Characterization on the thermal anisotropic behaviors of high strength AA7075 alloy with the Yld2004-18p yield function

2021 ◽  
pp. 159955
Author(s):  
Hai Rong ◽  
Liang Ying ◽  
Ping Hu ◽  
Wenbin Hou
Keyword(s):  
High Strength ◽  
Yield Function

Application of Gotoh's Orthotropic Yield Function for Modeling Advanced High-Strength Steel Sheets

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Wei Tong
Keyword(s):  
High Strength Steel ◽  
Biaxial Tension ◽  
High Strength ◽  
Yield Function ◽  
Uniaxial Tensile ◽  
Plasticity Model ◽  
Advanced High Strength Steel ◽  
Directional Dependence ◽  
Steel Sheets ◽  
Tension Loading

An accurate description of the directional dependence of uniaxial tensile yielding and plastic flow in advanced high-strength steel sheets may require either a nonassociated plasticity model with separate quadratic yield function and flow potential or an associated plasticity model with nonquadratic yield function. In this paper, Gotoh's fourth-order homogeneous polynomial yield function is applied to model two advanced high-strength steel sheets in an associated plasticity model. Both the parameter selection for calibrating Gotoh's yield function and its positivity and convexity verification are given in some detail. Similarities and differences between the associated plasticity model presented here and the nonassociated one appeared in the literature are discussed in terms of the directional dependence of yield stresses and plastic strain ratios under uniaxial tension and yield stresses under biaxial tension loading.

Failure Mechanism of Laser Welds in Lap-Shear Specimens of a High Strength Low Alloy Steel

2010 ◽  
Author(s):  
Kamran Asim ◽  
Jaewon Lee ◽  
Jwo Pan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Failure Mechanism ◽  
Shear Failure ◽  
High Strength ◽  
Yield Function ◽  
Element Analysis ◽  
Lap Shear ◽  
Laser Welds ◽  
The Finite Element Analysis

In this study, the failure mechanism of laser welds in lap-shear specimens of a high strength low alloy (HSLA) steel under quasi-static loading conditions is examined based on the experimental results. Optical micrographs of the welds in specimens before tests were examined to understand the microstructure near the weld. A micrographic analysis of the failed welds in lap-shear specimens indicates a ductile necking/shear failure mechanism near the heat affected zone. Micro-hardness tests were conducted to provide an assessment of the mechanical properties of the joint area which has varying microstructure due to the welding process. A finite element analysis was also carried out to identify the effects of the weld geometry and different mechanical properties of the weld and heat affected zones on the failure mechanism. The computational results of the finite element analysis indicate that the material inhomogeneity and geometry of the weld bead play an important role in the ductile necking/shear failure mechanism. The computational results match well with the experimental observations of the necking/shear failure and its location. A finite element analysis with consideration of void nucleation and growth based on the Gurson yield function was also carried out. The results of the finite element analysis based on the Gurson yield function are in good agreement with the experimental observations of the initiation of ductile fracture and its location.

PLASTIC DEFORMATION BEHAVIOR OF HIGH STRENGTH STEEL SHEET UNDER NON-PROPORTIONAL LOADING AND ITS MODELING

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5394-5399 ◽  
Author(s):  
TAKESHI UEMORI ◽  
YUJI MITO ◽  
SATOSHI SUMIKAWA ◽  
RYUTARO HINO ◽  
FUSAHITO YOSHIDA ◽  
...  
Keyword(s):  
Steel Sheet ◽  
Large Strain ◽  
High Strength ◽  
Yield Function ◽  
Biaxial Stress ◽  
Cyclic Plasticity ◽  
Proportional Loading ◽  
Plastic Deformation Behavior ◽  
Strain Paths ◽  
Cyclic Plasticity Model

This paper deals with plastic deformations of a high tensile strength steel sheet (HTSS sheet) under biaxial stress condition including strain path. Using a cruciform specimen of a HTSS sheet of 780MPa-TS, experiments under proportional and non-proportional loadings were investigated. Numerical simulations of stress-strain responses for several strain paths after biaxial stretching were conducted using a large-strain cyclic plasticity model (Yoshida-Uemori model). The results of numerical simulation agrees well the corresponding experimental results, which is attributed to the accurate modeling of the backstress evolution of the anisotropic yield function.

A New Description of Yield Loci Based on Polycrystal Plasticity for High Strength Steels

2009 ◽  
Vol 410-411 ◽  
pp. 543-553
Author(s):  
Yu Guo An ◽  
Henk Vegter ◽  
Louisa Carless
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Yield Function ◽  
Mechanical Tests ◽  
Stress Factors ◽  
Shear Mode ◽  
Polycrystal Plasticity ◽  
Yield Loci ◽  
Constraint Model ◽  
The Hill

Recently, many flexible constitutive equations have been proposed for sheet forming simulations. However, various mechanical tests are required to determine the many material parameters needed for such models. In the present work, effort has been made to investigate the correlation between the polycrystal plasticity based yield loci and those determined from mechanical tests, in order to define yield functions easily and accurately with minimum amount of experimental work. The results for different materials indicate that, in many cases, the Hill’48 deviates significantly from the measured yield loci. The yield loci derived from measured texture and polycrystal plasticity perform better than the Hill’48 yield function in general. Based on the two yield loci derived from the Taylor full constraint model and the Pancake model, a new combined model is proposed. The new model uses the averaged biaxial points of the two models but keeps the shape of the yield loci derived from the Taylor full constraint model in the stretching regime. The stress factors in the uniaxial and shear mode are calculated by averaging the stress factors of the two models. The proposed new description has been validated using several steel grades.

Effect of Material Anisotropies of Hot-Rolled High-Strength Steel Sheet on Localized Deformation Behavior in Hole Expansion - Part-II Simulation and Evaluation of Anisotropic Yield Function

2016 ◽  
Vol 725 ◽  
pp. 598-603 ◽  
Author(s):  
Kazuo Okamura ◽  
Toshiya Suzuki ◽  
Yuya Ishimaru ◽  
Hiroshi Hamasaki ◽  
Fusahito Yoshida
Keyword(s):  
Circular Hole ◽  
High Strength Steel ◽  
Steel Sheet ◽  
Thickness Distribution ◽  
High Strength ◽  
Yield Function ◽  
Hole Diameter ◽  
Sixth Order ◽  
Hole Expansion ◽  
Yield Functions

In this study, the circular hole expansion process of high-strength steel sheet is numerically simulated using FE analysis with Hill48 quadratic, Gotoh’s fourth order, Yld2000-2d and Yoshida’s sixth order polynomial yield function. The effects of anisotropic yield functions on local reduction of thickness are evaluated. The thickness distribution around the circular hole edge at just before necking depends on the initial hole diameter. When the initial hole diameter is relative large, the simulation results give almost same thickness distribution among different yield functions. While the initial hole is relative small, individual characteristics of yield function becomes clear and the sixth order yield function gives the best prediction.

Determination of Anisotropy Parameters via the Optimization Process of V-Bending

2015 ◽  
Author(s):  
F. Ozturk ◽  
S. Toros
Keyword(s):  
Sheet Metal ◽  
High Strength ◽  
Optimization Methods ◽  
Optimization Method ◽  
Yield Function ◽  
Bulge Test ◽  
Model Parameters ◽  
Anisotropic Yield Function ◽  
Anisotropy Parameters ◽  
The Difference

In recent years, the use of optimization methods in sheet metal forming has been increased remarkably. In the finite element simulation of the sheet metal stamping operations, the model parameters are determined from the several tests like tensile, compression, and biaxial stretching tests (bulge test). In this study, Yld2000-2d anisotropic yield function parameters are determined for DP800 advanced high strength steel using a 60° V-shaped die bending process. The difference between the simulation and experiment is found to be 1 degree using the classical determination method of the anisotropy parameters. The difference is 0.1 degree using the optimization method.

Limit Strains Analysis of Advanced High Strength Steels Sheets Based on Surface Roughness Measurements

2018 ◽  
Vol 930 ◽  
pp. 349-355
Author(s):  
Lílian Barros da Silveira ◽  
Luciano Pessanha Moreira ◽  
Ladario da Silva ◽  
Rafael Oliveira Santos ◽  
Fabiane Roberta Freitas da Silva ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Strength Steels ◽  
High Strength ◽  
Yield Function ◽  
Forming Limit ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Advanced High Strength Steels ◽  
Anisotropic Yield Function ◽  
Localization Model

The limit strains of dual-phase steels DP600 and 800 were evaluated in this work with a localization model formulated in plane-stress conditions using elasto-plastic constitutive equations. In this model, a geometrical imperfection parameter is defined from the sheet nominal thickness, initial ferrite grain size and average surface roughness. The proposed identification procedure provided a more physically meaning for this parameter and at best more conservative predictions in the drawing Forming Limit Curve (FLC) range of both investigated dual-phase steels. Nevertheless, the corresponding limit strains in the biaxial stretching region are underestimated with the present theoretical model. Thus, more detailed anisotropic yield function and hardening descriptions must be implemented to improve the accuracy of the FLC prediction of advanced high strength steels.

Decomposition of the metastable beta titanium alloy Ti-15-3

1983 ◽  
Vol 41 ◽  
pp. 264-265
Author(s):  
Y. L. Chen ◽  
S. Fujlshiro
Keyword(s):  
Low Cost ◽  
High Strength ◽  
Alpha Phase ◽  
Thick Sheet ◽  
Omega Phase ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Beta Matrix ◽  
Metastable Beta ◽  
Very High

Metastable beta titanium alloys have been known to have numerous advantages such as cold formability, high strength, good fracture resistance, deep hardenability, and cost effectiveness. Very high strength is obtainable by precipitation of the hexagonal alpha phase in a bcc beta matrix in these alloys. Precipitation hardening in the metastable beta alloys may also result from the formation of transition phases such as omega phase. Ti-15-3 (Ti-15V- 3Cr-3Al-3Sn) has been developed recently by TIMET and USAF for low cost sheet metal applications. The purpose of the present study was to examine the aging characteristics in this alloy.The composition of the as-received material is: 14.7 V, 3.14 Cr, 3.05 Al, 2.26 Sn, and 0.145 Fe. The beta transus temperature as determined by optical metallographic method was about 770°C. Specimen coupons were prepared from a mill-annealed 1.2 mm thick sheet, and solution treated at 827°C for 2 hr in argon, then water quenched. Aging was also done in argon at temperatures ranging from 316 to 616°C for various times.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

Sign in / Sign up

Export Citation Format

Share Document