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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104 citations
"A variable strain hardening model f..." refers background in this paper
...The difference is mainly attributed to the non-conformance of power law behaviour of n at lower values of effective plastic strains.(10) It is evident from the observation that the experimental strain hardening exponent calculated from subsequent yield loci along the rolling axis is 0....
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TL;DR: In this article, Continuum anisotropic yield criteria have been developed to simulate the results of calculations based on the crystallographic nature of slip, which describe actual forming behavior better than the quadratic yield criterion postulated by Hill.
Abstract: Consideration of crystallographic texture has lead to a much better understanding of anisotopic yielding
behavior than yield criteria postulated without regard to deformation mechanisms. Continuum anisotropic
yield criteria have been developed to simulate the results of calculations based on the crystallographic
nature of slip. These criteria, which involve high stress exponents, describe actual forming behavior
much better than the quadratic yield criterion postulated by Hill. Today it is possible to calculate
anisotropic yielding behavior directly from texture data, although for metal forming analyses, some other
means must be used to characterize the strain-hardening behavior.
69 citations
TL;DR: In this article, the forming limit curve (FLC) of welded blanks for varied weld conditions was predicted by simulating the limit dome height (LDH) test using PAM-STAMP (ESI Group, PAM System International).
Abstract: This work aims at predicting the forming limit strains of welded blanks using a thickness gradient-based necking criterion. In order to reduce the complexity and synergistic effect of tailor-welded blank (TWB) parameters, the same material and thickness sheets are considered for the entire work. The forming limit curve (FLC) of welded blanks for varied weld conditions – namely, weld orientation and location – are predicted by simulating the limit dome height (LDH) test using PAM-STAMP (ESI Group, PAM System International), a finite element code. The un-welded blank and TWB FLCs thus predicted by the thickness gradient-based necking criterion are compared with the experimental FLCs obtained by LDH test. Dome height at failure and failure location data of TWBs from experiments and prediction are also compared for varied weld conditions. It is found from the analyses that limit strain predictions correlate well (less than five per cent error) with the experimental results in the drawing region of the forming...
44 citations
TL;DR: In this article, the authors proposed Forming Limit Curve (FLC) which is used to evaluate the necking risk, differs a lot while different yield criteria used, such as Hill 48, Hill 90 and Hill 93.
Abstract: The increasing application of numerical simulation in the field of metal forming has helped engineers to solve problems one after another to manufacture a qualified formed product in a reduced time. Accurate simulation results are vital for die and product designs. Many factors can influence the final simulation result, the most important of which is a suitable yield criterion. The proposed Forming Limit Curve (FLC), which is used to evaluate the necking risk, differs a lot while different yield criteria used. In this study, the theoretical FLC is calculated using Swift model, which considers three-yield criteria Hill 48, Hill 90 and Hill 93. Also, the simulation processes with two yield criteria, Hill 48 and Hill 90, are carried out with two types of material, SPCC (JIS G3141) and Al6xxx. The strain evolutions of elements located in two trajectories of two materials are investigated and compared. The simulation results are compared with the experimental ones to evaluate the effectiveness of the yield criterion.
43 citations
TL;DR: In this article, the deformation analysis of hemispherical-punch stretching was performed using the three-dimensional finite-element program "ROBUST" and the effects of the material properties on strain distribution and histories of deformation processes were investigated.
31 citations