How to measure fracture toughness in thin metallic sheet
ToughSteel is a European project funded under the frame of the Research Fund for Coal and Steel (RFCS) programme. The main aim of ToughSteel is the dissemination and valorisation of fracture toughness as a material property to rationalise crack-related problems in Advanced High Strength Steels.
This webinar aims to present the current methodologies to measure fracture toughness in thin sheet with a focus on the essential work of fracture. At the end of the seminar, you should be able to successfully implement the EWF methodology in your workflow.
25th February 202210.00h – 12.00h CET ONLINE
10:00 – 10:05 – Welcome and introductions
Pascal Jacques, Professor, Institute of Mechanics, Materials and Civil Engineering, UCLouvain
10:05 – 10:35 – Advantages and limitations of current methodologies to measure fracture toughness when applied on thin metallic sheet
David Frómeta, Project Leader, researcher, Metallic and Ceramic Materials Unit, Eurecat
10:35 – 11:05 – Mechanical principles and physical aspects of the essential work of fracture method
Thomas Pardoen, Professor, Institute of Mechanics, Materials and Civil Engineering, UCLouvain
11:05 – 11:35 – Technical aspects of the essential work of fracture method
Antoine Hilhorst, PhD Student, Institute of Mechanics, Materials and Civil Engineering, UCLouvain
11:35 – 12:00 – Open time for discussion
About the event topic
The fracture toughness quantifies the amount of energy per unit area needed to break the fracture process in front of a crack preexisting in the material. The ASTM E1820 describes the standard procedure to evaluate the fracture toughness of ductile engineering materials, by means of the traditional J-integral and Crack Tip Opening Displacement (CTOD) measurements. Nonetheless, it is intended to plane strain fracture toughness characterisation and the defined specimen thickness requirements are not satisfied for thin sheets (1-3 mm).
Alternative standards were developed later for the evaluation of the resistance to stable crack extension of thin-gauge materials, the ASTM E2472 and the ISO 22889. However, those standards methodologies are complex and involve exhaustive specimen preparation, rigorous data treatment and the measurement of the crack advance during the tests, which is one of the main difficulties in fracture toughness measurement.
Non-standard tests, such as the Essential Work of Fracture (EWF) methodology, offer a simpler solution for the determination of the fracture toughness of thin metal sheets. The EWF method has been extensively used to characterise the fracture resistance of sheet materials for engineering applications: polymers, aluminium alloys, steel, etc.