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Analysis of the low-blow charpy test

 
: Winkler, S.; Michael, A.; Lenkey, G.B.

Walle, E. van ; European Structural Integrity Society -ESIS-; Belgian Nuclear Research Centre:
Evaluating material properties by dynamic testing. Papers presented at the ESIS TC5 Workshop on the Physical Understanding and Use of Material Properties Determined by Dynamic Testing and Standards
Bury St. Edmunds: Mechanical Engineering Publications, 1996 (ESIS publication 20)
ISBN: 1-86058-004-1
pp.207-233
Workshop on the Physical Understanding and Use of Material Properties Determined by Dynamic Testing and Standards <1994, Mol, Turnhout>
English
Conference Paper
Fraunhofer IWM ()

Abstract
Low-blow experiments carried out with a Charpy machine and with an elastically behaving, strain gauge instrumented, high strength steel test piece do not appear to behave elastically in the sense that the input energy is not completely recovered by the repelled hammer. Energy losses of more than 30 percent have been measured. The analysis shows that about 1/3 of the losses are absorbed by the sample and 2/3 by the C-shaped hammer blade of this machine. Elastic oscillations of the sample and of the hammer blade are initiated and keep this energy trapped for a long time. Spreadsheet procedures are used for data evaluation. It is shown that due to these effects the common evaluation procedures necessarily lead to considerable errors in sample bending and Charpy energy determination. It seems that the correct sample-related data can he separated only from the total set of data when the correlated quantities are directly determined at the sample under test.

: http://publica.fraunhofer.de/documents/PX-3850.html