• 제목/요약/키워드: body stress

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ADINA & WINLIFE 활용한 압력용기 용접부 피로파괴 해석 (Effect of Weld Elastic Modulus on Simulation of Stress Concentration and Fatigue Life for Boiler Vessel)

  • 최병학;이범규;심종헌;박찬성;김진표;박남규
    • Journal of Welding and Joining
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    • 제34권5호
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    • pp.47-53
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    • 2016
  • The aim of this study is to consider effect of weld elastic modulus on simulations of stress concentration and fatigue life for pressure vessel. The investigations include analysis with ADINA and WINLIFE softwares for whole body model about using condition of the boiler vessel. Values of weld elastic modulus were divided by 5 steps in butt weld area of the boiler vessel body. The stress concentration of the butt weld more was increased in case of higher elastic modulus of weld area because of higher difference of material properties between matrix and weld. It was concluded that the fatigue lives were decreased along increasing stress concentration due to high elastic modulus of weld. The matrix microstructure was estimated as pearlitic structure of ${\alpha}$ ferrite and pearlite. And the microstructures of welds along 5 steps of elastic modulus were estimated as bainitic fine pearlite and martensite as increasing elastic modulus.

여대생의 건강 관련 삶의 질 영향 요인 (Factors Affecting Health-related Quality of Life in Women Undergraduates)

  • 차보경
    • 기본간호학회지
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    • 제20권4호
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    • pp.400-409
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    • 2013
  • Purpose: This study was conducted to define factors influencing health-related quality of life (HRQOL) in women undergraduates. Independent variables of physical activity, attitude to eating, satisfaction with body shape, stress and self-esteem were used to predict HRQOL. Method: Data were analyzed using the SPSS/WIN 20.0 program for descriptive statistics, Pearson correlation coefficients and stepwise multiple regression. Participants were 245 women undergraduates who were recruited from July to September 2012. Result: The mean for the physical component summary (PCS) of HRQOL was 73.89, and for the mental component summary (MCS) was 68.45. There were significant correlations between attitude to eating, satisfaction with body shape, stress, self-esteem and the two components of HRQOL. The groups with minimal or health enhancing activity were significantly higher in PCS and MCS than the inactivity group. Stepwise multiple regression analysis indicated that 35% of the variance in PCS was significantly accounted for by self-esteem, perceived stress, attitude to eating, and physical activity, and 45% of the variance in MCS was significantly accounted for by perceived stress, self-esteem, attitude to eating, and satisfaction with body shape. Conclusion: The results indicate that these factors influencing HRQOL should be considered when developing programs to improve HRQOL for women undergraduates.

MDO기법에 의한 임프란트설계에서 요구되는 저작시 상.하악골치아사이의 충격력 계산 (Calculation of the Impact Force Applied on the Tooth of Upper and Lower Jaw-Bones in Masticating for the Design of a Dental Implant System.)

  • 권영주
    • 한국CDE학회논문집
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    • 제7권1호
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    • pp.27-33
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    • 2002
  • MDO(Multidisciplinary Design Optimization) methodology is a new technology to solve a complicate design problem with a large number of design variables and constraints. The design of a dental implant system is a typical complicate problem, and so it requires the MDO methodology. Actually, several analyses such as rigid body dynamic analysis and structural stress analysis etc. should be carried out in the MDO methodology application to the design of a dental implant system. In this paper, as a first step of MDO methodology application to the design of a dental implant system, the impact force which is applied on the tooth in masticating is calculated through the rigid body dynamic analysis of upper and lower jaw-bones. This analysis is done using ADAMS. The impact force calculated through the rigid body dynamic analysis can be used for the structural stress analysis of a dental implant system which is needed for the design of a dental implant system. In addition, the rigid body dynamic analysis results also show that the impact time decreases as the impact force increases, the largest impact force occurs on the front tooth, and the impact force is almost normal to the tooth surface with a slight tangential force.

전복시 차체에 대한 구조 안전 해석 (Structural Safety Analysis on Car Body at Overturn)

  • 조재웅;김기선;이은종
    • 한국산학기술학회논문지
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    • 제12권1호
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    • pp.32-37
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    • 2011
  • 본 연구에서는 구조해석을 통하여 차체의 전복 시에 있어서의 차체의 두께에 따른 변형량과 응력 변화를 고찰하여 보았다. 차체의 두께가 5t인 자동차에서는 2초일 때에 차체의 오른쪽 천장에서 7.5024mm의 최대변형이 일어났으며, 차체의 왼쪽 밑 부분에서 113.69 MPa의 최대응력을 받았다. 차체의 두께가 10t인 자동차에서는 2초일 때에 차체의 오른쪽 천장에서 1.2557mm로 최대의 변형이 일어났으며 차체의 왼쪽 밑 부분에서 15.134 MPa의 최대응력이 발생했다. 차체의 두께가 15t인 자동차에서는 2초일 때에 0.42529mm로서 차체의 오른쪽 천장에서 최대의 변형이 일어났으며 응력은 2초일 때에 차체의 왼쪽 밑 부분에서 4.405MPa의 최대응력이 작용되었다. 두께가 15mm보다 커지는 경우에는 시간에 따른 응력 및 변형율의 분포가 고르게 나타나고 있어 설계의 안전성을 보이고 있다.

신체인지 왜곡 청소년의 스트레스, 슬픔과 절망감 영향 요인에 관한 연구 (A Study on the Factors Influencing Stress, Sadness and Despair of Body Image Distortion Adolescents)

  • 권명진;김선애
    • 한국융합학회논문지
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    • 제11권10호
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    • pp.377-385
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    • 2020
  • 본 연구는 신체를 왜곡되게 인지하고 있는 청소년의 성별에 따른 정서 관련요인을 파악하기 위한 목적으로 시행되었으며 제 15차(2019년) 청소년건강행태온라인조사 자료를 이차 분석한 연구이다. 본 연구의 대상자는 제 15차(2019년) 청소년건강행태온라인조사 전체 대상자 중 정상체질량 지수임에도 불구하고 자신의 체형을 살이 찐 편이라고 인지한 13-18세 청소년 9,635명으로 남자 3,640명과 여자 5,995명이었다. 주요 분석방법은 신체인지왜곡을 가진 청소년의 성별에 따른 정서와 일반적, 신체적 및 심리적 요인간의 관계는 복합표본통계의 로지스틱 회귀분석을 통해 분석하였다. 주요 결과는 패스트푸드를 많이 섭취할수록 남녀 모두 스트레스와 슬픔과 절망감이 높았으며 대부분 유의하였다(p<.05). 또한 신체활동을 안하는 경우 남녀 모두 스트레스를 더 받았으며 슬픔과 절망감은 신체활동을 안하는 경우 더 적게 인지하는 것으로 나타났다(p<.05). 본 연구결과는 신체인지 왜곡 청소년을 위한 중재 개발에 기초자료로 활용될 수 있다.

Solution for a semi-infinite plate with radial crack and radial crack emanating from circular hole under bi-axial loading by body force method

  • Manjunath, B.S.;Ramakrishna, D.S.
    • Interaction and multiscale mechanics
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    • 제2권2호
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    • pp.177-187
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    • 2009
  • Machine or structural members subjected to fatigue loading will have a crack initiated during early part of their life. Therefore analysis of members with cracks and other discontinuities is very important. Finite element method has enjoyed widespread use in engineering, but it is not convenient for crack problems as the region very close to crack tip is to be discretized with very fine mesh. However, as the body force method (BFM), requires only the boundary of the discontinuity (crack or hole) to be discretized it is easy versatile technique to analyze such problems. In the present work fundamental solution for concentrated load x + iy acting in the semi-infinite plate at an arbitrary point $z_0=x_0+iy_0$ is considered. These fundamental solutions are in complex form ${\phi}(z)$ and ${\psi}(z)$ (England 1971). These potentials are known as Melan potentials (Ramakrishna 1994). A crack in the semi-infinite plate as shown in Fig. 1 is considered. This crack is divided into number of divisions. By applying pair of body forces on a division, the resultant forces on the remaining 'N'divisions are to be found for which ${\phi}_1(z)$ and ${\psi}_1(z)$ are derived. Body force method is applied to calculate stress intensity factor for crack in semi-infinite plate. Also for the case of crack emanating from circular hole in semi-infinite plate radial stress, hoop stress and shear stress are calculated around the hole and crack. Convergent results are obtained by body force method. These results are compared with FEM results.

돌외 에탄올 추출물 엑스의 전기쇼크 스트레스 저항력 개선작용 (Ameliorating Effects of the Ethanol Extracts from Gynostemma pentaphyllum on Electric Footshock Stress)

  • 최현숙;임선아;박미숙;황방연;이종길;김승환;임성실;이명구
    • 생약학회지
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    • 제39권4호
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    • pp.341-346
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    • 2008
  • The effects of the ethanol extracts from Gynostemma pentaphyllum (GP extracts) on body weights, grip strengths, endurances and catecholamine levels after electric footshock (EF) stress in mice and rats were investigated. The animals were treated with GP extracts (50 mg/kg/day, p.o.) for 21 days before exposure to EF (duration and interval 10 sec for 3 min, 2 mA) once a day. The increases in body weights were delayed by 13.1% of the control levels by EF-induced stress in mice, which were recovered to 24.1% of the control levels in GP extract-treated groups. The grip strengths were significantly decreased by EF stress in mice and the EF-stressed groups treated with GP extracts increased grip strengths to 115.2% compared to control levels. The endurance times by forced swimming, which reduced significantly by EF stress, were also maintained similar to control levels by GP extracts in rats. In addition, the levels of norepinephrine and epinephrine in serum and brain, and dopamine in brain were significantly increased to 17.5-95.0% of the control levels after exposure of EF stress in mice. However, EF stressinduced increases in norepinephrine and epinephrine in serum were reduced to 17.1-17.3% of the control levels by treatments of GP extracts, and those in dopamine, norepinephrine and epinephrine in brain were also reduced to 5.0-19.5%. These results suggest that GP extracts showed the protective effects on EF stress-induced physiological functions and can be developed as the promising anti-stress agents.

The influence of screw type and osseointegration ratio on stress distribution in two different endosseous implants

  • Han, Jung-Suk
    • 대한치과보철학회지
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    • 제38권3호
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    • pp.348-357
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    • 2000
  • The purpose of this study is to examine the effect of partial osseointegration situation on bone loading patterns around two different free-standing screw shaped implants (Nobel Biocare, Gothenburg, Sweden and Degussa-Huls, Hanau, German). Two dimensional axisymmetric Finite element models of two implants(10mm length and 4mm diameter) were created according to different bone quantity, quality and osseointegration ratio in maxilla and mandible bone. At the same time uni-cortical and hi-cortical fixation were analyzed. Generally, full bond case showed less stress than partial bond case in overall area and mandibular model showed less amount of stress than that of maxilla model. Maximum stress of the Branemark implant is higher than that of ANKYLOS regardless of bonding ratio at crestal and apex region. However, more stress concentration was noted in ANKYLOS implant at screw body area especially in mandible. The effect of bicortical fixation on crestal bone stress reduction is dramatical in mandible however, there was no significant effect in maxillary case. The effect of partial bond on stress distribution was more significant at screw body and apex region than in crestal region. Partial bond cases demonstrated greater stress accumulation in trabecular bone than cortical bone. It is concluded that the more accurate model of implant and bone which affects stress and strain distribution is needed to mimic in vivo behavior of implants.

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대학생의 체질량지수, 체형인식, 비만스트레스, 자아존중감에 따른 체중조절행동 예측요인 (Predictors of Weight Control Behavior According to College Students' BMI, Perception of Body Shape, Obesity Stress, and Self-Esteem)

  • 김종임
    • 한국산학기술학회논문지
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    • 제17권6호
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    • pp.438-448
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    • 2016
  • 본 연구는 대학생들의 체중조절행동에 영향을 미치는 요인을 파악하고자 실시하였다. 연구대상자는 C지역 대학에 재학 중인 대학생을 대상으로 자가보고식 설문조사로 시행되었다. 조사기간은 2015.12.01-12.20일 까지였고, 분석대상은 289명 이었다. 자료는 기술적 통계, t-tset, ANOVA, pearson correlation과 stepwise multiple regression으로 분석 하였다. 그 결과 대학생들은 자신의 체형에 대한 인식에 왜곡된 현상이 두드러지며, 특히 타인평가에 의한 체형인식과 비만스트레스, 체중조절경험이 체중조절행동에 영향을 미치는 것으로 나타났다. 체중조절행동과의 상관관계에서는 본인체형인식(r=.31, p<.001), 타인평가체형(r=.30, p<.001), 비만스트레스(r=.43, p<.001)등이 체중조절행동과 관련성이 높게 나타났다. 다중회귀분석결과, 체중조절행동에 영향을 미치는 요인으로는 비만스트레스(${\beta}=.37$, p<.001), 타인평가체형(${\beta}=.15$, p=.009)이 밀접하게 관련되는 영향요인임을 알 수 있었으며, 이 변수들의 설명력은 20% 인 것으로 나타났다(F=37.30, p<.001). 결론적으로, 대학생의 체형인식에서 타인평가체형, 비만스트레스가 체중조절행동관련 예측요인으로 나타났다. 이러한 예측요인 등을 파악하여 자신의 체형을 객관적으로 판단하여 인식할 수 있고 적절한 체중조절을 할 수 있는 정보제공, 식이와 운동을 격려하는 예방프로그램, 건강교육 및 중재 프로그램의 개발과 실시가 필요하다고 생각된다.

대학생의 외모 관련 사회문화적 태도 및 사회적 압박감, 스트레스가 신체상 불일치에 미치는 영향 (Effect of Sociocultural Attitudes toward Appearance, Social Pressure and Stress on University Students' Body Figure Discrepancy)

  • 이은미;김유정
    • 한국산학기술학회논문지
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    • 제18권12호
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    • pp.173-181
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    • 2017
  • 본 연구의 목적은 대학생의 외모 관련 사회문화적 태도와 사회적 압박감, 스트레스가 신체상 불일치에 미치는 영향을 파악하기 위함이다. 연구 대상자로 C시와 A시 4년제 대학에 다니는 대학생 363명을 표집하였다. 구조화된 자가보고 설문지를 통해 2016년 10월 27일부터 12월 9일까지 자료를 수집하였다. 자료분석을 위해 SPSS 20.0 통계 프로그램의 기술 통계 및 상관 분석, 다중 회귀분석을 적용하였다. 연구결과에서 신체상 불일치 정도는 여학생의 외모 관련 사회문화적 태도(r=.406, p=.006), 친구에 의한 압박감(r=.197, p<.001), 부모에 의한 압박감(r=.176, p=.002), 스트레스(r=.218, p<.001)와 양의 상관관계가 있는 것으로 나타났다. 신체상 불일치는 친구에 의한 압박감(${\beta}=.159$, p=.007), 스트레스(${\beta}=.186$, p=.002), BMI(${\beta}=.186$, p=.002)가 증가할수록 높게 나타났으며, 이 변수들은 대상자의 신체상 불일치에 대해 10.9%의 설명력을 보였다. 따라서 신체상 불일치를 줄이기 위해서는 대학생들이 건강 유지 목적으로 체중과 스트레스 관리를 할 수 있게 하고, 타인의 시선이나 평가로 인해 상처받지 않고, 긍정적인 자기 인식을 가질 수 있도록 하는 보건교육 및 건강증진 프로그램 개발이 요구된다.