The Biaxial Stress-Strain Curves of Sheet Metals

2010 ◽  
Vol 44-47 ◽  
pp. 2519-2523
Author(s):  
Hai Bo Wang ◽  
Min Wan ◽  
Yu Yan ◽  
Xiang Dong Wu
Keyword(s):  
Transverse Direction ◽  
Biaxial Loading ◽  
Testing Machine ◽  
Rolling Direction ◽  
Biaxial Stress ◽  
Loading Path ◽  
Sheet Metals ◽  
Stress Strain ◽  
Loading Paths ◽  
Loading Ratio

Biaxial tensile tests of 5754O aluminum alloy sheet and B170P1 steel sheet were performed under linear loading paths with cruciform specimens and a biaxial loading testing machine. The stress-strain curves under different loading paths were obtained. It is found that the loading path has a significant influence on the stress-strain curves, i.e., the stress-strain curves vary with the loading path. The stress-strain curves in the rolling direction become higher with the decrease of the loading ratio (the ratio of the load along the rolling direction to that along the transverse direction) from 4:0 to 4:4. Meanwhile the stress-strain curves in the transverse direction become lower with the decrease of the loading ratio from 4:4 to 0:4. Based on Yld2000-2d yield criterion, the experimental phenomena of the two kinds of sheet metals under biaxial tension were explained theoretically.

Integrated Hydraulic Bulge and Forming Limit Testing Method and Apparatus for Sheet Metals

2014 ◽  
Vol 626 ◽  
pp. 171-177 ◽  
Author(s):  
Yan Yo Chen ◽  
Yu Chung Tsai ◽  
Ching Hua Huang
Keyword(s):  
Forming Limit Diagram ◽  
Close Correlation ◽  
Biaxial Stress ◽  
Forming Limit ◽  
Hydraulic Pressure ◽  
Sheet Metals ◽  
Stress Strain ◽  
Testing Method ◽  
Hydraulic Bulge ◽  
Strain Relationship

This paper proposes an integrated hydraulic bulge and forming limit testing method and apparatus for sheet metals. By placing a PU (Polyurethane) plate between molds and uniformly applying hydraulic pressure to sheet metals, a biaxial stress-strain relationship and forming limit diagram (FLD) displaying both left and right sides were acquired using the same apparatus. An uniaxial tension test and traditional drawing test were conducted to compare the results obtained from the proposed hydraulic bulge and forming limit testing methods, respectively. A close correlation between the results of the stress-strain relationship and FLD in both comparisons verified the feasibility and capability of this integrated hydraulic testing method and apparatus for use with sheet metals.

Determination of the Anisotropic Hardening of Sheet Metals at Large Strain from Stretch Bending Test

2016 ◽  
Vol 725 ◽  
pp. 677-682
Author(s):  
Gustavo Capilla ◽  
Hiroshi Hamasaki ◽  
Fusahito Yoshida ◽  
Toshiya Suzuki ◽  
Kazuo Okamura
Keyword(s):  
Large Strain ◽  
Rolling Direction ◽  
High Strength ◽  
Uniaxial Stress ◽  
Bending Test ◽  
Weighting Coefficient ◽  
Large Strains ◽  
Sheet Metals ◽  
Stress Strain ◽  
Stretch Bending

The present study aims to determine stress-strain curves at large strains of sheet metals under the uniaxial stress state by using the in-plane stretch-bending test. The combined Swift-Voce model, which describes the large-strain work-hardening of materials by means of a weighting coefficient μ, was used for FE simulation of the stretch-bending. The coefficient μ was determined by minimizing the difference in punch stroke vs. bending strain responses between the experimental data and the corresponding experimental results. By using this inverse approach, stress-strain curves of two levels of high-strength steel sheets of a precipitation hardening type, 590R and 780R, in three sheet directions (0, 45 and 90o from rolling direction), were determined.

A Comparative Study on the Formability Prediction of Steel Sheets by Anisotropic Models Based on Associated Flow Rule and Non-Associated Flow Rule

2015 ◽  
Vol 651-653 ◽  
pp. 150-155 ◽  
Author(s):  
Jun He Lian ◽  
Deok Chan Ahn ◽  
Dong Chul Chae ◽  
Sebastian Münstermann ◽  
Wolfgang Bleck
Keyword(s):  
Comparative Study ◽  
Transverse Direction ◽  
Steel Sheet ◽  
Rolling Direction ◽  
Tensile Tests ◽  
Biaxial Stress ◽  
Flow Rule ◽  
Anisotropic Models ◽  
Formability Prediction ◽  
Associated Flow Rule

A comparative study on the formability prediction of a ferritic steel sheet by anisotropic models based on associated flow rule and non-associated rule is carried out. The uniaxial tensile tests along seven directions of the sheet from rolling direction to transverse direction with an interval of 15° are performed for the anisotropic yield stress and r-value. For the biaxial stress state, both bulge test and punch test are performed. The BBC2003 based on the associated flow rule is employed and its anisotropic parameters are calibrated to the yield stresses and r-values from the tensile tests along rolling direction, transverse direction and diagonal direction and the biaxial test. The non-associated quadratic Hill48 model is also calibrated to the same set of experimental data. Similar level of the predicative capability on the yield and plastic deformation directionality by the associated and non-associated based models is observed. With the common basis on the anisotropic plasticity characteristics, they are combined with the Marciniak–Kuczynski (MK) model to predict the formability of the steel sheet and distinct difference in the prediction is observed between the two models.

scholarly journals Deep neural network approach to estimate biaxial stress-strain curves of sheet metals

2020 ◽  
Vol 195 ◽  
pp. 108970 ◽  
Author(s):  
Akinori Yamanaka ◽  
Ryunosuke Kamijyo ◽  
Kohta Koenuma ◽  
Ikumu Watanabe ◽  
Toshihiko Kuwabara
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Biaxial Stress ◽  
Network Approach ◽  
Sheet Metals ◽  
Stress Strain ◽  
Neural Network Approach

Effects of anisotropy and diaphragm size on biaxial stress—strain curves for sheet metals

1981 ◽  
Vol 16 (1) ◽  
pp. 53-57 ◽  
Author(s):  
M Fazli Ilahi
Keyword(s):  
Biaxial Tension ◽  
Diameter Ratio ◽  
Tension Test ◽  
Biaxial Stress ◽  
Sheet Metals ◽  
Stress Strain ◽  
Normal Anisotropy ◽  
Strain Characteristic ◽  
Bending Stresses ◽  
Theoretical Stress

When a circular diaphragm clamped at the edge is deformed by unilateral hydrostatic pressure the pole is under balanced biaxial tension if the absence of edge effects is assumed. The diaphragm test is an excellent way of obtaining the work-hardening characteristics of sheet metals to fairly high strains. Some previous investigators have tried to correlate the experimental and theoretical stress-strain characteristics of the pole of a diaphragm. In this present work 10 in. and 4 in. diameter dies and sheet metals with an average thickness of 0·040 in. have been used. Previous investigators used diaphragms of smaller sizes; but if the thickness—diameter ratio can be kept small the bending stresses will be negligible. All sheet metals are anisotropic and for simplicity anisotropy in the plane is neglected, so that an average R value can be adopted. Hill's theory of yielding and plastic flow for anisotropic materials has been used together with the uniaxial tension test values to predict the stress—strain characteristic at pole. The effects of the diameter of the die and the normal anisotropy of the sheet metals on the stress—strain characteristics at pole are discussed.

scholarly journals Fatigue Life Properties of Stainless Steels in Wide Ranged Biaxial Stress States using a Hollow Cylinder Specimen

2019 ◽  
Vol 300 ◽  
pp. 09004
Author(s):  
Shunsuke Saito ◽  
Fumio Ogawa ◽  
Takamoto Itoh
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Hollow Cylinder ◽  
Stainless Steels ◽  
Equivalent Stress ◽  
Testing Machine ◽  
Biaxial Stress ◽  
Loading Path ◽  
Stress Range ◽  
Inner Pressure

Stress controlled multiaxial fatigue tests were carried out using hollow cylinder specimens of type 430 and 316 stainless steels at room temperature. A newly developed fatigue testing machine which can apply push-pull loading and inner pressure to the specimen was used. For inner pressure, oil was put inside of the specimen. 7 types of cyclic loading paths were employed by combining axial and hoop stresses; a Pull, an Inner-pressure, a Push-pull, an Equi-biaxial, a Square-shape, a LT-shape and a LC-shape. Fatigue lives vary depending on the loading path when those were evaluated by the maximum Mises’ equivalent stress range on inner surface of the specimen. The fatigue lives of both the steels showed a similar tendency. However, the following difference was identified. Specifically, differences in fatigue lives of type 430 stainless steel between the uniaxial loading and the multiaxial tests were large, while those of type 316 stainless steel were small. To discuss difference in fatigue life properties between both steels, this study investigates the effect of the shear stress range, mean stress and additional hardening and which leads to evaluate the lives suitably.

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