ADDIS ABABA UNIVERSITY INSTITUTE OF TECHNOLOGY SCHOOL OF MECHANICAL AND INDUSTRIAL ENGINEERING Finite Element Analysis and Optimization of Single Cylinder Engine Crankshaft for Improving Fatigue Life A Thesis Submitted to the Graduate School of Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Masters of Science In Mechanical Engineering (Mechanical Design) By Tamana Dabasa Advisor Dr. Daniel Tilahun June, 2016