An Analytic Study on Structural Stability according to Boundary Conditions and H-section Column Lengths Made of An Ordinary Grade Structural Steels (SS 400) at High Temperatures

Fire resistance performance of structural members has been evaluated from each singular section and standard fire curve since the beginning of fire tests. However, the need of the exact fire resistance of H-section columns applied in the steel buildings has increased. The main reason for this is there is a difference between the conditions being conducted during the fire test and that from real situation. In this paper, the structural stability of H-section column made of an ordinary strength grade structural steels, SS 400, SM 400, and SM 490 at high temperature were evaluated and compared with boundary conditions and column’s length. This was done in order to suggest a new guideline for the application of fire protective materials in steel column in which the boundary conditions and column lengths are different from that tested with hinge to hinge and 3500 mm. The findings from this study showed hinge to hinge boundary condition was more conservative. And fire resistance performance of longer columns in the case of hinge to fixed and fixed to fixed boundary condition than from 3500 mm and hinge to hinge boundary condition can sustain at high temperature without adding fire protective materials.

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Recrystallisation Resistance of Extruded and Cold Rolled Aluminium Alloys with Additions of Hf, Sc and Zr

Materials Science Forum ◽

10.4028/www.scientific.net/msf.519-521.525 ◽

2006 ◽

Vol 519-521 ◽

pp. 525-530 ◽

Cited By ~ 3

Author(s):

Håkon Hallem ◽

W.J. Rittel ◽

Børge Forbord ◽

Knut Marthinsen

Keyword(s):

Cold Rolling ◽

Structural Stability ◽

High Temperatures ◽

High Resistance ◽

Aluminium Alloys ◽

Cold Rolled

A high recrystallisation resistance is required in aluminium alloys intended for processing or use at temperatures between 450°C-600°C. Additions of Hf, Sc and Zr significantly improve the resistance to recrystallisation through the formation of Al3X-dispersoids (X=Hf,Sc,Zr), and in this work different concentrations and combinations of these elements were added to five aluminium alloys. The alloys were extruded, subjected to various degrees of cold rolling (0%-80%) and finally annealed at high temperatures in order to study the structural stability. All variants displayed a high resistance towards recrystallisation, but the best results were obtained in the alloy containing only Sc and Zr. In this alloy no signs of recrystallisation were observed even after 1 hour annealing of extruded and 80% cold rolled profiles at 600°C.

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Convergence Results for the Double-Diffusion Perturbation Equations

Symmetry ◽

10.3390/sym14010067 ◽

2022 ◽

Vol 14 (1) ◽

pp. 67

Author(s):

Jincheng Shi ◽

Shiguang Luo

Keyword(s):

Boundary Conditions ◽

Structural Stability ◽

A Priori ◽

Double Diffusion ◽

A Priori Bounds ◽

Poincaré Inequalities ◽

Convergence Results ◽

Poincare Inequalities ◽

Diffusion Perturbation ◽

Perturbation Equations

We study the structural stability for the double-diffusion perturbation equations. Using the a priori bounds, the convergence results on the reaction boundary coefficients k1, k2 and the Lewis coefficient Le could be obtained with the aid of some Poincare´ inequalities. The results showed that the structural stability is valid for the the double-diffusion perturbation equations with reaction boundary conditions. Our results can be seen as a version of symmetry in inequality for studying the structural stability.

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Recent Advances on Boundary Conditions for Equations in Nonequilibrium Thermodynamics

Symmetry ◽

10.3390/sym13091710 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1710

Author(s):

Wen-An Yong ◽

Yizhou Zhou

Keyword(s):

Boundary Conditions ◽

Structural Stability ◽

Stability Condition ◽

Hyperbolic Systems ◽

Moment Closure ◽

First Order ◽

Nonequilibrium Phenomena ◽

Classical Models ◽

Spatial Domains ◽

Kreiss Condition

This paper is concerned with modeling nonequilibrium phenomena in spatial domains with boundaries. The resultant models consist of hyperbolic systems of first-order partial differential equations with boundary conditions (BCs). Taking a linearized moment closure system as an example, we show that the structural stability condition and the uniform Kreiss condition do not automatically guarantee the compatibility of the models with the corresponding classical models. This motivated the generalized Kreiss condition (GKC)—a strengthened version of the uniform Kreiss condition. Under the GKC and the structural stability condition, we show how to derive the reduced BCs for the equilibrium systems as the classical models. For linearized problems, the validity of the reduced BCs can be rigorously verified. Furthermore, we use a simple example to show how thus far developed theory can be used to construct proper BCs for equations modeling nonequilibrium phenomena in spatial domains with boundaries.

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