Engineering Mechanics

Proceedings Vol. 10 (2004)

ENGINEERING MECHANICS 2004

Copyright © 2004 Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Prague

 

Vavřík D., Jakůbek J.
pages 305 - +8p., full text

The subject of this work is implementation of the incremental Prager-Ziegler plasticity theory for experimental results acquired by the “Method of Interpolated Ellipses” (MIE). The MIE is a technique based on an optical monitoring of deformations during loading processes of hexagonal grids of dots deposited on the surface of the monitored specimen. Loading deforms a circle on the specimen surface into an ellipse. Knowledge of the ellipse parameters directly yields the magnitude and the direction of principal strains. The principal strain evolution yields knowledge of evolution of the plastic strain field by numerical post processing. The commonly used power low plasticity theory has strong condition of proportional loading for its use. This condition isn’t usually fulfilled for high ductile body with a stress concentrator. Therefore the incremental Prager-Ziegler plasticity theory was implemented. Evaluated increments of plastic strain field show surprising results for aluminium specimens used. Besides non-proportional plastic strain evolution, plastic work rate exhibited substantial discontinuous character.

Text and facts may be copied and used freely, but credit should be given to these Proceedings.

All papers were reviewed by members of the scientific committee.