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A New Testing Method to Evaluate Edge Cracking with Considerations of the Shear Clearance and Press Speed
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 14, 2020 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
As the automotive industry increasingly adopts Advanced High Strength Steel (AHSS) for the vehicle light-weighting and crashworthiness, the edge cracking significantly increases in stamping AHSS. Different lab-scale test methods such as the ISO standard hole-expansion test and the half specimen dome test are available to evaluate edge formability. However, none of these lab-scale testing methods emulates production conditions such as various shear clearances, part complexity, and shearing speed associated with the mechanical or hydraulic press operation. To address these limitations of the available testing methods, a new punching and stamping test was developed.
This paper introduces the simulation and experimental approach in developing this unique testing method to design the peanut-shaped hole that is sensitive to edge cracking in stamping. Three different sheet materials, DP780, 980 GEN3, and aluminum 6016-T4 were tested to validate the reliability of the newly developed testing method. Selected materials were punched with two different shear clearances between 10~20% that are commonly used for industrial applications. Also, two different press motions, conventional mechanical press motion and variable-speed servo press motion, were used for punching the peanut-shaped holes. The punched-hole blank was subsequently formed with the stamping tool. During the forming test, the die stroke corresponding to the edge cracking was detected by the load analyzer from the servo press. Strain distribution on the tested parts was measured and compared using the optical strain measurement tool, ARGUS. The work-hardening on the sheared edge was quantified with the hardness measurements. The edge formability was evaluated with the measured die stroke corresponding to the edge cracking and strain measurements.
CitationGu, J., Zoller, L., and Kim, H., "A New Testing Method to Evaluate Edge Cracking with Considerations of the Shear Clearance and Press Speed," SAE Technical Paper 2020-01-0758, 2020, https://doi.org/10.4271/2020-01-0758.
Data Sets - Support Documents
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- Pathak, N., Butcher, C., and Worswick, M. , “Assessment of the Critical Parameters Influencing the Edge Stretchability of Advanced High Strength Steel,” Journal of Materials Engineering and Performance 25(11), 2016.
- Konieczny, A. and Henderson, T. eds., “On Formability Limitations in Stamping Involving Sheared Edge Stretching,” SAE Technical Paper 2007-01-0340, 2007, https://doi.org/10.4271/2007-01-0340.
- Lee, J.S., Ko, Y.K., Huh, H., Kim, H.K., and Park, S.H. , “Evaluation of Hole Flangeability of Steel Sheet with Respect to the Hole Processing Condition,” Key Engineering Materials 340:665-670, 2007.
- Huberta, C., Dubara, L., Dubara, M., and Dubois, A. , “Finite Element Simulation of the Edge-Trimming/Cold Rolling Sequence: Analysis of Edge Cracking,” Journal of Materials Processing Technology 212(5):1049-1060, 2012.
- Hu, X., Sun, X., and Golovashchenko, F.S. , “Predicting Tensile Stretchability of Trimmed AA6111-T4 Sheets,” Computational Materials Science 85:409-419, 2014.
- Wang, K., Greve, L., and Wierzbicki, T. , “FE Simulation of Edge Fracture Considering Pre-Damage from Blanking Process,” International Journal of Solids and Structures 71:206-218, 2015.
- Kim, H., Shang, J., Dykeman, J., Samant, A., and Hoschouer, C. , “Practical Evaluation and Prediction of Edge Cracking in Forming Advanced High Strength Steels (AHSS),” SAE Technical Paper 2017-01-0308, 2017, https://doi.org/10.4271/2017-01-0308.
- Gu, J.C., Kim, H., Dykeman, J., and Shih, H. , “A Practical Methodology to Evaluate and Predict Edge Cracking for Advanced High-Strength Steel,” in IOP Conference Series: Materials Science and Engineering, 418, 2018, 012072, doi:10.1088/1757-899x/418/1/012072.