Accessible Requires Authentication Published by De Gruyter May 26, 2013

Approximation of Damage Accumulation in Fibre Reinforced Polymers

Approximation der Schadensakkumulation in faserverstärkten Polymeren
Georgi Zachariev
From the journal Materials Testing

Abstract

A unified approach for the derivation of the known equations describing damage accumulation as a result of loading of fibre-reinforced polymers is proposed. The investigated materials are short glass fibre-reinforced polyoxymethylene (GF/POM) and long glass fibre-reinforced epoxyresin (GFRP). The damage structures themselves consist of the accumulation of additional internal surfaces within the entire material volume as measured by small angle scattering X-ray refractometry. On the basis of the concept for a loading percentage under creep, damage accumulations applying short-term and long-term loading are compared. It is shown that for the investigated materials our approximations by a double exponent function are more effective than the approximations according to Weibull. It is also shown how the coefficients of the double exponent cumulative function can be found.

Kurzfassung

Ein einheitlicher Ansatz zur Herleitung bereits bekannter Gleichungen zur Beschreibung der Schadensakkumulation in faserverstärkten Polymeren unter Belastung wird aufgestellt. Die untersuchten Werkstoffe sind Glas-Kurzfaser-verstärktes Polyoxymethylen (GF/POM) und lang Glasfaserverstärktes Epoxidharz (GFK). Als relevante Schädigung wird die Akkumulation zusätzlicher innerer Oberflächen im Werkstoff angesetzt, wie sie mit dem Kleinwinkel-Streuverfahren der Röntgen-Refraktometrie ermittelt werden. Die Akkumulationen der Schädigung unter Kurz- und Langzeitbelastung werden als Funktion des Belastungsgrads verglichen. Für die untersuchten Werkstoffe sind die Approximationen der Schädigung nach unserer Gleichung mit doppeltem Exponenten erfolgreicher als die der kumulativen Funktion nach Weibull. Es wird auch gezeigt, wie die Koeffizienten der kumulativen Funktion mit doppeltem Exponenten bestimmt werden können.


Prof. Dr.-Ing. habil. Georgi Zachariev, born 1939, has studied civil engineering at the Technical University of Sofia, Bulgaria and has focused on material science and mechanics. Since 1963 he is collaborator and since 1995 director of the Central Laboratory of Physico-Chemical Mechanics at the Bulgarian Academy of Science in Sofia, Bulgaria. He has received his Dr.-Ing. in 1968, his DSc. in 1994. and habilitation in 1975 and 1996. Furthermore, he holds a fellowship of the Alexander von Humboldt-Foundation. He has recently retired.


References

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

© 2013, Carl Hanser Verlag, München