• 대한토목학회논문집
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• 제11권3호
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• pp.59-65
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• 1991

본 연구에서는 국내 고속도로의 표준단면들을 포함한 포장구조 해석모델을 사용하여 아스팔트 콘크리트 포장체의 피로파괴 기준식을 개발하였다. 해석 대상 모델은 쇄석 및 아스팔트 안정처리 기층을 갖는 2430개의 4충 포장구조로 하였으며, 각 모델의 물성을 공용성 한계를 PSI=2.5로 한 AASHTO 설계식과 다층 탄성해석 프로그램인 SINELA에 적용, 포장체의 통과예상 교통량과 아스팔트 콘크리트층 하단에서의 최대 인장 변형률과의 관계를 회귀분석하였다. 분석 결과로부터, 신뢰도 50%와 95% 수준의 파괴기준식을 제안하였다. 타 연구결과와 비교한 결과 신뢰도 95% 수준의 파괴기준식은 균열의 발생을 공용성 한계로 보는 기존의 피로 파괴기준식과 같은 정도의 교통량을 추정하고 있음을 알 수 있었다. 또한 신뢰도 수준에 따른 파괴기준식을 신뢰도 50%, 수준의 파괴기준식으로부터 간접 추정할 수 있는 관계식을 제안하였다.

• Geomechanics and Engineering
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• 제15권6호
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• pp.1183-1191
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• 2018

Reliability analysis is generally regarded as the most appropriate method when uncertainties are taken into account in slope designs. With the help of limit analysis, probability evaluation for three-dimensional rock slope stability was conducted based upon the Mote Carlo method. The nonlinear Hoek-Brown failure criterion was employed to reflect the practical strength characteristics of rock mass. A form of stability factor is used to perform reliability analysis for rock slopes. Results show that the variation of strength uncertainties has significant influence on probability of failure for rock slopes, as well as strength constants. It is found that the relationship between probability of failure and mean safety factor is independent of the magnitudes of input parameters but relative to the variability of variables. Due to the phenomenon, curves displaying this relationship can provide guidance for designers to obtain factor of safety according to required failure probability.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권4호
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• pp.280-286
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• 2016

Purpose: Recently, Jiang defines the tradeoff B life to minimize a sum of life lost by preventive maintenance (PM) and corrective maintenance (CM) contribution parts and sets up an optimal replacement age of age replacement policy as this tradeoff life. In this paper, Jiang's model only considering the known lifetime distribution is extended by assigning different weights to two parts of PM and CM in order to reflect the practical maintenance situations in application. Methods: The new age replacement model is formulated and the meaning of a weight factor is expressed with the implied cost of failure under asymptotic expected cost model and also discussed with one-cycle expected cost criterion. Results: The proposed model is applied to Weibull and lognormal lifetime distributions and optimum PM replacement ages are derived with corresponding implied cost of failure. Conclusion: The new age replacement policy to escape the estimation of cost of failure in classical asymptotic expected cost criterion based on the renewal process is provided.

• 한국세라믹학회지
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• 제34권2호
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• pp.157-162
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• 1997

소결온도 및 열처리에 의하여 미세조직을 변화시킨 질화규소의 파괴강도특성 및 그 신뢰성 평가를 하였다. 결정립이 클수록 파괴인성치는 증가하였지만 굽힘강도는 저하하였다. 균열재의 파괴응력 $\sigma$c와 등가균열길이 ae와의 관계는 프로세스 존 크기 파기기준에 의한 계산 결과와 매우 잘 일치하였다. 그리고 굽힘파괴응력 $\sigma$F와 파괴인성치 KIC의 통계적 특성을 고려한 파괴평가고건을 제안하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 추계학술발표대회 논문집
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• pp.98-101
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• 2000

Recently, composite material which has much excellent mechanical characteristics has been applied in many industries. However, it has a brittle characteristic under impact condition and its invisible characteristics of the damaged area has been the motivation of many engineers investigation. The modified failure criterion is implemented to predict the failure behavior of the composite plate subjected to low velocity impact using commercial finite element analysis code, ABAQUS-Ver. 5.8. The new criterion is in good agreement with experimental results and can predict the failure behavior of the composite plate subjected to low velocity impact more accurately.

• 대한기계학회논문집
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• 제16권7호
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• pp.1285-1293
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• 1992

본 연구에서는 glass/epoxy 직조된 복합재료에 있어서 원공 및 판폭의 크기가 노치강도에 미치는 영향을 명확히 하고, 또한 노치강도 및 파괴조건과 위에서 언급한 특성길이와의 관계를 검토하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.600-605
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• 2004

The road construction with horizontal expansion of country using and augmentation of traffic demand is advanced actively and it accompanies hereupon, the above of 70% of the country is formed at the mountain in our country where the hazard cut slope has been created. In this study, It is prepared a effective management countermeasure of cut slope introduced priority investigation decision method against hazard cut slope which is influenced by abnormally rainfall by an unusual change in the weather such as a guerilla rainfall character. In meaning link, It was executed collapse cause by failure character analysis in the cut slope which has failed for the last five years and it is prepared the hazard grade criterion from E to A grade according to collapse cause. It is decided that a maintenance management grade by the hazard grade classification criterion of cut slope. So It is possible to hazard cut slope. It is established failure protection counter countermeasure by effective maintenance management through the hazard grade c1assification criterion and it will be able to dispose to advanced nation level like Hong Kong and Japanese.

• 대한기계학회논문집A
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• 제31권3호
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• pp.304-312
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• 2007

The objective of this study is to develop a local failure criterion for a wall thinning defect of piping components. For this purpose, a series of tensile tests was performed using several types of simulated specimens with different stress states, including smooth round bar, notched round bar (five different notch radii), and grooved plate (three different groove radii). In addition, finite element (FE) simulations were performed on the simulated specimen tests and the results were compared with the test results. From the comparisons, the equivalent stress and strain corresponding to maximum load and final failure of notched specimens were proposed as failure criteria under tensile load. The criteria were verified by employing them to the estimation of failure of grooved plate specimens that simulate the wall thinning defect. It showed that the proposed criteria accurately estimate the maximum load and final failure of grooved plate specimen tests.

• Computers and Concrete
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• 제28권6호
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• pp.585-603
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• 2021

The validation based on the experimental data demonstrates that the concrete strength under triaxial compression (TC) is overestimated by Lubliner-Oller strength criterion (SC) but underestimated by Lubliner-Lee SC in ABAQUS. Moreover, the discontinuous derivatives of failure criterion exists near the unexpected breakpoints. Both resulted from the piecewise linear meridians of the original Lubliner SC with constants γ. Following the screen for the available failure criteria to determine the model parameter γ of Lubliner SC, Menétrey-Willam SC (MWSC) is considered the most promising option with a reasonable aspect ratio Kc but no other strength values required and only two new model parameters introduced. The failure surface of the new Lubliner SC based on MWSC (Lubliner-MWSC) is smooth and has no breakpoints along the hydrostatic pressure (HP) axis. Finally, predicted results of Lubliner-MWSC are compared with other concrete failure criteria and experimental data. It turns out that the Lubliner-MWSC can represent the concrete failure behavior, and MWSC is the optimal choice to improve the applicability of the concrete damaged plasticity model (CDPM) under TC in ABAQUS.

• 한국지반공학회지:지반
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• 제19권6호
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• pp.26-38
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• 2003