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Material Composition Optimization of FGM Plates Containing a Hole

Hassan S. Hedia, Saad M. Aldousari and Tawfik T. El Midany
From the journal Materials Testing

Abstract

By definition, Functionally graded materials (FGM) are new advanced composite materials which are used to produce components featuring engineered gradual transitions in microstructure and/or composition. FGMs permit tailoring of material composition so as to derive maximum benefits from their inhomogeneity. The aim of the study behind this contribution is to optimize the composition variation between the ceramic and the metal in order to minimize the maximum stress concentration around the hole in a plate made of FGMs in case of the plate is subjected to pressure, heating or both pressure and heating. The finite element method (FEM) has been used to optimize the material composition of functionally graded materials made from Al 1100 as the metal portion and SiC as the ceramic portion using the ANSYS package. The objective has been to minimize the stress concentration factor around a hole in a plate expressed by the ratio between the principal stress calculated by the ANSYS and the applied stress at different volume fractions of the metal and the ceramic. The investigations have shown that when applying pressure or heating to the plate the optimum for minimizing the stress concentration is to have a ceramic-rich plate and when the plate is subjected to both pressure and heating the optimality is to have a metal-rich plate.

Kurzfassung

Optimierung der Zusammensetzung von Gradientenwerkstoffen für gelochte Platten. Definitionsgemäß sind Gradientenwerkstoffe (Functionally Graded Materials (FGM)) neue Verbundwerkstoffe die zur Produktion von Komponenten verwendet wwerden, die graduelle Übergänge in ihrer Mikrostruktur und/oder Zusammensetzung aufweisen. Gradientenwerkstoffe lassen einen Zuschnitt der Materialzusammensetzung in einer Weise zu, dass aus ihrer Inhomogenität die größten Vorteile gezogen werden können. Die diesem Beitrag zugrunde liegende Studie hatte zum Ziel, die Variation der Verbindung zwischen Keramik und Metal so zu optimieren, dass die maximale Spannung in einer Platte aus einem solchen Gradientenwerkstoff, die Druck und Temperatur sowie beiden Beanspruchungen zusammen ausgesetzt wurde, zu minimieren. Um die Komposition eines Werkstoffes aus Al 1000 als metallischen und SiC als keramischen Anteil zu optimieren, wurde die Finite Elemente Methode (FEM) unter Verwendung des Programmpaketes ANSYS angewendet mit dem Ziel, den Spannungskonzentrationsfaktor um ein Loch in einer Plate zu minimieren. Der Spannungskonzentrationsfaktor wurde hierbei als das Verhältnis zwischen der numerisch berechneten Hauptspannung und der aufgebrachten Spannung definiert, wobei verschiedene Volumenanteile des Metals und der Keramik betrachtet wurden. Die Untersuchungen zeigten, dass unter einer Druckoder Temperaturbeanspruchung das Optimum hinsichtlich der Minimierung der Spannungskonzentration sich dann einstellt, wenn bei Druck- oder Temperaturbeanspruchung eine Platte mit einem hohen Keramikanteil und bei Koppelung beider Beanspruchungen eine Platte mit einem hohen Metallanteil vorliegt.


Prof. Dr. Hassan S. Hedia, born in Egypt in 1959, is a professor of materials and solid mechanics. He is working in King Abdulaziz University (KAU), KSA. He received his BSc in 1981 at the Mechanical Engineering Department of the Cairo University, Egypt. In 1989, received his MSc 1989 in Production Engineering at the Mansoura University, Egypt. In 1996, he achieved his PhD in the Mechanical Engineering Department of the Leeds University, United Kingdom, and at the Mansoura University, Egypt via the channel system. His fields of interest are advanced materials, fracture mechanics, stress analysis and biomechanics.

Dr. S. M. Aldousari, born in KSA in 1956, is an Assistant Professor at the King Abdulaziz University (KAU), KSA. He received his BSc in 1980 at the Mechanical Engineering Department of the Collage of Engineering, King Abdulaziz University, KSA. He achieved both, the PhD and MSc at the Bradford University, United Kingdom. His field of interest is manufacturing technology.

Prof. Dr. T. T. El Midany, born 1940 in Egypt, is a professor for Manufacturing Technology at the Mansoura University, Egypt. He received his BSc degree in Production Engineering in 1966 at the Helwan Institute, Egypt. Further on, he achieved his Postgraduate Diploma in 1976, his MSc degree in 1977, and his PhD degree in 1979 at Manchester University, United Kingdom. His field of interest is CAD/CAM and CNC Machines.

Eng. M. Kamel, born in Egypt in 1978, is Assistant Lecturer at Labour University, Egypt. She received her BSc degree in 2001 and her MSc degree in 2007 in Production Engineering at the Mansoura University, Egypt. Her field of interest is advanced materials and stress analysis.


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Published Online: 2013-05-26
Published in Print: 2010-11-01

© 2010, Carl Hanser Verlag, München