• Safety and Health at Work
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• 제1권1호
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• pp.43-50
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• 2010

Objectives: The objective of this study was to investigate the effect of chain installation condition on stress distribution that could eventually cause disastrous failure from sudden deformation and geometric rupture. Methods: Fractographic method used for the failed chain indicates that over-stress was considered as the root cause of failure. 3D modeling and finite element analysis for the chain, used in a crane hook, were performed with a three-dimensional interactive application program, CATIA, commercial finite element analysis and computational fluid dynamic software, ANSYS. Results: The results showed that the state of stress was changed depending on the initial position of the chain that was installed in the hook. Especially, the magnitude of the stress was strongly affected by the bending forces, which are 2.5 times greater (under the simulation condition currently investigated) than that from the plain tensile load. Also, it was noted that the change of load state is strongly related to the failure of parts. The chain can hold an ultimate load of about 8 tons with only the tensile load acting on it. Conclusion: The conclusions of this research clearly showed that a reduction of the loss from similar incidents can be achieved when an operator properly handles the installation of the chain.

• International Journal of Safety
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• 제1권1호
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• pp.36-42
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• 2002

This paper is aimed at predicting the life of rubber insulating gloves under normal operating stresses from relatively rapid test performed at higher stresses. Specimens of rubber insulating gloves are subject to multiple stress conditions, i.e. combined electrical and thermal stresses. Two modes of electrical stress, step voltage stress and constant voltage stress are used in specimen aging. There are two types of test for electrical stress in this experiment: the one is Breakdown Voltage (BDV) test under step voltage stress and thermal stress and the other is lifetime test under constant voltage stress and temperature stress. The ac breakdown voltage defined as the break-down point of insulation that leakage current excesses a limit value, l0mA in this experiment, is determined. Because the very high variability of aging data requires the application of statistical model, Weibull distribution is used to represent the failure times as the straight line on Weibull probability paper. Weibull parameters are deter-mined by three statistical methods i.e. maximum likelihood method, graphical method and least squares method, which employ SAS package, Weibull probability paper and FORTRAN, respectively. Two chosen models for predicting the life under simultaneous electrical and thermal stresses are inverse power model and exponential model. And the constants of life equation for multistress aging are calculated using numerical method, such as Gauss Jordan method etc.. The completion of life equation enables to estimate the life at normal stress based on the data collected from accelerated aging test. Also the comparison of the calculated lifetimes between the inverse power model and the exponential model is carried out. And the lifetimes calculated by three statistical methods with lower voltage than test voltage are compared. The results obtained from the suggested experimental method are presented and discussed.

• 한국안전학회지
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• 제14권3호
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• pp.25-32
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• 1999

This study has been performed to investigate the stress distribution around defects that behave as stress concentrators. Besides, the effect of stress interaction effects on the initiation of primary cracks were also investigated by rotary bending fatigue tests which were performed with specimens drilled micro surface defects and the stress distribution was analyzed using Finite Element Method. In addition, the stress interaction effects around defects and cracks were investigated by comparing the results of experiments and F.E.M. The results obtained are summarized as follows ; 1) Area which slip and micro cracks initiated at micro surface defects is between the maximum shear stress points and this area is over than ${\pm}30^{\circ}$ from the maximum stress point along the defect edge. 2) The stress interaction effect for the small size defect is larger than that of large size defect when the interval between them is near 3) Interval which there is no shear stress interaction effect analyzed by F.E.M. is larger than that of experimental results.

• 대한안전경영과학회지
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• 제7권3호
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• pp.73-84
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• 2005

This study examined the associations between job stress and psychosocial stress in telecommunication service workers. In this survey, four hundred seventy workers and six variables(general characteristics, state of health, job characteristics, personality, psychosocial characteristics, and job stress) were used to measure worker's subjective satisfaction and status of stress. The results of this study indicated that 135 workers($28\%$) were classified into a high risk group to stress, 317 workers($67\%$) were into a potential risk group, and only 18 workers($6\%$) were into a healthy group. Also the results indicated that job stress outcomes related to job characteristics, personality, and psychosocial characteristics.

• 한국가스학회지
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• 제20권2호
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• pp.43-48
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• 2016

본 논문에서는 돌출구조물을 장착한 안전모의 지지하중과 응력분포에 대한 유한요소 해석결과를 제시하고 있다. 9.4mm의 동일한 변위하중을 안전모에 가한 5가지의 서로 다른 해석모델에 대하여 지지하중과 von Mises 최대응력을 해석하였다. 이들 모델에서, 모델 4와 모델 5는 주어진 9.4mm의 변위하중에 대하여 최고의 지지하중과 낮은 최대응력을 보여준다는 측면에서 우수한 것으로 나타났다.

• 한국기계기술학회지
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• 제13권4호
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• pp.15-21
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• 2011

The safety at this study is investigated by flow or stress analyses due to configuration or installation direction of fuel tank in the existing CNG bus. In case of the lower ceiling with sharp type, the equivalent stress due to the explosion of fuel tank is less than the type of flat or arc. it becomes safer on passenger. In case of the installation direction of fuel tank in the existing CNG bus, the stress applied on the lower ceiling at transverse direction becomes less than at longitudinal direction. It is more stable on the safety of passenger. The harm on the explosion accident can be prevented by use of the analysis result at this study.

• 한국항해항만학회지
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• 제48권2호
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• pp.88-96
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• 2024

This study examined challenges posed by two ferry routes, namely, Likoni and Mtongwe crossings, in the Mombasa Channel and their impact on navigational safety. Utilizing the Environmental Stress (ES) model, this study analyzed current ship traffic and assessed stress levels imposed by ferry crossing traffic on navigators. ES values revealed significant stress at these ferry crossings attributed to varying transit speeds. Standardizing transit speeds at two ferry passages can reduce high stress levels, presenting a viable solution. Furthermore, the IWRAP Mk2 simulation underscores crossing collisions as a significant concern, particularly at Likoni and Mtongwe crossings, due to increased ferry traffic. This research offers valuable insights for stakeholders, such as the Kenya Ports Authority (KPA), to develop targeted safety measures and enhance the flow of ship traffic in the channel.

• Safety and Health at Work
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• 제6권1호
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• pp.25-29
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• 2015

Background: Shift work has been associated with occupational stress in health providers and in those working in some industrial companies. The association is not well established in the law enforcement workforce. Our objective was to examine the association between shift work and police work-related stress. Methods: The number of stressful events that occurred in the previous month and year was obtained using the Spielberger Police Stress Survey among 365 police officers aged 27-66 years. Work hours were derived from daily payroll records. A dominant shift (day, afternoon, or night) was defined for each participant as the shift with the largest percentage of total time a participant worked (starting time from 4:00 AM to 11:59 AM, from 12 PM to 7:59 PM, and from 8:00 PM to 3:59 AM for day, afternoon, and night shift, respectively) in the previous month or year. Analysis of variance and covariance were used to examine the number of total and subscale (administrative/professional pressure, physical/psychological danger, or organizational support) stressful events across the shift. Results: During the previous month and year, officers working the afternoon and night shifts reported more stressful events than day shift officers for total stress, administrative/professional pressure, and physical/psychological danger (p < 0.05). These differences were independent of age, sex, race/ethnicity, and police rank. The frequency of these stressful events did not differ significantly between officers working the afternoon and night shifts. Conclusion: Non-day shift workers may be exposed to more stressful events in this cohort. Interventions to reduce or manage police stress that are tailored by shift may be considered.

• 한국콘텐츠학회논문지
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• 제22권3호
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• pp.222-235
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• 2022

본 연구는 중소병원 응급실 간호사의 감정노동, 직무스트레스가 환자안전관리활동에 미치는 영향을 규명하고자 시도되었다. 중소병원 응급실에 근무하는 간호사 143명을 대상으로 자가보고 설문지를 이용하여 자료를 수집하였다. 환자안전관리활동 영향요인으로 감정노동, 직무스트레스, 인구사회학적특성, 근무특성 등을 조사하였다. 변수 특성에 따른 환자안전관리활동 차이는 평균비교분석, 관련성은 상관분석을 이용하였으며, 환자안전관리활동 영향요인은 단계적 회귀분석을 이용하였다. 단변수분석 결과 연령, 응급실 경력, 직위, 근무형태, 타 부서 이동의향이 환자안전관리활동에 유의한 차이가 있었다. 직무스트레스는 환자안전관리활동과 유의한 중간 정도의 양의 상관관계가 있었으며(r=.48), 감정노동은 환자안전관리활동과 유의하지만 약한 양의 상관관계가 있었다(r=.19). 회귀분석결과 환자안전관리활동에 유의한 영향을 미치는 변수는 직무스트레스, 응급실 근무 선택 여부였고, 이들 변수의 설명력은 27%로 나타났다. 직무스트레스가 높을수록, 응급실 근무가 타의 선택일 경우 환자안전관리활동이 감소하는 것으로 나타났다. 따라서 중소병원 응급실 간호사의 환자안전관리활동 향상을 위해 직무스트레스 관리와 개인의 요구에 따른 부서 배치가 필요하다.

• Safety and Health at Work
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• 제3권1호
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• pp.43-49
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• 2012

In recent years, various international organizations have raised awareness regarding psychosocial risks and work-related stress. European stakeholders have also taken action on these issues by producing important documents, such as position papers and government regulations, which are reviewed in this article. In particular, 4 European models that have been developed for the assessment and management of work-related stress are considered here. Although important advances have been made in the understanding of work-related stress, there are still gaps in the translation of this knowledge into effective practice at the enterprise level. There are additional problems regarding the methodology in the evaluation of work-related stress. The European models described in this article are based on holistic, global and participatory approaches, where the active role of and involvement of workers are always emphasized. The limitations of these models are in the lack of clarity on preventive intervention and, for two of them, the lack of instrument standardization for risk evaluation. The comparison among the European models to approach work-related stress, although with limitations and socio-cultural differences, offers the possibility for the development of a social dialogue that is important in defining the correct and practical methodology for work stress evaluation and prevention.