• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.987-992
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• 1997

Burrs always come out with the machining of ducterial with small size. Though the size of burrs is small, burrs dominate deterioration of the accuracy of the micro grooves. So the burr generation model especially side burr generation model was investigated to predict the size of the burrs at the given cutting conditions. The side shear plane is introduced to build the burr generation model and the width of side shear plane nomalized with cutting depth is defined with the shear angle. From the theoretical observation, the width of side shear plane can vary up 40% of the cutting depth. To determine the size of burr and stiffness, single groovings were carried out and it was found that there exist a critical depth of cut that the size or stiffness of the burr vary.

• Steel and Composite Structures
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• v.42 no.1
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• pp.49-57
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• 2022

This paper presents a study on the behavior of a bolted T-stub to square tube connection using Thread-fixed One-side Bolts (TOBs) through tests and numerical simulations. It outlines a research work of four connections with focus on the failure modes and strengths of the connection under tensile load. It was observed that the thread anchor failure caused by shear failure of hole threads controlled the final failure of the connection in the tests. Meanwhile, the out-of-plane deformation of tube wall resulted in the contact separation between hole threads and bolt threads, which in turn reduced the shear strength of hole threads. Finite element models (FEMs) allowing for the configuration details of the TOBs fixed connection are then developed and compared with the test results. Subsequently, the failure mechanism of hole threads and stress distribution of each component are analyzed based on FEM results. It was concluded that the ultimate strength of connection was not only concerned with the shear strength of hole threads, but also was influenced by the plastic out-of-plane deformation of tube wall. These studies lay a foundation for the establishment of suitable design methods of this type of connection.

• Journal of the Korean Geotechnical Society
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• v.26 no.8
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• pp.5-14
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• 2010

To simulate two-dimensional plane-strain conditions in the laboratory model test, the side frictional resistance between the soil and thick glass or plastic sheet of the soil container should be reduced as much as possible. However, in fact this side friction cannot be removed completely. In this paper, the ground model simulated as a multi-sized aluminium rod mixture was introduced to get rid of the side frictional resistance and applied to the laboratory shear box test. In addition, an application of the close range photogrammetric technique to the shear box test was validated. As a result, it was found that a mean value of dilation angle from the close range photogrammetry was close to the dilation angle defined by the curve of shear strain vs. volumetric strain.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.5
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• pp.239-248
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• 2019

In this study, the out-of-plane seismic resistance of lightly-reinforced existing walls strengthened with thick RC jacket was investigated. The thick RC jacket with a thickness of 500 mm was placed at one side of the thin existing wall with a thickness of 150 mm. At the interface between the wall and RC jacket, a tee-shaped steel section with a number of anchor bolts and dowel bars was used as the shear connector. To investigate the connection performance and strengthening effects, the cyclic loading tests of four jacketed wall specimens were performed. The tests showed that the flexural strength of the jacketed walls under out-of-plane loading was significantly increased. During the initial behavior, the tee shear connector transferred forces successfully at the interface without slip. However, as the cracking, spalling, and crushing of the concrete increased in the exiting walls, the connection performance at the interface was significantly degraded and, consequently, the strength of the jacketed walls was significantly decreased. The flexural strength of the jacketed walls with tee shear connector was estimated considering the full and partial composite actions of the tee shear connector.

• Journal of the Korean Society for Precision Engineering
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• v.5 no.1
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• pp.29-39
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• 1988

Plastically deformed layer beneath metal surface machined by orthogonal cutting was evaluated in terms of residual stress, microvickers hardness, side spread, and the side strain. An attempt was made to predict the depth of layer according to machining conditions particularly tool geometry and the shear plane angle. In this paper, we employed two models concerning the sliplines. The exact model was validated by comparision of computed and measured tool force and its angle, and the model offers an upper boundary of the deformed layer to be in good agreement with the experiment.

• Transactions of Materials Processing
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• v.11 no.8
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• pp.682-690
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• 2002

The formation of adiabatic shearband in tungsten heavy alloys(WHA) was studied in this investigation. Five prismatic specimens were loaded by high velocity impacts and treated as plane strain problems. To find out the effect of particle's volume ratio, specimens containing 81%, 93% and 97% volume percents of tungsten particles were used. Also the effects of particle's geometry and size on the formation of shearband were studied for 81% volume percent alloys by small size particle model, large size particle model and undulated particle models, and the results were discussed.be used to diagnose the causes of necking and fracture in industrial practice and to investigate whether these defects were caused by material property variation, changes in lubrication, or incorrect press settings. In non-axisymmetric deep drawing, three modes of forming regimes are found: draw, stretch, plane strain. The stretch mode for non-axisymmetric deep drawing could be defined when the major and minor strains are positive. The draw mode could be defined when the major strain is positive and minor strain is negative, and plane strain mode could be defined when the major strain is positive and minor strain is zero. Through experiments the draw mode was shown on the wall and flange are one of a drawn cup, while the plane strain and the stretch mode were on the punch head and the punch corner area respectively, We observed that the punch load of elliptical deep drawing was decreased according to increase of die corner radius and the thickness deformation of minor side was more large than major side.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.190-196
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• 1999

In this study, a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool has been established. The edge of a single point tool including circular nose is modified to the equivalent straight edge, then 3-D cutting with a single point tool is reduced to equivalent oblique cutting. Transforming the conventional coordinate systems and using the measured three component of cutting forces, force components on the rake face and the shear plane of the equivalent oblique cutting system can be obtained. And it can be possible to assess the chip-tool friction and shear characteristics in 3-D cutting with a single point tool.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.1
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• pp.15-21
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• 2000

This study presents a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool. The edge of a single point tool including a circular nose is modified to an equivalent straight edge, thereby reducing the 3-D cutting with a single point tool to the equivalent of oblique cutting. Then, by transforming the conventional coordinate systems and using the measurements of three cutting force components, the force components on the rake face and shear plane of the equivalent oblique cutting system can be obtained. As a result, the chip-tool friction and shear characteristics of 3-D cutting with a single point tool can be assessed.

• Steel and Composite Structures
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• v.27 no.3
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• pp.311-325
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• 2018

This article presents the bending analysis of FGM rectangular plates resting on non-uniform elastic foundations in thermal environment. Theoretical formulations are based on a recently developed refined shear deformation theory. The displacement field of the present theory is chosen based on nonlinear variations in the in-plane displacements through the thickness of the plate. The present theory satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. Unlike the conventional trigonometric shear deformation theory, the present refined shear deformation theory contains only four unknowns as against five in case of other shear deformation theories. The material properties of the functionally graded plates are assumed to vary continuously through the thickness, according to a simple power law distribution of the volume fraction of the constituents. The elastic foundation is modeled as non-uniform foundation. The results of the shear deformation theories are compared together. Numerical examples cover the effects of the gradient index, plate aspect ratio, side-to-thickness ratio and elastic foundation parameters on the thermo-mechanical behavior of functionally graded plates. Numerical results show that the present theory can archive accuracy comparable to the existing higher order shear deformation theories that contain more number of unknowns.

• Steel and Composite Structures
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• v.37 no.2
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• pp.117-136
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• 2020

Curved steel-concrete composite box girder has been widely adopted in urban overpasses and ramp bridges. In order to investigate its mechanical behavior under complicated and combined bending, shear and torsion load, two large-curvature composite box girders with interior angles of 25° and 45° were tested under static hogging moment. Based on the strain and deflection measurement on critical cross-sections during the static loading test, the failure mode, cracking behavior, load-displacement relationship, and strain distribution in the steel plate and rebar were investigated in detail. The test result showed the large-curvature composite box girders exhibited notable shear lag in the concrete slab and steel girder. Also, the constraint torsion and distortion effect caused the stress measured at the inner side of the composite beam to be notably higher than that of the outer side. The strain distribution in the steel web was approximately linear; therefore, the assumption that the plane section remains plane was approximately validated based on strain measurement at steel web. Furthermore, the full-process non-linear elaborate finite element (FE) models of the two specimens were developed based on commercial FE software MSC.MARC. The modeling scheme and constitutive model were illustrated in detail. Based on the comparison between the FE model and test results, the FE model effectively simulated the failure mode, the load-displacement curve, and the strain development of longitudinal rebar and steel girder with sufficient accuracy. The comparison between the FE model and the test result validated the accuracy of the developed FE model.