• Journal of Advanced Marine Engineering and Technology
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• v.33 no.1
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• pp.28-36
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• 2009

In this paper, based on the measured data of hull deflection, an approximated hull deflection curve is drawn using reverse analyzed hull deflection data and the estimation method for flexibility analysis of shaft alignment is proposed by use of the approximate hull deflection curve. Generally an offset value of after stern tube bearing is a datum point with an fore stern tube bearing however the shaft alignment has a tendency which is able to get higher flexibility if the shafting system has the deflection value from after stern tube bearing as reference to bottom direction according to results of on this study. By applying this result of study, the shaft alignment for next similar ships will be able to estimate how to follow the hull deflection and how to be influenced by hull deflection at shaft alignment analysis state using the approximated hull deflection curve.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.76-83
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• 2006

Machining accuracy is closely related with tool deflection induced by cutting forces. In this research, cutting forces and tool deflection in end milling are expressed as a closed form of tool rotational angle and cutting conditions. The discrete cutting fores caused by periodic tool entry and exit are represented as a continuous function using the Fourier series expansion. Tool deflection is predicted by direct integration of the distributed loads on cutting edges. Cutting conditions, tool geometry, run-outs and the stiffness of tool clamping part are considered together far cutting forces and tool deflection estimation. Compared with numerical methods, the presented method has advantages in prediction time reduction and the effects of feeding and run-outs on cutting forces and tool deflection can be analyzed quantitatively. This research can be effectively used in real time machining error estimation and cutting condition selection for error minimization since the form accuracy is easily predicted from tool deflection curve.

• Bulletin of the Society of Naval Architects of Korea
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• v.25 no.1
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• pp.33-46
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• 1988

This paper describes a simplified method for estimation of the ultimate compressive strength of actual ship panels with initial deflection of complex shape. The proposed method consists of the elastic analysis using the large deflection theory and the rigid-plastic analysis based on the collapse mechanism which also includes the large deformation effect. In order to reduce the computing time for the elastic large deflection theory and the rigid-plastic analysis based on the collapse mechanism which also includes the large deformation effect. In order to reduce the computing time for the elastic large deflection analysis, only one term of Fourier series for the plate deflection is considered. The results of the proposed method are in good agreement with those calculated by the elasto-plastic large deflection analysis using F.E.M. and the computing time of the proposed method is extremely short compared with that of F.E.M.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.3
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• pp.119-128
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• 1994

Deflection estimation at engine room upper deck panel is performed for the actual ship structure. These deflection behaviours are basically investigated from not only the data based on the full series results of nonlinear analysis using Incremental Galerkin's Method but also actual deflection data measured from damaged ship under construction in dry dock. The effects of residual stress, initial deflection and static loading are also included. The computed estimation results of upper deck plate panel including theme effects are shown that upper deck platings of new ship expected less deflection magnitude than damaged ship.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.781-785
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• 2005

Cutting forces and tool deflection in end milling are represented as the closed form of tool rotational angle and cutting conditions. The discrete cutting forces caused by tool entry and exit are continued using the Fourier series expansion. Tool deflection is predicted by direct integration of the distributed loads on cutting edges. Cutting conditions, tool geometry, run-outs and the stiffness of tool clamping pan are considered for cutting forces and tool deflection estimation. Compared to numerical methods, the presented method has advantages in short prediction time and the effects of feeding and run-outs on cutting forces and tool deflection can be analyzed quantitatively. This research can be effectively used in real time machining error estimation and cutting condition selection for error minimization since the ferm accuracy is easily predicted by tool deflect ion curve.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.4
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• pp.498-503
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• 2010

The main purpose of this study strongly concerned micro machining error estimation by using FEM analysis of tool deflection shapes in micro flat end-milling process. For the precision micro flat end-milling process, analysis of micro cutting errors is mandatory. In general, tool deflection is a major factor which causes cutting error and limits realization of the high-precision cutting process. Especially, in micro end-milling process, micro tool deflection generates very serious problems in contrast to macro tool deflection. Methods which deal with compensation of cutting error by tool deflection in macro end-milling process have been studied plentifully but, few researches transact with micro scaled cutting tool deflection in micro cutting process. Therefore, the trend of micro tool deflection was estimated by using FEM analysis in this paper. Cutting forces were acquired by micro dynamometer and these were utilized in FEM analysis. In order to verify FEM analysis results, micro machining processes were carried out and real machined profiles were compared with FEM results. Finally through the proposed approach well suited FEM results were obtained.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.66-71
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• 2004

Estimation of the CANDU pressure tube deflection is important since the deflection may cause significant structural failure due to hydrogen diffusion and blister. However, there is no appropriate engineering model to estimate it exactly. The purpose of this paper is to propose a new analysis method and program to resolve this issue. For development of proper analysis method, a series of finite element analyses has been carried under elastic-creep condition. In addition, for effective estimation of the creep deflection, an analysis program named PC-DAS was developed based on the proposed method. Comparison of simple case study results with corresponding reference ones showed good agreement. Therefore, the proposed method and program can be utilized as one of valuable toolkit for integrity assessment of CANDU pressure tube.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.62-68
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• 2000

In order to automate straightening process of deflected beams an adaptive three-point bending controller is studies which estimates and controls springback of beams under three-point bending. An analytical load-deflection model for three-point bending of beams with circular cross sections is derived nondimensionally. In spite of variation of material and process parameters this model can be applied to springback estimation by measuring real-time values of reactive load and deflection of the beam. A hydraulic punch stroke controller is designed to take real-time controls of the permanent deflection of the beam. The validity of the proposed system is verified through experiments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.3
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• pp.311-317
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• 2004

This paper proposes engineering estimation equations for the maximum deflection of a cylinder subject to bending under elastic-plastic and elastic-creep conditions. Being based on the reference stress approach, the proposed equations are simple to use and can accommodate general tensile and creep behaviours. Validation against detailed 3-D FE results using actual stress-strain data and realistic creep-deformation data shows excellent agreement, which provides confidence in the use of the proposed equation. Based on the proposed equations, together with information on in-service inspection data, discussion is given how to estimate future time-dependent and time-independent deflection of the CANDU pressure tube. Thus the present result would be valuable information for integrity assessment of the CANDU pressure tube.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.6
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• pp.460-465
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• 2016

Long pipe structures are usually installed in fixtures located with regular intervals or laid underground. Therefore, deflection and deformation could easily occur due to their weight or ground activity. A shape monitoring technique can be used effectively to evaluate the integrity of the pipe structures. Fiber Bragg grating (FBG) sensors, which have an advantage of multiplexing could be used to measure strains at multiple-points of a long structure. In this study, to evaluate the integrity of a pipeline, a shape estimation technique based on strain information was proposed. Furthermore, different experiments were conducted to verify the performance of the proposed technique. Thus, the proposed shape estimation technique can represent the shape according to the deformation of the specimen using the FBGs. Moreover, calculated deflection of the pipeline using the estimation technique showed a good agreement with the actual deflection of the pipeline.