• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.337-344
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• 2015

The purpose of this study is to determine the effects of vibration on primary (e.g. plasma cortisol), secondary (e.g. plasma glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), $Na^+$, $K^+$ and $Cl^-$) and tertiary (e.g. mortality) stress responses in cultured catfish, Silurus asotus. For this purpose, three groups (one control group and two stress groups) were set up. The control group was exposed to vibration corresponding to 48 decibel (dB) volt (V) (produced using electric vibrators) for 15 minutes per hour every day, and the two stress groups were exposed to vibrations corresponding to 58 and 68 dB (V) (produced using the same electric vibrators), equally, for 15 minutes per hour every day. Blood was sampled at day 0 (before starting vibration stress tests), and at days 1, 3, 5, 7, 9 and 11 (after starting vibration stress tests). According to the results, the catfish physiologically showed ''typical'' stress responses when they were exposed to chronic vibration. This indicates that such chronic vibration caused substantial stress to catfish; especially, persistently elevated plasma AST and ALT levels observed caused adverse effects to them. In conclusion, chronic vibration could significantly affect hematological characteristics in catfish.

• Journal of Environmental Impact Assessment
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• v.21 no.5
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• pp.609-615
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• 2012

In recent years, the development of computer technique was possible to the simulation analysis of the structure caused by ground vibration. Generally, finite element method(FEM) has been used in these structural analysis. In this study, it was calculated to the vibration energy as measuring vibration waveform, and estimated about principal stress due to medium characteristics of the ground as processing dynamic analysis by the vibration energy. The results are as follows : Firstly, the principal stress distribution in all mediums was different due to a medium condition, and the principal stress at concrete medium was represented to difference due to physical characteristics. Secondly, the principal stress by time increasing was represented to maximum amplitude within 0.03 second. And also, the principal stress after maximum amplitude was very large at concrete medium, which was considered to be formed compression or tension range at a medium boundary. Thirdly, the variation of principal stress at concrete medium was represented in the order of RC medium, NC=H medium, NC=S medium. It was considered that the vibration energy propagated fast when a medium have a big elasticity and density.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.2
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• pp.97-101
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• 2017

Fruits are subjected to a variety of vibration stress during the transportation from a production area to markets. Vibration inputs are transmitted from the transporting vehicle through the packaged fruit. And the steady state vibration input may cause serious internal damage of fruit. Product quality of fruits declines by various factors while they are stored right after harvesting and among the substance in charge of post ripening action, ethylene ($C_2H_4$) biosynthesis increases fruits' respiration process after harvesting and decreases storage expectancy. Ethylene production of apples rapidly increases while storage duration becomes longer. This tendency is much clearer for the apples with vibration stress at input acceleration level. When there was no vibration stress, change in ethylene production level of apples are not very large during storage. Ethylene production rates inside the gas collecting container increased significantly ($p{\leq}0.05$) after 24 hours storage, particularly for apples with vibration stress ($0.7{\mu}l/kg{\cdot}hr$ (1st stack), $0.78{\mu}l/kg{\cdot}hr$ (2nd stack), $0.96{\mu}l/kg{\cdot}hr$ (3rd stack)); whereas less ethylene was produced in control apples ($0.18{\mu}l/kg{\cdot}hr$ during storage. Also ethylene production rates of apples according to the stack position were significantly different ($p{\leq}0.05$). The vibration stress clearly accelerated the degradation of apple quality during storage, resulting in increased ethylene production.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1098-1103
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• 2011

The structural integrity of APR1400 reactor vessel internals has been being assessed referring the US Nuclear Regulatory Commission regulatory guide 1.20, comprehensive vibration assessment program. The program is composed of a vibration and stress analysis, a vibration and stress measurement, and an inspection. This paper covers the vibration and stress analysis on the reactor vessel internals by the pulsation of reactor coolant pump. 3-dimensional models to calculate the hydraulic loads and structural responses were built and the pressure distributions and the structural responses were predicted using ANSYS. This paper presents that APR1400 reactor vessel internals have enough structural integrity against the pulsation of reactor coolant pump as the peak stress of the reactor vessel internals is much lower than the acceptance limit.

• Development and Reproduction
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• v.13 no.1
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• pp.43-49
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• 2009

We examined the effects of the vibration stress on cortisol secretion and hematological characteristics in soft-shelled turtle, Pelodiscus sinensis. For the stressed group vibration of $45{\sim}78 dB(V)$ from electric vibrator applied for 30 min with 2-h intervals during daytime ($08:00{\sim}18:00$) up to 28 days. Using the blood samples collected from ten turtles held once a week after vibration stress, we measured hematocrit, hemoglobin, red blood cells, cortisol, glucose, lactic acid, osmolality, $Na^+,\;K^+,\;Cl^－$, aspartate aminotransferase (AST), and alanine aminotransferase (ALT). The results have showed that P. sinensis received vibration stress exhibit the 'typical' stress-induced physiological responses (cortisol, glucose, lactic acid, osmolality, ions, hematocrit and hemoglobin) induced by vibration stress. Our data suggested that chronic vibration stress caused substantial stress in the animal, and in particular, the persisting elevated levels of AST and ALT would be highly correlated with the adverse effects of the stress. The high hematological characteristics during entire experimental period showed that the P. sinensis could not adapt to chronic stimuli provoked by vibration stress.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.4 s.121
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• pp.310-316
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• 2007

This paper presents a theoretical approach to describe the characteristics of vibration transmission in the waveguide with varying cross-section. The waveguide considered in this paper has a tapered section in the middle of an axisymmetric stepped rod. The distributions of the vibration displacement and stress along the waveguide were derived and they were verified by comparing the theoretically-calculated results with those obtained by the finite-element analysis. The vibration magnification and the concentrated stress under forced vibration were calculated for this rod according to the taper length. The paper established a theoretical basement of designing waveguides for maximizing the vibration transmission under minimum stress concentration.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.300-305
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• 2012

The vibration and stress analysis program of comprehensive vibration assessment program (CVAP) is to verify theoretically the structural integrity of reactor vessel internals (RVI) and to provide the basis for selecting the locations monitored in measurement and inspection programs. This paper covers the verification of the vibration and stress analysis methodology of APR1400 RVI CVAP. The analysis methodology was developed to use 3-dimensional hydraulic and structural models with ANSYS and CFX. To validate the methodology, the hydraulic loads and structural reponses of OPR1000 were predicted and compared with the calculated and measured data in the OPR1000 RVI CVAP. Since the results predicted with this methodology were close to the measured values considerably, it was confirmed that the analysis methodology was developed properly.

• Journal of Marine Life Science
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• v.3 no.2
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• pp.81-86
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• 2018

The purpose of this study is to determine the effects of vibration on primary (e.g. plasma cortisol), secondary (e.g. plasma glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), Na⁺, K⁺ and Cl^- and tertiary (e.g. mortality) stress responses in cultured eel, Anguilla japonica. For this purpose, three groups (including one control group and two stress groups) were set up. The control group was made exposed to vibration corresponding to 48 decibel (dB, V) (produced using electric vibrators) for 15 minutes per hour every day, and the two stress groups was made exposed to vibration corresponding to 58 and 68 dB (V) (produced using the same electric vibrators), equally, for 15 minutes per hour every day. Blood was sampled at day 0 (before starting vibration stress tests, BS), and days 1, 3, 5, 7, 9 and 11 (after starting vibration stress tests). As a result, plasma cortisol showed trend to continuously rise by consecutive stress from 4.1±0.1 ng/ml in BS. In 48 dB group (control), cortisol showed the highest level with 7.6±0.9 ng/ml after 7 days (p<0.05), but at 9 and 11 days was not significantly compared with BS level. In 58 dB group, the cortisol showed the highest level with 43.1±4.8 ng/ml after 1st day. Cortisol of 68 dB group increased significantly during the experimental period (14.4±2.3~32.0±5.7 ng/ml) (p<0.05). In 58, and 68 dB groups during the experimental period differed significantly compared to 48 group (p<0.05). Glucose in 48 dB were increased from 42.0 ±5.7 (BS) to 52.5±2.1 (1 day), the level was not significantly from 1 to 11 days. Glucose in 58 and 68 dB groups was increased significantly than BS during experimental period (p<0.05). K⁺ in 68 dB increased significantly (p<0.05) from 2.3±0.2 mE/ql (BS) to 3.3±0.5 mE/ql at 5 days. In 48 and 58 dB groups during the experimental period differed significantly (p<0.05). Na⁺ and Cl^- levels were not differed significantly during the experimental period. AST and ALT in 58 and 68 dB groups showed trend to continuously rise by consecutive stress. At 7 and 9 days in AST, between 48, 58 and 68 dB groups differed significantly (p<0.05). In 48, 58 and 68 dB groups at 1 day, blood hematocrit increased significantly higher than BS. The 11 days after vibration stress, the mortality in 48, 58 and 68 dB groups was 1.1, 5.1 and 5.8%, respectively. The present results have shown that A. japonica exhibited ''typical'' physiological responses when exposed to chronic vibration stress. These data suggested that chronic vibration stress caused substantial stress in the fish; especially the persisting elevated plasma AST and ALT levels observed would be expected to adverse effect. In conclusion, chronic vibration stress could greatly affects the hematological characteristics in A. japonica.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.8
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• pp.749-756
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• 2004

While designing shafting in reciprocating machines with internal combustion engines which derive generators, pumps, and vehicles, it is very important to calculate the additional stress of shafting by torsional vibration. In this paper, the transfer stiffness coefficient method which is based on the successive transfer of stiffness coefficient was applied to the calculation of the additional stress of shafting in reciprocating machine by torsional vibration. In order to confirm the effectiveness of the present method, a propulsion shafting with a diesel engine in a vessel was considered as the computational example of shafting in reciprocating machine. The results calculated by the present method were compared with those of the modal analysis method, the mechanical impedance method, and free vibration analysis.

• Structural Engineering and Mechanics
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• v.37 no.4
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• pp.367-383
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• 2011

In this paper, nonlinear partial differential equations of motion for a hybrid composite plate subjected to initial stresses on elastic foundations are established to investigate its nonlinear vibration behavior. Pasternak foundation and Winkler foundations are used to represent the plate-foundation interaction. The initial stress is taken to be a combination of pure bending stress plus an extensional stress in the example problems. The governing equations of motion are reduced to the time-dependent ordinary differential equations by the Galerkin's method. Then, the Runge-Kutta method is used to evaluate the nonlinear vibration frequency and frequency ratio of hybrid composite plates. The nonlinear vibration behavior is affected by foundation stiffness, initial stress, vibration amplitude and the thickness ratio of layer. The effects of various parameters on the nonlinear vibration of hybrid laminated plate are investigated and discussed.