• Title/Summary/Keyword: Fatigue Behavior

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Consumer confusion, shopping fatigue, and negative purchasing behavior in internet shopping environment (인터넷 쇼핑환경에서의 소비자 혼란과 쇼핑 피로감이 부정적 구매행동에 미치는 영향)

  • Kim, Jong-Ouk
    • The Research Journal of the Costume Culture
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    • v.29 no.4
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    • pp.505-521
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    • 2021
  • This study analyzed the effects of consumer confusion on shopping fatigue and negative purchasing behaviors in an internet shopping environment. Further, the effects of shopping fatigue on negative purchasing behaviors were analyzed. The survey was conducted among consumers in their 20s and 40s in the Seoul metropolitan area who had experience of purchasing fashion products through internet shopping. A total of 392 questionnaire were analysis, with frequency, reliability, factor, correlation, and regression analysis completed using the SPSS statistics program. The results of the study showed that consumer confusion and shopping fatigue in internet shopping environment affected negative purchasing behaviors. First, consumer confusion comprised overload confusion, similarity confusion, and ambiguity confusion. It was found that overload confusion and similarity confusion significantly affected shopping fatigue. Second, shopping fatigue significantly affected negative purchasing behaviors, and an increased level of shopping fatigue result in, increased purchase delay and non-purchase behavior. Third, consumer confusion (overload confusion, similarity confusion, ambiguity confusion) significantly affected purchase delay behavior, while similarity confusion and ambiguity confusion significantly affected non-purchasing behavior. These results will provide useful data for e-CRM and marketing directions of internet companies and will contribute to rational decision-making of internet consumers and improve the quality of consumer life.

Creep-Fatigue Crack Growth Behavior of a Structure with Crack Like Defects at the Welds

  • Lee, Hyeong-Yeon;Kim, Seok-Hoon;Lee, Jae-Han;Kim, Byung-Ho
    • Journal of Mechanical Science and Technology
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    • v.20 no.12
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    • pp.2136-2146
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    • 2006
  • A study on a creep-fatigue crack growth behavior has been carried out for a cylindrical structure with weldments by using a structural test and an evaluation according to the assessment procedures. The creep-fatigue crack growth behavior following the creep-fatigue crack initiation has been assessed by using the French A16 procedure and the conservatism for the present structural test has been examined. The structural specimen is a welded cylindrical shell made of 316 L stainless steel (SS) for one half of the cylinder and 304 SS for the other half. In the creep-fatigue test, the hold time under a tensile load which produces the primary nominal stress of 45 MPa was one hour at $600^{\circ}C$ and creep-fatigue loads of 600 cycles were applied. The evaluation results for the creep-fatigue crack propagation were compared with those of the observed images from the structural test. The assessment results for the creep-fatigue crack behavior according to the French Al6 procedure showed that the Al6 is overly conservative for the creep-fatigue crack propagation in the present case with a short hold time of one hour.

Effect of Single Overload on the Fatigue Crack Growth Behavior of Laser Welded Sheet Metal (단일 과대하중에 의한 레이저 용접 판재의 피로균열 전파거동)

  • 곽대순;김석환;오택열
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.4
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    • pp.161-169
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    • 2004
  • In this study, we investigated fatigue crack growth behavior of laser welded sheet metal due to a single overload. Fatigue specimens were made using butt joint of cold rolled sheet metal that was welded by $CO_2$ laser. The fatigue crack propagation tests were performed in such a way that fatigue loading was parallel to the weld line while crack propagation was perpendicular to the weld line. Single overload was applied when fatigue crack tip was arrived near the weld line. The distances between the crack tip and the weld line at which a single overload was applied were 6, 4 and 2mm. The effect of specimen thickness and overload ratio on the fatigue behavior was determined. The plastic zone size of crack tip due to the single overload was determined from the finite element analysis. For investigating fatigue crack growth behavior, we used different thickness specimen 0.9mm and 2.0mm, and variable overload ratio applied fatigue crack propagation test. Also we used finite element analysis for investigating the plastic zone size of crack tip when single overload applied

Fatigue Analysis of Spot Welded Joints in Suspension Mounting Part

  • Yum, Youung-Jin;Chu, Young-Woo;Chu, Seok-Jae;Kim, Jung-Han;Hee You
    • Journal of Mechanical Science and Technology
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    • v.17 no.8
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    • pp.1113-1119
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    • 2003
  • Experimental and numerical analyses were performed to characterize the fatigue behavior of spot welded joints in suspension mounting of a passenger car body. Static and fatigue tests were carried out for the tensile-shear and cross-tension specimens. S-N curve and fatigue strengths were obtained from the fatigue test of various specimens. Nonlinear finite element analysis showed that fatigue behavior of spot welded joints could be well estimated in terms of Von Mises stress at the nugget edge. Fatigue behavior of spot welded joint was represented by Von Mises stress better than the fatigue load.

Life Prediction by Retardation Behavior of Fatigue Crack and its Nondestructive Evaluation (피로균열의 지연거동에 따른 수명예측 및 비파괴평가)

  • Nam, Ki-Woo;Kim, Seon-Jin
    • Journal of Ocean Engineering and Technology
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    • v.13 no.3 s.33
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    • pp.36-48
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    • 1999
  • Fatigue life and crack retardation behavior after penetration were experimentally examined using surface pre-cracked specimens of aluminium alloy 5083. The Wheeler model retardation parameter was used successfully to predict crack growth behavior after penetration. By using a crack propagation rule, the change in crack shape after penetration can be evaluated quantitatively. Advanced, waveform-based acoustic emission (AE) techniques have been successfully used to evaluate signal characteristics obtained form fatigue crack propagation and penetratin behavior in 6061 aluminum plate with surface crack under fatigue stress. Surface defects in the structural members are apt to be origins of fatigue crack growth, which may cause serious failure of the whole structure. The nondestructive analysis on the crack growth and penetration from these defects may, therefore, be one of the most important subjects on the reliability of the leak before break (LBB) design. The goal of the present study is to determine if different sources of the AE could be identified by characteristics of the waveforms produced from the crack growth and penetration. AE signals detected in four stages were found to have different signal per stage. With analysis of waveform and power spectrum in 6061 aluminum alloys with a surface crack, it is found to be capabilities on real-time monitoring for the crack propagation and penetration behavior of various damages and defects in structural members.

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Influences of Fiber Laminate Orientation on the Behavior of Fatigue Delamination in GLARE (GLARE 의 섬유층 배향이 피로층간분리 거동에 미치는 영향)

  • 황진우;송삼홍;김철웅
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.479-482
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    • 2004
  • The behavior of fatigue delamination in a GLARE(Glass Fiber Reinforced Metal Laminates) under fatigue loading conditions investigated. The behavior of fatigue delamination was examined basing on investigation of the crack and delamination using a SAM (Scanning Acoustic Microscope). The crack and delamination behavior on the relationship among a-N, SAM images and crack length-delamination length were considered. The test results indicated the features of different fatigue delamination and crack growth according to each fiber orientation angle and also obtained to more increase delamination than crack through the relationship between crack length and delamination length in GLARE.

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Numerical Analysis for Prediction of Fatigue Crack Opening Level

  • Choi, Hyeon Chang
    • Journal of Mechanical Science and Technology
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    • v.18 no.11
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    • pp.1989-1995
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    • 2004
  • Finite element analysis(FEA) is the most popular numerical method to simulate plasticity-induced fatigue crack closure and can predict fatigue crack closure behavior. Finite element analysis under plane stress state using 4-node isoparametric elements is performed to investigate the detailed closure behavior of fatigue cracks and the numerical results are compared with experimental results. The mesh of constant size elements on the crack surface can not correctly predict the opening level for fatigue crack as shown in the previous works. The crack opening behavior for the size mesh with a linear change shows almost flat stress level after a crack tip has passed by the monotonic plastic zone. The prediction of crack opening level presents a good agreement with published experimental data regardless of stress ratios, which are using the mesh of the elements that are in proportion to the reversed plastic zone size considering the opening stress intensity factors. Numerical interpolation results of finite element analysis can precisely predict the crack opening level. This method shows a good agreement with the experimental data regardless of the stress ratios and kinds of materials.

Study on the Fatigue Behavior of a Joint between RC and SFRC Subjected to Shear (철도하중에 대한 철근 콘크리트와 강섬유 보강 철근 콘크리트 전단이음부의 피로거동에 관한 실험적 연구)

  • 강보순
    • Journal of the Korean Society for Railway
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    • v.3 no.4
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    • pp.194-202
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    • 2000
  • Fatigue behavior of shear joints between the combined reinforced concrete(RC) and the reinforced steel fiber concrete(SFRC) specimens has been experimentally investigated. Experimental parameters used are the amount of steel fiber and the type of shear joint. Six specimens have been tested under static load, and eight specimens have been subjected to the fatigue load in a range of 50 % and 5 % of the ultimate static load. The purpose of this research is to propose an empirical formula for fatigue shear behavior of the combined RC and SFRC structures on the basis of experimental result. It can be observed from experimental results that addition of steel fibers to concrete specimen increases the static ultimate load by approximately 25 %, enhances the fatigue behavior, and also reduces vertical and lateral displacements at the shear joint for a given load cycle after the occurrence of first crack.

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A Stochastic Study on Fatigue Crack Propagation and Retardation Behavior of Pressure Vessel Steel (압력용기용강의 피로균열전파 및 지연거동에 관한 확률통계적 연구)

  • 김선진;남기우;김부안
    • Journal of Ocean Engineering and Technology
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    • v.9 no.1
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    • pp.132-141
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    • 1995
  • The purpose of the present study is to investigate the statistical characteristics of m and C in the fatigue crack propagation law, da/dN=C(.DELTA.K)/sup m/ and to studies on the randomness of fatigue crack propagation and retardation behavior. Fatigue tests were perfomed on 32 CT specimens of SPV50 steel under the same one condition. First, the value of m and C were determined for each specimen, and all the data were analyzed statistically. second, the material's resistance to fatigue crack propagation is modeled as a stchastic process, which varies randomly along the crack path. The statistical analysis of the material resistance is performed with the data obtained by constant load controlled tests. Finally, retardation behavior was examined experimentally by using a CT specimen, and a retardation parameters were analyzed statistically.

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A Study on the High Temperature Fatigue Behavior of Hot Forging Die STD61 Steel (STD61 열간 금형강의 고온피로거동에 관한 연구)

  • 여은구;이태문;이용신
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.711-714
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    • 2002
  • Although recent research of metallic materials in high temperature fatigue have been much accomplished, many studies about brittle material as a die steel in high temperature fatigue does not have been reported. Especially, the study on the fatigue behavior over the transformation temperature is not studied sufficiently because of its difficult analysis and experiment. Therefore, reliable results of brittle material in high temperature fatigue behavior are needed. In this paper, stress-strain curves and stress-life curves in die STD61 steel at 700 and 900 are carefully examined, as the basic experimental data are used to predict from fatigue life over 700.

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