• Title/Summary/Keyword: body stress

Search Result 2,341, Processing Time 0.032 seconds

Fracture mechanical evaluation of fatigue strength of a single spot welded lap joint under tension-shear load (인장-전단하중을 받는 일점 Spot용접재의 파괴역학적 피로강도 평가)

  • 배동호
    • Journal of the korean Society of Automotive Engineers
    • /
    • v.13 no.5
    • /
    • pp.42-50
    • /
    • 1991
  • According as the members and inner and outer plates of the automobile body structure have been thinned their thickness and have become high strength, each part of the body structure has been put more severe stress condition. Therefore, it has been increasingly required to improve the fatigue strength of the spot welded structures. As one of the improving methods for such problem, the author had previously proposed the method of alleviating stress concentration at nugget edge of the spot weld part and improving its fatigue strength [1]. But, because fatigue strength of the spot welded lap joint is influenced by its geometrical and mechanical factors, welding condition and etc., there needs a quantitative and systematic estimation method of them. In this report, by considering nugget edge of the spot weld part of the spot welded lap joint subjected to tensile load to the ligament crack, fatigue strength of various spot welded lap joints was estimated with the stress intensity factor (S.I.F.) K which is fracture mechanical parameter. It is known that evaluation of fatigue strength of the spot welded lap joint by the stress intensity factor (S.I.F.) K is more effective than the maximum stress $(\sigma_{ymax}$) at edge of the spot weld part on the center line of width of the plate.

  • PDF

A Flexible Multi-body Dynamic Model for Analyzing the Hysteretic Characteristics and the Dynamic Stress of a Taper Leaf Spring

  • Moon Il-Dong;Yoon Ho-Sang;Oh Chae-Youn
    • Journal of Mechanical Science and Technology
    • /
    • v.20 no.10
    • /
    • pp.1638-1645
    • /
    • 2006
  • This paper proposes a modeling technique which is able to not only reliably and easily represent the hysteretic characteristics but also analyze the dynamic stress of a taper leaf spring. The flexible multi-body dynamic model of the taper leaf spring is developed by interfacing the finite element model and computation model of the taper leaf spring. Rigid dummy parts are attached at the places where a finite element leaf model is in contact with an adjacent one in order to apply contact model. Friction is defined in the contact model to represent the hysteretic phenomenon of the taper leaf spring. The test of the taper leaf spring is conducted for the validation of the reliability of the flexible multi-body dynamic model of the taper leaf spring developed in this paper. The test is started at an unloaded state with the excitation amplitude of $1{\sim}2mm/sec$ and frequency of 132 mm. First, the simulation is conducted with the same condition as the test. Then, the simulations are conducted with various amplitudes in a loaded state. The hysteretic diagram from the test is compared with the ones from the simulation for the validation of the reliability of the model. The dynamic stress analysis of the taper leaf spring is also conducted with the developed flexible multi-body dynamic model under a dynamic loading condition.

Elastic-plastic Analysis of a 3-Dimensional Inner Crack Using Finite Element Alternating Method (유한요소 교호법을 이용한 삼차원 내부 균열의 탄소성 해석)

  • Park, Jai-Hak;Park, Sang-Yun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.31 no.10
    • /
    • pp.1009-1016
    • /
    • 2007
  • Finite element alternating method has been suggested and used effectively to obtain the fracture parameters in assessing the integrity of cracked structures. The method obtains the solution from alternating independently between the FEM solution for an uncracked body and the crack solution in an infinite body. In the paper, the finite element alternating method is extended in order to obtain the elastic-plastic stress fields of a three dimensional inner crack. The three dimensional crack solutions for an infinite body were obtained using symmetric Galerkin boundary element method. As an example of a three dimensional inner crack, a penny-shaped crack in a finite body was analyzed and the obtained elastc-plastic stress fields were compared with the solution obtained from the finite element analysis with fine mesh. It is noted that in the region ahead of the crack front the stress values from FEAM are close to the values from FEM. But large discrepancy between two values is observed near the crack surfaces.

The Effect of Stress Reduction of Human Body by the Vibroacoustic Equipment (음향진동장치에 의한 인체의 스트레스 저감효과)

  • Moon, D.H.;Kim, Y.W.;Kang, H.J.;Choi, M.S.
    • Proceedings of the KSME Conference
    • /
    • 2007.05a
    • /
    • pp.1063-1068
    • /
    • 2007
  • The present study describes the effects of music and vibroacoustic stimuli to the relaxation of human body. We have carried out the experiment on 6 human subjects of which are composed 3men and 3women. We have investigated the electroencephalogram(EEG) of all subjects before and after the stimuli of which are made a strong noise or the meditatiom music and the acoustic vibration. The vibroacoustic device has transmitted meditation music as vibration between 20Hz and 250Hz to the body. From the experimental results, we made sure the effects that the meditation music and vibroacoustic stimuli influenced the stress reduction of human body for good as alpha-wave was increased continuously during the good stimuli and after that.

  • PDF

Mind-body Intervention for Treating Atopic Dermatitis (아토피 피부염 치료를 위한 심신의학적 접근)

  • Cho, Il-Young;Park, Soon-Kwon
    • The Journal of the Korea Contents Association
    • /
    • v.8 no.11
    • /
    • pp.242-250
    • /
    • 2008
  • Patients with atopic dermatitis, an intractable disease, suffer uncontrollable psychological distress as well as various symptoms in their skin. Recent findings showed that mental factors such as stress may play a role in the disease and that some techniques for alleviating psychological problems were efficacious in the atopic dermatitis. Therefore, we proposed the mind-body medicine that has been used to decrease the negative influences of stress and to cure psychosomatic disorders as an additional remedy for the atopic dermatitis. A model on the therapeutic effect of mind-body medicine and some qualities of practician also were discussed.

Factors affecting Quality of Life according to BMI of Women College Students (여대생의 체질량지수 군에 따른 삶의 질 영향 요인)

  • Yom, Young-Hee;Chang, Hae Kyung
    • Journal of Korean Academy of Fundamentals of Nursing
    • /
    • v.20 no.2
    • /
    • pp.168-176
    • /
    • 2013
  • Purpose: The purpose of this study was to identify factors affecting quality of life according to Body Mass Index (BMI) of women college students. Methods: The research design was a descriptive survey design using a convenience sampling. Data were collected using self-report questionnaires. Participants were 348 women college students. Data analysis was done using SPSS/WIN 18.0 program for descriptive statistics, Pearson correlation coefficients and hierarchial multiple regression. Results: According to BMI, 3 groups of students were identified. Differences between the groups for quality of life were significant. The major factors affecting quality of life in the underweight group were departments (college), body stress and ego-resilience which explained 27.9% of the variance in quality of life. Body stress and ego-resilience were significant predictors explaining 23.1% of the variance in quality of life in the normal weight group. Ego-resilience was also a significant predictor in the overweight group explaining 15.2% of the variance in quality of life. Conclusion: Findings indicate a need to decrease body stress and strengthen ego-resilience to improve quality of life of women college students. Further studies are needed to examine nursing intervention strategies for improving quality of life for women college students.

Associations between Job Stress and Work-related Musculoskeletal Symptoms in Street Sanitation Workers (거리 환경미화원의 직무 스트레스와 근골격계 증상 간의 관련성)

  • Kim, Hye-Jin;June, Kyung-Ja;Shin, Gyeyoung;Choo, Jina
    • Research in Community and Public Health Nursing
    • /
    • v.24 no.3
    • /
    • pp.314-322
    • /
    • 2013
  • Purpose: The purpose of the study was to examine associations between job stress and work-related musculoskeletal symptoms (WRMS) in street sanitation workers. Methods: A cross-sectional correlational study was conducted with 87 male street sanitation workers at E Gu in Seoul. The Job stress and WRMS were measured by using the Korean Occupational Stress Scale-Short Form and the KOSHA GUIDE H-9-2012 instrument, respectively. The WRMS was evaluated according to the National Institute of Occupational Safety and Health criteria. Results: The participants reported greater levels of insufficient job control and interpersonal conflict than the general Korean population. Of the participants, 44.8% reported WRMS at any body parts. Specifically, 28.7% reported WRMS at upper parts, while 16.5% reported WRMS at lower parts. Compared to low levels of job demand, its high levels were significantly associated with WRMS at both upper and lower parts of the body (OR=3.62, 95% CI=1.15~11.38; OR=3.60, 95% CI=1.04~12.39). Compared to low levels of occupational climate, its high levels were significantly associated with WRMS at upper parts of the body (OR=3.18, 95% CI=1.22~8.26). Conclusion: Among street sanitation workers, job stress may be a correlate of WRMS. Therefore, nursing strategies for reducing job stress are needed to prevent and manage WRMS.

The Effects of a Compound Exercise and a Walking Exercise Program on Body Composition, Perceived Health Status, and Stress for Thin-Obesity College Women (복합운동과 걷기운동 프로그램이 여대생의 체구성, 건강상태 지각 및 스트레스에 미치는 효과 비교: 마른 비만 대상자를 중심으로)

  • Yoo, Jae-Hee;Jo, Hyun-Sook
    • Korean Journal of Health Education and Promotion
    • /
    • v.26 no.4
    • /
    • pp.91-103
    • /
    • 2009
  • Objectives: The purpose of this study was to compare the effects of a 8-week compound exercise and a home-based walking exercise on body composition, perceived health status, and stress of nursing students. Methods: A non-equivalent control group design with pre-post test was employed. Participants, having BMI below 23 and Percent Body Fat above 26%, were assigned to three groups; 21 for the compound exercise(A), 26 for the walking exercise(B), and 23 for the control group. For data analysis, ANOVA in SPSS was used. Results: Body Fat Mass(kg), Visceral Fat Area(cm2), and Percent Body Fat(%) of both group A and B were significantly decreased. Lean Body Mass(kg) and Fitness Score of both group A and B were significantly increased in comparing with the control group. Especially the score of PBF(%) in group A was significantly decreased than the group B. The perceived physical health status in both group A and B was significantly increased. Conclusion: Both 8-week compound exercise and walking exercise were effective in enhancing BFM(kg), VFA($cm^2$), PBF(%), LBM(kg), Fitness Score and perceived physical health status. Especially the Compound exercise program was much more effective in decreasing PBF(%) than the walking exercise program.

Bounary Element Analysis of Thermal Stress Intensity Factors for Cusp Cracks (커스프 균열에 대한 열응력세기 계수의 경계요소해석)

  • 이강용;조윤호
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.14 no.1
    • /
    • pp.119-129
    • /
    • 1990
  • In case that the body with a cusp crack is under uniform heat flow, thermal stress intensity factors are calculated by using boundary element method with linearized body force term. The crack surface is under insulated or fixed temperature condition and the types of crack are symmetric lip and airfoil cusps. Numerical values of thermal stress intensity factors for a Griffith crack and cusp cracks in infinite bodies are proved to be in good agreement within .+-.5% when compared with the previous numerical and exact solutions, respectively. The thermal stress intensity factors for symmetric lip and airfoil cusp cracks in finite bodies are calculated about various effective crack lengths, configuration parameters, and heat flow directions. With the same crack surface thermal boundary conditions, heat flow directions and crack lengths, there are no appreciable differences in variations of thermal stress intensity factors between symmetric lip and airfoil cusp cracks. The signs of thermal stress intensity factors for each cusp crack are changed with each crack surface thermal boundary condition.

Studies on Self-Selection of 3 macronutrients and the Effect of Electric Stress on Food Selection in Male Rats (3대 열량소를 스스로 선택하게 했을 때 흰쥐의 식이 선택성향 및 저전류 Stress가 이에 미치는 영향)

  • 장영애
    • Journal of Nutrition and Health
    • /
    • v.23 no.7
    • /
    • pp.504-512
    • /
    • 1990
  • In experiment 1, dietary self-selection of the 3 macronutrients, protein, fat, and carbohydrate were examined in male rats given 3 food cups of 80% carbohydrate, 80% protein, and 70% fat diets simultaneously. All the rats showed normal growth pattern and organ weight, which means they have ability to select just right kinds and amounts of nurients in order to support their growth and development. Mean values of caloric intake, body weight gain, serum lipid values and empty carcass compositions were not significantly differ between the upper and lower quartile groups of fat proportion of empty carcass compared to the lower quartile group(LF). Same feeding design was employed in experiment 2 where the effect of mild electric stress on food selection was studied. The rats in both control and electric stress group revealed a normal growth curve and organ weights. The rats in both control and electric stress group revealed a normal growth curve and organ weights. The stress group showed higher caloric intake and body weight gain than control group, but no significant effects of stress on serum and empty carcass components was found. Even though normal rats seemed to select macronutrients according to their physiolosical needs, there were individual differences in food selection whether they were exposed to stress or not. Therefore life long individual food selection pattern may have a great influence on nutritional status and chronic degenerative diseases of eldery, and on aging process.

  • PDF