• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.442-445
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• 2004

The mock-up test was carried out to solve several problems of the hot weathered high strength concrete. The workability of concrete could be guaranteed by using high range water reducer containing polycarboxylic acid. The compressive strength calculation by rebound value of Schumidt hammer underestimated the actual strength of concrete structure. The temperature of concrete should be lowered by control of raw material temperature and transportation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.981-984
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• 1995

The feed system using ball screw is constructed by ball screw, support bering and LM guide, and servo system for driving ball screw. AC servo motr drives ball screw which was connected by coupling. In this study, a new axial direction dynamic modeling of ball screw driving system was developed, and forced vibraition test using the impact hammer was experimented. The simulation result is compared with experimental result, which defines the reliability of mathematical modeling.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.334-339
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• 1998

The free vibration analysis of the simply supported steel and composite cylindrical shells are investigated. The natural frequencies and mode shapes of the shell are experimentally obtained by impact testing using an impact hammer and an accelerometer. The effects of the material and geometry on the vibrational characteristics of the shell are examined. The experimental results are compared with the analytical and a finite element results. They showed good agreement with each other.

• Explosives and Blasting
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• v.9 no.3
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• pp.10-16
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• 1991

On the ground foundation works for Bldg site, Rock classification test can be obtained as follows due to the International Society for Rock Mechanics. 1. In-situ test : Compressive strength, Point load test. 2. In-situ test Schmidt hammer test. Burden test finaly the convinient co-relation table between strength and 5. H, test were carried out for site-engineer, This project is one of contineous works regarding to Burden test from Jack leg drill($\phi{\;}75mm$) use.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.103-106
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• 1998

본 논문은 상용 FEM-BEM 프로그램을 사용하여 점-조화 가진(harmonic point excitation)에 의한 자유지지 경계 조건을 갖는 원통 셸(cylindrical shell)의 방사 효율(radiation efficiency) 실험의 결과와 비교하였다. 우선 충격 해머 실험(impact hammer test)을 통한 모드 시험(modal testing)으로 원통 셸의 공진 주파수(natural frequency)와 모드 형상(mode shape)의 특징을 살펴보고 다음으로 점-조화 가진에 의한 원통 셸의 방사 효율을 SYSNOISE와 ANSYS로 해석해 보았다. 동시에 음향 세기 실험을 통한 방사 효율을 측정하여 전산 해석의 결과와 실험의 결과를 비교해 보았다.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.485-486
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• 2009

Schmidt hammer and ultrasonic test are the ordinary nondestructive tests for the safety evaluation of harbor structures. This paper investigates the effectiveness of these methods by comparing in-situ test results with in-field experimental data.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.651-654
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• 2003

Non-destructive testing is essential in the inspection of alteration, repair and new construction in construction industry. This paper is to evaluate the strength variation of fire damaged concrete by non-destructive testing. Furthermore, It is to infer the recovery degree of residual strength of fire-damaged concrete. For this purpose, researchers are exploring the performance of non-destructive testing method using ultrasonic testing and Schmidt hammer in concrete specimens. Testing is performed four-times: before fire test, directly after fire test, after 20 days and after 60 days.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.61-64
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• 1993

This study is aimed to analyze the influencing factor on the non-destructive testing by measuring rebound number of schmidt hammer and ultrasonic pulse velocity according to the variation of recycled aggregate kinds. And this study is to provide the reference data on application of practical use.

• Tribology and Lubricants
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• v.20 no.1
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• pp.27-32
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• 2004

This paper presents unsteady oil flow behaviors in the engine lubrication network to clarify the differences between continuous and discontinuous oil supply crankshaft system. Using commercial network analysis program, Flowmaster2, engine lubrication network system analysis were carried out. And effects of crankshaft speed and supplied oil pressure on pressure fluctuation in oil groove and oil flow rate to each bearing were analyzed.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.207-209
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• 2003

In FE analysis for residual stress of a casting, contact force between mould and casting material and gravity force must be considered for exact simulation. Preheating of a repair weldment had a little effects on the reduction of residual stress. However, preheating with hammer peening had a great deal of effects on the reduction of residual stress. A method for estimation of fatigue life for a repair weldment has been established.