• Title/Summary/Keyword: SIF

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Delamination of a composite laminated under monotonic loading

  • Achache, Habib;Benzerdjeb, Abdelouahab;Mehidi, Abdelkader;Boutabout, Benali;Ouinas, Djamel
    • Structural Engineering and Mechanics
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    • v.63 no.5
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    • pp.597-605
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    • 2017
  • Our work aims to analyze using the finite element method the evolution of the stress intensity factor (SIF) parameter K of three laminated folded plates stacks [$+{\alpha}$, $-{\alpha}$], made of the same epoxy matrix and different reinforcement fibers (boron, graphite and glass). Our results show that the angle of orientation of the boron/epoxy composite has no great influence on the variation of the parameter KI. Compared to composite graphite/epoxy and glass/epoxy, the laminated composite boron/epoxy reduces more the SIF KI in the middle of the plate for angles $0^{\circ}{\leq}{\alpha}{\leq}30^{\circ}$.

Analysis of Crack Behavior of Brazed Interface in Dissimilar Materials using BEM (이종재 브레이징 계면에서의 균열거동 해석)

  • 오환섭;김시현;김성재;양인수
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.6
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    • pp.91-97
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    • 2002
  • Applications of brazing in the studying fields such as high-speed machining are very increasing in various industry fields. Therefore, applying to the fracture mechanics by numerical analysis method is very important to analyse the crack problem dissimilar materials in brazed interface. In this study, stress intensity factor(SIF) is analysed to investigate crack behavior on the crack tip of dissimilar materials in brazed interface such as a hardmetal and a HSS by two dimensional(2-D) BEM. Kelvin's solution was used as a fundamental solution in BEM analysis and stress extrapolation method was used to determine SIF.

Crack growth behavior in the lntegrally stiffened plates(1) -Numerical evaluation of SIF (일체형 보강판의 균열성장거동(I)-SIF의 수치해석)

  • Rhee, Hwan-Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.5
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    • pp.150-156
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    • 1997
  • Three dimensional finite element analysis was conducted to estimate the effect of shape parameters (plate width and thickness) on the stress intensity factor for crack in the integrally stiffened plate. Analysis was done for width ratios of 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, and thickness ratios of 2, 3, 4, 6. Based on these results, an empirical equation of geometry factor is formulated as a function of crack length and thickness ratio.

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Crack Growth Behavior in the Integrally Stiffened Plates(ll) - Experimental Evaluation of SIF- (일체형 보강판의 균열성장거동(II) - SIF의 실험해석 -)

  • Rhee, Hwan-Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.6
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    • pp.114-120
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    • 1997
  • To assess the validity of the previously computed finite element analysis results, the photoelastic experiment was carried out to determine stress intensity factors for crack originating from thin section of integrally stiffened plates having discontinuous thickness interface. The stress intensity factors were deter- mined by using linear slope method of photoelastic data. Results are presented as variable thickness geometry factor. $F_{IV}$ , for various crack lengths and thickness ratios. The experimental values of F/ sub IV/are compared with 3-D finite element analysis results. The correlation between experimental values and analysis results is resonably good.

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Finite element analysis of corner cracked aluminum panels repaired with bonded composite patch

  • Abdelkader Boulenouar;Mohammed A. Bouchelarm;Noureddine Benseddiq
    • Steel and Composite Structures
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    • v.49 no.3
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    • pp.271-280
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    • 2023
  • In this study, the three-dimensional finite element method is used to analyze the behavior of corner cracks in finite-thickness plates repaired with a composite patch. The normalized stress intensity factor at the crack front is used as fracture criterion. Comparison of stress intensity factor values at the internal and external positions of repaired quarter-elliptical corner crack was done, for three repair techniques. The influence of mechanical and geometrical properties of the adhesive layer and the composite patch on the variation of the stress intensity factor (SIF) at the crack-front was highlighted. The obtained results show that the application of double patch leads to a remarkable reduction of SIF at the crack front, compared to facial and lateral repairs.

Fracture analysis for nozzle cracks in nuclear reactor pressure vessel using FCPAS

  • Abdurrezzak Boz;Oguzhan Demir
    • Nuclear Engineering and Technology
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    • v.56 no.6
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    • pp.2292-2306
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    • 2024
  • This study addresses cracks and fracture problems in engineering structures that may cause significant challenges and safety concerns, with a focus on pressure vessels in nuclear power plants. Comprehensive parametric three-dimensional mixed mode fracture analyses for inclined and deflected nozzle corner cracks with various crack shape aspect ratios and depth ratios in nuclear reactor pressure vessels are carried out. Stress intensity factor (SIF) solutions are obtained using FRAC3D, which is part of Fracture and Crack Propagation Analysis System (FCPAS), employing enriched finite elements along the crack front. Also, improved empirical equations are developed to allow the determination of mixed mode SIFs, KI, KII, and KIII, for any values of the parameters considered in the study. This study provides practical solutions to assess the remaining life and fail-safe conditions of nuclear reactors by providing accurate SIF determination.

On the Fracture Behaviour of the Concrete Gravity Dam Subjected to Water Pressure at the Crack Faces (균열면에 수압을 받는 중력식 콘크리트 댐의 파괴거동에 관한 연구)

  • 장희석
    • Computational Structural Engineering
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    • v.9 no.4
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    • pp.189-198
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    • 1996
  • The fracture behaviour of concrete gravity dam mainly due to uplift pressure acting at the crack face was studied. Triangular type and parabolic type distribution of the uplift pressure including uniform type were first considered in case of calculating stress intensity factor(SIF) by the surface integral method. Second, the directions of crack propagation according to the uplift pressure distribution were pursued by FRANC(FRacture ANalysis Code). Third, critical crack lengths according to the uplift pressure distribution under the overflow depth were calculated. The SIF values obtained from the surface integral method were compared with those by FRANC and relatively good agrements could be obtained between both of them. And it could be seen that the direction of crack propagation in case of triangular pressure distribution was a little benter to the dam base than the one by the uniform type. Maximum critical crack lengths under the overflow depth were obtained at about 2/5-1/2 of the dam height.

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A Study of Risk Reduction by SIL(Safety Integrity Level) Determination (SIL(Safety Integrity Level) 선택에 의한 리스크 감소에 관한 연구)

  • Kim, Jung-Hwan;Kim, Bum-Su;Yang, Jae-Mo;Jang, Chang-Bong;Kim, Min-Seop;Jung, Sang-Yong;Ko, Jae-Wook
    • Journal of the Korean Institute of Gas
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    • v.15 no.5
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    • pp.57-62
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    • 2011
  • Modern chemical plants including petroleum refinery and gas industries have evolved into more complex and specialized. In these industrial complexes, it is important to maintain acceptable safety level protecting from various potential disasters caused by fire, explosion and the leakage of toxic materials. Recently possibility and consequence of accidents are increasing in the industrial process. So there is a trade-off between the plant operation efficiency and safety level. In this study SIF(Safety instrument Functions) was incorporated into SIL(Safety Integrity Levels). As a result, the safety level was upgraded by designing resonable allocation of safety instruments.

A Study on the Improvement of Reliability of Safety Instrumented Function of Hydrodesulfurization Reactor Heater (수소화 탈황 반응기 히터의 안전계장기능 신뢰도 향상에 관한 연구)

  • Kwak, Heung Sik;Park, Dal Jae
    • Journal of the Korean Society of Safety
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    • v.32 no.4
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    • pp.7-15
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    • 2017
  • International standards such as IEC-61508 and IEC-61511 require Safety Integrity Levels (SILs) for Safety Instrumented Functions (SIFs) in process industries. SIL verification is one of the methods for process safety description. Results of the SIL verification in some cases indicated that several Safety Instrumented Functions (SIFs) do not satisfy the required SIL. This results in some problems in terms of cost and risks to the industries. This study has been performed to improve the reliability of a safety instrumented function (SIF) installed in hydrodesulfurization reactor heater using Partial Stroke Testing (PST). Emergency shutdown system was chosen as an SIF in this study. SIL verification has been performed for cases chosen through the layer of protection analysis method. The probability of failure on demands (PFDs) for SIFs in fault tree analysis was $4.82{\times}10^{-3}$. As a result, the SIFs were unsuitable for the needed RRF, although they were capable of satisfying their target SIL 2. So, different PST intervals from 1 to 4 years were applied to the SIFs. It was found that the PFD of SIFs was $2.13{\times}10^{-3}$ and the RRF was 469 at the PST interval of one year, and this satisfies the RRF requirements in this case. It was also found that shorter interval of PST caused higher reliability of the SIF.

Hybrid Phenomena in Modern Sports-Inspired Fashion (현대 스포츠 인스파이어드 패션에 나타난 하이브리드)

  • Lee, Young-Min;Park, Jae-Ok
    • The Research Journal of the Costume Culture
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    • v.18 no.3
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    • pp.569-587
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    • 2010
  • In the field of fashion in this modern era, the tendency of diversification has created a variety of hybrid patterns and this tendency is being accelerated simultaneously by the hybrid trend. This research aims to analyze the aesthetic features of hybrid fashion in the modern "Sports Inspired Fashion(SIF)." We analyze fashion in the past 10 years from 2001 S/S to 2010 S/S. We focus on the four largest worldwide collections from New York, Paris, Milano, and London and concentrate on analyzing the contents from 38 volumes of Gap Press magazine. To accomplish our goal of study, we first define the concept of sports-inspired fashion and propose a framework of analysis to study hybrid patterns by reviewing the previous studies on hybrid patterns. Second, we analyze a wide range of sports-inspired fashion examples that have appeared in Gap Press magazines for the past 10 years(those which have been inspired by sports uniforms and training wears). Third, we analyze and classify the hybrid patterns of sports-inspired fashion. The results of our research are as follows. We have collected a total of 534 SIF works from the whole set of 61359 pictures and examined 23 sports fields. In terms of seasonal changes, the SIF works were found the most in the spring collections. Then, we have identified 25 hybrid patterns. The time hybrid pattern comprises more than half of the data(58.2%). The class-culture hybrid patterns comprise 18.8%, while the gender hybrid patterns comprise 18.2%. However, the intercultural hybrid patterns were rarely found, comprising merely 5% of the data. Our analysis confirms that sports and sports wear fashion are changing and developing in truly diverse ways in this modern era. This trend has continued to influence the high fashion in the modern age and is expected to exert a continuous impact on the change of fashion in the future.