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Institut für Struktur- und Funktionskeramik

Notched Roller Test (NRT) – Strength Testing

Description

A new strength test for ceramic rollers (cylinders) is presented, following the idea of the previously published and since that time standardized notched ball test. The specimen is prepared by cutting a long narrow notch along the symmetry plane of the roller, perpendicular to the end faces. By applying compressive forces perpendicular to the notch, tensile stresses are induced in the outer surface region of the roller opposite to the notch, mainly pointing in tangential direction with respect to the roller axis. The stress amplitude is proportional to the applied force and depends also on the test geometry and the Poisson´s ratio, which has been analysed carefully with FE methods.

Strength tests have been performed on two different qualities of commercial silicon nitride rollers of 10 mm diameter and length. According to their specification a significant difference in the strength has been obtained.

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Terms of Use

This tool is provided by ISFK to promote the use of the NRT-test. The practical use of the test is simple, but its evaluation requires FEM-calculations which we make available here. The use of the tool is free of charge.

If you use data generated with the applet (strength) for your work, please cite:

More information, references and application examples

S. Strobl, P. Supancic, O. Schöppl, R. Danzer: "A new Strength Test for Ceramic Cylinders – The Notched Roller Test", Journal of the European Ceramic Society 2013 (accepted)