• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.126-133
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• 2017

This report investigates the stress distribution according to the location and shape change of the circular hole for the lightweight design of the cross beam of a railway passenger car and studies the lightweight design. To design a lightweight cross beam with a circular hole, we selected the non-circular crossbeam as a basic model, examined the stress distribution and displacement by position and determined the location, shape, size and quantity of the hole for light weight. We analyzed the effects of the position and shape of the hole on the maximum equivalent stress and displacement. The influencing factors were set as the design parameters, and the stress value was examined according to the variation of each variable. By considering the stress value according to the change of each variable and selecting the design parameter with the narrowest scattering value of the stress at each position of the hollow cross beam with various hole positions and shapes, we studied a cross beam with a circle hole under identical load condition to have an equal stress distribution to that of a non-circular cross beam.

• Structural Engineering and Mechanics
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• v.57 no.2
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• pp.221-238
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• 2016

One of the objectives of this study is to implement the direct calculation of the torsional moment of inertia for non-circular cross-sections, which is based on the St. Venant torsion formulation and the finite element method. Recently the proposed method provides a unique calculation of the torsional rigidity of simply and multiply connected cross-sections. Next, free vibration analyses of cylindrical and non-cylindrical helices with non-circular cross-sections are solved by a curved two-nodded mixed finite element based on the Timoshenko beam theory. Some thin-thick closed or open sections are handled and the natural frequencies of cylindrical and non-cylindrical helices are compared with the literature and the commercial finite element program SAP2000.

• Computational Structural Engineering
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• v.9 no.3
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• pp.135-143
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• 1996

The differential equations governing both the free vibrations and buckling loads of tapered beam-columns of circular cross-section with constant volume are derived and solved numerically. The effects of axial load are included in the differential equations. The parabolic equation is chosen as the variable radius of circular cross-section for the tapered beam-column. In numerical examples, the clamped-clamped, clamped-hinged and hinged-hinged end constraints are considered. The variations of the frequency parameters and buckling load parameters with the non-dimensional system parameters are presented in figures and the configurations of strongest columns are obtained.

• Structural Engineering and Mechanics
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• v.54 no.3
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• pp.433-451
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• 2015

This paper focuses on large deflection static behavior of edge cracked simple supported beams subjected to a non-follower transversal point load at the midpoint of the beam by using the total Lagrangian Timoshenko beam element approximation. The cross section of the beam is circular. The cracked beam is modeled as an assembly of two sub-beams connected through a massless elastic rotational spring. It is known that large deflection problems are geometrically nonlinear problems. The considered highly nonlinear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. There is no restriction on the magnitudes of deflections and rotations in contradistinction to von-Karman strain displacement relations of the beam. The beams considered in numerical examples are made of Aluminum. In the study, the effects of the location of crack and the depth of the crack on the non-linear static response of the beam are investigated in detail. The relationships between deflections, end rotational angles, end constraint forces, deflection configuration, Cauchy stresses of the edge-cracked beams and load rising are illustrated in detail in nonlinear case. Also, the difference between the geometrically linear and nonlinear analysis of edge-cracked beam is investigated in detail.

• Fire Science and Engineering
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• v.30 no.3
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• pp.7-15
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• 2016

The cross-sectional shape factor is used worldwide to evaluate the scientific performance of fire-resistant structures. In South Korea, however, a system for applying a cross-sectional shape factor has not been arranged and circular or rectangular steel pipes are commonly used for large-scale steel frame buildings. On the other hand, coating material-spray steel beams and pillars that have received the certification of a fire-resistant structure from recognized organizations are mostly limited to a H-beam. A H-beam is granted a wide range of certifications without size limitations from a non-loading performance test with test standards based on the relevant provisions. Other types of steel pipe are to be certified for fireresistance according to shape. In this study, a cross-sectional shape factor was used to propose standard testing specifications for the application of coating material-sprayed circular and rectangular steel pipes, eventually to set the scope of certification for reasonable fire-resistant structures.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.1
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• pp.41-54
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• 1999

For free vibration of non-symmetric thin-walled circular arches including restrained warping effect, the elastic strain and kinetic energy is derived by introducing displacement fields of circular arches in which all displacement parameters are defined at the centroid axis. The cubic Hermitian polynomials are utilized as shape functions for development of the curved thin-walled beam element having eight degrees of freedom. Analytical solution for in-plane free vibration behaviors of simply supported thin-walled curved beams with monosymmetric cross-sections is newly derived. Also, a finite element formulation using two noded curved beams element is presented by evaluating elastic stiffness and mass matrices. In order to illustrate the accuracy and practical usefulness of this study, analytical and numerical solutions for free vibration of circular arches are presented and compared with solutions analyzed by the straight beam element and the ABAQUS's shell element.

• Steel and Composite Structures
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• v.18 no.3
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• pp.659-672
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• 2015

This research deals with the analytical solution of a curved beam with different shapes made of functionally graded materials (FGM's). It was assumed that modulus of elasticity is graded along the thickness direction of curved beam based on a power function. The beam was loaded under pure bending. Using the linear theory of elasticity, the general relation for radial distribution of radial and circumferential stresses of arbitrary cross section was derived. The effect of nonhomogeneity was considered on the radial distribution of circumferential stress. This behavior can be investigated for positive and negative values of nonhomogeneity index. The novelty of this study is application of the obtained results for different combination of material properties and cross sections. Achieved results indicate that employing different nonhomogeneity index and selection of various types of cross sections (rectangular, triangular or circular) can control the distribution of radial and circumferential stresses as designer want and propose new solutions by these options. Increasing the nonhomogeneity index for positive or negative values of nonhomogeneity index and for various cross sections presents different behaviors along the thickness direction. In order to validate the present research, the results of this research can be compared with previous result for reachable cross sections and non homogeneity index.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.341-348
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• 2000

The differential equations governing the free vibrations of stepped horizontally circular curved beams with circular cross-section are derived and solved numerically. In numerical method, the Runge-Kutta and Determinant Search methods are used for computing the natural frequencies and mode shapes. Frequencies and mode shapes are reported as the functions of non-dimensional system parameters. The numerical method developed herein for computing frequencies and mode shapes are efficient and reliable.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.10a
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• pp.3-10
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• 1996

Numerical methods are developed for solving the buckling loads and the elastica of clamped- free columns of circular cross-section with constant volume. The column model is based rut the Timoshenko beam theory. The Runge-Kutta and Regula-Falsi methods, respectively, are used to solve the governing differential equations and to compute the eigenvalues. Extensive numerical results, including buckling loads, elastica of buckled shapes and effects of shear de-formation, are presented in non-dimensional form for elastic columns whose radius of circular cross-section varies both linearly and parabolically with column length.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.29-36
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• 2003

This paper deals with the free vibration analysis of horizontally circular mea beams with variable cross sectional width on elastic foundations. Taking into account the effects of rotatory inertia and shear deformation differential equations governing the free vibrations of such beams are derived, in which the Whlkler foundation model is considered as the elastic foundation. The variable width of beam is chosen as the linear equation. The differential equations are solved numerically to calculate natural frequencies. In numerical examples, the curved beam with the hinged-hinged, hinged-clamped, clamped-hinged and damped-clamped end constraints are considered The parametric studies are conducted and the lowest four frequency parameters are reported in figures as the non-dimensional forms.