New Formulae for Determining Fracture Toughness of a Wide Range of Different Materials with Chevron-Notched Short-Rod and Short-Bar Specimens

Abstract

New formulae are presented to re-evaluate plain strain fracture toughness of brittle and ductile materials from previous works on chevron-notched specimens. The fracture toughness KIm from the new formulae agree with values of KIC from ASTM specimens. The KIm measurements are successful in tests of tough aluminum when the fracture toughness exceeds 40 MPa · m1 2 and steel 20G with the plasticity factor p approach 1. It is found that the valid specimen size could be smaller than 1.25(KIC/σS)2 for aluminum alloys, and even less than 0.1(KIC/σS) for steel 20G when the KIm formulae are used.