Numerical Simulation for the Formability Prediction of the Laser Welded Blanks (TWB)

Tailor-welded Blanks (TWBs) are tailor made for different complex component designs by welding multiple metal sheets with different thicknesses, shapes, coatings or strengths prior to forming. In this study the Hemispherical Die Stretching (HDS) test (out-of-plane stretching) of TWBs were simulated via ABAQUS/Explicit to obtain the Forming Limit Diagrams (FLDs) of Stainless steel (AISI 304) laser welded blanks with different thicknesses. Two criteria were used to detect the start of necking to determine the FLD for TWBs and parent sheet metals. These two criteria are the second derivatives of the major and thickness strains that are given from the strain history of simulation. In the other word, in these criteria necking starts when the second derivative of thickness or major strain reaches its maximum. With having the time of onset necking, one can measure the major and minor strains at the critical area and determine the forming limit curve.

Authors:

• Hossein Mamusi
• Abolfazl Masoumi
• Ramezanali Mahdavinezhad

Keywords:

• TWB
• Forming Limit Diagram
• Necking criteria
• ABAQUS/Explicit

References:

[1] L. C. Chan; C. H. Cheng and C. L. Chow "Weldment properties
evaluation and formability study of tailor-welded blanks of different
thickness combinations and welding orientations." Journal of Materials
Science Vol. 42, No. 15, pp 5982-5990, 2007.
[2] D. T. Llewellyn and R. C. Hudd Steels metallurgy and applications,
1998, Oxford, Butterworth-Heinemann. pp. 28.
[3] Z. Marciniak; J. L. Duncan and S. J. Hu Mechanics of sheet metal
forming, 2002, Oxford, Butterworth-Heinemann. pp. 75.
[4] S. P. Keeler, "Determination of forming limits in automotive
stampings". Sheet Metal Ind., Vol. 42, pp 683-691, 1965.
[5] G. M. Goodwin,. "Application of strain analysis to sheet metal forming
problems in the press shop." SAE paper 680093, 1968
[6] A. Petek; T. Pepelnjak and K. Kuzman,. "An improved method for
determining a forming limit diagram in the digital environment."
Strojniski Vestnik-Journal of Mechanical Engineering, Vol. 51, No. 6,
pp 330-345, 2005
[7] Q. Situ, M. Jain and M. Bruhis,. "A suitable criterion for precise
determination of incipient necking in sheet materials."Materials Sience
Forum", Vol. 519-521, pp 111-116, 2006
[8] B. S. Naik, P. J. Ramulu and R. G. Narayanan;. "Application of a few
necking criteria in predicting the forming limit of unwelded and tailorwelded
blanks."Journal of Strain Analysis for Engineering Design, Vol.
45, No. 2, pp 79-96, Feb. 2010
[9] S. K. Panda; V. H. B. Hernandez; M. L. Kuntz and Y. Zhou,.
"Formability Analysis of Diode-Laser-Welded Tailored Blanks of
Advanced High-Strength Steel Sheets." Metallurgical and Materials
Transactions a-Physical Metallurgy and Materials Science Vol. 40A,
1955-1967, Aug. 2009