Structural, Economic And Material Comparison
Of Various Steel Grades Under
Dynamic/fatigue Loading
Author(s)
I. U. Amobi & H. C. Uzoegbo
Abstract
As industries are upgrading rapidly from a lower steel grade to higher ones it has
become necessary to study the effect of changing from lower steel grades to
higher grades. This paper reports on fatigue life and behaviour, economic
implications and material composition of these higher strength steels (HSS) as
compared to the conventional grades. Three grades are commercially available in
South Africa: 300W, 350W and 460W. These different steel grades
(conventional and HSS) with the same moment capacities were subjected to
constant dynamic stresses and the fatigue crack growth of the overloading and
unloading were monitored and compared with each other. The influences of the
overloading and unloading made standard grades perform better under repeated
loading than the HSS, since HSS have been proved to have poor ductility,
resulting in a lower number of cycles to failure. An 85% increase in material cost
was generated as HSS replaces the conventional lower steel grades. A reduction
in the number of cycles to failure in HSS was over 500%.
Keywords: steel grade, HSS, fatigue, low-cycle fatigue, high-cycle fatigue, load
capacity, cycles to failure.
1 Introduction
There is a trend towards increasing the strength grade of the general purpose
steel for construction in most countries. This trend was prompted by increased
loading on structures, larger spans and architectural designs that require smaller
sections. Australia and other countries around the world have in recent years
changed from lower steel grades to higher ones. In 2005, South Africa changed
Keywords
steel grade, HSS, fatigue, low-cycle fatigue, high-cycle fatigue, load
capacity, cycles to failure.
Related Book
Other papers in this volume
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