• Structural Engineering and Mechanics
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• v.60 no.2
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• pp.211-223
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• 2016

Static loading and fluid impact tests on plates containing mesh reinforcement and polypropylene fibers in ratios of 0 to 3% by volume were performed. The objective was to observe the effect of fluid mass on the total impulse that caused the impact event and the influence of fiber amount on the impact resistance, and to estimate the velocity of fluid that causes scabbing, perforation or total disintegration. The study is the first to express the fluid impact resistance of polypropylene fiber reinforced concrete plates.

• Structural Engineering and Mechanics
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• v.60 no.2
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• pp.225-235
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• 2016

Fluid impact tests on plates containing mesh reinforcement and polypropylene fibers were modeled and simulated using explicit finite element analysis software, LS-DYNA. The scabbing dimensions obtained by the experiments and the simulations were compared and crack formations were matched. The objective was to test the accuracy and fidelity of the model and to confirm that damage caused by fluid impact on the plates can be estimated with a reasonable accuracy over a wide range of impact velocity.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.50-57
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• 2003

This paper presents the experimental results to verify the atomization characteristics and environmental impact of cutting fluid. Even though cutting fluid improves the productivity through the cooling, Lubricating effects, environmental impact due to cutting fluid usage is also increased on factory shop floor Cutting fluid's aerosol via atomization process can be affected human health risk such as lung cancer and skin diseases. Experimental results show that the generated fine aerosol which particle size less than 10 micron appears near working tone under typical operational conditions. The aerosol concentration also exceeds NIOSH regulations. This research can be provided a basis of environmental impact analysis fur environmental consciousness.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.14-20
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• 1998

Cutting fluid is a factor which has big effects on both machinability and environment in machining process. The loss of cutting fluids may be reduced by the optimization of machining parameters in process planning. In this study, the environmental impact of fluid loss is analyzed. The fluid loss models in milling process are constructed with the machining parameters. The models are utilized to obtain the optimal machining parameters to minimize the fluid loss. The factors with significant effects on the fluid loss are analyzed by ANOVA test. Finally, optimal parameters are suggested considering both machining economics and environmental impact. This study is expected to be used as a part of a framework for the environmental impact assessment of machining process.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.3
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• pp.3-7
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• 2005

This paper presents the experimental results to verify the atomization characteristics and environmental impact of cutting fluid. Even though cutting fluid improves the productivity through the cooling and lubricating effects, environmental impact due to cutting fluid usage is also increased on factory shop floor. Cutting fluid's aerosol via atomization process can generate human health risk such as lung cancer and skin diseases. Experimental results show that the generated fine aerosol of which particle size less than 10 micron appears near working zone under typical operation conditions. The aerosol concentration also exceeds NIOSH regulations. This research can be provided as a basis of environmental impact analysis for environmental consciousness.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.7 s.112
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• pp.754-761
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• 2006

This paper presents the dynamic characteristics of MR impact damper for vehicle collision system. Various types of mechanism have been proposed to reduce force transmitted to the vehicle chassis and finally to protect occupants from injury. In the case of head-on collision, the bumper makes main role of isolation material for collision attenuation. In this study, the proposed bumper system consists of MR impact damper and structures. The MR impact damper utilizes MR fluid which has reversible properties with applied magnetic field. The MR fluid operates under flow mode. The bellows is used for generation of fluid flow. A mathematical model of the MR impact damper is derived incorporating with Bingham model of the MR fluid. Field dependent damping force is investigated with time and frequency domain. The MR impact damper is then incorporated with vehicle crash system. The governing equation of motion of vehicle model is formulated considering occupant model. Dynamic characteristics of vehicle collision system investigated with computer simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.147-152
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• 2006

This paper presents the dynamic characteristics of MR impact damper for vehicle collision system. Various types of mechanism have been proposed for reduce transmitted force to vehicle chassis and finally protect occupants from injury. In the case of frontal collision, the bumper make main role of isolation material for collision attenuation. In this study, proposed bumper system composed of MR impact damper and structures. The MR impact damper is to adopted MR fluid which has reversible properties with applied magnetic field. MR fluid operates under flow mode with Bingham flow and bellows is used for generation of fluid flow. Mathematical model of MR impact damper incorporated with MR fluid is established. Field dependent damping force is investigated with time and frequency domain. The MR impact damper is then incorporated with vehicle crash system. The governing equation of motion of vehicle model is formulated considering occupant model. Dynamic characteristics of vehicle collision system investigated with computer simulation.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.3
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• pp.73-79
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• 2002

This paper presents the experimental results to verify the environmental consciousness with economic balances due to cutting fluid behaviors, effectiveness in machining process. Even though cutting fluid improves the Productivity through the cooling, lubricating effects, its environmental impact is also increased according to the cutting fluid usage. The primary mechanism considered in this study is the spin-off motion of fluids away from rotating workpiece. In this study some parameters arc adopted to analyze the productivity(tool wear), environmental impact(mist diffusion rate). The results present talc criteria for the resonable cutting fluid usage quantitative1y to develop the environmentally conscious machining process.

• International Journal of Precision Engineering and Manufacturing
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• v.4 no.1
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• pp.49-55
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• 2003

This paper presents the experimental results to verify the environmental consciousness with economic balances due to cutting fluid behaviors and effectiveness in machining process. The cutting fluid improves the productivity through cooling, lubricating effects, however its environmental impact also increases according to the cutting fluid usage. The primary mechanism in this study is the spin-of motion of cutting fluids away from the rotating workpiece. In this study some machining parameters are adopted to analyze the productivity as well as environmental impact. This study provides the criteria for the resonable cutting fluid usage quantitatively to develop the environmentally conscious machining process.

• Tribology and Lubricants
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• v.27 no.1
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• pp.34-39
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• 2011

In this study, finite element analysis of particle-surface collision using 2-dimensional elements was performed to observe the effects of abrasive size and impact angle. The result of the simulation on the change in abrasive size revealed that larger abrasive particle induced larger contact stress due to force transfer through slurry fluid as the particle moved and pushed the fluid. This observation brought an important finding that the slurry fluid could make the workpiece surface soften and then change the mechanical properties of the surface layer such as elastic modulus and yield strength. As for the impact angle, it was found that the contact stress increased with the angle of impact and jumped up at a specific angle. Such result would be attributed to the complex effects of the impact velocity and angle.