Wrinkle Generation Process in Press Forming of High-strength Steel Sheet

2021 ◽  
Vol 62 (730) ◽  
pp. 159-167
Author(s):  
Yasuharu TANAKA ◽  
Zhigang WANG ◽  
Hiroaki KARASAKI ◽  
Minoru SUGAWARA
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Generation Process ◽  
Press Forming ◽  
Wrinkle Generation

Resistance Heating Characteristics of High-Strength Steel Sheet Blank for Hot Press Forming

2007 ◽  
Vol 340-341 ◽  
pp. 749-754 ◽  
Author(s):  
Seijiro Maki ◽  
Yuuki Tanaka ◽  
Kenichiro Mori
Keyword(s):  
High Strength Steel ◽  
Steel Sheet ◽  
High Strength ◽  
Single Pair ◽  
Resistance Heating ◽  
Hot Press ◽  
Press Forming ◽  
Hot Press Forming ◽  
Blank Shape ◽  
Material Utilization

Resistance heating performance in some shaped blanks of high-strength steel sheet is examined by experiment and FE simulation, and the feasibility and effectiveness of the application of resistance heating to the hot press forming of high-strength steel sheet are discussed. The followings are made clear through this study. (1) A uniformly distributed current density is essential to uniform blank heating. (2) For a certain shaped blank, no matter how the electrodes are disposed, uniform blank heating is difficult. (3) A blank shape suitable for uniform heating by a single pair of parallel electrodes is restricted to a rectangle.(4) In case a uniformly heated blank is required, two-piece simultaneous forming with point-symmetric die layout is recommended from the viewpoint of material utilization.

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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