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.

Effect of Material Anisotropies of Hot-Rolled High-Strength Steel Sheet on Localized Deformation Behavior in Hole Expansion - Part-I Experimental Consideration to Circular and Oval Hole

2016 ◽  
Vol 725 ◽  
pp. 592-597 ◽  
Author(s):  
Toshiya Suzuki ◽  
Kazuo Okamura ◽  
Yuya Ishimaru ◽  
Hiroshi Hamasaki ◽  
Fusahito Yoshida
Keyword(s):  
High Strength Steel ◽  
Deformation Behavior ◽  
Steel Sheet ◽  
High Strength ◽  
Localized Deformation ◽  
Hole Expansion ◽  
Expansion Test ◽  
Hole Edge ◽  
Hole Expansion Test ◽  
Hot Rolled

In this study, the effect of the material anisotropies of hot-rolled high-strength steel sheet on localized deformation behavior in hole expansion test has been investigated experimentally. First, the hole expansion test with the circular hole has been conducted to investigate the effect of anisotropies of material properties on the localized deformation behavior around the hole edge. Next, the hole expansion test with the oval hole has been conducted to investigate the effect of the major axis direction of the oval hole on the localized deformation behavior around the hole edge. As a result, it was clarified that the effect of anisotropies of r-value and n-value on the localized deformation behavior is strong, especially the anisotropy of n-value.

1517 Accurate simulation of hole expansion process of high strength steel sheet

2011 ◽  
Vol 2011.49 (0) ◽  
pp. 477-478
Author(s):  
Shohei TAMURA ◽  
Toshiya SUZUKI ◽  
Hiroshi HAMASAKI ◽  
Takeshi UEMORI ◽  
Kazuo OKAMURA ◽  
...  
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Expansion Process ◽  
Hole Expansion

Increasing the Hole Expansion Ability of High Strength Steel Sheet by Improving the Pre-Hole Shearing Process

2019 ◽  
Vol 962 ◽  
pp. 167-174
Author(s):  
Prasan Saengkhiao ◽  
Komgrit Lawanwong ◽  
Pakorn Chumrum
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Expansion Ratio ◽  
Expansion Process ◽  
Forming Process ◽  
Research Papers ◽  
Hole Expansion ◽  
Hole Edge ◽  
Hole Expansion Ratio

The hole expansion process is a forming process that the fracture easily occurred on the hole edge. Therefore, many research papers presented various processes to make a precision pre-hole shearing to a hole expansion process such as wire cut, EDM, and laser cut. The purpose of this work is to increase a hole expansion ratio on the high strength steel sheet. The conventional piercing by piercing punch and piercing with a counter punch was used to make a pre-hole shearing process in this research paper. The high strength steel grade 590 and 980 MPa of 1.2 mm of thickness were used in the experiments. From experimental results, it was found that the pre-hole shearing by piercing with a counter punch can be increased a shear surface on cutting edge of workpiece. Moreover, the used piercing with counter punch can improve the hole expansion ratio more than the conventional piercing process because sheared surface around the hole edge was increased.

Hole expansion simulation of high strength steel sheet

2010 ◽  
Vol 3 (S1) ◽  
pp. 259-262 ◽  
Author(s):  
K. Hashimoto ◽  
T. Kuwabara ◽  
E. Iizuka ◽  
J. W. Yoon
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Hole Expansion

Modeling of Anisotropic Plastic Behavior of Advanced High Strength Steel Sheet TRIP 780

2011 ◽  
Vol 410 ◽  
pp. 232-235 ◽  
Author(s):  
Sansot Panich ◽  
Vitoon Uthaisangsuk ◽  
Surasak Suranuntchai ◽  
Suwat Jirathearanat
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
Plastic Anisotropy ◽  
High Strength ◽  
Uniaxial Tensile ◽  
Plastic Behavior ◽  
Biaxial Test ◽  
Advanced High Strength Steel ◽  
Yield Criteria ◽  
Anisotropic Plastic

Anisotropic plastic behavior of advanced high strength steel sheet of grade TRIP780 (Transformation Induced Plasticity) was investigated using three different yield functions, namely, the von Mises’s isotropic, Hill’s anisotropic (Hill’48), and Barlat’s anisotropic (Yld2000-2d) criterion. Uniaxial tensile and balanced biaxial test were conducted for the examined steel in order to characterize flow behavior and plastic anisotropy for different stress states. Especially, disk compression test was performed for obtaining balanced r-value. All these data were used to determine the anisotropic coefficients. As a result, yield stresses and r-values for different directions were calculated according to these yield criteria. The results were compared with experimental data. To verify the modelling accuracy, tensile tests of various notched samples were carried out and stress-strain distributions in the critical area were characterized. By this manner, the effect of stress triaxiality due to different notched shapes on the strain localization calculated by the investigated yield criteria could be studied.

Flipping Carbon Nanotubes to Continuously Produce Strong, Transparent, Multifunctional Sheets

2005 ◽  
Author(s):  
Mei Zhang ◽  
Shaoli Fang ◽  
Anvar A. Zakhidov ◽  
Sergey B. Lee ◽  
Ali E. Aliev ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Nanotube Arrays

We demonstrate carbon nanotube assembly by cooperatively rotating carbon nanotubes in vertically-oriented nanotube arrays (forests) and make 5-centimeter-wide, meter-long transparent sheets. These self-supporting nanotube sheets are initially formed as a highly anisotropic electronically conducting aerogel that can be densified into strong sheets that are as thin as 50 nanometers. The measured gravimetric strength of orthogonally oriented sheet arrays exceeds that of high strength steel sheet.

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