Plenary Lecture

Life-Time Prediction of Structural Parts under
Variable Creep Conditions

Professor Dimitrios G. Pavlou
Technological Institute of Halkida (TEI-Halkida)
Faculty of Mechanical Engineering
34400 Psahna, Halkida, Evoia
Greece
E-mail: dpavlou@teihal.gr

Abstract: The life time of structural components under variable stress and temperature creep conditions is difficult to be estimated. Although a lot of models describing the micro-mechanisms of creep failure are currently available, above models are not suitable for solving real engineering problems because of using large number of experimental parameters. The present lecture is concerned with the presentation of a non-linear macroscopic model for creep-life prediction of structural elements under step-wised variable stress and temperature conditions. Proposed model has two main advantages: (a) takes into account the previous damage history and the loading order effect, and (b) it is based on results of conventional constant stress and temperature tests. It is shown that the most known of the existing models are particular cases of the proposed model. Theoretical predictions are correlated well with test results for two metallic materials (austenitic steel and aluminum) subjected to high temperatures and square block loading. Comments of the evaluation of the proposed model by other independent researchers are also presented.

Brief Biography of the Speaker:
Dimitrios G. Pavlou is Professor of Metallic Structures and Applied Mechanics in the Faculty of Mechanical Engineering of the Technological Institute of Halkida –TEI Halkida– Greece (website: www.teihal.gr). He earned undergraduate degree in Mechanical Engineering and PhD in Fracture Mechanics at the University of Patras. He has extensive industrial experience in engineering design and many years of experience in teaching Strength of Materials (theory and experimental exercises), Fracture Mechanics, Metallic Structures, Structural Analysis and Material Science at the Hellenic Air-Force Academy, University of Piraeus, University of Patras and Technological Institute of Halkida. He has been the General Manager of the VIOTE S.A. (Viotia’s Prefecture Company for Industrial Development), Head of the Secretary of the Research Centre of the University of Piraeus and Chair of the Faculty of Mechanical Engineering of the Technological Institute of Halkida. Pavlou has been on the Faculty of the TEI of Halkida since 1999 and is currently Visiting Professor in the “Polytechnic” University of Timisoara, Romania. He is: (a) author of numerous research articles in referee journals and international conferences, (b) author of national and international books covering fracture mechanics, metallic structures, damage mechanics and strength of materials, and (c) referee of numerous research works submitted to international journals and conferences. His research interests are: (a) Analytical and Numerical methods in Fracture Mechanics with special emphasis on solution of Boundary Integral Equations (BIE) using Green’s functions and BEM, (b) Damage Mechanics with special emphasis in Fatigue and Creep Damage Accumulation under variable loading as well as life-time prediction of structural parts in service conditions, and (c) Analysis of elastostatic problems using Integral Transforms with special emphasis οn Hankel Transforms.