Applicability of Nonpolynomial Yield Function and Associated Flow Rule to Deformation Analysis in Sheet Metal Forming

1989 ◽  
pp. 61-64
Author(s):  
Y. Kurosaki
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Yield Function ◽  
Deformation Analysis ◽  
Flow Rule ◽  
Associated Flow Rule

Application of Associated and Non-Associated Flow Metal Plasticity for F.S.S Sheet

2021 ◽  
Vol 406 ◽  
pp. 473-480
Author(s):  
Oualid Chahaoui ◽  
Houssem Soltani ◽  
Nadjoua Matougui
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Mechanical Anisotropy ◽  
Flow Rule ◽  
Plastic Behavior ◽  
Sheet Plane ◽  
Yield Criteria ◽  
Plastic Potential ◽  
Associated Flow Rule

In the last decade, several phenomenological yield criteria for anisotropic material has been proposed to improve the modeling predictions about sheet metal-forming processes. In regard to this engineering application, two proprieties of models have been used. If the yield function and the plastic potential are not same (not equal), the normality rule is non associative flow rule (NAFR), otherwise, when the stresses yield has been completely coupled to the anisotropic strain rate ratio (plastic potential), is called the associated flow rule (AFR). The non-associated flow rule is largely adopted to predict a plastic behavior for metal forming, accurately about à strong mechanical anisotropy presents in sheet metal forming processes. However, various studies described the limits of the AFR concept in dealing with highly anisotropic materials. In this study, the quadratic Hill1948 yield criteria is considered to predict mechanical behavior under AFR and NAFR approach. Experiment and modeling predictions behaviour of normalized anisotropic coefficient r (θ) and σ (θ) evolved with θ in sheet plane. and the equibiaxial yield stress σb was assumed σb=1 but the rb-values was computed from Yld96 [15].

Bending Deformation Analysis in the Basic Forms of Axisymmetric Sheet Metal Forming

2011 ◽  
Vol 268-270 ◽  
pp. 360-365
Author(s):  
Si Ji Qin
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Symmetry Plane ◽  
Deformation Analysis ◽  
Analysis Method ◽  
Forming Process ◽  
Bending Analysis ◽  
Small Width ◽  
Hole Flanging

In basic sheet metal forming process such as cylindrical deep drawing, bulging, hole flanging (or reaming), etc., deformations in-plane can be considered as changes of the curvature of different microrings. The deformation of each microring is equivalent to a bending process of plate with small width. The differential balance equation of the deformation region can be expressed as simple form of unification. The deformations in the symmetry plane of the sheet metal are part of bending and reverse bending, so the bending analysis method can be used to analyze operation. Some results were obtained by the bending analysis method.

A Novel Approach for Transversely Anisotropic 2D Sheet Metal Forming Simulation

2011 ◽  
Vol 347-353 ◽  
pp. 3939-3945
Author(s):  
Jin Yan Wang ◽  
Ji Xian Sun
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Yield Function ◽  
Plane Stress Condition ◽  
Hill Model ◽  
Shell Elements ◽  
Forming Simulation ◽  
Novel Approach ◽  
Transversely Anisotropic

In most FEM codes, the isotropic-elastic & transversely anisotropic-elastoplastic model using Hill's yield function has been widely adopted in 3D shell elements (modified to meet the plane stress condition) and 3D solid elements. However, when the 4-node quadrilateral plane strain or axisymmetric element is used for 2D sheet metal forming simulation, the above transversely anisotropic Hill model is not available in some FEM code like Ls-Dyna. A novel approach for explicit analysis of transversely anisotropic 2D sheet metal forming using 6-component Barlat yield function is elaborated in detail in this paper, the related formula between the material anisotropic coefficients in Barlat yield function and the Lankford parameters are derived directly. Numerical 2D results obtained from the novel approach fit well with the 3D solution .

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