Elastic Critical Force for Torsional-Flexural Buckling of Metal Members with Mono-Symmetric Cross-Sections

2015 ◽  
Vol 769 ◽  
pp. 36-42
Author(s):  
Michal Kovac
Keyword(s):  
Boundary Conditions ◽  
Approximate Method ◽  
Cross Section ◽  
Cross Sections ◽  
Parametric Study ◽  
Critical Force ◽  
Flexural Buckling ◽  
Fem Method ◽  
Thin Walled ◽  
Open Cross Section

The paper deals with torsional-flexural buckling of thin-walled metal members with mono-symmetric open cross-sections and with various torsional and flexural boundary conditions. An approximate method, which is located in recent norms, for calculation of critical forces of such member cases are focused on. For chosen type of mono-symmetric open cross-section a parametric study of critical forces by the approximate method and by as a reference taken FEM method are performed.

scholarly journals Elastic Critical Axial Force for the Torsional-Flexural Buckling of Thin-Walled Metal Members: An Approximate Method

2015 ◽  
Vol 23 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Michal Kováč
Keyword(s):  
Differential Equations ◽  
Approximate Method ◽  
Axial Force ◽  
Reference Method ◽  
Critical Force ◽  
Buckling Mode ◽  
Flexural Buckling ◽  
Coupled Equations ◽  
Thin Walled ◽  
Critical Axial Force

Abstract Thin-walled centrically compressed members with non-symmetrical or mono-symmetrical cross-sections can buckle in a torsional-flexural buckling mode. Vlasov developed a system of governing differential equations of the stability of such member cases. Solving these coupled equations in an analytic way is only possible in simple cases. Therefore, Goľdenvejzer introduced an approximate method for the solution of this system to calculate the critical axial force of torsional-flexural buckling. Moreover, this can also be used in cases of members with various boundary conditions in bending and torsion. This approximate method for the calculation of critical force has been adopted into norms. Nowadays, we can also solve governing differential equations by numerical methods, such as the finite element method (FEM). Therefore, in this paper, the results of the approximate method and the FEM were compared to each other, while considering the FEM as a reference method. This comparison shows any discrepancies of the approximate method. Attention was also paid to when and why discrepancies occur. The approximate method can be used in practice by considering some simplifications, which ensure safe results.

Torsional-Flexural Critical Force for Various Boundary Conditions

2016 ◽  
Vol 710 ◽  
pp. 303-308 ◽  
Author(s):  
Ivan Balaz ◽  
Michal Kovac ◽  
Tomáš Živner ◽  
Yvona Kolekova
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Differential Equations ◽  
Boundary Conditions ◽  
Approximate Method ◽  
Cross Sections ◽  
Critical Force ◽  
Various Boundary Conditions ◽  
Element Method

The system of governing differential equations of stability of members with the rigid open cross-sections was developed by Vlasov [1] in 1940. Goľdenvejzer [2] published in 1941 solution of this system by an approximate method. He proposed formula for torsional-flexural critical force Ncr.TF calculation which is modified and used in EN 1999-1-1 [3] (I.19). By introducing factor αzw he take into account any combination of boundary conditions (BCs).The purpose of this paper is to verify this formula and explore the possibility to improve the factor αzw. In the large parametrical study the authors investigated a lot of different shape of cross-sections, all 100 theoretical possible combinations of BCs and various member lengths. All results are evaluated regarding the reference results by finite element method (FEM).

scholarly journals Buckling of elastically restrained cantilever wall with free edge stiffening

2014 ◽  
Vol 13 (3) ◽  
pp. 291-298
Author(s):  
Andrzej Szychowski
Keyword(s):  
Boundary Conditions ◽  
Cross Section ◽  
Free Edge ◽  
Stability Loss ◽  
Buckling Analysis ◽  
Thin Walled ◽  
The Stability ◽  
Elastically Restrained ◽  
Plate Deflection ◽  
Open Cross Section

The issue of the stability loss in a compressed wall of a thin-walled member with an open cross section was reduced to the buckling analysis of the cantilever wall. The wall was unilaterally elastically restrained against rotation. The stiffening of the free edge of the wall was susceptible to deflection. The plate deflection functions and stiffenings that allow the modelling of boundary conditions on both longitudinal edges were proposed. Graphs of buckling coefficients for different indexes of the elastic restraint of the supported edge and different geometries of the edge stiffening were determined.

Critical Force Analysis of Thin-Walled Symmetrical Open-Section Beams

2016 ◽  
Vol 827 ◽  
pp. 283-286
Author(s):  
Diana Šimić Penava ◽  
Maja Baniček
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Local Buckling ◽  
Fem Analysis ◽  
Critical Force ◽  
The Finite Element Method ◽  
Force Analysis ◽  
Standard Specimens ◽  
Thin Walled ◽  
The Stability

This paper analyzes critical forces and stability of steel thin-walled C-cross-section beams without lateral restraints. Mechanical properties of the rods material are determined by testing standard specimens in a laboratory. Based on the obtained data, the stability analysis of rods is carried out and critical forces are determined: analytically by using the theory of thin-walled rods, numerically by using the finite element method (FEM), and experimentally by testing the C-cross-section beams. The analysis of critical forces and stability shows that the calculation according to the theory of thin-walled rods does not take the effect of local buckling into account, and that the resulting critical global forces do not correspond to the actual behaviour of the rod. The FEM analysis and experimental test show that the simplifications, which have been introduced into the theory of thin-walled rods with open cross-sections, significantly affect final results of the level of the critical force.

Numerical Investigation of Cross-Section on Aluminum A6063 Thin-Walled Structures under Low-Velocity Impact Loading

2014 ◽  
Vol 1019 ◽  
pp. 96-102
Author(s):  
Ali Taherkhani ◽  
Ali Alavi Nia
Keyword(s):  
Energy Absorption ◽  
Cross Section ◽  
Cross Sections ◽  
Peak Load ◽  
Circular Cross Section ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Crush Strength

In this study, the energy absorption capacity and crush strength of cylindrical thin-walled structures is investigated using nonlinear Finite Elements code LS-DYNA. For the thin-walled structure, Aluminum A6063 is used and its behaviour is modeled using power-law equation. In order to better investigate the performance of tubes, the simulation was also carried out on structures with other types of cross-sections such as triangle, square, rectangle, and hexagonal, and their results, namely, energy absorption, crush strength, peak load, and the displacement at the end of tubes was compared to each other. It was seen that the circular cross-section has the highest energy absorption capacity and crush strength, while they are the lowest for the triangular cross-section. It was concluded that increasing the number of sides increases the energy absorption capacity and the crush strength. On the other hand, by comparing the results between the square and rectangular cross-sections, it can be found out that eliminating the symmetry of the cross-section decreases the energy absorption capacity and the crush strength. The crush behaviour of the structure was also studied by changing the mass and the velocity of the striker, simultaneously while its total kinetic energy is kept constant. It was seen that the energy absorption of the structure is more sensitive to the striker velocity than its mass.

Free Vibration of Thin-Walled Open Section Beams With Unconstrained Damping Treatment

1981 ◽  
Vol 48 (1) ◽  
pp. 169-173 ◽  
Author(s):  
S. Narayanan ◽  
J. P. Verma ◽  
A. K. Mallik
Keyword(s):  
Free Vibration ◽  
Cross Section ◽  
Transverse Vibration ◽  
Natural Frequencies ◽  
Vibration Characteristics ◽  
Numerical Results ◽  
Simply Supported ◽  
Clamped Beams ◽  
Thin Walled ◽  
Open Cross Section

Free-vibration characteristics of a thin-walled, open cross-section beam, with unconstrained damping layers at the flanges, are investigated. Both uncoupled transverse vibration and the coupled bending-torsion oscillations, of a beam of a top-hat section, are considered. Numerical results are presented for natural frequencies and modal loss factors of simply supported and clamped-clamped beams.

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