A variable strain hardening model for anisotropic sheet metals
16 May 2012-Journal of Strain Analysis for Engineering Design (SAGE Publications)-Vol. 47, Iss: 5, pp 289-296
TL;DR: In this article, a phenomenological approach is proposed to model the influence of texture-induced anisotropy in the variation of strain hardening characteristics of a sheet material, and the results showed that a variable strain-hardening exponent provided greater accuracy of numerical prediction than the existing isotropic model.
Abstract: A phenomenological approach is proposed to model the influence of texture-induced anisotropy in the variation of strain hardening characteristics of a sheet material The variation of uniaxial strain hardening exponent with rolling direction is modelled using existing anisotropic yield criteria assuming power law strain hardening behaviour The model is extended to the biaxial region to predict the effective strain hardening exponent with the assumption of constant plastic work The prediction of both uniaxial and biaxial strain hardening is compared with the experimental data available in the literature It is observed that a variable strain hardening exponent provided greater accuracy of numerical prediction than the existing isotropic model The accuracy of the proposed model is dependent on the yield criteria and the flow rule used for the modelling
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TL;DR: In this article, the suitability of interstitial free (IF) steel sheets of thickness 0.6, 0.9, 1.2, and 1.6mm for press forming operations were examined by obtaining the forming limit diagrams.
31 citations
Journal Article•
TL;DR: In this paper, the authors presented the results of experimental investigation of three typical materials: low carbon Al killed steel DC04 sheet metal, alloy AlMg4.5Mn 0.7 sheet metal and stainless steel X5CrNi18-10 sheet metal.
Abstract: Cold rolled thin sheet metals are typical anisotropic materials as a consequence of the production process of rolling. Anisotropy is usually described from two aspects: as plane anisotropy and as a normal one. Most frequently used anisotropy parameter is the normal anisotropy ratio or the r value, which represents strains ratio in sheet metal plane and along its thickness. It is determined experimentally, usually as mean constant numeric valu, without testing the possible variation in dependence on realized plastic strain. Accurate defining of the r value has great significanc, since it is not only the formability parameter, but also the crucial anisotropy parameter in software for simulation of the plastic forming process. The paper presents the results of experimental investigation of three typical materials: low carbon Al killed steel DC04 sheet metal, alloy AlMg4.5Mn0.7 sheet metal and stainless steel X5CrNi18-10 sheet metal. Particular attention is given to defining the dependence of the r value on plastic strain during the forming process. The experiment requires sophisticated devices and accurate calculations. In the actual case, the computerized measuring system Zwick/Roell Z 100 was used In addition, the paper contains the proposal on how to take into account variations of the r values during the plastic forming process.
27 citations
TL;DR: In this article, the authors show that the behavior described by Hu of sharply decreasing r-value as the strain increased in a tensile test has been confirmed in two strongly textured steels, but only for conditions of discontinuous yielding.
Abstract: The behavior described by Hu of a sharply decreasingr-value as the strain increased in a tensile test has been confirmed in two strongly textured steels, but only for conditions of discontinuous yielding. It does not occur in the absence of interstitial elements when yielding is homogeneous. The present work shows that two distinct anisotropies exist, one in the Luders range and one in subsequent uniform deformation. Possible reasons for this behavior are discussed. The enhanced anisotropy due to discontinuous yielding does not confer benefits in terms of improved drawability and it is recommended that prestrained or temper rolled material should be used when determingr-values.
26 citations
09 Feb 2013
TL;DR: In this article, the monotonic and low cycle fatigue properties of a thin sheet produced from an interstitial free steel containing titanium additions were investigated, and a special grip alignment fixture permitted the fatigue tests to be conducted under deformation control and completely reversed cyclic strain.
Abstract: Abstract In the present work, the monotonic and low cycle fatigue properties of a thin sheet produced from an interstitial free steel containing titanium additions were investigated. A special grip alignment fixture permitted the fatigue tests be conducted under deformation control and completely reversed cyclic strain. The material presented different fatigue behavior for the transverse and longitudinal directions, related to the rolling direction. A comparison between the monotonic and cyclic stress—strain curves in the transverse direction showed that the material exhibits cyclic hardening at all tested strain amplitudes. The strain—life relationship was obtained for the transverse direction; buckling of longitudinal specimens made it impossible to obtain such a relationship.
24 citations
TL;DR: In this paper, the monotonic and low cycle fatigue properties of a thin sheet produced from an interstitial free steel containing titanium additions were investigated, and a special grip alignment fixture permitted the fatigue tests to be conducted under deformation control and completely reversed cyclic strain.
23 citations