The aim of the present paper is to investigate the scaling behaviour of the experimental tensile softening (or catastrophic) curves and it concludes a series of papers from the same research group published inMaterials and Structures [1–4]. Experimentally, it is evident how these curves become steeper by increasing the size of the specimens (ductile-to-brittle transition). To study this phenomenon, a completely new testing apparatus, made up of three orthogonally placed actuators, was bult at the Politecnico di Torino by the authors [1, 5–7]. This set-up makes it possible to apply a purely tensile force, so that the secondary flexural stresses, if kept under control, constitute a degree of error comparable to the values allowed for normal testing apparatus. The method enables a stress vs. strain curve to be plotted with the descending (softening) branch up to the point where the cross section of the tensile specimen breaks away. The results of a new experimental investigation, performed over a very large scale-range of unnotched concrete specimens (16∶1), will be presented. Particular attention will be paid to the scale effects both on nominal tensile strength and on fracture energy. The renormalized experimental curves will be presented in a load vs. displacement plane characterized by anomalous physical dimensions. The renormalization of experimental curves enables obtaining the same response for all specimen dimensions, and then defining the universal (scale-independent) behaviour of the material.
|Titolo:||Scaling behaviour and dual renormalization of experimental tensile softening responses|
|Data di pubblicazione:||1998|
|Digital Object Identifier (DOI):||10.1007/BF02480671|
|Appare nelle tipologie:||1.1 Articolo in rivista|