• Proceedings of the KSME Conference
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• 2000.11a
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• pp.849-855
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• 2000

This study evaluated the effect of restraint of pressure induced bending(PIB) on crack mouth opening displacement(CMOD) for circumferential through-wall crack in pipe by using both elastic and elastic-plastic finite element analyses. The analyses results showed the restraint of PIB was decreased crack opening for a given crack length and tensile stress, and the effect was considerable for large crack and short restraint length. Also, the restraint effect on CMOD was independent on the variation in pipe diameter and decreased with increasing pipe thickness, and it depended on not total restraint length but short restraint length for non-symmetrically restrained. Additionally, the effect of restraint of PIB was more significant in the elastic-plastic analysis results compared with in the elastic analysis results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1134-1141
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• 2006

This paper presents the model for evaluating restraint effect of pressure induced bending (PIB) on the circumferential through-wall crack opening displacement (COD), which considers plastic behavior of crack. This study performed three-dimensional elastic-plastic finite element (FE) analyses for different crack angle, restraint length, pipe geometry, stress level, and material conditions, and evaluated the influence of each parameter on the PIB restraint effect on COD. Based on these evaluations and additional perfectly-plastic FE analyses, a closed-form model to evaluate the restraint effect of PIB on the plastic crack opening of circumferential through-wall crack, was proposed as functions of crack angle, restraint length, radius to thickness ratio, axial stress corresponding to an internal pressure, and normalized COD evaluated from linear-elastic crack opening condition.

• Nuclear Engineering and Technology
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• v.39 no.1
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• pp.75-84
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• 2007

This paper presents a closed-form model for evaluating the restraint effect of pressure induced bending on the opening of a circumferential through-wall crack, which is considered plastic deformation behavior. Three-dimensional finite element analyses with different crack lengths, restraint conditions, pipe geometries, magnitudes of internal pressure, and tensile properties were used to investigate the influence of each parameter on the pressure-induced bending restraint on the crack opening displacement. From these investigations, an analytical model based on elastic-perfectly plastic material was developed in terms of the crack length, symmetric restraint length, mean radius to thickness ratio, axial stress corresponding to the internal pressure, and normalized crack opening displacement evaluated from a linear-elastic crack opening condition. Finite element analyses results demonstrate that the proposed analytical model reliably estimated the restraint effect of pressure-induced bending on the plastic crack opening of a circumferential through-wall crack and properly reflected the dependence on each parameter within the range over which the analytical expression was derived.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1873-1880
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• 2001

The effects of restraint of pressure induced bending(PIB) on crack opening for circumferential through-wall crack in a pipe were investigated. In this study, the elastic and elastic-plastic finite element analyses were performed to evaluate crack opening displacement(COD) for various restraint conditions and crack size. The results showed the restraint of PIB decreased crack opening for a given crack size and tensile stress, and the decrease in crack opening was considerable for large crack and short restraint length. A1so, the effect was more significant in tole results of elastic-plastic analysis compared with in the elastic analysis results. In the elastic-plastic analysis results, tole restraint effect was increased with increasing applied tensile stress corresponding to internal pressure. Additionally, the restraint effect on COD was independent on the variation in pipe diameter and decreased with increasing pipe thickness, and It depended on not total restraint length but shorter restraint length for non-symmetrically restrained.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.275-279
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• 1996

In this study, the effect of external restraint on the thermal stresses and thermal cracking mode in mass concrete are analysed using the two major factors affecting external restraint such as the ratio of width go height of the placed structure (L/H) and the elastic modulus of base structure (E). For this parametric study, many cases with different values of L/H and Er are analysed by the FEM program and the co-relationship of the those major factors is examined. To evaluate the effect of external restraint on the thermal behavior of placing structure, internal restraint stress caused by temperature difference is subtracted from total thermal stress. In the case of small value of L/H or Er, it shows as internally restricted mode indicating maximum tensile stress in surface at early age, and the external restraint makes the possibility of thermal cracking higher. However, in the case of the large values of L/H and Er, the crack index at center is smaller than at surface due to the effect of external restraint. Thus, the initial location of the thermal crack is shifted from the surface to the center and the resulting crack is formed at later age.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.496-499
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• 2006

In this study, a practical method of shrinkage stress analysis on concrete slab in multi-story building is proposed, which considers both internal restraint and external restraint variation resulting from construction sequence. The shrinkage stress due to external restraint is obtained by multiplying relaxation coefficient to elastic shrinkage stress. The additional shrinkage stress due to internal restraint is obtained by residual strain of the elastic analysis. A verification example was analyzed and compared by the proposed method and commercial analysis program that is capable of time-dependent analysis of concrete. The results of 10-story example building show that the internal restraint of reinforcement increases the shrinkage stress considerably at the slabs under loose external restraint.

• Quality Improvement in Health Care
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• v.20 no.1
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• pp.42-57
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• 2014

Objective: The objective of this research was to develop a guideline for more effective use of physical restraint on patients in the intensive care unit and training the nurses on it and applying it on clinical practice to assess its effectiveness. Method: This research analyzed the before and after effect of the development of a guideline for physical restraint by dividing the category into nurse and patient. In the case of nurse, a comparison of knowledge and nursing service regarding the use of physical restraint from before the training on physical restraint guideline(Jan. 2011) and after the training on physical restraint guideline(Dec. 2011) was made. In the case of patient, a comparison of physical restraint usage rate and average usage time, the number of unplanned extubation cases were compared from before the use of physical restraint (Jan.~Apr. 2011) and after the use of physical restraint (Sep.~Dec. 2011) were made. Result: After the training on the physical restraint guideline, the knowledge of the nurse and the nursing practice showed notable improvement by (p<0.000) and (p<0.048) respectively and in patient, physical restraint usage rate and average time of usage decreased by (p<0.001) and (p<0.001) respectively. And despite the decrease in the number of cases in which the physical restraint was used, the number of unplanned extubation cases remained the same. Conclusion: Physical restraint guideline training and guideline usage can be stated to have brought out positive effect in both the nurse and patient. In order to maintain such positive effects, continuous training is necessary and continuous revaluation is necessary, regarding knowledge and nursing practices.

• Journal of the Korean Society of Costume
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• v.16
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• pp.173-185
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• 1991

We measured change of peripheral skin temperature and mean skin temperature when the upper arm and thigh pressured in order to know the effect of skin pressure applied by clothing on blood circulation. After release from pressure, we observed also recovery condition. At the same time, we examined relation between pressure and a feeling of tightness. Three physiques of healthy females, namely slender, standard and plump, served as subjects. We used intermittent method with skin pressure applied by experimental fabric at l-minute intervals. Besides we made a comparative study with results according to different restraint method (continuous method and intermittent method). As a result of this experiment, we obtained following findings. 1. The significant difference was marked at the pressure, measuring time, physique and measuring region with change of skin temperature under upper arm and thigh restraint by intermittent method. The peripheral skin temperature decreased with the lapse of restraint time. A remarkable tendency observed according to the. increase of restraint pressure. Recovery condition after release from pressure not yet recovered to original state, for all after a lapse of 10 min. The mean skin temperature decreased with the lapse of restraint time in case of upper arm restraint, it was not an obvious tendency except 60mmHg under thigh restraint. 2. Main factor affecting the evaluation of a feeling of tightness was restraint pressure, when the upper arm and thigh restraint by intermittent method. The respondence rate of 'very tight' grew larger according to the increase of restraint pressure. The value of pressure sensation declined after restraint ten times as compared with one time, but there was difference according to restraint pressure. 3. We reexamined change of skin temperature and feeling of tightness by different restraint method(continuous method and intermittent method). The results were as follows. 1) The skin temperature decreased more greatly during skin pressure by continuous method than intermittent method, especially in the peripheral. Without different restraint method, the skin temperature of slender plysique decreased more greatly than that of plump physique. 2) The value of pressure sensation by intermittent method was highly on both sites of upper arm and thigh.

• Journal of Welding and Joining
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• v.28 no.3
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• pp.59-64
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• 2010

The purpose of this study is to identify the principal factor controlling transverse residual stress at the weldment for joining unit hull blocks. In order to do it, the comprehensive FE analyses were carried out to evaluate the effect of distance between fillet and butt weldments, stiffener span and in-plane restraint degree on the amount and distribution of transverse residual stress in way of the weldments between unit hull blocks. In accordance with FEA results, principal factor controlling the amount of transverse residual stress at the weldments was identified as in-plane restraint degree of butt weldment for unit blocks. The effect of other variables on the transverse residual stress was very small relatively.

• Journal of the Korean Home Economics Association
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• v.29 no.1
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• pp.13-25
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• 1991

We measured change of peripheral skin temperature and mean skin temperature when the upper arm and thigh are pressured in order to know the effect of skin pressure applied by clothing on blood circulation. After release from pressure, we observed also recovery condition. At the same time, we examined relation between pressure and a feeling of thightness. Three physiques of healthy females, namely slender, standard and plump, served as subjects. We used continuous restraint method with skin pressure applied by experimental fabric for 10 min. As a result of this experiment, we obtained following findings. 1. The significant difference was marked at the pressure, measuring time and physique with change of skin temperature under upper arm restraint. The peripheral and mean skin temperature decreased with the lapse of restraint time. A remarkable tendency observed according to the increase of restraint pressure. Recovery condition after release from pressure not yet recovered to original state, for all after a lapse of 10 min. 2. The significant difference was marked at the pressure, measuring time and physique with change of skin temperature under thigh restraint, especially different physique was remarkable among them. The peripheral skin temperature decreased or decreased. Recovery condition after release from pressure was the same upper arm. 3. Main factor affecting the evaluation of a feeling of tightness was restraint pressure. The value of pressure sensation made remarkable declined after a lapse of 10 min restraint time. Individual differences, however, were shown in pressure sensation.