Engineering Mechanics

Proceedings Vol. 11 (2005)

ENGINEERING MECHANICS 2005

Copyright © 2005 Institute of Mechanics of Solids, Faculty of Mechanical Engineering, Bruno University of Technology, Brno

 

Vavřík D., Bryscejn J., Holý T., Jakůbek J., Jakůbek M., Valach J., Vykydal Z.
pages 331 - +6p., full text

Failure of a high ductile specimen usually precedes a decrease of the loading force (material softening) under the condition of displacement control in the monotonic loading. This phenomenon is usually induced by a large plastic deformation and eventually by a related dynamic development of voids and microcracks inside the specimen (damage process). The experimental investigation of this highly interesting stage can be made accessible only under very well controlled loading. Unfortunately, the elastic energy stored in the loading equipment can result in sudden failure within very short time corresponding to the loading unstability. We can follow this time interval with real fast readout system or, alternatively, we can prolong this time interval by reducing the elastic energy in the loading equipment or both. The proposed new loading frame fulfils the indicated requirements and enables extraordinary precise displacement loading control even beyond the maximal loading force. Plastic deformation on a surface is investigated by the optical Method of Interpolated Ellipses and together with damage processes inside of the specimen are simultaneously observed by the X-ray Dynamic Defectoscopy method.

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