scholarly journals Modeling plastic anisotropy evolution of AISI 304 steel sheets by a polynomial yield function

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Bora Sener ◽  
Emre Esener ◽  
Mehmet Firat
Keyword(s):  
Plastic Strain ◽  
Plastic Anisotropy ◽  
Stress Gradient ◽  
Rolling Direction ◽  
Yield Function ◽  
Fe Analysis ◽  
Flow Strength ◽  
Plastic Strain Ratio ◽  
Aisi 304 ◽  
Aisi 304 Steel

AbstractIn this study, a numerical model for the evolution of plastic anisotropy is investigated for the purpose of stamping method design by Finite Element (FE) analysis and proved experimentally via process simulations of a cold-rolled austenitic stainless steel (AISI 304) sheet. The plastic anisotropy of the sheets is described with a fourth-order homogenous polynomial yield function and this modelling approach is enhanced by plastic strain dependent material coefficients. Tensile tests of coupon specimens taken along the different directions from rolling direction, and flow strength and deformation anisotropies are described with the planar variations of yield stress and plastic strain ratio computed at four plastic strain levels (0.002, 0.02, 0.05 and 0.18). A new numerical approach is, then, applied to identify polynomial coefficients ensuring an orthotropic positive-definite, convex yield surface with a well-defined stress gradient at every loading point on plane stress subspace. The developed computational model is implemented into general purpose explicit FE analysis software Ls-Dyna by a user-defined material model subroutine (UMAT) and applied in the stamping simulation of AISI 304 steel rectangular cups for the house-hold applications. The computed thickness distributions and the flange geometries were compared with measurements and it was observed that the best predictions were done with material parameters at %5 plastic strain level.

scholarly journals Effects of Initial Precipitate on Shear Deformation during Asymmetric Rolling of Al-Mg-Si Alloy: Texture and Formability

2020 ◽  
Vol 58 (10) ◽  
pp. 703-714
Author(s):  
Wonkee Chae ◽  
Bong-Kyu Kim ◽  
Jongbeom Lee ◽  
Jun Hyun Han
Keyword(s):  
Shear Deformation ◽  
Room Temperature ◽  
Tensile Deformation ◽  
Texture Evolution ◽  
Plastic Anisotropy ◽  
Rolling Direction ◽  
Strain Ratio ◽  
Equivalent Strain ◽  
Asymmetric Rolling ◽  
Plastic Strain Ratio

Al-Mg-Si alloy was rolled asymmetrically at several temperatures to apply shear deformation, and the effects of the initial precipitate on shear deformation, texture evolution, formability, and plastic anisotropy were studied. Texture was analyzed using a EBSD, and the formability and plastic anisotropy of the specimen were evaluated using the value and value calculated from the plastic strain ratio (r-value) which was determined from the change in the length of the specimen during tensile deformation. Asymmetric rolling induces a larger equivalent strain than symmetric rolling, and the equivalent strain increases as the asymmetric rolling temperature increases. When a specimen with peak-aged initial precipitates was asymmetrically rolled, less shear deformation occurred at room temperature than in a solution-treated specimen without initial precipitates. In contrast, a larger shear deformation occurred at high temperatures (500°C). With asymmetric rolling at room temperature, the specimens without initial precipitates had higher formability and lower plasticity, while for asymmetric rolling at high temperature, the specimens with initial precipitates had higher formability and lower plastic anisotropy. This is due to the <111>//ND texture, such as {111}<110> and {111}<112> orientation that has similar and high r-values at 0°, 45°, and 90° to the rolling direction, developed by the shear deformation that occurred during asymmetric rolling.

Finite Element Calculation of Anisotropy of Hole Expansion in a Thin Steel Sheet with Six Degrees Polynomial Yield Function

2019 ◽  
Vol 794 ◽  
pp. 260-266
Author(s):  
Seung Yong Yang ◽  
Wei Tong
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Strain Ratio ◽  
Yield Function ◽  
Sixth Order ◽  
Isotropic Hardening ◽  
Flow Rule ◽  
Anisotropic Plasticity ◽  
Plastic Strain Ratio ◽  
Hole Expansion

A sixth order yield function was used to analyze the anisotropic plasticity behavior of sheet metal forming. Based on a complete sixth order homogenous polynomial in plane stress, the yield function was implemented as user material subroutines in the FE code ABAQUS Explicit and Standard. The associated flow rule and isotropic hardening were assumed. Material parameter values in the yield function were decided by uniaxial yield stresses and plastic strain ratios along 7 different loading orientations and plane strain yield and equal biaxial stresses and plastic strain ratio. To show the superiority of the sixth order yield function, the hole expansion test by Kuwabara et al.[1] was considered. The results of finite element simulation using the sixth order yield function showed a better agreement with the test results than YLD2000-2D yield function with M=6.

scholarly journals Variation of Plastic Strain Ratios of α-Brass Sheet With Tensile Strain

1999 ◽  
Vol 32 (1-4) ◽  
pp. 355-367 ◽  
Author(s):  
Hyo-Tae Jeong ◽  
Seung-Hyun Hong ◽  
Dong Nyung Lee
Keyword(s):  
Plastic Strain ◽  
Cold Rolling ◽  
Recrystallization Texture ◽  
Tensile Strain ◽  
Rolling Direction ◽  
Strain Ratio ◽  
Plastic Strain Ratio ◽  
Brass Sheet ◽  
Complete Recrystallization ◽  
Constraints Model

A study has been made of the changes in the instantaneous plastic strain ratios along various directions of α-brass sheet as a function of tensile strain. The α-brass sheet was fabricated by 88% cold rolling and subsequent annealing at 450℃ for 1.5 h, which lead to complete recrystallization. The recrystallization texture of the α-brass sheet could be approximated by {110} 〈110〉. The plastic strain ratio along the rolling direction decreased with increasing tensile strain, whereas those along 45 90 to the rolling direction were almost independent of tensile strain. The results were in agreement with those calculated using the recrystallization textures based on the Taylor-Bishop-Hill full constraints model.

Optimization of Cutting Parameters Considering Surface Roughness When Milling AISI 304 Steel Using Coated Wc-Co and Tialn / Wc-Co Coated

2019 ◽  
Author(s):  
Murilo Pereira Lopes ◽  
Jose Rubens Gonçalves Carneiro ◽  
Gilmar Cordeiro da Silva ◽  
Carlos Eduardo Santos ◽  
Ítalo Bruno dos Santos
Keyword(s):  
Surface Roughness ◽  
Cutting Parameters ◽  
Aisi 304 ◽  
Aisi 304 Steel ◽  
Optimization Of Cutting Parameters

scholarly journals Study on the Influence of the Ball Material on Abrasive Particles’ Dynamics in Ball-Cratering Thin Coatings Wear Tests

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 668
Author(s):  
Gustavo Pinto ◽  
Andresa Baptista ◽  
Francisco Silva ◽  
Jacobo Porteiro ◽  
José Míguez ◽  
...  
Keyword(s):  
Aisi 304 ◽  
Thin Coatings ◽  
Iron And Steel ◽  
Test Configuration ◽  
Abrasive Particles ◽  
Aisi 52100 ◽  
Aisi 304 Steel ◽  
Aisi 52100 Steel ◽  
Steel Balls ◽  
Particles Dynamics

Micro-abrasion remains a test configuration hugely used, mainly for thin coatings. Several studies have been carried out investigating the parameters around this configuration. Recently, a new study was launched studying the behavior of different ball materials in abrasive particles’ dynamics in the contact area. This study intends to extend that study, investigating new ball materials never used so far in this test configuration. Thus, commercial balls of American Iron and Steel Institute (AISI) 52100 steel, Stainless Steel (SS) (AISI) 304 steel and Polytetrafluoroethylene (PTFE) were used under different test conditions and abrasive particles, using always the same coating for reference. Craters generated on the coated samples’ surface and tracks on the balls’ surface were carefully observed by Scanning Electron Microscopy (SEM) and 3D microscopy in order to understand the abrasive particles’ dynamics. As a softer material, more abrasive particles were entrapped on the PTFE ball’s surface, generating grooving wear on the samples. SS AISI 304 balls, being softer than the abrasive particles (diamond), also allowed particle entrapment, originating from grooving wear. AISI 52100 steel balls presented particle dynamics that are already known. Thus, this study extends the knowledge already existing, allowing to better select the ball material to be used in ball-cratering tests.

scholarly journals Influence of Polyurea Composite Coating on Selected Mechanical Properties of AISI 304 Steel

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3137 ◽  
Author(s):  
Monika Duda ◽  
Joanna Pach ◽  
Grzegorz Lesiuk
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Composite Coating ◽  
Composite Coatings ◽  
Glass Fabric ◽  
Coated Sample ◽  
Hemp Fiber ◽  
Aisi 304 ◽  
Aisi 304 Steel ◽  
The Impact

This paper contains experimental results of mechanical testing of the AISI 304 steel with composite coatings. The main goal was to investigate the impact of the applied polyurea composite coating on selected mechanical properties: Adhesion, impact resistance, static behavior, and, finally, fatigue lifetime of notched specimens. In the paper the following configurations of coatings were tested: EP (epoxy resin), EP_GF (epoxy resin + glass fabric), EP_GF_HF (epoxy resin + glass fabric hemp fiber), EP_PUA (epoxy resin + polyurea) resin, EP_GF_PUA (epoxy resin + glass fabric + polyurea) resin, and EP_GF_HF_PUA (epoxy resin + glass fabric + hemp fiber + polyurea) resin. The highest value of force required to break adhesive bonds was observed for the EP_PUA coating, the smallest for the single EP coating. A tendency of polyurea to increase the adhesion of the coating to the base was noticed. The largest area of delamination during the impact test was observed for the EP_GF_HF coating and the smallest for the EP-coated sample. In all tested samples, observed delamination damage during the pull-off test was located between the coating and the metallic base of the sample.

Effect of Cu Content on the Formability and Portevin-Le Chatelier Effect of Al-Mg Alloys

2015 ◽  
Vol 817 ◽  
pp. 150-157
Author(s):  
Peng Cheng Ma ◽  
Di Zhang ◽  
Lin Zhong Zhuang ◽  
Ji Shan Zhang
Keyword(s):  
Plastic Strain ◽  
Stress Drop ◽  
Strain Ratio ◽  
Mg Alloys ◽  
Dynamic Strain ◽  
Strain Hardening Exponent ◽  
Drawing Ratio ◽  
Plastic Strain Ratio ◽  
Cu Content ◽  
Al Mg Alloys

Al-Mg alloys developed for auto body sheets with different Cu contents were fabricated in the laboratory scale. The effects of Cu content on the microstructures, formability and Portevin–Le Chatelier(PLC) effect of the alloys were investigated by polarizied optical microscopy and room temperature tensile testing. It has been found that with increasing Cu content, there was little change of the strain hardening exponent, but the plastic strain ratio and limiting drawing ratio increased firstly and then decreased. A quantitative statistical analysis of the characteristics of the PLC effect was made, including the stress drop and the reloading time, which follow a common linear relationship with plastic strain, and the increase rate of stress drop and reloading time was bigger with more Cu content. A detailed discussion of the corresponding mechanism of Cu and Cu-containing precipitates on the dynamic strain aging(DSA) was made.

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