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A Three-Dimensional Finite Element Analysis of the Stress Intensity Factors for Different Fracture Modes of Homogeneous Bimaterial

Dreidimensionale Finite-Element-Analyse der Belastungsintensitätsfaktoren für verschiedene Bruchmodi von homogenen Bimaterial
Hassan S. Hedia, S. M. Aldousari and N. Fouda
From the journal Materials Testing

Abstract

The failure of cracked components is governed by the stresses in the vicinity of the crack tip. The singular stress contribution is characterized by stress intensity factors. The stress intensity factors depend on the geometry of the component and on loading condition. This paper addresses the evaluation of stress intensity factors (SIFs) of opening, shearing and tearing modes for compact tension specimens for bonding homogeneous materials. The aim of this work is to find the optimal pre-cracked length, crack notch radius, and crack notch angle in order to eliminate the effect of them on the SIF and then on the fracture toughness. To achieve this goal, a three- dimension finite element analysis (FEA) model using the ANSYS program is constructed for specimens made of homogeneous materials such as stainless steel bonding with epoxy as a filler material. The effects of notch angle, notch tip radius and pre-crack length on the stress intensity factors are studied for different fracture modes. The results for the stress intensity factors KI, KII and KIII are obtained using the linear elastic fracture mechanics (LEFM) approach.

Kurzfassung

Der Ausfall von Komponenten mit Rissen wird durch Belastungen in der Nähe der Rissspitze bestimmt. Ein einfacher Belastungsbeitrag ist durch Belastungsintensitätsfaktoren gekennzeichnet. Die Belastungsintensitätsfaktoren hängen von der Komponentengeometrie und der Beanspruchungsbedingung ab. Der vorliegende Artikel behandelt die Auswertung von Belastungsintensitätsfaktoren (Stress Intensity Factors, (SIFs) des Öffnungs-, Scher- und Rissbildungsmodus für kompakte Spannungsproben zum Verbinden homogener Materialien. Das Ziel dieser Untersuchung ist die Ermittlung der optimalen Länge vor dem Riss, des Risskerbenradius und des Risskerbenwinkels, um die Auswirkung davon auf den SIF und damit auf den Bruchwiderstand zu beseitigen. Dazu wird ein dreidimensionales Finite-Element-Analyse-Modell mit dem Programm ANSYS für die Proben homogener Materialien wie Edelstahlverbindungen mit Expoxid als Füllmaterial erstellt. Die Auswirkungen von Kerbwinkel, Kerbspitzenradius und der Länge vor dem Riss auf die Belastungsintensitätsfaktoren werden für verschiedene Bruchmodis untersucht. Die Ergebnisse der Belastungsintensitätsfaktoren KI, KII und KIII werden mithilfe des Ansatzes für lineare elastische Bruchmechaniken (Linear Elastic Fracture Mechanics, LEFM) erhalten.


Prof. Dr. Hassan S. Hedia, born 1959, is professor of materials and solid mechanics. He is working at the King Abdulaziz University, KSA. He achieved his BSc in 1981 from the Mechanical Engineering Department at the Cairo University, Egypt and his MSc in 1989 at the Mansoura University, Egypt. His PhD achieved Prof. Helal from the Mechanical Engineering Department at the Leeds University, UK and the Mansoura University, Egypt under channel system. His fields of interest are advanced materials, fracture mechanics, stress analysis and biomechanics.

Dr. S. M. Aldousari, born 1956, is an assistant professor at King Abdulaziz University, KSA. He achieved his BSc in 1980 from the Mechanical Engineering Department at the Collage of Engineering, King Abdulaziz University, KSA and his PhD and MSc in 1993 from the Bradford University, United Kingdom. His field of interest is manufacturing technology.

Dr. N. Fouda, born 1973, is an assistant professor at the Mansoura University, Faculty of Engineer, Mansoura, Egypt. She received her BSc (production Eng,) in 1995 from the Mansoura University, Egypt and her MSc in 2000, her PhD in 2006 from the Mansoura University, Egypt. Her fields of interest are optimum design, stress analysis and mechanics of materials.


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Published Online: 2013-05-26
Published in Print: 2010-03-01

© 2010, Carl Hanser Verlag, München