Accessible Unlicensed Requires Authentication Published by De Gruyter May 26, 2013

Assessment of Fracture Behaviour under Impact Loading with Simultaneous Recording of Acoustic Emission

Bewertung des Bruchverhaltens unter schlagartiger Beanspruchung mit simultaner Aufzeichnung der Schallemissionen
Marcus Schoßig, Christian Bierögel and Wolfgang Grellmann
From the journal Materials Testing

Abstract

The objective of this paper is the assessment of the toughness of glass fiber-reinforced polypropylene and polybutene-1 by means of fracture mechanics concepts to describe the resistance against unstable crack initiation for these materials. In addition, the acoustic emissions during the instrumented Charpy impact test were recorded, which allows the characterization of the damage kinetics. For this purpose, the recorded transient signals of the acoustic sensor were analyzed with the wavelet transform. Thus, it was possible to describe the onset of the damage in the time domain, as well as the load Fs and the corresponding deflection fs. In dependence on the bonding conditions of the materials, the damage onset was detected for polypropylene before and for polybutene-1 at the transition from elastic to elastic-plastic behaviour.

Kurzfassung

Ziel des vorliegenden Beitrages ist die Bewertung der Zähigkeit von glasfaserverstärkten Polypropylen und Polybuten-1-Werkstoffen mit Hilfe bruchmechanischer Konzepte zur Beschreibung des Widerstands gegenüber instabiler Rissinitiierung. Zusätzlich wurden die schädigungssensitiven Schallemissionen im instrumentierten Kerbschlagbiegeversuch aufgezeichnet, um eine Bewertung der Schädigungskinetik unter schlagartiger Beanspruchung durchzuführen. Hierzu wurden die aufgezeichneten Hochfrequenzsignale des akustischen Sensors mit Hilfe der Wavelet-Transformation in den Frequenzraum überführt. Damit konnte der Schädigungsbeginn durch die Messgrößen Kraft Fs und Durchbiegung fs bestimmt werden. In Abhängigkeit von den Haftungsbedingungen der Werkstoffe wurde der Schädigungsbeginn für Polypropylen vor und für Polybuten-1 beim Übergang vom elastischen zum elastisch-plastischen Werkstoffverhalten beobachtet.


Dr.-Ing. Marcus Schoßig was born in Halle (Saale) in 1978. He studied material science from 1998 until 2003 at the Martin-Luther University Halle-Wittenberg, Germany and received his PhD in 2010. At the moment he works at the Hochschule Merseburg, Germany – University of Applied Sciences on the field of fiber-reinforced plastics, nondestructive testing as well as aging of polymers by artificial weathering.

Dr.-Ing. Christian Bierögel was born in 1953 in Dresden. From 1974 until 1978 he studied material science at the TH Leuna-Merseburg, Germany and received his diploma here in 1978. He finished his PhD in 1984. Since 1992 he is senior associate scientist in the field of material testing and the leader of the accredited test laboratory “Mechanische Prüfung von Kunststoffen”. He works on the field of nondestructive testing, hybrid methods of polymer diagnostics as well as polymer testing for medicine and pharmacy.

Prof. Dr. Wolfgang Grellmann was born in 1949 in Ammendorf, Germany and studied physics at the Martin-Luther University Halle-Wittenberg, Germany from 1968–1974. He received his diploma in physics 1974 and the PhD in 1978 with the work “Determination of micro hardness on glasses and ceramics” at the same university. In 1986, he received his habilitation in material science with the work “Evaluation of crack resistance behaviour of polymers with fracture mechanical values” and since 1995 he is head of the professorship “Materials testing/materials diagnostics” at the Department/Centre of Engineering Sciences at the Martin-Luther University Halle-Wittenberg, Germany. Prof. Grellmann is manager of the “Polymer Service GmbH Merseburg”, scientific-technical director of the “Kunststoff-Kompetenzzentrum Halle-Merseburg” and chairman of the foundation “Akademie Mitteldeutsche Kunststoffinnovationen” as well as an expert of the “Industrie- und Handelskammer Halle-Dessau”.


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Published Online: 2013-05-26
Published in Print: 2013-02-01

© 2013, Carl Hanser Verlag, München