computational results from reference for verification. Then, the detailed failure initiation and propagation was studied using the verified model for both tensile and compression loading cases. The failure modes of each part of the model were assessed at different stages of failure. Effect of ply stacking and number of unit cells considered were then investigated using the resulting stress-strain curves and damage patterns. Finally, the effect of matrix plasticity was examined for the compressive failure behavior of the same model using elastic, elastic - perfectly plastic and multi-linear elastic-plastic matrix properties.

Progressive Failure Analysis and Strength Prediction based on Hashin Failure Criterion of Bolted Composite Joint (Hashin 파손이론을 이용한 복합재 볼트체결부의 점진적 파손 해석 및 강도 예측)

  • Kim, Seongmin;Kim, Pyunghwa;Doh, Sungchul;Kim, Hyounggun;Park, Jungsun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.936-938
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    • 2017
  • In this paper, the progressive failure analysis of a bolted composite joint which is used in combustion tubes of projectiles and weapon systems is performed. Hashin's failure criterion is considered as fiber tensile failure mode, fiber compressive failure mode, matrix tensile failure mode, and matrix compressive failure mode for this analysis. And this criterion is used to make user subroutine, UMAT. Through the progressive failure analysis we predicted failure strength and compared failure strength with specimen test result.

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Type-II stepwise progressive censoring

  • Bayat, Mohammad;Torabi, Hamzeh
    • Communications for Statistical Applications and Methods
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    • v.23 no.1
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    • pp.57-70
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    • 2016
  • Type-II progressive censoring is one of the censoring methods frequently used in clinical studies, reliability trials, quality control of products and industrial experiments. Sometimes in Type-II progressive censoring experiments, the failure rate is low so the waiting time to observe the $m^{th}$ failure will be very long; however, the experimenter may have to terminate the experiment before a predetermined time. In this article, if two generalized types of Type-II progressive censoring are reminded, we then make some changes in the removal method of Type-II progressive censoring such that without reducing the deduction quality, the termination time of the experiment decreases. This can be done with decreasing withdraws throughout the steps of the experiment with a special reasonable method. A simulation study is done and the results are tabulated at the end of this article for a comparison between introduced method and Type-II progressive censoring.

Considerable Parameters and Progressive Failure of Rock Masses due to the Tunnel Excavation (터널 굴착시 고려해야 할 주변앙반의 매개변수와 진행성 파괴)

  • 임수빈;이성민
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.231-234
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    • 1994
  • Concentrated stresses due to the tunnel excavation easily cause failure around opening in the soft rock mass layer. Thus, while excavatng tunnel in the soft rock mass layerm it is very important to predict the possibility of failure or yielding zones around tunnel boundary. There are two typical methods to predict these; 1) the analysis of field monioring data and 2) numerical analysis. In this study, it was attempted to describe the time-dependent or progressive rock mass manner due to the continuous failure and fracturing caused by surrounding underground openings using the second method. In order to apply the effects of progressive failure underground, an iterative technique was used with the Hoek and Brown rock mass failure theory. By developing and simulating, three different shapes of twin tunnels, this research simulated and estimated the proper size of critical pillar width between tunnels, distributed stresses on the tunnel sides, and convergences of tunnel crowns. Moreover, results out progressive failure technique based on the Hoek and Brown theory were compared with the results out of Mohr-Coulomb theory.

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Numerical analysis of Bearing Capacity and Progressive Failure of Footings (기초지반의 지지력 및 진행성 파괴에 대한 수치해석)

  • 김영민
    • Geotechnical Engineering
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    • v.13 no.6
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    • pp.139-146
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    • 1997
  • The failure of footing generally involves the concentration of deformation into one or more narrow bands. With the displacement of the footing, the failure plane will subsequently form The purpose of this paper is to assess the capabilities of numerical techniques to predict bearing capacity and progressive failure of footings. By using the method of large deformation theory and strain softening we have investigated the progressive failure of strip footing on undrained clay. This paper describes the procedure to predict the entire loadfisplacement curve and the failure mechanism of strip footing. The presented results show that it is Possible to analyze the Post Peak behavior of strip footing numerically and to give a progressive failure mechanism clearly.

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Complex failure mechanism of rock slopes (암반 사면의 복합 파괴 메커니즘 규명)

  • Yoon, Woon-Sang;Jeong, Ui-Jin;Park, Sung-Wook;Choi, Jae-Won
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.268-273
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    • 2006
  • Slope failures can be occurred by complex mechanism. In this cases, failures shows characteristics of complex failure mechanism during progressive mass movements. A case is a merged large slide with two sliding events triggered by slip on fault plane. Another case shows extension of failure area by sliding or subsidence at backyards of toppling areas. Generally, areas of progressive failures have wider than them of simple events.

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Study on Strain Localization and Progressive Failure of Concrete (콘크리트의 변형률 국소화 및 진행성 파괴에 관한 연구)

  • 송하원;김형운;우승민
    • Journal of the Korea Concrete Institute
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    • v.11 no.3
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    • pp.181-192
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    • 1999
  • The progressive failure following strain localization in concrete can be analyzed effectively using finite element modeling of fracture process zone of concrete with a finite element embedded discontinuity. In this study, a finite element with embedded discontinuous line is utilized for the analysis of progressive failure in concrete. The finite element with embedded discontinuity is a kind of discrete crack element, but the difficulties in discrete crack approach such as remeshing or adding new nodes along with crack growth can be avoided. Using a discontinuous shape function for this element, the displacement discontinuity is embedded within an element and its constitutive equation is modeled from the modeling of fracture process zone. The element stiffness matrix is derived and its dual mapping technique for numerical integration is employed. Then, a finite element analysis program with employed algorithms is developed and failure analysis results using developed finite element program are verified through the comparison with experimental data and other analysis results.

Progressive collapse resistance of flat slabs: modeling post-punching behavior

  • Mirzaeia, Yaser;Sasani, Mehrdad
    • Computers and Concrete
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    • v.12 no.3
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    • pp.351-375
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    • 2013
  • Post-punching resistance of a flat slab can help redistribute the gravity loads and resist progressive collapse of a structure following initial damage. One important difficulty with accounting for the post-punching strength of a slab is the discontinuity that develops following punching shear. A numerical simulation technique is proposed here to model and evaluate post-punching resistance of flat slabs. It is demonstrated that the simulation results of punching shear and post-punching response of the model of a slab on a single column are in good agreement with corresponding experimental data. It is also shown that progressive collapse due to a column removal (explosion) can lead to punching failure over an adjacent column. Such failure can propagate throughout the structure leading to the progressive collapse of the structure. Through post-punching modeling of the slab and accounting for the associated discontinuity, it is also demonstrated that the presence of an adequate amount of integrity reinforcement can provide an alternative load path and help resist progressive collapse.