• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1482-1488
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• 2010

Recently to increase the productivity and improve the quality in the industrial process, suppressing the residual vibration in motion control systems becomes the essential problem to solve. One of the methods to suppress the residual vibration is the input shaping technique. It is based on parameters of the system model; however, the parameters are usually difficult to obtain. This paper shows the effects of the residual vibration caused by the variation of the general velocity profile for the system with two vibration modes, and also shows the effects of the input shaping filter based on the parameters of system model. Finally, the simulation results show that the proposed input shaping filter using an artificial immune algorithm is more effective for suppressing residual vibrations than genetic algorithm.

• Proceedings of the KWS Conference
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• 1999.05a
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• pp.237-240
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• 1999

In this study, residual stresses of the weldment were calculated by finite element analysis(FEA) and experiment. And, the crack closure behaviour and fatigue crack growth characteristics in field of residual stress of A106 Gr B steel pipe weldment were investigated under various stress ratio. Obtained results are as follows. I) $K_{op}$ was independent of $K_{max}$, and load ratio in fatigue crack growth. 2) In variation of load ratio, the scatter band of crack growth curve was reduced by half considering crack closure. and 3) Neglecting crack closure behaviour, actual fatigue crack growth rate can be underestimated' and Actual fatigue crack growth rate can be overestimated by $K_{res}$, in tensile residual stress field.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.208-213
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• 2002

Railway wheel and axle are the most critical components in railway system. A wheel and axle failure can cause a derailment with its attendant loss of life and property. The service conditions of railway vehicles have become severe in recent years due to a general increase in operating speeds. Therefore, more precise evaluation of wheelset strength and safety has been desired. Damages of railway wheel are a spatting by wheel/rail contact and thermal crack by braking heat etc. One of the main source of damage is a residual stress. therefore it is important to evaluate exactly. A Residual stress of wheel is formed at the process of heat treatment when manufacturing. it is changed by contact stress developed by wheel/rail contact and thermal stress from heat induced in braking. The objective of this paper is to estimate the variation and magnitude of the residual stress of railway wheel.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.12
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• pp.3748-3758
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• 1996

This study is to investigate experimentally relationships between the impact energy and moisture absorption characteristies vs.the residual bending strength with the variation of stacking seqences. When Carbon-fiber reinforced plastics(CFRP) impact-induced laminates are subjected to the high temperatures and hygrothermal effects, it is found that what CFRP laminates are impacted by a steel ball (5 mm in diametar) ; thus, the generated delamination is observed by the ultrasonic microscope. And the residual bending strength is evaluated by a three-point bending test. Also, a thermostat is used in test with the unimpacted and impacted specimens for the moisture experimentaiton. The percision electro lever scles is used to measure the moisture content(1/10, 000g).

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1043-1044
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• 2008

In this study, a novel algorithm of the improvement residual non-uniformity (RNU) in thermal imaging system is proposed using correlated double sample signal processing. The proposed method attempts to eliminate offset variation of ROIC in IR detector causing the variation of FPA (focal plane array) temperature and suppling power. Experimental results show that the proposed method confirmed a better performance than the existing RNU system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.275-282
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• 2002

Tensile residual stress happen by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). In this study, TiNi fiber was used to solve the tensile residual stress as the reinforced material. TiNi fiber improves the tensile strength of composite by occurring compressive residual stress in matrix using shape memory effect of it. Pre-strain was added to generate compressive residual stress inside TiNi/A16061 composite. It was also evaluated the effect of compressive residual stress corresponding to pre-strains variation. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain difference of TiNi/A16061 shape memory alloy composite.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.186-191
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• 2001

Tensile residual stress happen by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). In this study, TiNi alloy fiber was used to solve the problem of the tensile residual stress as the reinforced material. TiNi alloy fiber improves the tensile strength of composite by occurring compressive residual stress in matrix using shape memory effect of it. Pre-strain was added to generate compressive residual stress inside TiNi/A16061 shape memory alloy(SMA) composite. It was also evaluated the effect of compressive residual stress corresponding to pre-strains variation and volume fraction of TiNi alloy. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain difference of TiNi/A16061 SMA composite. In addition, two dimensional AE source location technique was applied to inspect the crack initiation and propagation in composite.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.72-77
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• 2001

Tensile residual stress happen by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). In this study, TiNi fiber was used to solve the tensile residual stress as the reinforced material. TiNi fiber improves the tensile strength of composite by occurring compressive residual stress in matrix using shape memory effect of it. Pre-strain was added to generate compressive residual stress inside TiNi/A16061 composite. It was also evaluated the effect of compressive residual stress corresponding to pre-strains variation. AE technique was used to clarify the microscopic damage behavior at high temperature and the effect of pre-strain difference of TiNi/A16061 shape memory alloy composite.

• Proceedings of the Korean Sanitation Conference
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• 2004.11a
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• pp.54-65
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• 2004

Use of aluminum salts as coagulants In water treatment may lead to increased concentrations of aluminum in finished water. Aluminum is a suspected causative agent of neurological disorders such as Alzheimer's disease. The objective of this study was to examine variation and minimizing in residual aluminum concentration during water treatment process. The aluminum sources at Bokjeong Water Plant were present naturally aluminum in the raw water and derived due to use of PACS as a coagulant. Much of the raw water total aluminum were in particulate and suspended aluminum. In this study was compared the optimize condition to minimize the concentration of residual aluminum using Jar-test with the various coagulants such as alum, PAC, PACS. The results indicated that PACS was more effective than alum, PAC and insufficient or excessive alum, PAC, PACS addition led to increase residual aluminum. Adjustment raw water pH $6.5\~7.0$ before coagulation using PACS was capable of minimizing total and dissolved aluminum. Thus it is important that the optimal dosage of coagulant and the optimal pH adjustment before coagulation can decided to minimize the concentration of residual aluminum in treated water.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.532-538
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• 2004

MEMS technology applying to the sensors and micro-electro devices is complete system. These microsystems are made by variable processes. Especially, the mentallization process has very important functions to transfer the power operating the sensor and signal induced from sensor part. But in the structures of MEMS the local stress concentration and deformation are often yielded by an irregular geometrical shape and different constraint. Therefore, this paper studies the effect of supporting type and thickness ratio about thin film of the substrate on the residual stress variation when the thermal loads is applied to the multi-layer thin film fabricated by metallization process. Specimens were made from several materials such as Al, Au and Cu. Then, uniform thermal load was applied, repeatedly. The residual stress was measured by FE Analysis and nano-indentation method using AFM. Generally, the specimen made of Al induced the larger residual stress than that of made of other materials. Specimen made of Cu and Au having the low thermal expansion coefficient induces the minimum residual stress. Similarly, the lowest indentation length was measured by nano-indentation method in the Si/Au/Cu specimen. Particularly, clusters are created in the specimen made of Cu by thermal load and the indentation length became increasingly large by cluster formation.