An experimental study of material flow and surface quality using image processing in the hydraulic bulge test
Sławomir Świłło
Faculty of Production Engineering, Warsaw University of Technology, Warsaw/Poland.
DOI:
https://doi.org/10.7494/cmms.2013.2.0443
Abstract:
The paper presents a method for the surface shape and strain measurement applied in the determination of metal flow and product quality. Accurate determination of these characteristics in the sheet metal forming operation is extremely important, especially in automotive applications. However, the sheet metal forming is a very complex manufacturing process, and its success depends on many factors. This involves a number of tests that should be carried out to find optimal, yet cost-effective solutions. In this study the author discusses the investigations that are focused on better understanding of the strain values and their distribution in a product, and checking if they do not exceed certain limit resulting in the loss of stability. The hydraulic bulge test was identified as a method most applicable in these investigations, where both theoretical and experimental analysis was conducted. First, the presented solution in the field of reconstruction of three-dimensional (3D) objects significantly expands the capabilities of the analysis, compared with the solutions existing so far. Second, a new method for the 3-dimensional geometry and strain measurement based on laser scanning technique is presented. Next, the image acquisition process and digital image correlation (DIC) are presented to recognize and analyze the objects taken from camera. The 3D shape and strain analysis presented in this paper offers a valuable tool in the metal products quality control, along with a complete testing equipment for maximum strain calculation just before cracking. The computer measurement system is directly connected to the hydraulic bulge test apparatus, thus providing fast and accurate results for material testing and process analysis.
Cite as:
Świłło, S. (2013). An experimental study of material flow and surface quality using image processing in the hydraulic bulge test. Computer Methods in Materials Science, 13(2), 283 – 288. https://doi.org/10.7494/cmms.2013.2.0443
Article (PDF):
Keywords:
Strain analysis, Sheet metal forming, Hydraulic bulge test
References:
Feldmann, P., Schatz, M., 2006, Effective Evaluation of FLCTests with the optical in-process strain analysis system AutoGrid, Proc. Conf. FLC, ed, Hora P., Zurich, 69-73.
Feldmann P., 2007, Application of strain analysis system AUTOGRID for evaluation of formability tests and for strain analysis on deformed parts, Proc. Conf. International Deep Drawing Research Group, ed, Tisza M., Gyor, 483–490.
Hijazi, A., Yardi N., Madhavan V., 2004, Determination of forming limit curves using 3D digital image correlation and in-situ observation, Proc. Conf. SAMPE, Long Beach, 791-803.
Koga, N. and Murakawa, M., 1996, Application of visioplasticity to experimental analysis of shearing phenomena, Proc. Conf. Advanced Technology of Plasticity, Vol. II, ed, T. Altan, Columbus, 571-574.
Liewald, M., Schleich R., 2010, Development of an Anisotropic Failure Criterion for Characterising the Influence of Curvature on Forming Limits of Aluminium Sheet Metal Alloys, Int. Journal of Material Forming, 3,1175-1178.
Marciniak, Z., Kuczyński, K., 1967, Limits strains in the processes of stretch-forming sheet metal, Int. Journal of Mechanics Science, 9, 609-612.
Marciniak Z., 1961, Influence of the sign change of the load on the strain hardening curve of a copper test piece subject to torsion, Archives of Mechanics, 13, 743-752 (in Polish).
Sirkis, S., 1990, System response to automated grid methods. Opt. Eng., vol. 29, 1485-1493
Swillo, S., and Jaroszewicz, L.R., 2001, Automatic shape measurement on base of static fiber-optic fringe projection method. Proc. Conf. Engineering Design & Automation, eds, Parsaei, H.R., Gen, M., Leep, H.R., Wong J.P., Las Vegas, 476-481.
Swillo, S., 2001, Automatic of strain measurement by using image processing. Proc. Conf. Engineering Design & Automation, eds, Parsaei, H.R., Gen, M., Leep, H.R., Wong J.P. Las Vegas, 272-277.
Świłło, S., Kocańda, A. and Piela, A., 2000, Determination of the forming limit curve by using stereo image processing. Proc. Conf. Metal Forming 2000, eds, Pietrzyk M., Kusiak J. & Majta J. and Hartley P., & Pillinger I., Kraków, 545-550.
Świłło, S., Czyżewski, P., Lisok, J., 2012, An experimental study for hydro-bulging process using advanced computer technique, Proc. Conf. Metal Forming 2012, eds, Kusiak J., Majta J., Szeliga D. and Weinheim, Kraków, 1411-1414.