• Composites Research
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• v.13 no.1
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• pp.78-88
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• 2000

Tribological properties of fiber composite materials were measured and wear resistant hybrid structure was proposed based upon the understanding of tribological behavior of the composite materials. Unidirectional composites with glass fibers, carbon fibers, and aramid fibers were tested for tribological properties in order to propose a wear resistant hybrid structure. Hybrid composites which contain carbon and aramid fibers were prepared, the specimens were sliced by a water-jet cutter, and friction and wear properties were measured. An experimental set-up was designed and built for the friction and wear test of the composite specimens. Unidirectional fiber composite and hybrid composite specimens were tested to evaluated the tribological behavior for biomimetic applications. It is observed that the friction and wear behavior of fiber composites depends upon fiber orientation, sliding speed, and type of reinforcing fibers.

• Composites Research
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• v.21 no.2
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• pp.1-7
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• 2008

Composite materials are currently used in aero-space industry, sport and leisure industry but it has many problems such as mechanical properties deterioration by moisture absorption. In this study, we appraised interlaminar shear strength with specimen that immersed/ immersed-dried in water environment(distilled/sea) during $100{\sim}200$days. In the result, properties degradation of resin part and silan part by moisture absorption is judged early on main cause of interlaminar shear strength, and later destruction of mechanical bonding between silan part and fiber by moisture absorption is Judged later main cause of interlaminar shear strength. In conclusion, the recovery of interlaminar shear strength is judged to difficult due to interfacial destruction by moisture when pass over irreversible by moisture in composite material.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.227-260
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• 2018

Recently, as the use of drones increases, the risk of drone accidents and third-party property damage is also increasing. In Korea, due to the recent increase in drone use, accidents have been frequently reported in the media. The number of reports from citizens, and military and police calls regarding illegal or inappropriate drone use has also been increasing. Drone operators may be responsible for paying damages to third parties due to drone accidents, and are liable for paying settlements due to illegal video recording. Therefore, it is necessary to study the idea of providing drone insurance, which can mitigate the liability and risk caused by drone accidents. In the US, comprehensive housing insurance covers damages caused by recreational drones around the property. In the UK, when a drone accident occurs, the drone owner or operator bears strict liability. Also, in the UK, drone insurance joining obligation depends on the weight of the drones and their intended use. In Germany, in the event of personal or material damage, drone owner bears strict liability as long as their drone is registered as an aircraft. Germany also requires by law that all drone owners carry liability insurance. In Korea, insurance is required only for "ultra-light aircraft use businesses, airplane rental companies and leisure sports businesses," where the aircraft is "paid for according to the demand of others." Therefore, it can be difficult to file claims for third party damages caused by unmanned aerial vehicles in personal use. Foreign insurance companies are selling drone insurance that covers a variety of damages that can occur during drone accidents. Some insurance companies in Korea also have developed and sell drone insurance. However, the premiums are very high. In addition, drone insurance that addresses specific problems related to drone accidents is also lacking. In order for drone insurance to be viable, it is first necessary to reduce the insurance premiums or rates. In order to trim the excess cost of drone insurance premiums, drone flight data should be accessible to the insurance company, possibly provided by the drone pilot project. Finally, in order to facilitate claims by third parties, it is necessary to study how to establish specific policy language that addresses drone weight, location, and flight frequency.