Aquesta és una còpia de la versió author's final draft d'un article publicat a la revista Materials and Design. ABSTRACTThere is a wide variety of stainless steel alloys, but all are characterized by a rounded stressstrain response with no sharply defined yield point. This behaviour can be represented analytically by different material models, the most popular of which are based on the RambergOsgood formulations or extensions thereof. The degree of roundedness, the level of strain hardening, the strain at ultimate stress and the ductility at fracture of the material all vary between grades, and need to be suitably captured for an accurate representation of the material to be achieved. The aim of the present study is to provide values and predictive expressions for the key parameters in existing stainless steel material models based on the analysis of a comprehensive experimental database. The database comprises experimental stress-strain curves collected from the literature, supplemented by some tensile tests on austenitic, ferritic and duplex stainless steel coupons conducted herein. It covers a range of stainless steel alloys, annealed and cold-worked material, and data from the rolling and transverse directions. In total, more than 600 measured stress-strain curves have been collected from 15 international research groups. Each curve from the database has been analysed in order to obtain the key material parameters through a curve fitting process based on least squares adjustment techniques. These parameter values have been compared to those calculated from existing predictive models, the 2 accuracy of which could therefore be evaluated. Revised expressions providing more accurate parameter predictions have been proposed where necessary. Finally, a second set of results, containing material parameters reported directly by others, with information of more than 400 specimens, has also been collected from the literature. Although these experimental results were not accessible as measured raw data, they enabled further confirmation of the suitability of the proposed equations. KEYWORDSConstitutive law, material modelling, nonlinear stress-strain behaviour, stress-strain curves, stainless steel, tensile tests HIGHLIGHTS Tensile tests on austenitic, ferritic and duplex stainless steel coupons are presented. A database of over 600 stainless steel stress-strain curves has been collected.
This paper studies the cross-sectional behaviour of austenitic, ferritic and duplex stainless steel hollow sections subjected to several loading conditions and presents a full slenderness range DSM approach for the prediction of cross-sectional strengths. Pure compression, pure bending moment and combined uniaxial bending and compression loading resistances are predicted using the same strength curve, which is based on experimental data gathered from the literature and ultimate strengths generated through parametric studies. The proposed approach is applicable to slender and stocky cross-sections leading to an accurate full slenderness range DSM design approach since the resistance reduction due to local buckling and the effect of strain hardening are taken into account, as is the effect of partial yielding of the cross-section in bending. A new method based on the actual stress distribution of the cross-section is also presented for combined loading conditions, where the cross-sectional behaviour is directly tackled through the same strength curve, providing more accurate results than the methods considering the uncoupled problem. Finally, a statistical analysis is presented to demonstrate the reliability of the proposed DSM approach.Peer ReviewedPostprint (author's final draft
In structural frames, second order effects refer to the internal forces and moments that arise as a result of deformations under load (i.e. geometrical nonlinearity). EN 1993-1-1 states that global second order effects may be neglected if the critical load factor of the frame cr is greater than 10 for an elastic analysis, or greater than 15 when a plastic global analysis is used. No specific guidance is provided in EN 1993-1-4 for the design of stainless steel frames, for which the nonlinear stress-strain behaviour of the material will result in greater deformations as the material loses its stiffness. A study of the effects of material nonlinearity on the stability of stainless steel frames is presented herein. A series of different frame geometries and loading conditions are considered. Based on the findings, proposals for the treatment of the influence of material nonlinearity on the global analysis and design of stainless steel frames are presented. KeywordsContinuous Strength Method, Frame stability, Global analysis, Numerical Modelling, Second order effects, Stainless steel IntroductionStainless steel is widely used across a range of industries with its key advantage over ordinary carbon steel being its corrosion resistance and durability. Although a number of design standards for stainless steel currently exist, their provisions have generally been based on a presumed equivalence with the carbon steel design rules. However, stainless steel and carbon steel have distinctly different material characteristics; while carbon steel is accurately characterised by a bilinear (elastic, perfectly plastic) stress-strain response, stainless steel exhibits nonlinear rounded stress-strain behaviour with no sharply defined yield point. It is important that the codes reflect these differences so as to ensure safe, efficient, and structurally sound design. The current European rules for global analysis and design are examined in this paper, assessing whether the methods provided are suitable for stainless steel. Particular attention is given to the extent to which the differences between the behaviour of stainless steel and carbon steel frames are adequately recognised.EN 1993-1-4 [1] gives supplementary guidance for the design of stainless steel structures that complement the design rules given for structural carbon steel in EN 1993-1-1 [2] . Section 5 of EN 1993-1-1 outlines the rules for structural analysis with detailed subsections on structural modelling, global analysis and imperfections, as well as methods of analysis considering material nonlinearities. The guidance on material nonlinearities largely relates to the occurrence of traditional idealised plastic hinges, as seen in carbon steel structures. However, such hinges do not form in stainless steel structures; instead zones of plasticity with gradually reducing stiffness, but with peak capacities well in excess of the traditional plastic moment are exhibited [3] . EN 1993-1-1 also states that "elastic global analysis may be used in all cases" and that...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.