• Title/Summary/Keyword: experimental stress analysis

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An experimental study of the effects of Husband s supportive behavior reinforcement education on stress relief of primigravidas (초임부의 스트레스감소에 미치는 지지강화교육의 효과에 관한 실험적 연구)

  • 안황란
    • Journal of Korean Academy of Nursing
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    • v.15 no.1
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    • pp.5-16
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    • 1985
  • This study examined the effects of husband's supportive behavior reinforcement education on stress relief of primigravidas. The purpose was to reinforce husbands' supportive behavior and relieve primigravidas' stress. The purposes of this study were to determine lactors influencing Primigravidas' stress and the effect of husbands' supportive behavior reinforcement education on stress relief of primigravidas. The subjects, consisting of 140 primigravidas who registered or visited in three obstetrics and gynecology clinics in J city, were divided into at random experimental and control groups. Data were collectpe from April To July, 1984 through interviews during hospital visits, and by questionaires. The husbands' supportive behavior reinforcement education and the measurement tools were developed by the investigator from the literature and during pilot study: the instruments to measure primigravidas' stress and husbands' supportive behavior were tested for reliability and validity. Personality characteristisc were measured by Chestnuts' Stress Management instrument. T-test, ANOVA, ω², and Pearson Correlation were used in analysing the data to confirm the intensity of the influence and the relation between general characteristics and primigravidas' stress. Pearson correlation and Stepwise Multiple Regression were used to confirm the predictors of primigravidas' stress. Independent variables were compared by means of t-test and χ³-test to confirm significant discrepancy of experimental and control groups. T-test, paired t-test, pearson correlation were used in analyzing the data to confirm the effect of husband's supportive behavior reinforcement education on stress relief of primigravidas. The results of the study are summarized. Results from analyzing the effect of husbands' supportive behavior reinforcement education: There was no significant difference between the general characteristics of the experimental and control groups. And husbands' supportive behavior, personality, marital Satisfaction, natural abortion variables influenced at primigravidas' stress. A hypothetical test by comparative analysis of the measurement of primigravidas' stress and husbands' support behavior between the experimental and the control group before and after the experiment to confirm the effect of husbands' supportive behavior reinforcement education resulted in the following: The first hypothesis that husbands' supportive behavior reinforcement education will increase husbands' support behavior to relieve primigravidas' stress was supported. The second hypothesis that husbands' supportive behavior reinforcement education will relieve primigravidas' stress was supported. As a result, it u·as shown that husbands' supportive behavior reinforcement education relieved primigravidas' stress, and the hypotheses were supported. The third hypothesis that the higher the degree of husbands' supportive behavior, the lower the primigravidas' stress was supported. It was concluded that husbands' supportive behavior reinforcemen education increase husbands' supportive behavior and relieves Primigravidas' stress.

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Comparison analysis of psychological and biochemical indices of chronic life stress

  • Kim, Dongsoo;Park, Se-kwon;Chung, Yeon-Soo;Moon, Soo-Jong
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2003.10b
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    • pp.162-162
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    • 2003
  • The psychological and biochemical stress responses of healthy men and women were measured under the normal situation. Experimental subjects, who were cadets of the Korea Air Force Academy, were selected by the random sampling. Quantitative scaling of the psychological stress was obtained by life stress test(Cheon et al, 2000) and Minnesota Multiphasic Personality Inventory(MMPI).(omitted)

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Finite Element Analysis of Creep Crack Growth Behavior Including Primary Creep Rate (1차 크리프 속도를 고려한 크리프 균열 진전의 유한요소 해석)

  • Choi, Hyeon-Chang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.7 s.166
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    • pp.1120-1128
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    • 1999
  • An elastic-viscoplastic finite element analysis is performed to investigate detailed growth behavior of creep cracks and the numerical results are compared with experimental results. In Cr-Mo steel stress fields obtained from the crack growth method by mesh translation were compared with both cases that the secondary creep rate is only used as creep material property and the primary creep rate is included. Analytical stress fields, Riedel-Rice(RR) field, Hart-Hui-Riedel(HR) field and Prime(named in here) field, and the results obtained by numerical method were evaluated in details. Time vs. stress at crack tip was showed and crack tip stress fields were plotted. These results were compared with analytical stress fields. There is no difference of stress distribution at remote region between the case of 1st creep rate+2nd creep rate and the case of 2nd creep rate only. In case of slow velocity of crack growth, the effect of 1st creep rate is larger than the one of fast crack growth rate. Stress fields at crack tip region we, in order, Prime field, HR field and RR field from crack tip.

THE THREE DIMENSIONAL FINITE ELEMENT ANALYSIS OF THE STRESS DISTRIBUTION IN THE THREE TREATMENT OPTIONS OF IMPLANTS RESTORATIONS FOR THE POSTERIOR PARTIAL EDENTULISM (구치부 부분 무치악 결손에서 유용한 세 가지 임프란트 수복법들의 응력분산에 관한 3차원 유한요소법적 비교연구)

  • Kim, Il-Kyu;Lee, Hyeung-Uk;Ryu, Seung-Hyun;Choi, Jin-Ho;Han, Ye-Sook;Son, Choong-Yul;Byun, Hyo-In
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.30 no.3
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    • pp.175-180
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    • 2004
  • In this study, three treatment options to replace two posterior missing teeth were investigated using three dimensional finite element analysis: two wide(${\phi}5.0mm$) implants(the experimental model I), two standard(${\phi}3.75mm$) implants(the experimental model II), and three standard(${\phi}3.75mm$) implants(the experimental model III). Two kinds of load case were applied ; 1) perpendicular on occlusal surface(axial load), parallel on occlusal surface(lateral load). 2) perpendicular on occlusal surface(3mm lateral to central point). The results obtained from this study were as follows; value of Von-mises stress (equivalent stress) was smallest in the two wide implant among the three experimental models. It was reported that the diameter is the efficient factor than osseointegrated surface area.

Die Design for the Hot Extrusion with TiB$_2$Insert (TiB$_2$ 인서트를 체결한 열간압출 금형설계 및 제작)

  • Kwon, Hyuk-Hong;Lee, Jung-Ro
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.9
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    • pp.118-124
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    • 2002
  • The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The shrink fit analysis has been performed that enables optimal design of the dies taking into account the elastic deflections which generated in shrink fitting the die inserts and that caused by the stresses generated in the process and by using DEFORM software for process analysis. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the die design. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.

Fatigue life evaluation of socket welded pipe with incomplete penetration defect: I-test and FE analysis

  • Lee, Dong-Min;Kim, Seung-Jae;Lee, Hyun-Jae;Kim, Yun-Jae
    • Nuclear Engineering and Technology
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    • v.53 no.11
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    • pp.3852-3859
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    • 2021
  • This paper presents experimental and numerical analysis results regarding the effects of an incomplete penetration defect on the fatigue lives of socket welded pipes. For the experiment, four-point bending fatigue tests with various defect geometries (defect depth and circumferential length) were performed, and test results are presented in terms of stress-life data. The results showed that for circumferentially short defects, the fatigue life tends to increase with increasing crack depth, but for longer defects, the trend becomes the opposite. Finite element analysis showed that for short defects, the maximum principal stress decreases with increases in crack depth. For a longer defect, the opposite trend was found. Furthermore, the maximum principal stress tends to increase with an increase in defect length regardless of the defect depth.

The Fatigue Behavior by Variety of Crack Length of Surface Cracked Plate with Stress Concentration Part (응력집중부를 갖는 표면균열재의 균열길이 변화에 따른 피로거동)

  • 남기우;김선진
    • Journal of Ocean Engineering and Technology
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    • v.9 no.1
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    • pp.83-91
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    • 1995
  • Surface defects in structural members are apt to be origins of fatigue cracks growth, which may cause serious failure of whole structures. Most structure has a part where stress concentrates such as welded joints, corner parts, etc. And then, analysis on crack growth and penetration from these defects, therefore, is one of the most important subjects for the reliability of LBB design. The present paper has performed an experimental and analysis on the fatigue crack propagation by variety in crack length of surface cracked plate with stress concentration part. The crack growth behavior can be explained quantitatively by using Newman-Raju equation and the stress partitioning method proposed by ASME B&P Code Sec. XI. The stress concentration factor $K_t$ has affected on the crack growth. The crack growth after penetration depends upon the initial front side crack length.

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Stress-strain behavior of geopolymer under uniaxial compression

  • Yadollahi, Mehrzad Mohabbi;Benli, Ahmet
    • Computers and Concrete
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    • v.20 no.4
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    • pp.381-389
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    • 2017
  • The various types of structural materials that are available in the construction industry nowadays make it necessary to predict their stress-strain behavior. Geopolymer are alternatives for ordinary Portland cement concrete that are made from pozzolans activation. Due to relatively new material, many mechanical specifications of geopolymer are still not yet discovered. In this study, stress-strain behavior has been provided from experiments for unconfined geopolymers. Modulus of Elasticity and stress-strain behavior are critical requirements at analysis process and knowing complete stress-strain curve facilitates structural behavior assessment at nonlinear analysis for structures that have built with geopolymers. This study intends to investigate stress-strain behavior and modulus of elasticity from experimental data that belongs for geopolymers varying in fineness and mix design and curing method. For the sake of behavior determination, 54 types of geopolymer are used. Similar mix proportions are used for samples productions that have different fineness and curing approach. The results indicated that the compressive strength ranges between 7.7 MPa and 43.9 MPa at the age of 28 days curing.

Cold expansion effect on the fatigue crack growth of Al 6082: numerical investigation

  • Aid, Abdekrim;Semari, Zahar;Benguediab, Mohamed
    • Structural Engineering and Mechanics
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    • v.49 no.2
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    • pp.225-235
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    • 2014
  • Cold expansion is an efficient way to improve the fatigue life of an open hole. In this paper, three finite element models have been established to bind the crack growth from an expanded hole and simulated. Expansion and its degree influence are studied using a numerical analysis. Stress intensity factors are determined and used to evaluate the fatigue life. Residual stress field is evaluated using a nonlinear analysis and superposed with the applied stresses field in order to estimate fatigue crack growth. Experimental tests are conducted under constant loading. Results of this investigation indicate expansion and its degree are beneficial to fatigue life and a good agreement was observed between FEM simulations and experimental results.

The Measurement of Real Deformation Behavior in Pilot LNG Storage Tank Membrane by using Strain Gage (스트레인 게이지를 이용한 Pilot LNG 저장탱크 멤브레인 실 변형 거동 측정)

  • Kim, Young-Kyun;Yoon, Ihn-Soo;Oh, Byoung-Taek;Hong, Seong-Ho;Yang, Young-Myung
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.108-113
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    • 2004
  • Korea Gas Corp. has developed the design technology of the LNG storage tank. The membrane to be applied inside of the LNG storage tank is provided with corrugations to absorb thermal contraction and expansion caused by LNG temperature changes. It is very important to measure their thermal strains under LNG temperatures by analytical and experimental stress analysis of the membrane. We have developed a stress measurement system using strain gages and measured the strain during cooldown and storing the LNG. We also analyzed the measured data by comparison with the FEM data. On the basis of these results, we could design and assure the application of the Kogas Membrane to large scale LNG storage.

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