• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.4A
• /
• pp.383-389
• /
• 2010

The concrete structural design provisions in Korea are based on ultimate strength design. Up to service load stage, it is assumed a linear stress-strain relation, but there is no stress-strain relationship for a concrete material from service load stage to limat state. According to the current provisions, an independent method is provided for the each calculation of deflection and crack width. In EC2 provisions based on limit state design, however, a stress-strain relationship of concrete is provided. Thereby, it is able to calculate a strength as well as a deflection directly from concrete stress-strain relationship. In this paper the moment-curvature relationship is directly calculated from a material law using equilibrium and compatibility conditions. Then strength and deflection are formulated. These results are compared with the values from the current provisions in Korea. From the results, the deflection based on a moment-curvature relationship is well agreed with experimental results and it is appeared that the deflection after the yielding of steel is also possible.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.286-289
• /
• 1997

In the design of structure the forces acting on the structure are important parameter for noise and vibration control. However, in the complex structure, the forces at the injection pomt on the structure cannot be measured directly. Thus it is necessary to find out indirect force evaluation method. In thls paper forces have been measured with in-situ vibration responses and system information. Three existing techniques of indirect force measurement, viz. direct inverse, principal component analysis and regularization have been compared. It has been shown that multi-vibration responses are essential for the precise estimation of the forces. To satisfy those cond~tions, Rotary compressor is adopted as test sample, because it is very difficult to measurc the injection forces from internal excitat~on to shell. It has also been obtained that relatively higher force IS transmitted through three welding paths to the compressor shell. It shows a good agreement between direct and indirect force evaluation wlth curvature shell and plate and is investigated the possibility of force evaluation of rotary compressor as a complex structure.

• Structural Engineering and Mechanics
• /
• v.64 no.4
• /
• pp.487-494
• /
• 2017

The present paper deals with a theoretical study of delamination fracture in the Crack Lap Shear (CLS) functionally graded beam configuration. The basic purpose is to analyze the fracture with taking into account the material non-linearity. The mechanical behavior of CLS was described by using a non-linear stress-strain relation. It was assumed that the material is functionally graded along the beam height. The fracture was analyzed by applying the J-integral approach. The curvature and neutral axis coordinate of CLS beam were derived in order to solve analytically the J-integral. The non-linear solution of J-integral obtained was verified by analyzing the strain energy release rate with considering material non-linearity. The effects of material gradient, crack location along the beam height and material non-linearity on fracture behavior were evaluated. The J-integral non-linear solution derived is very suitable for parametric studies of longitudinal fracture in the CLS beam. The results obtained can be used to optimize the functionally graded beam structure with respect to the fracture performance. The analytical approach developed in the present paper contributes for the understanding of delamination fracture in functionally graded beams exhibiting material non-linearity.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.04a
• /
• pp.1061-1064
• /
• 2008

Shear connectors have a finite slip capacity because of the mechanism by which they transfer the shear between UHPFRC and NC elements. At high degree of shear connection, non-linear analysis techniques are required to allow for compressive plasticity and tensile cracking behaviour of the elements. As with all non-linear problems, a closed form solution is difficult to find. A Modified Shooting Method Technique is developed here for non-linear analysis of UHPFRC/concrete composite. The initial effective moment is derived according to the prestressing force. The composite structure is divided into small segments which length is much less than the length of the structure and it can be assumed that the forces and displacements within each segment are constant. An equivalent analysis in composite girders would be to fix the slip strain in each segment and develop a moment curvature relationship for this slip strain in each segment. Additive forces and moment analysis on each section of the segments are analyzed by MSMT. Finally the ultimate slippage of the interface can be evaluated by the MSMT model. This paper presents a nonlinear analysis method for limited slip capacity of UHPFRC-NC interface.

• Ocean Systems Engineering
• /
• v.5 no.2
• /
• pp.77-89
• /
• 2015

As the exploitation of oil and gas resources advances into deeper waters and harsher environments, the design and analysis of the flexible risers has become the research focus in the offshore engineering filed. Due to the complexity of the components and the sliding between the adjacent layers, the bending response of the flexible risers is highly non-linear. This paper presents the finite element analysis of the flexible risers under bending loads. The detailed finite element model of the flexible riser is established in ABAQUS software. This finite element model incorporates all the fine details of the riser to accurately predict its nonlinear structural behavior. Based on the finite element model, the bending moment-curvature relationships of a flexible riser under various axisymmetric loads have been investigated. The results have been compared with the analytical ones obtained from the literature and good agreements have been found. Moreover, the stress of the tendon armors has been studied. The non-linear relationship between the armor tendons' stress and the bending loads has been obtained.

• Structural Engineering and Mechanics
• /
• v.62 no.4
• /
• pp.443-453
• /
• 2017

The performance of bolted side-plated (BSP) beams is affected by the degree of transverse partial interaction, which is a result of the interfacial slip caused by transverse shear transfer between the bolted steel plates and the reinforced concrete beams. However, explicit formulae for the transverse shear transfer profile have yet to be derived. In this paper, a simplified piecewise linear shear transfer model was proposed based on force superposition principle and simplification of shear transfer profiles derived from a previous numerical study. The magnitude of shear transfer was determined by force equilibrium and displacement compatibility condition. A set of design formulae for BSP beams under several basic load cases was also derived. Then the model was verified by test results. A worked example was also provided to illustrate the application of the proposed design formulae. This paper sheds some light on the shear force transfer mechanism of anchor bolts in BSP beams, and offers a practical method to evaluate the influence of transverse partial interaction in strengthening design.

• Korean Journal of Optics and Photonics
• /
• v.5 no.1
• /
• pp.138-143
• /
• 1994

A speckle correlation method was applied to measure the in-plane translation of a diffuse object which has rough surface using a linear CCD sensor and personal computer. Displacement of a speckle pattern produced from the object illuminated by a laser beam was measured by the cross-correlation functions between the I-D speckle profiles before and after the object translation, which were measured by linear CCD array sensor to be sent to IBM 386 personal computer. The sensitivity of the measurement was dependent on the radius of the wavefront curvature of incident beam as well as the spatial resolution of linear CCD array. A linear CCD array had 15 Jlffi pitch and 1728 pixels. The ratio of the speckle displacement and object translation varied from 1.03 to 5.20. The object translation of $3\mu\textrm{m}$ can be measured br the linear CCD sensor of which pitch was $15\mu\textrm{m}$, when the ratio of the speckle displacement and object translation was 5.20.s 5.20.

• Geophysics and Geophysical Exploration
• /
• v.16 no.1
• /
• pp.36-44
• /
• 2013

We conducted the airborne magnetic and radiometric survey for the characterization of the black shale related and pyrometamorphic uranium deposits distributed in Geumsan area. For the successful characterization of the uranium deposits, the general geological and structural geological features were investigated based on the lithological and linear feature analysis to individual magnetic and radiometric data as the first step. Lithological analysis from the magnetic reduction to the pole and downward continuation map revealed that prominent positive anomalies caused by black and dark gray slate member were clearly recognized as magnetic sources. These results indicate that magnetic survey, even though it is not a direct method for the detection of uranium, can be a useful tool in uranium detection. By the linear feature analysis based on 2nd vertical derivative and curvature map, two linearments corresponded the gray hornfels and black slate member were extracted and in succession, the additional uranium potential zone was inferred. Final discrimination whether uranium-rich or not was confirmed by radiometric and uranium anomaly map. From these analysis, we finally concluded that uranium deposit originated by pyrometamorphic process was confined near the intrusive area only. On the contrary, it was found that black shale related uranium deposit is distributed and extended through out the entire survey area with south-west to north-east direction. In addition, from the linear feature analysis based on radiometric total anomaly map, the typical discontinuous characteristics were recognized in areas where uranium-contained linearments cross the faults. From the above discussion, we concluded that airborne magnetic and radiometric survey are complementary to each other. So it is preferable to carry out simultaneously for the efficient data processing and fruitful interpretation.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.7 no.1
• /
• pp.39-51
• /
• 2004

This study aims to suggest new algorithm, named as Simoo, in order to improve spatial conflicts and vector displacement between linear features in generalization of the linear features. Main principles of Simoo algorithm is adoption of simplification and smoothening methods. Tolerance conditions used in Simoo are perpendicular length, external angle, and average vertex length. Main characteristics of Simoo are the application of scale, cartographic refinement, minimization of logical errors, and maintenance of geographical properties. The Simoo was applied through comparison to existing Douglas-Peucker algorithm. Resultantly, maintenance ratios of line such as coastal line and stream network were over 97% in both algorithms. The elimination ratio of vertex points may be more effective in Douglas-Peucker than in Simoo. Spatial conflicts between linear features may be more minimized in Simoo. The curvature and smoothening of lines become decreased in scale in application of Simoo. Finally, Simoo algorithm may be more effective than Douglas-Peucker for cartographic generalization.

• Journal of the Korea Computer Graphics Society
• /
• v.28 no.4
• /
• pp.31-40
• /
• 2022

This study assumed two key parameters that describe smoothness. Previously, the number of studies that defined smoothness with the concept of curvature has been limited. The parameters were the two physical characteristics of curvature: the number of waves and the amplitude of them. The purpose of the study was to observe which of the two parameters influences the perception of smoothness and to examine the relationship between the sense of aesthetic beauty and smoothness. The visual stimuli used in the study were transformed three-dimensional spheres, based on the combination of the three levels of the two parameters of nine distinct conditions. We analyzed the three responses that measured the preference of each visual stimuli, the familiarity score, and the smoothness evaluation score, each with the linear mixed model whose fixed effects were the two parameters and random effects were the participants' individual differences. Nearly the eighty percent of the variance of the smoothness evaluation score was explained by the linear model with the two key parameters and their interaction. The physical characteristics of a viewed object were far more significant than individual differences such as personality factors and the manner of art appreciation. In conclusion, the study examined the perception of smoothness based on the change of the physical characteristics of a shape. The study further recognized the relationship between smoothness and the aesthetic preference. No significant influence of the participants' individual difference such as gender, the degree in fine arts, personality factors, and the manner of art appreciation was observed. The amplitude of waves, rather than the number of them, was far more significant to the perception of smoothness.