OPTICAL MEASUREMENT OF THE STRAINSTRESS RESPONSE DURING UNLOADING OF METAL SHEETS UNDERGOING LARGE PLASTIC DEFORMATIONS |
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| C. Dudescu, J. Naumann, M. Stockmann |
- Abstract:
- The optical measurement techniques have shown more precise results about the mechanical behaviour of materials. They enjoy the advantages of being non-contact, full-field, with a high spatial resolution and offer the possibility to observe the local mechanical behaviour. The paper presents the analysis by Electronic Speckle Pattern Interferometry (ESPI) of the unloading behaviour of metal sheets that undergone large plastic deformations. The springback of the sheet metals after large deformations during deep drawing is not a strongly linear process with a constant Young’s modulus but, the stress-strain behaviour during the unloading phases, shows considerably non-linear and inelastic effects. Unloading of two types of steel sheets for cold forming, a cold-rolled high strength micro-alloyed steel and a low carbon steel sheet, and an aluminium alloy sheet have been analysed using the ESPI method. The experimental measurements showed that the stress-strain curve during unloading is non-linear and the secant moduli of unloading curves decrease with increasing of prestrain.
- Keywords:
- unloading, ESPI method, springback, metal sheets
- Download:
- IMEKO-YSESM-2012-33.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC15
- Event name:
- TC15 Youth Symposium 2012
- Title:
11th Youth Symposium on Experimental Solid Mechanics (TC15)
- Place:
- Brasov, ROMANIA
- Time:
- 30 May 2012 - 02 June 2012