• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.2
• /
• pp.153-170
• /
• 2022

Waterjet has been comprehensively used in urban areas owing to a suitable technique for cutting concrete and rock, and low noise and vibration. Recently, the abrasive waterjet technique has been adopted and applied by the Korea Atomic Energy Research Institute to demolish concrete plugging without disturbing and damaging In-situ Demonstration of Engineered Barrier System in the disposal research tunnel. In this study, the use of abrasive waterjet in the tunnel was evaluated for practical applicability and the existing cutting model was compared with the experimental results. As a variable for waterjet cutting, multi-cutting, water flow rate, abrasive flow rate, and standoff distance were selected for the diversity of analysis. As regarding the practical application, the waterjet facilitated path selection for cutting the concrete plugging and prevented additional disturbances in the periphery. The pump's noise at idling was 64.9 dB which is satisfied with the noise regulatory standard, but it exceeded the standard at ejection to air and target concrete because the experiment was performed in the tunnel space. The experimental result showed that the error between the predicted and measured cutting volume was 12~13% for the first cut and 16% for second cut. The standoff distance had a significant influence on the cutting depth and width, and the error tended to decrease with decrement of standoff distance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.05a
• /
• pp.228-233
• /
• 2007

An experimental and numerical approach has been carried out to characterize the noise and the safety of circular diamond saw with chinks by laser-cutting. The sound pressure level of a circular diamond saw with chinks was measured when cutting workpieces. Therefore, frequency analysis results show us that the sound level was reduced as position of chinks approach to out-diameter. But the safety of circular diamond saw was lower due to the stress concentrated at the edge of chinks while cutting workpieces. FEM analysis was used for safety evaluation with the variation position of chinks. The noise characteristics of circular diamond saw were also estimated during cutting test.

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 1998.11a
• /
• pp.99-104
• /
• 1998

산업현장에서 많이 쓰이는 절삭설비(Metal Working : MW)는 매우 다양하여 일일이 열거하기는 어렵고 주로 자동차생산업종, 농기구제조업종, 각종 기계기구 생산업종, 경금속가공업종 등에서 매우 광범위하게 사용되고 있다. 이들 업종에서 연마, 절단, 천공, 드릴링, 터닝(turning)등을 수행하는 많은 근로자들이 다량의 MWF(Metal Working Fluids) 뿐만 아니라 열악한 소음환경에 노출되고 있다. (중략)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.04a
• /
• pp.473-474
• /
• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.05a
• /
• pp.264-265
• /
• 2010

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.21 no.3
• /
• pp.258-263
• /
• 2011

The direction of the cutting tool plays a critical role in elliptical vibration cutting(EVC) where the cutting tool cuts workpiece in a trochoidal motion. In this study, EVC cutting device was developed using two parallel piezoelectric materials and it was observed that the rotation direction of the tool reverses as the EVC device undergoes resonance at which either flexural(cutting direction) or longitudinal( thrust direction) mode shapes occurs. To analytically explain reversal of the rotation direction, kinematic motion analysis of the tool was modified to incorporate amplification of the vibration amplitude and phase introduced by resonance. It successfully demonstrated, through Matlab simulation, reversal of the rotation direction of the cutting tool as the excitation frequency increases beyond resonance frequencies at which either flexural or longitudinal vibration occurs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.05a
• /
• pp.614-615
• /
• 2010

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.39 no.10
• /
• pp.1069-1077
• /
• 2015

In tunnel excavation using blast, the wire saw rock cutting method generates a discontinuity perimeter around the center cut, and thus prevents blast vibration propagation to reduce vibration and noise. Therefore, the method is expected to be easy to use and economical compared with other methods. In this paper, the cutting mechanism of wire saw in tunnel excavation is investigated. A model describing the changes in cutting depth and wire saw shape inside a rock during cutting is established and validated for this purpose. Through a simulation using the model, the important characteristics of wire saw cut are investigated, and the influences of cutting conditions, such as wire saw tension, wire saw speed, feed speed, depth, and diameter of boring, on cutting performance are also examined. A method to improve the cutting performance is proposed based on the results.

• 한국정보통신설비학회:학술대회논문집
• /
• 2003.08a
• /
• pp.367-372
• /
• 2003

도심의 편리한 생활을 위해 초고속 데이터 통신, 상하수도, 가스등의 원할 한 공급이 요구되고 있으며 이러한 인프라 시설들은 지하터널을 통하여 공급이 되게 된다. 도심지의 교통혼잡과 소음, 진동으로 인한 사회비용의 증가와 민원으로 사실상 개착식 공법은 적용되기 어려운 실정에 있다. 특히 앞에 열거한 인프라 시설들은 2m이하의 중소형 크기로 마이크로터널링 공법이 널리 사용되고 있으며 최근에는 현실적인 현장의 요구와 공사비용의 절감을 위해 1m이하의 소형터널에 대한 요구가 늘어 나고 있으나 마이크로터널링 머신의 소형화에 따른 절삭력의 감소와 지하 장애물에 대한 대처가 어려워짐으로 이에 대한 해결책이 요구되고 있다. 이를 위해 워터젯이 장착된 마이크로터널링 머신이 소개된바 있지만 면판에 단순고정된 형태라 절삭면적 및 효율에 한계가 있다. 본 연구는 절삭면적의 확대 및 효율의 증가를 위해 공전하는 면판에 자전하는 워터젯 보조면판을 제안하였으며 워터젯에 가장 적합한 커터종류를 찾기 위해 절삭력을 고려한 성능계수를 제안하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.11
• /
• pp.1106-1112
• /
• 2012

This paper deal with a technique for monitoring machining conditions by measuring the vibration of cutting forces at milling machining. The vibrations of cutting forces in milling process were measured and analyzed to be related with processing parameters. The magnitude of cutting force is linearly proportional to the feed rate and cutting depth, and frequency of cutting force is linearly proportional to the rotating speed. Wired and wireless communication methods were applied in transmitting the measured vibration signals and the two methods were compared. The magnitude of the vibration signals transmitted by the wireless communication method was similar to that transmitted by the wired communication method.