• Title/Summary/Keyword: Examination stress

Search Result 756, Processing Time 0.027 seconds

FINITE ELEMENT ANALYSIS AND MEASUREMENT ON THE RELEASE OF RESIDUAL STRESS AND NON-LINEAR BEHAVIOR IN WELDMENT BY MECHANICAL LOADING(I) -FINITE ELEMENT ANALYSIS-

  • Jang, Kyoung-Bok;Kim, Jung-Hyun;Cho, Sang-Myoung
    • Proceedings of the KWS Conference
    • /
    • 2002.10a
    • /
    • pp.378-383
    • /
    • 2002
  • In previous study, the decrease and recovery of total stiffness in welded structure was discussed on the basis of experimental examination through tensile loading and unloading test of welded specimen. The recovery of structure stiffness was caused by the release of welding residual stress through mechanical loading. In this study, analysis model that is indispensable for the effective application of MSR method was established on the basis of test and measurement result. Thermal elasto-plastic analysis for welding process was performed by non-coupled analysis. Analysis results of welding process were transfer to elasto-plastic model for tensile loading & unloading by restart technique. In elasto-plastic analysis model for mechanical loading & unloading, hardening appearance of weld metal was considered by rezoning technique and tying technique was used for JIG condition of test machine.

  • PDF

Effect of Compressive Residual Stress on the High Temperature fatigue Crack Propagation Behavior of Shot-peened Spring Steel (압축잔류응력이 스프링강의 고온환경 피로균열 진전거동에 미치는 영향)

  • 정찬기;박경동
    • Journal of Ocean Engineering and Technology
    • /
    • v.16 no.5
    • /
    • pp.73-79
    • /
    • 2002
  • In this paper, the effect of the compressive residual stresses was obtained at the test conditions of the higher temperature than the ambient temperature. The examination was performed with the CT specimen result of the material(JISG SUP9) which is being commonly used for the marine engine parts and the ocean structures. As a result, the test conditions at the higher temperature were acquired considering the peak values of the compressive residual stresses of the specimens and the effect on the fatigue crack propagation speed da/dN in stage II and the threshold stress intensity factor range Δth in stage I. Also the material constant C and the fatigue crack propagation index m in the formula of Paris Law da/dN=C (ΔK)$^{m}$ were suggested to estimate the dependence on the test temperature.

A study on the eigenvector analyses for V-notched cracks in Anisotropic Dissimilar Materials by the Reciprocal Work Contour Integral Method (상반일 등고선 적분법(RWCIM)을 이용한 이방성 이종재료 내의 V-노치 균열에 대한 고유벡터 해석)

  • Roh, Hong-Rae;Kim, Jin-Kwang;Cho, Sang-Bong
    • Proceedings of the KSME Conference
    • /
    • 2000.04a
    • /
    • pp.115-120
    • /
    • 2000
  • This paper examines that it is possible to apply RWCIM for determining eigenvector coefficients associated with eigenvalues for V-notched cracks in anisotropic dissimilar materials using the complex stress function. To verify the RWCIM algorithm, two tests will be shown. First it is performed to ascertain whether predicted coefficients associated with eigenvectors is obtained exactly. Second, it makes an examination of the state of stress for FEM and RWCIM according to a number of eigenvectors at a location far away from the V-notched crack tip.

  • PDF

A Study on Factors Affecting the Elderly Suicidal Ideation in Korea (우리나라 노인의 자살생각에 영향을 미치는 요인에 관한 연구)

  • Sohn, Shin-Young
    • The Korean Journal of Health Service Management
    • /
    • v.8 no.2
    • /
    • pp.149-160
    • /
    • 2014
  • The suicide rate in the elderly is continually increasing. Effective suicide prevention requires that factors affecting suicidal ideation are specifically identified and personalized intervention programs are developed. This study aimed to identify the influencing factors of suicidal ideation in Korean elderly. The data of the 2012 Korean National Health & Nutrition Examination Survey was analyzed by using the SPSS program. Frequency, percentile, Chi-square test, multiple logistic regression were used. The influencing factors of suicidal ideation were education, income, exercise, perceived stress and depression. The Odds Ratio of the depression was 5.68 and the Odds Ratio of the perceived stress was 3.45. This study suggested that elderly suicidal prevention programs should be developed in preventing and reducing stress and depression.

Effect of axial load on flexural behaviour of cyclically loaded RC columns

  • Au, F.T.K.;Bai, Z.Z.
    • Computers and Concrete
    • /
    • v.3 no.4
    • /
    • pp.261-284
    • /
    • 2006
  • The flexural behaviour of symmetrically reinforced concrete (RC) columns cast of normal- and high-strength concrete under both monotonic and cyclic loading is studied based on an analytical procedure, which employs the actual stress-strain curves and takes into account the stress-path dependence of concrete and steel reinforcement. The analysis is particularly extended into the post-peak stage with large inelastic deformation at various applied axial load level. The effect of axial load on their complete flexural behaviour is then identified based on the results obtained. The axial load is found to have fairly large effect on the flexural behaviour of RC columns under both monotonic and cyclic loading. Such effects are discussed through examination of various aspects including the moment-curvature relationship, moment capacity, flexural ductility, variation of neutral axis depth and steel stress.

Response of the Higher Basidiomycetic Ganoderma resinaceum to Sodium Chloride Stress

  • Mahmoud, Yehia A.-G.;Mohamed, Eman H. F. A.;E. H. F., Abd Elzaher
    • Mycobiology
    • /
    • v.35 no.3
    • /
    • pp.124-128
    • /
    • 2007
  • Ganoderma resinaceum tolerated sodium chloride salt stress within a range of 0 mM till 300 mM. It responded to salt stress with fluctuation in proline formation at different NaCl concentrations. However, the mycelial dry weight, total protein contents and exopolysaccharides did not changed considerably. Increasing sodium chloride concentration led to morphological alteration in fungal mycelia with disappearance of fungal cell wall, plasmolysis, and vacuolation as indicated with electron microscopic examination of the fungal growth.

Finite Element Analysis and Measurement on the Release of Residual Stress and Non-linear Behavior in Weldment by Mechanical Loading(I) -Finite Element Analysis-

  • Jang, K.B.;Kim, J.H.;Cho, S.M.
    • International Journal of Korean Welding Society
    • /
    • v.2 no.1
    • /
    • pp.29-32
    • /
    • 2002
  • In previous study, the decrease and recovery of total stiffness in welded structure was discussed on the basis of experimental examination through tensile loading and unloading test of welded specimen. The recovery of structure stiffness was caused by the release of welding residual stress through mechanical loading. In this study, analysis model that is indispensable for the effective application of MSR method was established on the basis of test and measurement result. Thermal elasto-plastic analysis for welding process was performed by non- coupled analysis. Analysis results of welding process were transfer to elasto-plastic model for tensile loading & unloading by restart technique. In elasto-plastic analysis model for mechanical loading & unloading, hardening appearance of weld metal was considered by rezoning technique and tying technique was used for JIG condition of test machine.

  • PDF

Eating Habits of the University Students affected by Stress Levels in the Areas of Seoul and Gangwon Province (서울과 강원 일부지역 대학생들의 스트레스 정도가 식습관에 미치는 영향)

  • Lee, Jeongsill
    • The Korean Journal of Food And Nutrition
    • /
    • v.28 no.5
    • /
    • pp.782-793
    • /
    • 2015
  • The purpose of this study is the examination of stress levels and the eating habits that are affected by stress, and the provision of basic nutritional education data for the improvement of the eating habits of students who have experienced stress-related nutritional problems. Using the BEPSI-K instruments, a questionnaire survey was administered to 327 student subjects (166 male and 161 female) in the areas of Seoul and Gangwon province. The subjects were classified into 3 groups (low-stress, medium-stress and high-stress), and 59 students (18%) belonged the high-stress group. The BMI readings of the Gangwon province students are significantly higher than those of the Seoul students. The survey results show that the lunch frequency and vegetable intake levels are lower in the high-stress group, whereas the intakes of hot spicy food is higher in this group; they also show that Gangwon province students had eating habits that are relatively undesirable compared with the Seoul students. There are significant differences between the Seoul students and Gangwon porvince students regarding residence type, household economic level, types of leisure activities and level of some stresses. The Gangwon province students ate occasionally breakfast, lunch and snacks, but their midnight snack consumption is relatively frequent compared with the Seoul students. The results of the survey indicate that the BEPSI-K score has a negative correlation with the following variables : sleeping time, economic level of household, degrees of satisfaction regarding appearance and academic achievements, lunch frequency and vegetable intakes. Desirable eating habits are essential for the maintenance of a favorable health status and for the stress-management of university students who need to be a healthy members of society in the near future. To facilitate the formation of desirable eating habits among university students, community-based nutritional assistance and appropriate nutritional education programs should be considered necessary.

Effects of Dental Hygienists Job Stress on Somatization in an Area

  • Kim, Mi-Jeong;Kim, Hyeon-Sun;Lim, Cha-Young
    • Journal of dental hygiene science
    • /
    • v.20 no.1
    • /
    • pp.59-66
    • /
    • 2020
  • Background: This study aims to analyze the job stress of dental hygienists and the factors affecting somatization and to provide basic data for effectively managing job stress and somatization of dental hygienists. Methods: In this study, the data collected from 208 dental hygienists working in Jeollabuk-do Province were analyzed. Job stress was investigated using a questionnaire with 43 questions. In addition, the degree of somatization was evaluated through a simplified psychotherapy examination (Symptom Check List-90-Revision). Results: Age, employment history, position, average monthly income, night duty execution status, and perceived health status were significantly associated with job stress (p<0.05). The job stress sub-items scores based on general characteristics showed significance in 'workload' for those working a five-day workweek and perceived health status (p<0.05). Age, average monthly income, and perceived health status were noted in 'role conflict as a professional'. In 'lack of expertise and skill', it was noted that age, employment history, position, income, and night clinic were implemented. In 'improper treatment and interpersonal issues', level of education and perceived health status were significant (p<0.05). The higher the job stress, the higher the somatization symptom score (p<0.05), and the higher the job stress component, the higher the somatization symptom score (p<0.01). Conclusion: The job stress of dental hygienists should be reduced, and the symptoms of somatization should be mitigated. To improve the quality of medical services and the work efficiency of dental hygienists, proper treatment and compensation systems should be implemented for them to take pride as professional. Further, programs and regulations on mitigating job stress and somatization symptoms should be developed.

Investigation of microstructure and surface effects on vibrational characteristics of nanobeams based on nonlocal couple stress theory

  • Shariati, Ali;Barati, Mohammad Reza;Ebrahimi, Farzad;Toghroli, Ali
    • Advances in nano research
    • /
    • v.8 no.3
    • /
    • pp.191-202
    • /
    • 2020
  • The article brings the study of nonlocal, surface and the couple stress together to apparent the frequency retaliation of FG nanobeams (Functionally graded). For the examination of frequency retaliation, the article considers the accurate spot of neutral axis. This article aims to enhance the coherence of proposed model to accurately encapsulate the significant effects of the nonlocal stress field, size effects together with material length scale parameters. These considered parameters are assimilated through what are referred to as modified couple stress as well as nonlocal elasticity theories, which encompasses the stiffness-hardening and softening influence on the nanobeams frequency characteristics. Power-law distribution is followed by the functional gradation of the material across the beam width in the considered structure of the article. Following the well-known Hamilton's principle, fundamental basic equations alongside their correlated boundary conditions are solved analytically. Validation of the study is also done with published result. Distinct parameters (such as surface energy, slenderness ratio, as nonlocal material length scale and power-law exponent) influence is depicted graphically following the boundary conditions on non-dimensional FG nanobeams frequency.