scholarly journals A micropolar isotropic plasticity formulation for non‐associated flow rule and softening featuring multiple classical yield criteria

2021 ◽  
Author(s):  
Andrea Panteghini ◽  
Rocco Lagioia
Keyword(s):  
Flow Rule ◽  
Yield Criteria ◽  
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].

Experimental Study and Modelling of the Ferritic Steel Anisotropic Behavior under Associated and Non-Associated Flow Rule

2021 ◽  
Vol 1016 ◽  
pp. 1356-1360
Author(s):  
Houssem Soltani ◽  
Oualid Chahaoui ◽  
Nadjoua Matougui
Keyword(s):  
Experimental Study ◽  
Tensile Test ◽  
Ferritic Steel ◽  
Experimental Results ◽  
Flow Rule ◽  
Plastic Behavior ◽  
Anisotropic Behavior ◽  
Yield Criteria ◽  
Anisotropic Coefficient ◽  
Associated Flow Rule

In the present study, two different yield criteria were investigated to model and compare the yield thresholds functions for the plastic behavior of rolled sheets. These two different yield criteria as described via Hill48 yield quadratic and F. Barlat Yld2000-2d non-quadratic criterion. For this purpose, an experimental device of simple tensile test and the studied material are described. The experimental results in terms of Yield stress and Anisotropic coefficient are estimated from the Associated Flow Rule (AFR) and Non-Associated Flow Rule (NAFR). However, it is found that the criterion of Yld2000-2d is the most appropriate model in comparison with the experimental results.

Gradient of Soil Constitutive Model

2010 ◽  
Vol 168-170 ◽  
pp. 1126-1129
Author(s):  
Wen Xu Ma ◽  
Ying Guang Fang
Keyword(s):  
Plastic Strain ◽  
Strain Gradient ◽  
Soil Analysis ◽  
Natural Material ◽  
Flow Rule ◽  
The Finite Element Method ◽  
Gradient Effect ◽  
Non Local ◽  
Associated Flow Rule ◽  
Plastic Strain Gradient

For the soil is a very complex natural material, significant strain gradient effect exist in soil analysis. Based on the "gradient" phenomenon, we add the plastic strain gradient hardening item into the traditional Cambridge yield surface. By using the consistency conditions and associated flow rule, we get the explicit expression of plastic strain gradient stiffness matrix. And the finite element method of plastic strain gradient is also shown in this article. Plastic strain gradient is actually a phenomenological non-local model containing microstructure information of the material. It may overcome the difficulties in simulating the gradient phenomenon by traditional mechanical model.

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