• Journal of Advanced Marine Engineering and Technology
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• v.29 no.8
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• pp.923-928
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• 2005

The estimation of fatigue life at the design stage of the compressed air tank on board is very important in order to arrive at feasible and reliable solutions considering the total lifetime of the tank. In this paper the compressed air tank on board was selected as a model and the change of inside pressure of the tank during normal navigation period was measured and the cycle of fluctuation stress was presumed statistically based on this. Also the effect of stress concentration with the FEM analysis on the longitudinal weld and the mean stress effect on the fatigue strength of compressed air tank were discussed.

• Wind and Structures
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• v.13 no.2
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• pp.207-220
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• 2010

The 'chain reaction' effect of the interaction between wind pressure and windborne debris is likely to be a major cause of damage to residential buildings during severe wind events. The current paper (Part II) concerns the quantification of such pressure-debris interaction in an advanced vulnerability model that integrates the debris risk model developed in Part I and a component-based wind-pressure damage model. This vulnerability model may be applied to predict the cumulative wind damage during the passage of particular hurricanes, to estimate annual hurricane losses, or to conduct system reliability analysis for residential developments, with the effect of windborne debris fully considered.

• Journal of Welding and Joining
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• v.16 no.5
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• pp.67-75
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• 1998

This study aimed at he experimental and finite element analytic investigation of the effect of preheating on he residual stress of weldment. In this study, an autogenous arc welding was used on type 304 stainless steel and MARC as F.E.M. common code was utilized in analysis The analyses include transient and moving heat source and thermal properties as function of temperature. During welding, the thermal cycles of four locations in the weldment were recorded to investigate of the behavior of thermal stress and residual stress. The experimental and analytic results had good coincidence and show that there are two factors influencing the formation of welding residual stress in preheat process. One is the elevation of welding equilibrium temperature and the other is the increase of amount of heat input. The former decrease welding residual stress and the latter increase welding residual stress. Therefore, the cumulative effects result in the welding residual stress not being improved significantly with preheating in 304 stainless steel.

• Advances in Traditional Medicine
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• v.8 no.4
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• pp.354-364
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• 2008

The present study was carried out to investigate the antihypertensive effect of a folklore herbal formulation (HF) (300mg/kg/day; p.o.) in deoxycorticosterone acetate (DOCA)-salt induced and fructose induced hypertensive rats. In DOCA model, DOCA (15 mg/kg, s.c., twice a week) was administered to unilateral nephrectomized rats for 4 weeks. In fructose model, drinking water was replaced with 10% fructose solution for 6 weeks to induce hypertension. Systolic blood pressure (BP) was measured once every week during the treatment schedule. After completion of treatment schedule, BP and vascular reactivity to various agonists like Noradrenaline, Adrenaline, Phenylephrine and Serotonin (5-hydroxytrptamine; 5-HT) were recorded in rats of both models. A cumulative concentration response curve of 5-HT was carried out in isolated rat fundus strip of the DOCA-salt induced and fructose induced hypertensive rats. The results tend to suggest that HF possesses antihypertensive activity.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.4
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• pp.760-780
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• 1988

Using the fatigue test results obtained in the SAE Fatigue Cumulative Damage Test Program, prediction methods of fatigue crack initiation life for notched members undergoing random loaming histories were discussed in detail. Conventional fatigue life predictions based on so-called modified Miner's rule were found to be apt to give nonconservative estimate, due to lack of sufficient consideration for stress-interaction effect. A modified .epsilon.-N curve concept was proposed to account for the stress-interaction effect. The predicted fatigue life based on the modified .epsilon.-N curve concept was in good agreement with the experimental results of SAE Test Program. Specifically for the cases when fatigue data was not available at hand, was proposed a procedure to give conservative estimate of fatigue life.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.1
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• pp.172-179
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• 1996

For mechanical systems operating at high tempertature, thermal fatigue phenomenon has been recognized as a major cause of mechanical component failures. To evaluate cumulative fatigue damage as a conesquence of thermal fatugue on real time, the stress tranfer function(Green's function) approach is popularly used. The objective of this paper is to investigate the effect of thermophsical properties on the stress tranfer function. For this purpose a modified Green's function approach considering temperature-dependent thermophysical properties is proposed. Two case studies were performed and the proposed approach agrees well with full finite element analysis.

• Journal of the Korean Ceramic Society
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• v.31 no.3
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• pp.312-320
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• 1994

Effect of the laser shot number on the particulates density of the pulsed laser deposited YBa2Cu3O7-x thin films and the laser irradiated surface morphology of the YBa2Cu3O7-x bulk target have been investigated. Until 100 laser shots of cumulative irradiation, the films has the particulates density of ~103 mm-2. However, after 100 laser shots, the density was increased more than 10 times. This results has been explained by the change of particulate ejection path with the development of conical structure at the target surface.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.473-480
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• 1998

The substructuring pseudodynamic test is a hybrid testing method consisting of a numerical simulation of the earthquake response of an analytical model and a loading test of a specimen. The substructuring pseudodynamic testing technique has been applied to various seismic experiments since it has advantages over the shaking table test to study dynamic behaviors of relatively large scale structures. However, experimental errors are inevitable in substructuring pseudodynamic testing. Some of these errors can be monitored during the test, but, due to limitations in control system, they cannot be eliminated. For example, one cannot control exactly the displacements that are actually imposed on the structures at each time step. This paper focuses on a technique to minimize the cumulative effect of such control errors for MDOF system. For this purpose, the modified posterior adjustment of the time increment from a target value $\Delta$t$_{n}$ to an adjusted value is performed to minimize the effect of the control errors for MDOF system.for MDOF system.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.3
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• pp.121-128
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• 1990

Germination of Italian ryegrass and sorghum were measured at a range of temperatures and with PEG treatment at several different levels of concentration and treatment period to evaluate the effects of osmoconditioning with polyethylene glycol(PEG-8000). The results obtained are summarized as follows: 1. Cumulative germination percentage of intact Italian ryegrass seeds did not show much difference among temperatures, while that of sorghum seeds decreased markedly at low temperature. 2. Italian ryegrass seeds osmoconditioned with 20% PEG solution for two days at 10^{\circ}C.$ accelerated germination at 10^{\circ}C.$, with injurious effect of osmoconditioning at higher temperature for many days. 3. Osmoconditioning with 20% PEG solution for two or four days at 10^{\circ}C.$ increased germination of sorghum seeds, while the seeds treated at higher temperatures for long period suppressed germination.

• Wind and Structures
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• v.32 no.5
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• pp.501-508
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• 2021

The turbine industry demands a reliable design with affordable cost. As technological advances begin to support turbines of huge sizes, and the increasing importance of wind turbines from day to day make design safety conditions more important. Wind turbines are exposed to environmental conditions that can affect their installation, durability, and operation. International Electrotechnical Commission (IEC) 61400-1 design load cases consist of analyses involving wind turbine operating conditions. This design load cases (DLC) is important for determining fatigue loads (i.e., forces and moments) that occur as a result of expected conditions throughout the life of the machine. With the help of FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open source software, the NREL 5MW land base wind turbine model was used. IEC 61400-1 wind turbine design standard procedures assessed turbine behavior and fatigue damage to the tower base of dynamic loads in different design conditions. Real characteristic wind speed distribution and multi-directional effect specific to the site were taken into consideration. The effect of these conditions on the economic service life of the turbine has been studied.