• Title/Summary/Keyword: Overload effect

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A Study on Fatigue Crack Growth Retardation Phenomena of Al 7075--T6 Alloy under Multiple overload(I) (다중 과하중에 의한 A1 7075-T6 합금의 피로균열 성장지연현상에 관한 연구)

  • 이택순;이유태
    • Journal of Ocean Engineering and Technology
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    • v.6 no.1
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    • pp.96-104
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    • 1992
  • Aircraft structures and engineering structures are always subject to variable amplitude loads. Variable amplitude loads include some kind of loading history; for example, constant amplitude load, single peak overload and block overload etc. Crack growth under variable amplitude loading exhibits retardation effect. In this study, the 4 point bending fatigue test was performed by hydrolic servo fatigue testing machine on 7075-T6 Al-alloy. The retardation effect of overload ratio and numbers of overload cycle was quantitatively studied. 1) Change of retardation effect against increment of overload ratio is more evident when the multiple overload is applied than single overload is done. 2) The number of overload cycle is very important factor about the crack growth retardation effect when the overload ratio is more than 1.75; that is not when the overload ratio is less than 1.75. 3) Overload affected zone size increased gradually by increment of crack growth retardation effect. 4) Crack driving force is more greatly reduced when the crack tip branched off two direction than it sloped to one direction.

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"Job Crafting Makes Safety": The Effect of Work Overload on ("잡 크래프팅이 안전을 만든다." : 직무 과부하가 안전 행동에 미치는 영향)

  • Kim, Byung-Jik
    • Journal of the Korea Safety Management & Science
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    • v.24 no.1
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    • pp.81-89
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    • 2022
  • Since the competitive environment, work overload among employees has been increasing. The purpose of this paper is to investigate the impact of work overload on safety behavior and its intermediating mechanisms. In specific, this paper delves into the mediating effect of job stress, as well as the moderating effect of job crafting in the association between work overload and job stress. To empirically test the hypotheses, this study utilized survey data from 168 Korean employees by conducting structural equation modeling(SEM) analysis. The results demonstrated that work overload has a positive (+) influence on job stress, which has a negative (-) influence on safety behavior. Moreover, job stress mediated the association between work overload and safety behavior. Furthermore, job crafting moderated the work overload-safety behavior link.

The Impact of Social Media Overload on Users' Unintentional Avoidance Behavior (소셜 미디어 과부하가 사용자의 비의도적 회피 행동에 미치는 영향)

  • Qiao, Xin;Oh, Se Hwan
    • The Journal of Information Systems
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    • v.32 no.3
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    • pp.165-181
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    • 2023
  • Purpose Digital platforms, together with the innovative technologies of modern society, are accelerating the digital innovation of the entire economy and society. Although social media platforms are gradually integrated into daily life, due to social media overload, users limit their use of the platform for a certain period of time or eventually choose to stop using it. In the context of social media platform, the purpose of this paper is to study the effects of information overload, social overload and system function overload on users' unintentional avoidance behavior, mediated by fatique and dissatisfaction. Design/methodology/approach This study empirically examines the influence of social media overload characteristics on users' unintentional avoidance behavior of platform utilization using the S-O-R framework. Data from 236 Chinese social media users were collected through a questionnaire survey, and the hypotheses were validated by evaluating the research model using the SmartPLS 4.0 program using Partial Least Square (PLS) method. Findings According to the empirical analysis result, based on the S-O-R model, first, it is confirmed that information overload and system feature overload have significant positive(+) effects on fatigue. Second, this study finds that information overload, social overload and fatigue have significant positive(+) effects on dissatisfaction. Thirdly, fatigue and dissatisfaction have significant positive(+) effects on unintentional avoidance. In addition, social overload has no significant effect on fatigue, while system feature overload has no significant effect on dissatisfaction.

Study on the Retardation Effect of Overload on the Corrosion Fatigue Crack Propagation Al-Alloy used for the Shipbuilding (과하중에 의한 선박용 알루미늄 합금재의 부식피로 파괴지연에 관한 연구)

  • Lim, Uh-Joh;Lee, Jong-Rark;Lee, Jin-Yeol
    • Journal of Ocean Engineering and Technology
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    • v.2 no.2
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    • pp.122-129
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    • 1988
  • Recently with the rapid development in marine and shipbuliding industries such as marine structures, ship and chemical plants, there occurs much interest in the study of corrosion fatigue characteristics which was closed up an important role in mechanical design. In this study, the 5086 Al-alloy was tested by use of rotary bending fatigue tester. The retardation effect of overload on the corrosion fatigue crack propagation in sea environment was quantitatively studied. 1) Retardation effect of corrosion fatigue crack propagation is most eminent when overload ratio is 1.52, overload magnitude corresponds to about 77% and 55% of yield strength and tensile strength respectively. 2) After overload ratio 1.52 was used, retardation of corrosion fatigue crack growth rate is largely retarded and quasi-threshold stress intensity factor range($\Delta\textrm{K}_{th}$) appears. 3) According to m of experimental constant, retardation effect of corrosion fatigue crack propagation corresponds to about 25% of constant stress amplitude when overload ratio is 1.52. 4) When overload ratio 1.52 was used, retardation parameter (RP) decreases to about 0.43 and corrosion sensitivity (S)decreses to about 2.1.

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The Effect of Salesperson's Self Efficacy and Work Overload on Emotional Labor and the Mediating Role of Emotion (판매원의 자기효능감 및 직무과부하가 감정노동에 미치는 영향과 감정의 매개효과)

  • Kim, Hyun-Sook;Jun, Dae-Geun;Choo, Ho-Jung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.35 no.10
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    • pp.1150-1160
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    • 2011
  • This study investigates i) the effect of salesperson's self efficacy and work overload on emotional labor and ii) the mediating role of emotion. A survey questionnaire is developed and implemented on salespersons working in the fashion retail stores of department stores. The measurement scales are composed of emotional labor, self efficacy, work overload and emotion. A total of 112 responses are analyzed by confirmatory factor analysis and a structural equation model with AMOS18.0. The results are as follows. Firstly, self efficacy has direct effect on both deep acting and surface acting of emotional labor without the mediating effect of emotion. Self efficacy has a positive effect on deep acting. Secondly, work overload has a negative effect on emotion. Job emotion has positive effect on deep acting and it has a negative effect on surface acting. Thirdly, emotion has a significant mediating effect between work overload and emotional labor. Finally, implications for personal management and job design in the fashion retail organizations are suggested.

The Factors Influencing on the Social Networking Service Fatigue and SNS Stresses based on the Smart Phone (소셜네트워크 특성이 스트레스 요인과 SNS 피로감에 미치는 영향)

  • Noh, Mi Jin;Jang, Sung Hee
    • The Journal of Information Systems
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    • v.25 no.4
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    • pp.163-179
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    • 2016
  • Purpose This study investigates the associations between SNS fatigue and stress of smartphone SNS, with SNS characteristics. The study focuses on two types of SNS characteristics: information and systems characteristics. We examine SNS stress factors that includes the communication and system overload. Design/methodology/approach To test the proposed hypotheses, the study conducted structural equation modeling with Smart PLS 3.0. The study conducted A sample of 286 participants was collected from SNS users. Findings The results indicated that the information relevance in the information characteristics had an effect on the communication overload, but it had not an effect on the system overload. The information accuracy had an effect on the communication and system overload. The app pace of change influenced the communication and system overload, but the app complexity influenced the system overload. Finally, the SNS stress showed significant relationship with SNS fatigue. The academic and managerial implications were discussed based on the this results.

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

The Association between Coaching Leadership and Safety Behavior: The Sequential Mediating Role of Perceived Organizational Support and Organizational Identification, and the Moderating Effect of Work Overload (코칭 리더십과 직원들의 안전 행동 사이의 관계: 조직 지원 인식과 조직 동일시의 순차적 매개 효과, 그리고 직무 과부하의 조절 효과를 중심으로)

  • Yunsook Hong
    • Journal of the Korea Safety Management & Science
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    • v.25 no.2
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    • pp.59-69
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    • 2023
  • Previous works on safety behavior have paid less attention to the influence of several leadership styles on safety behavior. Among the various leadership styles, I focus on the effect of coaching leadership on safety behavior. To be specific, this paper investigates the impact of coaching leadership on safety behavior and its underlying mechanisms (mediator) as well as contextual factor (moderator). This research examines the sequential mediating effect of perceived organizational support and organizational identification in the association between coaching leadership and safety behavior. Also, work overload will negatively moderate the coaching leadership-perceived organizational support link. My results showed coaching leadership increases employee safety behavior through the sequential mediation of perceived organizational support and organizational identification. In addition, work overload functions as a negative moderator which diminishes the positive effect of coaching leadership on perceived organizational support.

A Study on the Effect of the Overload Ratio on the Fatigue Crack Growth Retardation (과대하중비가 균열성장지연에 미치는 영향에 관한 연구)

  • Kim, Kyung-Su;Kim, Sung-Chan;Shim, Chun-Sik;Park, Jin-Young;Cho, Hyung-Min
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.05a
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    • pp.306-311
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    • 2003
  • A growing fatigue crack is known to be retarded on application of an overload cycle. The retardation may be characterized by the total number of cycles involved during retardation and the retarded crack length. The overload ratio plays an important role to influence the retardation behavior. The objective of the present investigation is to study the effect of different overload ratio on the retardation behavior. For DENT(double edge notched tension) specimens and ESET(eccentrically-loaded single edge crack tension) specimens, fatigue crack growth tests are conducted under cyclic constant-amplitude loading including a single tensile overloading with different overload ratios. The proposed crack retardation model predicts crack growth retardation due to a single tensile overloading. The predictions are put into comparison with the experimental results to confirm the reliability of this model.

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A Study on Corrosion Fatigue Crack Propagation Behaviors due to a Single Overload in 6063-T5 Aluminum Alloy (6063-T5 알미늄 합금의 단일과대하중에 의한 부식피로균열진전거동에 관한 연구)

  • 강동명;우창기;이하성
    • Journal of the Korean Society of Safety
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    • v.12 no.3
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    • pp.38-44
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    • 1997
  • 6063-T5 alloys are tested in laboratory air, water and 3% NaCl solution to investigate the effects of corrosive environment on the retardation behavior through single overload fatigue test. Also, the fatigue crack propagation and the crack closure behavior are studied. The results obtained in this experimental study are summarized as follows. 1) Behaviors of fatigue crack growth retardation are observed in water and 3% NaCl solution as they do in air. The number of delay cycles and the size of affected region by single overload decrease greatly in water and 3% NaCl compared with those in air. 2) In fractographic results, the overload marking by single overload appear remarkably in air, but indistinctly in water and 3% NaCl solution. 3) The effect of crack closure on crack propagation is most remarkable in the beginning of crack propagation. With crack propagation, the crack closure level and its effect decrease greatly.

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