This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Evaluation of DIC Based Forming Limit Curve Methods at Various Temperatures of Aluminum Alloys for Automotive Applications
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 28, 2017 by SAE International in United States
Annotation ability available
Aluminum alloys are increasingly utilized in automotive body panels and crash components to reduce weight. Accurately assessing formability of the sheet metal can reduce design iteration and tooling tryouts to obtain the desired geometry in aluminum stampings. The current ISO forming limit curve (FLC) procedure is a position dependent technique which produces the FLC based on extrapolation at the crack location. As aluminum sheet metal use increases in manufacturing, accurate determination of the forming limits of this material will be necessary prior to production. New time dependent methods using digital imaging correlation (DIC) account for variations in material behavior by continuously collecting strain data through the material necking point. This allows more accurate FLC determination that is necessary for efficient design in the automotive stamping industry. Two different time dependent FLC analysis techniques using DIC were evaluated and compared with the position dependent ISO technique. All of the techniques were tested at room and elevated temperatures with aluminum 6xxx and 7xxx alloys to show the versatility of the techniques. The resulting FLC diagrams were compared after analysis of the data. Regardless of the testing temperature both tested time dependent techniques resulted in minor variation between trials. The DIC time dependent techniques proved to be more efficient without sacrificing accuracy and consistency. Additionally, time dependent methods displayed less conservative values than the ISO method and the FLC obtained using time dependent method was generally more practical than the ISO method.
CitationRencheck, M., Zelenak, P., Shang, J., and Kim, H., "Evaluation of DIC Based Forming Limit Curve Methods at Various Temperatures of Aluminum Alloys for Automotive Applications," SAE Technical Paper 2017-01-0309, 2017, https://doi.org/10.4271/2017-01-0309.
- Harpell , E. , Worswick , M. , Finn , M. , Jain , M. et al. Numerical Prediction of the Limiting Draw Ratio for Aluminum Alloy Sheet Journal of Materials Processing Technology 100 3 April 2000
- Huang , G. , Sriram , S. , and Yan , B. Digital Image Correlation Technique and Its Application in Forming Limit Curve Determination International Deep Drawing Research Group (IDDRG) Olofström, Sweden June 16-18, 2008
- Merklein , M. , Kuppert , A. , Mutze , S. , and Geffert , A. New Time Dependent Method for Determination of Forming Limit Curves Applied to SZBS800 International Deep Drawing Research Group (IDDRG) Graz, Austria May 31-June 2, 2010
- International Organization for Standardization, ISO12004-2:2008 Metallic Materials - Sheet and Strip - Determination of forming-limit curves - Part 2: Determination of forming-limit curves in the laboratory 2008
- Huang , L. and Shi , M. Determining Forming Limit Curves of Advanced High Strength Steels with Digital Image Correlation Forming Limit Diagram Workshop May 13, 2016
- Martinez-Donaire , A. , Garcia-Lomas , F. , and Valleano , C. New Approaches to Detect the Onset of Localized Necking in Sheets under Through-Thickness Strain Gradients Materials and Design 57 135 145 2014
- DiCecco , S. , Butcher , C. , Worswick , M. , Chu , E. , Boettcher , E. Application of Time and Position Dependent Localized Necking Criteria To High Strength Aluminum Alloys at Elevated Temperatures Forming Technology Forum UTG, Technical University of Munich Germany Sept. 12-13, 2016
- Volk , W. and Hora , P. New Algorithm for a Robust User-Independent Evaluation of Beginning Instability for the Experimental FLC Determination International Journal of Material Forming 4 338 346 2011
- Hotz , W. , Merklein , M. , Kuppert , A. , Friebe , H. et al. Time Dependent FLC Determination - Comparison of Different Algorithms to Detect the Onset of Unstable Necking before Fracture Key Engineering Materials 549 397 404 2013