• 한국해양공학회지
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• 제7권2호
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• pp.37-43
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• 1993

The simplest vibrtion absorber is the impact damper which consists of a small mass allowed to impact between two gaps sp that energy is dissipated by conversion into noise and heat. Impact damping is a passive vibration control technique to attenuate the vibrations of lightly damped. It has been investigated to reduce the excessive vibrations of turbin blades, radar antennas, machine tools and tall light poles. In this paper, the efficiency of impact vibration absorber was investigated. A steady state vibration of two equispaced impacts per cycle was assumed. The analysis based on the assumption has been considered and the theory is examined experimentally.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.147-155
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• 1996

The purpose of present paper is to estimate the static and fatigue bending strengths of CFRP(carbon fiber reinforced plastic) laminates having impact damage(FOD). The specimens which are formed with the different stacking composition, EPOXY and PEEK matirx and orthotropic and quasi-isotropic laminated plates, are prepared for this experiment. A steel ball is impacted on CFRP laminates, generating impact damages, and the three-point fatigue bending test is carried out by using the impacted laminates to investigate the influence of the stackin composition on the fatigue strength of CFRP laminates.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회논문집(II)
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• pp.731-736
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• 1998

The dynamics and Durability of Permanent Form Mortar were observed. The results were as the followings. To construct New permanent form, this study constructed permanent form with fiber mortar. In this course glass fiber and polymer, fine aggregate were substituted with river sand and crush sand. To understand material quality effect, flexible mortar and inflexible mortar were tested. According to the microstructure of polymermatrix test by SEM, higher density by Co-matrix effect from polymer addiction was observed. This is considered to increase acid-resistanc, impact proof strenght. In the test of durability of freezing and thawing, polymer mortar was proved to be water proof. It seems to be improved in its characteristics in proportion to increasing W/C ratio. When the W/C ratio is 30%, it is most effective.

• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.519-524
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• 2017

본 연구는 황벽나무의 물리, 역학적 성질의 특성과 부후성을 조사하였다. 기건밀도는 실내, 외 방치한 목재에서 각각 0.41, $0.43g/cm^3$로 나타났다. 전수축율 시 T/R비는 실내, 외에서 각각 1.40, 1.32로 나타났다. 흡습성은 온도 $40^{\circ}C$ 상대습도 90% 경우 실내, 외에서 각각 16.30, 15.80%로 나타났다. 압축강도는 실내, 외에서 각각 43.81, 40.33 MPa 휨강도는 84.63, 68.80 MPa, 충격강도는 3.43, $4.00J/cm^2$, 경도는 횡단면에서 각각 47.92, 49.20 MPa로 나타났다. 경도는 횡단면에서 각각 47.92, 49.20 MPa로 나타났다. 1년간 실내에 방치한 목재와 실외에 방치한 목재는 부후에 강하고, 또한 T/R비도 낮은 편으로 치수가 안정한 나무로 판단된다.