Inicio de fi suración en probetas miniatura de punzonado miniatura de punzonado

Abstract

The main objective of the Small Punch Test on pre-cracked specimens is to obtain the fracture properties in those cases where there is not enough material for conducting conventional tests. One of the biggest challenges presented in achieving this goal is the accurate determination of the applied load at the onset of the crack initiation (Papl) during the test, because this point is not clearly reflected in the load-displacement curve obtained. To determine this load, three possible methods have been evaluated: the first one is based on interrupted tests, the second one consists of analyzing the slope of the load-displacement curve and the third one is defined as the compliance method used with compact specimens. The aim of this paper is to present these experimental methods and identify which of them is the most appropriate. As an immediate consequence, the relationship between Papl and the initial crack depth in the pre-cracked SPT specimens has been analyzed.