• Journal of the Korean Society for Railway
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• v.5 no.3
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• pp.196-200
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• 2002

In this paper, the straightening process of a steel bar straightener is studied. The straightener carries out the bending and reverse bending process repeatedly. Plastic theory is employed for the analysis of roller-supporting-load, and the residual stress and the axial load of a steel bar are calculated by using the bending moment. The Bauschinger effect and plastic moment are calculated by using the residual stress and Swift's method respectively. It is verified from the experiments that the displacement calculated from theory makes it possible to straighten a steel bar.

• Structural Engineering and Mechanics
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• v.74 no.2
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• pp.189-199
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• 2020

Researchers have elaborated several accurate methods to calculate member-end rotations or moments, directly, for bridge-type structures. Recently, the concept of rotation and moment propagation (RMP) has been presented considering bending flexibility, only. Through which, in spite of moment distribution method, all joints are free resulting in rotation and moment emit throughout the structure similar to wave motion. This paper proposes a new set of closed-form equations to calculate member-end rotation or moment, directly, comprising both shear and bending flexibility. Furthermore, the authors program the algorithm of Timoshenko beam theory cooperated with the finite element. Several numerical examples, conducted on the procedures, show that the method is superior in not only the dominant algorithm but also the preciseness of results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.2
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• pp.239-246
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• 2003

In the PCA Load Contour Method, the biaxial bending design coefficient of columns(${\beta}$) is based on the equivalent rectangular stress block (RSB). And coefficient of ${\beta}$ estimates the reinforcement index to be a influencing parameter on biaxial moment strength of RC columns without considering the arbitrary condition of bar arrangement. The experimental results of high strength concrete (HSC) columns subjected to combined axial load and biaxial bending moment were compared to the analysis results of RSB method. As result, the accuracy of RSB method is still acceptable for HSC columns and, as the reinforcement is placed densely in each corner of column section, the ${\beta}$ is decreased.

• Steel and Composite Structures
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• v.2 no.6
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• pp.461-474
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• 2002

This paper presents the experimental and theoretical results of SUS 304 stainless tubes with different diameter-to-thickness ratio (D/t ratio) subjected to pure bending creep. Pure bending creep occurs when a circular tube is bent to a desired moment and held at that moment for a period of time. It was found that the magnitudes of the creep curvature and ovalization of tube cross-section increase faster with a higher hold moment than that with a lower one. Due to continuously increasing curvature, the circular tubes eventually buckle. Finally, a theoretical form was proposed in this study so that it can be used to describe the relationship between the creep curvature and time. Theoretical simulations are compared with the experimental test data, showing that good agreement between the experimental and theoretical results has been achieved.

• Journal of Ocean Engineering and Technology
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• v.6 no.2
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• pp.103-112
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• 1992

The calculation method which takes into account the shear lag effects on the ultimate transverse bending moment of a SWATH(Small Waterplane Area Twin Hull) ship has been developed. In case of the ultimate bending strength analysis of conventional monohull ships and general box girder structures, the hypothesis that plane section remains plane after bending can be employed but not in the case of the structures having wide flange. For the ultimate bending strength analysis of such structures, a new method which can take into account the effect of shear lag on the ultimate bending strength has been developed by adopting more reasonable assumption that warping distortion of the section takes place inthe same way as the actual stress distribution. Finally, the proposed method has been applied to a a SWATH cross deck structure.

• Steel and Composite Structures
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• v.8 no.2
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• pp.99-114
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• 2008

This paper presents the theoretical simulation of the response of 1020 carbon steel tubes subjected to symmetric and unsymmetric cyclic bending with or without external pressure by using the endochronic theory. Experimental data of 1020 carbon steel tubes tested by Corona and Kyriakides (1991) were used for evaluating the theoretical simulation. Several cases were considered in this study, they were symmetric bending without external pressure, symmetric bending with external pressure, unsymmetric bending without external pressure, and unsymmetric bending with external pressure. The responses of the moment-curvature, ovalization-curvature and ovalization-number of cycles with or without external pressure were discussed. It has been shown that the theoretical simulations of the responses correlate well with the experimental data.

• Steel and Composite Structures
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• v.18 no.4
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• pp.873-887
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• 2015

The continuous composite I-girder should have a sufficient rotation capacity (or ductility) to redistribute the negative bending moment into an adjacent positive bending moment region. However, it is generally known that the ductility of the high strength steel is smaller than that of conventional steel, and application of high strength steel can cause ductility problems in a negative moment region of the I-girder. In this study, moment redistribution of the continuous composite I-girder with high strength steel was studied, where high strength steel with yield stress of 690 MPa was considered (the ultimate stress of the steel was 800 MPa). The available and required rotation capacity of the continuous composite I-girder with high strength steel was firstly derived based on the stress-strain curve of high strength steel and plastic analysis, respectively. A large scale test and a series of non-linear finite element analysis for the continuous composite I-girder with high strength steel were then conducted to examine the effectiveness of proposed models and to investigate the effect of high strength steel on the inelastic behavior of the negative bending moment region of the continuous composite I-girder with high strength steel. Finally, it can be found that the proposed equations provided good estimation of the requited and available rotation capacity of the continuous composite I-girder with high strength steel.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.55-61
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• 2005

The purpose of this study is to investigate the effect of circumferential location of local wall thinning defect on the collapse behavior of an elbow. Thus, the present study conducts three-dimensional finite element analysis on the 90-degree elbow containing a local wall thinning at intrados, crown and extrados of bend region and evaluates the collapse moment of wall thinned elbow under various thinning shapes and loading conditions. Combined internal pressure and bending moment are considered as an applied load. The internal pressure of $0\~20MPa$ and both closing and opening mode bending are employed. The results of analysis show that the reduction in collapse moment of the elbow by local wall thinning is more significant for a defect locating at crown than for a defect locating at intrados or at extrados. Also, the effect of internal pressure on the collapse moment of wall thinned elbow depends on the circumferential location of thinning defect and applied bending mode.

• Journal of the Korean Society of Safety
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• v.8 no.3
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• pp.13-18
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• 1993

This paper an application method of crankshaft of four cylinder internal combustion engine for studying stress analysis of the shaft. For simple analysis, uniform sections of journal, pin and arm parts were assumed. Transfer Metrix Method was used, considering branched part and coordinate transformation part. Bending, twisting moment and stresses of crank shaft were investigated.

• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.6-12
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• 1998

Test results of domestic softwood lumber were presented to examine the notch effect of beams and compare to present AIJ(Architecture Institute of Japan) formula in notched wood member especially positioned in bottom side (tension side) of a beam. Notched lumber was tested under following condition : each specimen supported simply, and subjected to third-point loading at points of 1/3 of the span length. Notch was located opposite side to loading direction and notch depth were 1/6, 1/4, 1/3 of beam depth. Deflection and load were measured by digital dial guage each in 25kgf increment. Bending test results were as follows; Mpro/Mmax range (proportional and maxium bending moment ratio in notched beam) was 0.5 - 0.65. It was considered that maxium bending moment was about 1.5 times to proportional bending moment in notched beam and showed same tendency in the test result of ordinary wood specimens. AU standard formula for the tension side notch, Mmat = 0.6 ${\times}$ (Zo $\sigma$), the constant 0.6 was suitble for notch ratio(notch depth to beam depth) 1/6, but this ratio for 1/4, and 1/3 was not. So it is preferable to accept smaller value than 0.6 for notch ratio more than 1/3. These experiment results showed critical effect in tension side notched wood beam especially in greater than notch ratio 1.3 of wood beam. From the above results, it is recommened to revise design formula adoptable to domestic wood constructon member with tension side notched member.