• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.535-542
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• 2010

Various difficulties have been increased in the construction of public structure; like the road in the overcrowding urban area, because of civil complaint, cost and period of construction. In oder to overcome these social problems, the tunnel has been planned the road design. Despite the resolution, there are many technical problems when constructed near facilities. The design of new tunnel below the existing service reservoir is applied to the ambient vibration blasting using Plasma. The result of test blasting was exceeded the standard ("2kine"). So it was considered a countermeasure for the vibration reduction applied to change the controlled blasting method, reduce the charge, add the pre middle horizontal hole in the cut blasting site, and so on. The result was satisfied the standard. Accordingly, if the quality of blasting process can be managed well, the application of this alternative method is highly effective one. Also, based on cost analysis between two methods, the alternative method is very competitive.

• 한국기계가공학회지
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• 제15권2호
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• pp.9-15
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• 2016

The dynamics of gas-particle flow from a supersonic abrasive blasting nozzle have been studied by 1-D analytical calculation, including wall friction effects inside the nozzle. The developed code in the present study shows a satisfactory agreement with the other study's results. By utilizing the code, the redesign and optimization of the inner contour of a commercial abrasive blasting nozzle were carried out, and it was found that the redesigned nozzle in the present study can produce faster particle velocities at the nozzle exit by up to 22% compared with the original commercial nozzle.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.296-301
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• 2002

In this study, we investigated the machinability of machinable ceramics which were developed by a research lab. of Inha Univ., Korea. The effect of the nozzle scanning times, the size of patterns and compositions of BN in ceramics on the erosion depth of samples with no mask and samples with three different mask pattern in powder blasting of machinable ceramics. The blasting conditions were the impact angles 90$^{\circ}$, scanning times of noble up to 30 and the stand-off distances 100mm. The widths of mask pattern were 0.1mm, 0.5mm and 1 mm. The powder was alumina sharp particles, WA#600. The mass flow rate of powder during the erosion test was fixed constant at 150g/min and the blasting pressure of powder at 0.25Mpa

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1185-1189
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• 2007

In this paper, to improve the efficiency of pressurized pneumatic grit conveying for ship block open blasting process. Pressurized pneumatic grit conveying is defined as the transportation of grit(abrasive) in a compressed air flow. Total Pressure loss in flexible hose for pneumatic conveying is sum of pressure losses due to gas and grit and needle type pressure transmitter for measured pressure loss. haracteristics of grit open blasting by pneumatic conveying were studied experimentally. Studies variables were blasting nozzle ID, length and ID of flexible hose, grit flow rate, flow rate and pressure of transport air. It was experimentally proved that optimal open blasting condition and cost effective operation regarding grit blasting, obtaining a high qulity surface preparation(Sa $2^{\frac{1}{2}}$).

• 한국공작기계학회논문집
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• 제15권2호
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• pp.66-72
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• 2006

The old technique of sandblasting which has been used for paint or scale removing, deburring and glass decorating has recently been developed into a powder blasting technique for brittle materials, capable of producing micro structures larger than $100{\mu}m$. In this paper, we studied on the predictive modeling of material removal and surface roughness in powder blasting of glass by design of experiments. The surface characteristics and surface shape of powder blasted glass surface were tested under different blasting parameter. Finally, we proposed a predictive model for powder blasting process, and compared with experimental results.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.341-344
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• 2008

In order to study the effect of shot blasting condition on the formability of thin high strength steels, specimens were made by changing line speed of a commercial shot blasting plant with maintaining constant impeller condition. Surface roughness of prepared specimens was multiplied by lowering line speed or increasing density of shot impact. Formability was reduced as increasing shot impact. The elongation and stretching formability of shot blasted sheet were decreased by about 10% compared to original sheet. More significant decrease in bending formability was observed after shot blasting. This might be due to the concentrated impact near the surface where major strain occurs during bending process.

• 화약ㆍ발파
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• 제34권2호
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• pp.10-17
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• 2016

발파작업을 위해 필요한 천공작업은 발파의 효과를 좌우하는 중요한 부분으로 인식되고 있다. 발파를 위한 천공작업 시 발생되는 천공오차는 잔류공 및 여굴 발생, 불균질한 파쇄입도 등 발파효율 저하요인들을 발생시킬 수 있다. 정확한 천공을 위해 자동 천공 점보드릴을 도입하였다. 그 결과 공간격, 저항선의 천공오차율 0~2.6%로 미미하게 나타났으며 이로 인하여 90%이상의 굴진율, 전체 굴착량 대비 여굴량 4.3%, 50cm 이하 파쇄석 비율 89%~95% 등 발파효과가 향상된 것을 확인하였고 이로 인해 발파 Cycle time을 절감할 수 있을 것으로 판단된다.

• 한국기계가공학회지
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• 제15권4호
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• pp.148-154
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• 2016

A study on the micro particle blasting was conducted to find the optimum conditions of the blasted surface of aluminum 6061. The particle type such as $Al_2O_3$ and SiC, nozzle diameter, pressure, standoff distance and injection time were used as blasting conditions. Statistical method of orthogonal arrays(ANOVA) was used to find optimum conditions of maximum depth and maximum diameter of blasted surface. Particle type, nozzle diameter, and pressure were found to be the main factors of maximum blasted depth and diameter. Maximum blasted diameter was affected by increasing pressure and nozzle diameter but saturated maximum diameter. Maximum blasted depth was affected by pressure and nozzle diameter when aluminum 6061 was blasted with $Al_2O_3$ particle. The value of surface roughness was increased as pressure and nozzle diameter increased when aluminum 6061 was blasted with SiC.

• Geomechanics and Engineering
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• 제25권2호
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• pp.111-121
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• 2021

Large deformation and rapid pressure propagation take place inside the rock mass under the dynamic loads caused by the explosives, on quarry faces in order to extract aggregate material. The complexity of the science of rock blasting is due to a number of factors that affect the phenomenon. However, blasting engineering computations could be facilitated by innovative software algorithms in order to determine the results of the violent explosion, since field experiments are particularly difficult to be conducted. The present research focuses on the design of a Finite Element Analysis (FEA) code, for investigating in detail the behavior of limestone under the blasting effect of Ammonium Nitrate & Fuel Oil (ANFO). Specifically, the manuscript presents the FEA models and the relevant transient analysis results, simulating the blasting process for three types of limestone, ranging from poor to very good quality. The Finite Element code was developed by applying the Jones-Wilkins-Lee (JWL) equation of state to describe the thermodynamic state of ANFO and the pressure dependent Drucker-Prager failure criterion to define the limestone plasticity behavior, under blasting induced, high rate stress. A progressive damage model was also used in order to define the stiffness degradation and destruction of the material. This paper performs a comparative analysis and quantifies the phenomena regarding pressure, stress distribution and energy balance, for three types of limestone. The ultimate goal of this research is to provide an answer for a number of scientific questions, considering various phenomena taking place during the explosion event, using advanced computational tools.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.175-180
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• 2007

This paper presents a case study on blasting vibration reduction in NATM(New Australian Tunnelling Method) tunnel construction carried out under a congested residential area. In NATM tunnel constructions, blasting is an essential process, thus vibration phenomenon is inevitable. Therefore, the vibration reduction was tried to avoid expected complaints from the public living in the area. Test blastings were performed to get the constants for an estimation formula of vibration velocity. Then the influence area was approximated using the estimation formula, and construction methods for the vibration reduction were sought based on the results.