Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 49: Topical Session: Fundamentals of Fracture - Novel Experimental Techniques I

MM 49.2: Vortrag

Donnerstag, 14. März 2013, 10:45–11:00, H4

Development and verification of an approach for determining fracture mechanical properties from tests on small size specimens — •Michael Mahler and Jarir Aktaa — Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM), 76344 Eggenstein-Leopoldshafen, Germany

In general, fracture mechanical properties will be identified on standard-sized specimens. Therefore special standard specifications are in use to determine J-R curves for ductile or fracture toughness for brittle fracture.
To determine fracture mechanical properties of sub-sized specimens an evaluation procedure based on finite element simulations of the crack propagation process will be used. The fracture process zone will be described by using a cohesive-zone-model (CZM). This surface based approach is able to describe the fracture mechanism in the ductile and brittle regime selecting proper law for the constitutive traction separation. The first of the two parameters for the CZM will be experimentally determined by notched tensile tests to identify the cohesive stress. The second parameter will be found by fitting the force-deflection curve of experimental three point bending tests to the simulated one. The geometry of the sub-sized specimen is 27x3x4 mm³ with side grooves. The applicability of the evaluation procedure will be verified on the ferritic martensitic steel T91. Therefore a comparison between standard- and sub-sized specimens is considered. The objective is to establish small size testing technology for the determination of fracture mechanical properties.