• 제목/요약/키워드: Average Stress Method

검색결과 401건 처리시간 0.027초

A 3-D Finite Element Model For R/C Structures Based On Orthotropic Hypoelastic Constitutive Law

  • Cho, Chang-Geun;Park, Moon-Ho
    • KCI Concrete Journal
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    • 제13권1호
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    • pp.19-25
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    • 2001
  • Based on the orthotropic hypoelasticity formulation, a constitutive material model of concrete taking account of triaxial stress state is presented. In this model, the ultimate strength surface of concrete in triaxial stress space is described by the Hsieh's four-parameter surface. On the other hand, the different ultimate strength surface of concrete in strain space is proposed in order to account for increasing ductility in high confinement pressure. Compressive ascending and descending behavior of concrete is considered. Concrete cracking behavior is considered as a smeared crack model, and after cracking, the tensile strain-softening behavior and the shear mechanism of cracked concrete are considered. The proposed constitutive model of concrete is compared with some results obtained from tests under the states of uniaxial, biaxial, and triaxial stresses. In triaxial compressive tests, the peak compressive stress from the predicted results agrees well with the experimental results, and ductility response under high confining pressure matches well the experimental result. The reinforcing bars embedded in concrete are considered as an isoparametric line element which could be easily incorporated into the isoparametric solid element of concrete, and the average stress - average strain relationship of the bar embedded in concrete is considered. From numerical examples for a reinforced concrete simple beam and a structural beam type member, the stress state of concrete in the vicinity of talc critical region is investigated.

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Study on push-out test and bond stress-slip relationship of circular concrete filled steel tube

  • Yin, Xiaowei;Lu, Xilin
    • Steel and Composite Structures
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    • 제10권4호
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    • pp.317-329
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    • 2010
  • According to the results of 9 circular concrete filled steel tube (CFT) push-out tests, a new theoretical model for average bond stress versus free end slip curve is proposed. The relationship between verage bond stress and free end slip is obtained considering some varying influential parameters such as slenderness ratio and diameter-to-thickness ratio. Based on measured steel tube strain and relative slip at different longitudinal positions, the distribution of bond stress and relative slip along the length of steel tube is obtained. An equation for predicting the varying bond-slip relationship along longitudinal length and a position function reflecting the variation are proposed. The presented method can be used in the application of finite element method to analyze the behavior of CFT structures.

일 지역 농촌노인의 건강증진행위와 생활만족도의 관계 (Health Promoting Behavior and Degree of Life Satisfaction in Rural Elderly People)

  • 성명숙;송병선
    • 기본간호학회지
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    • 제11권1호
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    • pp.82-91
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    • 2004
  • Purpose: The purpose of this study was to identify health promoting behavior and life satisfaction in rural elderly people. Method: The data were collected from October 1st 2002 to October 31th, 2003. The participants were 142 elderly people living in Hong Cheon, Korea. Data were collected using structured questionnaires and analyzed using the SPSS program. Result: The average score for the health promoting behavior was 2.64 (${\pm}0.34$), with a minimum of 1.48 and maximum of 3.80. The average scores for each subscale were, nutrition, 2.98, interpersonal support, 2.78, health responsibility, 2.67, self-actualization, 2.66, stress management, 2.58, and exercise, 1.93. Signifiant differences in health promoting behavior were found according to the following general characteristics: education level, religion, senior citizens center usage and allowance. The average score for life satisfaction was 2.68 (${\pm}0.42$), with a minimum of 1.38 and a maximum of 3.85. Senior citizens center usage was the only general characteristics that showed a significant difference for life satisfaction. There was a significant positive correlation between health promoting behavior and life satisfaction (r= 0.5783, p=0.001). Self-actualization and stress management had statistically significant casual effects on life satisfaction ($R^2$=0.3961). Conclusion: Effective methods to enhance life satisfaction of rural elderly should emphasize self-actualization and stress management.

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Shear Strength of an Aluminum Alloy Bonded with a DP-460 Adhesive: Single Lap-shear Joints

  • Kim, Hyun-Bum;Nishida, Tomohisa;Oguma, Hiroyuki;Naito, Kimiyoshi
    • 접착 및 계면
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    • 제21권1호
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    • pp.20-26
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    • 2020
  • Single lap-shear joints (SLJ) specimens with and without partial round fillets were fabricated to measure the average shear strength of adhesives. The effects of the length of the adherend on the SLJ specimens were also investigated. An epoxy adhesive was used to bond aluminum alloy. Tensile tests were performed on the adhesive bulk specimens to measure the mechanical properties. The finite element analysis (FEA) method was used to measure the adhesive stress distributions, i.e., the peel and shear stresses, on the bonded part. The experimental results revealed that the specimen consisting short length of adherend and without the partial round fillets exhibited the smallest average shear strength of adhesive among the investigated specimens. FEA revealed that the low average shear strength for the specimen with a short adherend length was caused by high stress concentrations on the adhesive at the edge of the bonded part.

신생아 중환자실에 입원한 환아 어머니의 스트레스 (A Study on the Perceived Stress of Mothers in Neonatal Intensive Care Unit)

  • 최성희
    • Child Health Nursing Research
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    • 제4권1호
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    • pp.60-75
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    • 1998
  • The parents have much expectation upon the pregnancy and child birth, and in most cases, they expect the healthy parturient child. However, we can be placed on the high-risk conditions which have the physical, social and immature infant, due to the unexpected results, among the new-born. Accordingly, these high-risk newborn and premature infants will be mostly in NICU, which the concentrated medical treatment can be given, upon their conditions. After their birth and during these periods, they will be divided from the parents, and the nurse will accomplish the bringing-up activities which they can take care of the infant, expected by the parents after their birth. The hospitalization of high-risk newborn including these premature infants is the shocking experience to the parents of family, and thus they can feel the fear and uneasiness, and these reactions of parents are troubled in the behavior at the usual days, and cause the disorder and spiritless status, and these results break the supporting ability of parents, and cause the obstruction. Also, the unavoidable division between the parents and the children as like hospitalization of children can make the parents to feel the alienation emotionally, and this causes the results which the pride on the bringing-up ability of baby gets to be lost. These problems can cause the difficulties on the bonding or the parenting in the further days, and can be related to the neglect and abuse of children. Also, it is gradually increased to study and report which the emotional division by the physical division between the mother and the baby obstructs the normal affection course between the parent and the infant. The stress caused by the birth and the hospitalization of high-risk newborn, as like this, is important in the points which it can uncertainly affect the potential energy for the relationship of parent-child who are finally healthy. Accordingly, the significance and purpose of this study are to understand the contents and degree of stress which the parents of high-risk newborn including the immature child can be experienced from the hospitalization of ICU for their new borns, and thus to offer the basic program to the nursing intervention program for these. The subject of this study is the mother of newborn in NICU of 10 General Hospitals located at the 3one of Pusan, Korea from September 1997 to October 1997, and thus makes the subject of 95 person of parents who agreed to take part in the study and it is descriptive study related to the stress of mother having the newborn in NICU. The method is based on the preceding study related to the stress of mother having the experience of child hospitalization and chronic disease child, and then acquires the advice of specialists group as like 5 nursing professors, and then is amended and supplemented. Total number of questions is 43 items and consists of 5 factors as like medical treatment &nursing procedures, disease status & prognosis, role of parents, communication & inter-personal relationships, hospital environment, and is 5 point Likert Scale. The reliability of this study method is very highly shown to be Cronbach α=0.95. The collected data is analysed as Average, Frequency, Standard Deviation, T-test, ANOVA, Pearson Correlation Coefficient, Duncan multifulrange test by use of SPSS /PC (V7.5). The results of this study is summarized as under. 1. Every characteristics of subject is which the party of mother is 28.70age(±7.48) in the average ages, 51% in the high-school graduate, 38.5% in the christianity, total monthly income is 212.55 thousand won(±1.971), 74.5% in the housewife, 72.9% in the parents and children together living and the number of children to be 1.48person(± 0.6) in average, the recognition on the prognosis of baby is 74.0% in 'Don't know', the relationship with the husband after the hospitalization of babyis 37.3% in 'More Intimate', the relationship with the family of husband to be 48% in 'No-change', and the degree which is consulted with the husband about the baby is 55% in 'very frequently' and the visiting number per week is 4.59(±1.63) in average and the accompanying person in the time of visiting is which the number of husband is 56.3% and thus is the highest. The characteristics of baby is which the age is 21.88days(±16.47) after the birth in average, the sex to be 50 person in the female 52.1% and the order of birth to be 54.2% in the first chid, and the weight in the birth to be 2770gm(±610) and the height in the birth to be 46.26cm(±7.62) in aver age. The medical diagnosis is 37.5% in the premature infant, the career of hospitalization is 96.9% in 'None', and the operation plan is 90.6% in 'None' and the execution of operation is 88% in 'None' and the nursing of incubator is 55.2% in 'Yes', and the method of feeding is 50.5% in 'Oral' and the contents of feeding is 46.9% in the 'Milk'. 2. The total stress degree of subject is almost highly shown to be as 3.36(±0.86). If it is compared upon each cause, 'stress on disease status & prognosis' is highest 3.79(±1.28), and it is in the order of 'stress on medical treatment & nursing procedures' 3.70(±0.93), 'stress on hospital environment' 3.14(±0.86), 'stress on role of parents' 3.18(±0.92) and 'stress on communication & inter personal relationship' 2.62(± 0.77) 3. As the results of checking the notworthiness of stress degree upon each variable of subject, the variable showing the noted difference was the birth weight(γ=-0.16, P=0.04), birth height(γ=-0.23, P=0.03), nursing in the incubator(F=8.93, P=0.04), feed method(F=2.94, P=0.04). That is to say, it is shown which the smaller the birth weight is, the higher the stress degree of mother is noteworthily. Also, the smaller the birth height baby is, the higher the stress of mother is. In the incubator, it os shown which the mother whose baby is nursing in the incubator is higher in the stress degree than other mothers. Upon the feeding method of baby, that is to say, TPNis the highest, and it is shown in the order of NPO, Tube feeding, and P.O. feeding. When we review the above-mentioned results, as the status is serious, it is thought which we include the supporting nursing for coping with the stress of parents in the setting-up od nursing plan for the baby in the NICU.

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디젤기계의 피스톤 열부하 특성에 관한 연구 (Themally Loaded Characteristics of Diesel Engine Piston)

  • 한문식;박태인
    • 한국기계연구소 소보
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    • 통권15호
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    • pp.91-103
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    • 1985
  • In this paper, temperature distribution and thermal stress are investigated considering engine peak pressure and the time average temperature distribution in the piston under running conditions for the diesel engine. The induced stress are calculated by the Finite Element Method(FEM). The results obtained are summerized as follows. 1) The results calculated by the FEM present good agreement with other numerical solution in literature. 2) It is confirmed that maximum compressive stress are induced in the part of outside wall between the piston crown and the pin bush. 3) In the axial direction, the hoop stresses are changed its sigh at the portion of crown near the inner wall side 4)Large gradient of temperature is shown in the piston crown near the side wall in the axial direction, in the part between the piton crown and the pin bush in radical direction 5)in case of stress distribution of piston wall surface in the axial direction, the hoop stress is a little greater than axial stress, and the latter is greater than the radial stress

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선박용 디젤기관의 피스톤 응력해석 (Stress analysis of marine diesel engine piston)

  • 한문식;김상철
    • Journal of Advanced Marine Engineering and Technology
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    • 제9권2호
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    • pp.143-152
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    • 1985
  • In this paper, temperature distribution and thermal stress are investigated considering engine peak pressure and the time average temperature distribution in the piston under running conditions for the marine diesel engine. The induced stress are calculated by the Finite Element Method (FEM). The results obtained are summerized as follows. 1) The results calculated by the FEM present good agreement with other numerical solution in literatures. 2) It is comfirmed that the maximum compressive stresses are induced in the part of outside wall between the piston crown and the pin bush 3) In the axial direction, the hoop stresses are changed its sign at the portion of crown near the inner wall side. 4) Large gradient of temperature is shown in the piston crown near the side wall in the axial direction, in the part between the piston crown and the pin bush in radial direction. 5) In case of stress distribution of piston wall surface in the axial direction, the hoop stress is a little greater than axial stress, and the latter is greater than the radial stress.

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적층판 결합공정의 불확정성을 고려한 강건최적설계 (A Study on Robust Design Optimization of Layered Plates Bonding Process Considering Uncertainties)

  • 최주호;이우혁;윤병동
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2006년도 정기 학술대회 논문집
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    • pp.836-840
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    • 2006
  • Design optimization of layered plates bonding process is conducted to achieve high product quality by considering uncertainties in a manufacturing process. During the cooling process of the sequential sub-processes, different thermal expansion coefficients lead to residual stress and displacement. thus resulting in defects on the surface of the adherent. So robust process optimization is performed to minimize the residual stress mean and variation of the assembly while constraining the distortion as well as the instantaneous maximum stress to the allowable limits. In robust process optimization, the dimension reduction (DR) method is employed to quantify both reliability and quality of the layered plate bonding. Using this method. the average and standard deviation is estimated. Response surface is constructed using the statistical data obtained by the DRM for robust objectives and constraints. from which the optimum solution is obtained.

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가정전문간호사의 업무 스트레스 (A Survey on the Job Stress of Home Care Nurses)

  • 김희승;유소영;김명자;백희정;김윤옥
    • 가정간호학회지
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    • 제10권1호
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    • pp.34-40
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    • 2003
  • Purpose: The purpose of this study was to investigate the job stress in home care nurses. Method: The subjects were 139 home care nurses of hospital in an urban cities. The data were collected from 26 Man to 27 June by self report adherence questionnaire. Job stress was measured using CHN-PWRSQ(Community Health Nurses Perceptions of Work-Related Stressors Questionnaire). Result: The average score of job stress was 60.8. There were significantly high levels of job stress in those who have less than 10 years office period, those who have less than 2000000 won monthly salary than in their counterparts. With regard to the level of job stress by item, 'driving long distance and traffic jam', 'risk of traffic accident', 'bad weather condition', 'uncooperative family members', and 'uncooperative client/patient' were higher than other items. The age and office period were negatively correlated with job stress. Conclusion: The average score of job stress was 60.8. 'driving long distance and traffic jam', 'risk of traffic accident', 'bad weather condition', 'uncooperative family members', and 'uncooperative client/patient' were higher than other items. The age and office period were negatively correlated with job stress.

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가족탄력성이 가족스트레스 인지에 미치는 영향 -기혼 중년남성 중심으로- (The Influence of Family Resilience upon the Perception of Family Stress -Focusing on Married Middle aged Men-)

  • 이희윤;박정윤;조유현
    • 가족자원경영과 정책
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    • 제17권4호
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    • pp.39-56
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    • 2013
  • The purpose of this study was to examine the influence of the resilience of families of middle-aged married men upon the perception of family stress. The subjects were 301 married men age 40.54 living in Seoul and Gyeonggi Province, Korea. Participants were selected using a purposive sampling method and a convenience sampling method. The data were statistically processed using the SPSS 18.0 program. First, participants who perceived family stress less and had higher family resilience tended to be better educated, have higher average family incomes, have permanent employment, be religious, and have no experience of unemployment. Participants who had low-paying, physical labor-based jobs or who were contract workers perceived family stress more and had lower family resilience. Second, among the variables that affected family resilience, those that most influenced the perceptual extent of family stress were the sense of belief system's family control, having a positive perspective, flexibility with regard to morality, religion, and organizational patterns, connectivity, family resources, communication-oriented mutual cooperative problem-solving, and emotional response. Third, the influence of family resilience upon the perception of family stress measured at 44.2% based on regression analysis and was statistically significant (F=4.606, ***p<.001).

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