• Title, Summary, Keyword: T-stress

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Evaluation of T-stress for cracks in elastic sheets

  • Su, R.K.L.
    • Structural Engineering and Mechanics
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    • v.20 no.3
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    • pp.335-346
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    • 2005
  • The T-stress of cracks in elastic sheets is solved by using the fractal finite element method (FFEM). The FFEM, which had been developed to determine the stress intensity factors of cracks, is re-applied to evaluate the T-stress which is one of the important fracture parameters. The FFEM combines an exterior finite element model with a localized inner model near the crack tip. The mesh geometry of the latter is self-similar in radial layers around the tip. The higher order Williams series is used to condense the large numbers of nodal displacements at the inner model near the crack tip to a small set of unknown coefficients. Numerical examples revealed that the present approach is simple and accurate for calculating the T-stresses and the stress intensity factors. Some errors of the T-stress solutions shown in the previous literature are identified and the new solutions for the T-stress calculations are presented.

The Relationship between the Types of Stress Coping and Life Goals for College Freshmen

  • Kim, Jungae
    • International Journal of Advanced Culture Technology
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    • v.8 no.2
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    • pp.85-95
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    • 2020
  • This study was a descriptive cross-sectional study using questionnaire that analyzed the relationship between stress coping types and life goals in the freshmen. The study period lasted from May 1, 2020 to May 20, 2020. A total of 282 people participated in the study, with freshmen enrolled in C and J provinces. The collected data were analyzed frequency, t-test, multiple regression, and Pearson correlation using SPSS 18.0. As a result, the passive(r=.202, p<0.05), aggressive(r=.243, p<0.05), Supportive(r=.255, p<0.01) and active stress coping types(r=.410, p<0.01) were correlated with achieve oriented life goal. And Supportive(r=.383, p<0.01), Active stress coping types(r=.497, p<0.01) were correlated with life oriented goal. According to gender, men (Mean 1.87, SD=0.62) had higher aggressive stress coping types than women (Mean=1.54, SD=0.52) (t=4.202, p=.000). People with achieve oriented life goals were found to have an effect on passive (t=7.176, p<0.01), aggressive (t=1.974, p<0.05) and evasive stress coping types (t=4.207, p<0.01). People with life oriented life goals were found to have ab effect on passive (t=6.331, p<0.01)), active stress coping types (t=2.101, p<0.05). In addition, passive (t=2.946, p<0.01), aggressive (t=4.067, p<0.01) and evasive stress coping types (t=2.624, p<0.01) affected achieve oriented goals, supportive stress coping types (t=5.438, p<0.01) affected the life oriented life goal, and active stress coping type affected on both achieve (t=4.061, p<0.01) and life oriented life goal (t=6.905, p<0.01).

A Study on the Time Dependent Strength-Stress Model with Fixed Strength Case (시간에 종속되는 스트렝스-스트레스 모형연구 - 스트렝스가 변하지 않는 경우 -)

  • Lee, Hyunwoo;Kim, Jae Joo
    • Journal of the Korean Society for Quality Management
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    • v.24 no.3
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    • pp.19-30
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    • 1996
  • We treat problems of estimating reliability R(t) = P[Y(t) > X(t)] in the time dependent strength-stress model in which a unit of stress X(t) is subjected to environmental strength Y(t) at time t. In this paper we introduce a special model of R(t) with fixed strength and unaccumulated stress case, and propose a Mann-Whitney-Wilcoxon type estimator of R(t).

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Evaluation of Stress Intensity Factors and T-Stress Using a Conservation Integral (보존적분을 이용한 응력강도계수와 T-응력의 계산)

  • 범현규;엄윤용
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.1
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    • pp.121-126
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    • 1994
  • A mutual integral, which has the conservation property, is applied to the problem of a crack in an isotropic elastic material. The stress intensity factors $K_{I}, K_{II}, K_{III}$ and T-stress for the problem in an infinite medium are easily obtained by using the mutual integral without solving the boundary value problem. The auxiliary solutions necessary in the proposed method are taken from the known asymptotic solutions. This method is amenable to numerical evaluation of the stress intensity factors and T-stress if the crack in a finite medium is considered.

Nonparametric Estimation of Reliability in Time Dependent Strength-Stress Model

  • Lee, Hyun-Woo;Na, Myung-Hwan
    • Journal of the Korean Data and Information Science Society
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    • v.10 no.1
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    • pp.111-118
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    • 1999
  • We treat the problem of estimating reliability R(t) = P[Y(t) < X(t)] in the time dependent strength-stress model in which a unit of strength X(t) is subjected to environmental stress Y(t) at time t. In this paper two nonparametric approaches to estimate of R(t) are analyzed and compared with parametric method by simulation.

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Effects of Swim Training and Vitamin C Supplementation on the Antioxidant System Following Exhaustive Exercise Stress

  • Hwang, Hye-Jin;Kwak, Yi-Sub;Yoon, Gun-Ae
    • Preventive Nutrition and Food Science
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    • v.10 no.2
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    • pp.151-155
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    • 2005
  • This study was intended to investigate the effects of regular swimming exercise and vitamin C supplementation on the antioxidant system following exercise stress. For the swimming exercise experiment, a swimming adaptation exercise of 1 week was given to a group of 6-week-old mice. Following this, a swimming exercise for 8 weeks was conducted. The experimental group was divided into 3: a control group (C), a swimming exercise trained group (T), and a group of swimming + vitamin C supplementation (TC: vitamin supplementation: 1.3 mg/l00 g diet). After the swimming exercise, these group were further divided into those that had received the exercise stress for 2 hours and those that had not experienced exercise stress group. Then, the activities of the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) concentrations were measured. There was a lower weight increase in the T and TC groups than in the C group, and there was no significant difference between T and TC group. When exercise stress was not experienced, the activity of SOD was significantly increased in the TC group than in the T group, but there was no significant difference between C and T groups. The groups that had experienced a 2-hour exercise stress showed the SOD activity levels according to the following order, C < T < TC, with a significant difference between the three groups (p<0.05). There was no difference in MDA concentration amongst the experimental groups in non-exercise stress group. As well, there was no differences in MDA concentration between the C group and T group in the 2 hour exercise stress group. However, the TC group showed a MDA concentration level significantly lower than that of the T group. A significant increase in MDA concentration was observed in C group, when exercise stress was provided with no significant difference in the T and TC groups. As a result, regular exercise and vitamin C supplementation can be considered important in controlling the formation of lipid peroxides in exercise stress.

A simplified method for evaluation of shear lag stress in box T-joints considering effect of column flange flexibility

  • Doung, Piseth;Sasakia, Eiichi
    • Structural Engineering and Mechanics
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    • v.73 no.2
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    • pp.167-179
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    • 2020
  • This study provides a simplified method for the evaluation of shear lag stress in rectangular box T-joints. The occurrence of shear lag phenomenon in the box T-joint generates stress concentration localized at both web-flange junctions of the beam, which leads to cracking or failure in the weld region of the joint. To prevent such critical circumstance, peak stress at the weld region is required to be checked during a preliminary design stage. In this paper, the shear lag stresses in the T-joints were evaluated using least-work solution in which the longitudinal displacements of the beam flange and web were presumed. The evaluation process considered particularly the effect of column flange flexibility, which was represented by an axial spring model, on the shear lag stress distribution. A simplified method for stress evaluation was provided to avoid solving complex mathematical problems using a stress modification factor βs from a parametric study. The results showed that the proposed method was valid for predicting the shear lag stress in the box T-joints manually, as well compared with finite element results. The results are further summarized, discussed, and clarified that more flexible column flange caused higher stress concentration.

A Study of Eating in Obese High School Girls during Stressful Situations (스트레스시 비만여고생의 섭식에 관한 연구 -방법론적 Triangulation의 적용-)

  • 김숙영
    • Journal of Korean Academy of Nursing
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    • v.29 no.6
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    • pp.1392-1402
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    • 1999
  • This study was carried out to find out stress-eating relationship in obese high school girls and to investigate the factors related to stress-induced eating. The conceptual framework used in this study was individual difference model. The research method was methodological triangulation. The data of the study were collected from purposively sampled 309 normal high school girls and 314 obese high school girls in S city. 15 volunteers, obese high school girls, enrolled in this qualitative research. Quantitative data was collected from May 6 to June 10, 1997 through questionnaires about stress and stress-related eating changes and from June 23 to August 26, 1997, qualitative data was collected. The results of the study were as follows : 1. Obese high school girls were unaffected by stress(t=-1.84, p=0.0662). 2. Through quantitative analysis, obese people divided into two groups in their response to stress. One group was composed of stress- eater. The other group was composed of non- stress eater. 3. Disinhibition(t=-3.1275, p=0.0019), cognitive restrain (t=-3.1597, p=0.0017), hunger(t=-3.5878, p=0.0004) were significantly different between stress-eaters and non-stress eaters. 4. According to the interview, 5 subjects of obese girls were stress eaters, and 10 subjects were non-stress eaters. Through qualitative research, the related factors of eating were eating attitude & behavior, stimuli situations on eating, and personality. In stress-eater group, they constantly went on a diet, however, they were prompted to eat when an uneasy feeling such as anxiety, depression, annoyance developed. Their personality were entirely optimistic. Whereas non-stress eater group had no interest in diet and didn't appear to have psychological factors to stimulate eating in stressful situations. Their personality was not only optimistic but also keenly characteristic. 5. To compare obese-normal high school girls on the effect of stress in eating. Normal weigh high school girls decreased their eating when stressed(t= -13.62, p=0.0001). In conclusion, this study suggests that there are two different groups in obese high school girls in regards to eating responses on stressful situations. As a result of these finding, clinical and school nurses can detect the stress-eaters who need stress management intervention, and can apply appropriate management program according to the individual needs.

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Factors Affecting on Turnover Intentions among Operating Room Nurses (수술실 간호사의 이직의도에 영향을 미치는 요인)

  • Kim, Yeo-Jin;Park, Keum-Sook;Yang, Eun-Ja
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.12
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    • pp.352-362
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    • 2016
  • The purpose of this study was to examine the level of stress, healthcare accreditation related job stress, adaptation, and turnover intentions, as well as to identify influencing factors of turnover intentions for operating room nurses. This study employed a descriptive correlational design. The data were collected from 163 operating room nurses using a structural questionnaire. Stress was different by age (F=5.629, p=.004), marital status (t=-2.907, p=.004), and children (t=-2.623, p=.010). Healthcare accreditation related job stress was different by age (F=11.924, p<.001), marital status (t=-4.747, p<.001), children (t=-4.434, p<.001), work experience in the OR (F=6.000, p=.003), and work reasons in the OR (t=-2.543, p=.012). Turnover intention was different by age (F=21.472, p<.001), education level (F=4.997, p<.008), religion (t=3.235, p=.001), work experience in the OR (F=13.599, p<.001), position (t=3.222, p=.002), work reasons in the OR (t=-3.001, p=.003), and a shift pattern of duties (t=-2.797, p=.006). Turnover intention was significantly correlated with stress, healthcare accreditation related job stress, and adaptation. Factors affecting turnover intention were healthcare accreditation related job stress, adaptation, and age. These factors accounted for 36.2% of turnover intention. These results suggest that relief of stress and healthcare accreditation related job stress and interventions for improving stress management.

Reference Stress Based Stress Analysis for Local Creep Rupture of a T-pipe (참조응력법에 입각한 T-배관 국부 크리프 파단 평가를 위한 응력해석 사례연구)

  • Shin Kyu-In;Yoon Kee-Bong;Kim Yun-Jae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.8
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    • pp.873-879
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    • 2006
  • To investigate applicability of the reference stress approach as simplified inelastic stress analysis to estimate local creep rupture, detailed finite element stress analyses of a T-piece pipe with different inner pressure and system loading levels are performed. The reference stresses are obtained from the finite element (FE) limit analysis based on elastic-perfectly-plastic materials, from which the local reference stress for creep rupture is determined from R5. The resulting inelastic stresses are compared with elastic stresses resulting from linear elastic FE calculations. Furthermore they are also compared with the stresses from full elastic-creep FE analyses. It shows that the stresses estimated from the reference stress approach compare well with those from full elastic-creep FE analysis, which are significantly lower than the elastic stress results. Considering time and efforts for full inelastic creep analysis of structures, the reference stress approach is shown to be a powerful tool for creep rupture estimates and also to reduce conservatism of elastic stress analysis significantly.