MOMENT AMPLIFICATION FACTOR OF BEAM-COLUMNS WITH INITIAL DEFLECTION

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Haruna Utsunomiya ◽  
Masayuki Haraguchi ◽  
Masae Kido ◽  
Keigo Tsuda
Keyword(s):  
Amplification Factor ◽  
Slenderness Ratio ◽  
Compressive Force ◽  
Bending Moment ◽  
Load Ratio ◽  
Initial Deflection ◽  
Axial Compressive Force ◽  
Beam Columns ◽  
Moment Ratio ◽  
The Moment

In the design of slender steel beam-columns, the moment amplification factor is used to estimate the maximum bending moment. The formulas for evaluating the factor have been presented on the basis of the elastic or elastic-plastic analysis, however the initial deflection of beam-columns is not considered. This paper discusses the effect of initial deflection on the value of the moment amplification factor by performing the analytical work. The analytical model is a simply supported beam-column subjected to constant axial compressive force and end moments. First of all, the equilibrium differential equation which governs the problem is solved and the formula for calculating the bending moment is obtained. In the parametric study, magnitude of the initial deflection, the axial load ratio, the slenderness ratio and the end moment ratio are selected as the parameters. The effects of magnitude of the initial deflection and the end moment ratio on the moment amplification factor are discussed.

EFFECTS OF THE INITIAL DEFLECTION SHAPE ON THE MOMENT AMPLIFICATION FACTOR OF BEAM-COLUMNS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Haruna Utsunomiya ◽  
Masayuki Haraguchi ◽  
Masae Kido ◽  
Keigo Tsuda
Keyword(s):  
Amplification Factor ◽  
Slenderness Ratio ◽  
Compressive Force ◽  
Bending Moment ◽  
Load Ratio ◽  
Longitudinal Direction ◽  
Initial Deflection ◽  
Axial Compressive Force ◽  
Beam Columns ◽  
The Moment

In the design of slender steel beam-columns, the moment amplification factor is used to estimate the maximum moment along with the longitudinal direction. While formulas for evaluating the factor have been presented on the basis of elastic or elastic-plastic analysis, the initial deflection of the column is not considered. The effect that the initial deflection on the strength and behavior of the column has been shown only when the initial deflection shape is half sine wave. This paper discusses the effect of the initial deflection shape on the value of the moment amplification factor by performing the analytical work. The analytical model is the hinged-end beam-column subjected to constant axial compressive force and end moments. First of all, the equilibrium differential equation which governs the problem is solved and the formula for calculating the bending moment is presented. In the parametric study, magnitude of initial deflection, initial deflection shape, axial load ratio, slenderness ratio and end moment ratio are selected as the parameters. In this paper, we discuss the effects of the amount of the initial deflection and the initial deflection shape.

Bending Capacity of Corroded Pipeline Subjected to Internal Pressure and Axial Loadings

2018 ◽  
Author(s):  
Jie Gao ◽  
Zengli Peng ◽  
Xin Li ◽  
Jing Zhou ◽  
Wenxing Zhou
Keyword(s):  
Internal Pressure ◽  
Local Buckling ◽  
Compressive Force ◽  
Bending Moment ◽  
Corrosive Media ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Offshore Pipelines ◽  
Bending Capacity ◽  
The Moment

Offshore pipelines operating in a harsh environment are usually subjected to combinations of bending moment and axial loadings in addition to internal pressure. Due to the corrosive media transported in the pipelines and corrosive substances within seawater and soil outside the pipelines, local corrosion defects will generate on the pipeline’s inner and outer walls, reducing its ultimate bearing capacity. This paper presents a series of full-scale failure tests and nonlinear finite element analysis (FEA) to study the bending capacity and failure mode of corroded pipelines with outside locally-thinned-areas (LTAs) subjected to combinations of internal pressure, axial compressive force and bending moment. The LTAs are loaded in compression to simulate corrosion. Material tests of API 5L X56 seamless pipe steel were conducted and the stress-strain relationship was obtained. FEA results of the moment versus curvature relation, bending capacity and local buckling behavior of each specimen model matched the experimental results very well, validating the accuracy of this simulation. Additional FEA is then performed to investigate the effect of corrosion geometric parameters, such as corrosion depth, corrosion width, and corrosion length, on the ultimate moment. Among them, the width is of the greatest impact, followed by is the depth, the length impact can be ignored.

ULTIMATE STRENGTH OF CONCRETE FILLED SQUARE STEEL TUBULAR BEAM-COLUMNS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Masayuki Haraguchi ◽  
Masae Kido ◽  
Keigo Tsuda
Keyword(s):  
Ultimate Strength ◽  
Axial Load ◽  
Shooting Method ◽  
Slenderness Ratio ◽  
Limit State ◽  
Load Ratio ◽  
Maximum Strength ◽  
Rotational Angle ◽  
Beam Columns ◽  
Axial Load Ratio

The objective of this study is to examine the ultimate strength of CFT columns. The range of the axial load ratio and the slenderness ratio in which CFT beam-columns reach the full plastic moment are examined on the basis of the strength formulas specified by AIJ Recommendation for Limit State Design of Steel Structures. The CFT columns are subjected to the constant axial compressive force and the monotonic moment at the one end, as the analytical parameters the axial load ratio and slenderness ratio are selected. The analysis is carried out by the shooting method. Bending moment-rotational angle relationships are calculated by the shooting method and the maximum strengths of CFT columns are obtained. When the value obtained by multiplying the axial load ratio and the second power of the slenderness ratio is 0.05, the maximum strength reach 95% of the full plastic moment under the condition that the axial load ratio value is less than or equal to 0.75. When the value obtained by multiplying the axial load ratio and the second power of the slenderness ratio is 0.1, the maximum strength reach 95% of the full plastic moment under the condition that the axial load ratio value is less than or equal to 0.5.

scholarly journals The Influence of the Material Properties on the Ultimate Behaviour of Aluminium H-shaped Beams

2021 ◽  
Vol 15 (1) ◽  
pp. 176-188
Author(s):  
Rosario Montuori ◽  
Elide Nastri ◽  
Vincenzo Piluso ◽  
Alessandro Pisapia
Keyword(s):  
Material Properties ◽  
Slenderness Ratio ◽  
Bending Moment ◽  
Constitutive Law ◽  
Rotation Capacity ◽  
Moment Gradient ◽  
Dimensional Parameters ◽  
The Moment ◽  
Plastic Rotation Capacity ◽  
Ultimate Resistance

Background: In this paper, the influence of the Ramberg-Osgood exponent on the ultimate behaviour of the H-shaped (or I-shaped) aluminium beams subjected to non-uniform bending moment is investigated. Methods: In particular, the results of a wide parametric analysis recently carried out by the authors are herein exploited to point out the influence of the material properties. The flange slenderness, the flange-to-web slenderness ratio, and the non-dimensional shear length, accounting for the moment gradient, are the main non-dimensional parameters governing the ultimate resistance and the rotation capacity of H-shaped aluminium beams. Results: The influence of these parameters was investigated considering four different materials covering both low yielding-high hardening alloys and high yielding-low hardening alloys, which are characterised by significant differences in the values of the Ramberg-Osgood exponent of the stress-strain constitutive law of the material. Conclusion: Finally, empirical formulations for predicting the non-dimensional ultimate flexural strength and the plastic rotation capacity of H-section aluminium beams under moment gradient have been provided as a function of the Ramberg-Osgood exponent and all the above non-dimensional parameters.

scholarly journals On the Flexural-Torsional Vibration and Stability of Beams Subjected to Axial Load and End Moment

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
M. Tahmaseb Towliat Kashani ◽  
Supun Jayasinghe ◽  
Seyed M. Hashemi
Keyword(s):  
Boundary Conditions ◽  
Axial Force ◽  
Axial Load ◽  
Natural Frequencies ◽  
Compressive Force ◽  
Elastic Beam ◽  
Axial Compressive Force ◽  
Various Boundary Conditions ◽  
Linear Eigenvalue Problem ◽  
The Moment

The free vibration of beams, subjected to a constant axial load and end moment and various boundary conditions, is examined. Based on the Euler-Bernoulli bending and St. Venant torsion beam theories, the differential equations governing coupled flexural-torsional vibrations and stability of a uniform, slender, isotropic, homogeneous, and linearly elastic beam, undergoing linear harmonic vibration, are first reviewed. The existing formulations are then briefly discussed and a conventional finite element method (FEM) is developed. Exploiting the MATLAB-based code, the resulting linear Eigenvalue problem is then solved to determine the Eigensolutions (i.e., natural frequencies and modes) of illustrative examples, exhibiting geometric bending-torsion coupling. Various classical boundary conditions are considered and the FEM frequency results are validated against those obtained from a commercial software (ANSYS) and the data available in the literature. Tensile axial force is found to increase natural frequencies, indicating beam stiffening. However, when a force and an end moment are acting in combination, the moment reduces the stiffness of the beam and the stiffness of the beam is found to be more sensitive to the changes in the magnitude of the axial force compared to the moment. A buckling analysis of the beam is also carried out to determine the critical buckling end moment and axial compressive force.

scholarly journals Buckling Knockdown Factors of Composite Cylinders under Both Compression and Internal Pressure

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 346
Author(s):  
Do-Young Kim ◽  
Chang-Hoon Sim ◽  
Jae-Sang Park ◽  
Joon-Tae Yoo ◽  
Young-Ha Yoon ◽  
...  
Keyword(s):  
Internal Pressure ◽  
Axial Compression ◽  
Shell Thickness ◽  
Slenderness Ratio ◽  
Compressive Force ◽  
Thickness Ratio ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Thin Walled ◽  
Composite Cylinders

The internal pressure of a thin-walled cylindrical structure under axial compression may improve the buckling stability by relieving loads and reducing initial imperfections. In this study, the effect of internal pressure on the buckling knockdown factor is investigated for axially compressed thin-walled composite cylinders with different shell thickness ratios and slenderness ratios. Various shell thickness ratios and slenderness ratios are considered when the buckling knockdown factor is derived for the thin-walled composite cylinders under both axial compression and internal pressure. Nonlinear post-buckling analyses are conducted using the nonlinear finite element analysis program, ABAQUS. The single perturbation load approach is used to represent the geometric initial imperfection of thin-walled composite cylinders. For cases with the axial compressive force only, the buckling knockdown factor decreases as the shell thickness ratio increases or as the slenderness ratio increases. When the internal pressure is considered simultaneously with the axial compressive force, the buckling knockdown factor decreases as the slenderness ratio increases but increases as the shell thickness ratio increases. The buckling knockdown factors considering the internal pressure and axial compressions are higher by 2.67% to 38.98% compared with the knockdown factors considering the axial compressive force only. The results show the significant effect of the internal pressure, particularly for thinner composite cylinders, and that the buckling knockdown factors may be enhanced for all the shell thickness ratios and slenderness ratios considered in this study when the internal pressure is applied to the cylinder.

scholarly journals Analytical predictions of moment curvature relationship of steel beam columns under fire attack

2018 ◽  
Vol 162 ◽  
pp. 04006
Author(s):  
Haitham Al-Thairy
Keyword(s):  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Compressive Force ◽  
Suggested Method ◽  
Steel Beam ◽  
Steel Buildings ◽  
Axial Compressive Force ◽  
Beam Columns ◽  
Resistance Moment ◽  
Relationship Of

Fire attack is one of the worst scenarios that may cause catastrophic consequences of steel buildings such as progressive collapse and failure. Current design codes and standards have addressed fire as one of the extreme loading conditions to be accounted for in the design of buildings. However, most of the approaches and procedures suggested by these codes and standards still lack accuracy and rationality. The purpose of this paper is to develop an analytical approach to predict the elastic-plastic moment-curvature relationship of steel beam - columns section under elevated temperature. The analytical method was derived based on dividing the steel section to layers and integrating the resistance moment equation of each layer in terms of the section curvature taking into account the effect of elevated temperature on the material properties of the steel by using EC3 reduction factors of the yield stress and modulus of elasticity. The suggested method has been validated against numerical simulation results. Validation results have shown the reliability of the suggested method to predict the resistance moment - curvature relationship of steel beam-column members at different elevated temperatures and under different values of the axial compressive force. The suggested methods may be used to develop more accurate design approaches for steel beam columns under fire condition.

scholarly journals On the Flexural-Torsional Vibration and Stability of Beams Subjected to Axial Load and End Moment

2021 ◽  
Author(s):  
M. Tahmaseb Towliat Kashani ◽  
Supun Jayasinghe Jayashinghe ◽  
Seyed M. Hashemi
Keyword(s):  
Boundary Conditions ◽  
Axial Force ◽  
Axial Load ◽  
Natural Frequencies ◽  
Compressive Force ◽  
Elastic Beam ◽  
Axial Compressive Force ◽  
Various Boundary Conditions ◽  
Linear Eigenvalue Problem ◽  
The Moment

The free vibration of beams, subjected to a constant axial load and end moment and various boundary conditions, is examined. Based on the Euler-Bernoulli bending and St. Venant torsion beam theories, the differential equations governing coupled flexural-torsional vibrations and stability of a uniform, slender, isotropic, homogeneous, and linearly elastic beam, undergoing linear harmonic vibration, are first reviewed. The existing formulations are then briefly discussed and a conventional finite element method (FEM) is developed. Exploiting the MAT LAB-based code, the resulting linear Eigenvalue problem is then solved to determine the Eigensolutions (i.e., natural frequencies and modes) of illustrative examples, exhibiting geometric bending-torsion coupling. Various classical boundary conditions are considered and the FEM frequency results are validated against those obtained from a commercial software (ANSYS) and the data available in the literature. Tensile axial force is found to increase natural frequencies, indicating beam stiffening. However, when a force and an end moment are acting in combination, the moment reduces the stiffness of the beam and the stiffness of the beam is found to be more sensitive to the changes in the magnitude of the axial force compared to the moment. A buckling analysis of the beam is also carried out to determine the critical buckling end moment and axial compressive force.

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