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Lectures: Ahmad Kamal Ariffin und Yasothorn Sapsathiarn

Lectures: Ahmad Kamal Ariffin und Yasothorn Sapsathiarn

Fatigue crack growth for a metal forming structural component using deterministic-probabilistic-experimental analysis, October 16th, 13:00, Room 010 (MZ 2), Appelstr. 9 A

Ahmad Kamal Ariffin    
Professor at the Department of Mechanical and Materials Engineering, UKM, Malaysia  

Fatigue crack growth for a metal forming structural component using deterministic-probabilistic-experimental analysis

Abstract

The aim of this talk is to highlight an overview of fatigue crack growth for a metal forming structural component using deterministic-probabilistic-experimental analysis. A finite element model with adaptive remeshing technique is used to accommodate changes in geometry during the powder compaction and fracture process. Friction between crack faces is modelled using the six-node isoparametric interface elements. Based on the fracture criterion of soil in compression, a displacement-based finite element model has been developed to analyze fracture initiation and crack growth. The crack growth and its direction are determined by the calculated stress intensity factors as the maximum circumference theory is also being involved in determining the direction. A simple square prismatic plate with surface and embedded crack subjected to a fatigue load is considered for fracture analysis. Monte Carlo and Latin Hypercube sampling methods are employed. The results from the strategies are compared to highlight the advantages of each sampling strategy. The distributions of the initial surface crack length and depth are extracted from the fatigue tests. The accuracy and consistency are evaluated. The comparison between the stress intensity factors obtained from the finite element, theoretical analysis and experimental work are compared.     

Biography

Ahmad Kamal Ariffin is a Professor at the Department of Mechanical and Materials Engineering, UKM.  He graduated with a Bachelor’s in Mechanical Engineering from UKM in 1990.  He then worked as an engineer before joining the Dept. of Mechanical and Materials Engineering, UKM and continued his studies in 1992.  End of 1995, he received his PhD from University of Wales Swansea under the Mechanical Engineering Department and Institute of Numerical Methods in Engineering.  Ahmad Kamal Ariffin teaches Mechanics of Materials, Computational Methods in Engineering and Finite Element Methods.

His specialty is in the computational method in engineering under the area of powder mechanics, fracture mechanics, friction, corrosion, finite element/discrete element and parallels computations. He is a Fellow of the Institute of Materials Malaysia, founder of Malaysian Association of Computational Mechanics and also a member of International Association of Computational Mechanics (IACM). Recently, he received an Apple Distinguished Educator as a recognition for being part of the global community of educators using apple technology in and out of the classroom.

 

 

 

Yasothorn Sapsathiarn    
Assistant professor at the Department of Civil and Environmental Engineering, Mahidol University, Thailand     

Dynamic soil models for backcalculation of material properties from falling weight deflectometer deflection data

Abstract

Falling Weight Deflectometer (FWD) test is one of the most widely used methods for in-situ nondestructive evaluation of pavement/soil properties and examination of the structural condition of in-service pavements. A dynamic half-space model is employed in the present work for backcalculation of engineering soil properties from the FWD data. The advantages, limitations and the reliability of the backcalculation elastic moduli evaluated from dynamic soil model are discussed. Selected numerical results are presented to portray the influence of governing parameters, for example, the presence of shallow stiff layer and the mass density of soil material on dynamic backcalculation of the soil elastic modulus. The investigation presented in this study provides a better understanding of dynamic backcalculation processes which is essential for the development of dynamic backcalculation program and its applications.    

 

Biography

Yasothorn Sapsathiarn is currently an assistant professor at the Department of Civil and Environmental Engineering, Mahidol University, Thailand. Dr. Yasothorn Sapsathiarn received the Ph.D. degree in Civil Engineering from Chulalongkorn University, Bangkok, Thailand, in 2009. He has been a Postdoctoral Research Fellow at the Faculty of Applied Sciences, Simon Fraser University, BC, Canada (2009-2012). Dr. Sapsathiarn’s research interests are in Applied Mechanics, with particular emphasis on the Mechanics of Advanced Materials and Structures.

 

Wednesday, October 16th, 2019, 1 pm
Building 3408 (Appelstraße 9a), Room 010 (MZ 2)