This paper presents the design of an experimental set-up to mechanically expand T5-6063 aluminum tubes using conical hardened steel mandrels. The effect of the expansion ratio and mandrel angle on the tube wall thickness and drawing force required to expand the tubes as well as failure modes near embedded circular holes are investigated. The experimental study considered four radial expansion ratios of 1.5, 5, 7 and 10% and three mandrel angles of 10, 22.5, and 30 degrees. It was shown experimentally that most of the tubes failed at the 90 degrees position of the hole indicating that the maximum stress concentration takes place at that position as compared to the zero degree location. The experimental study was supplemented by finite element models reflecting the lab tests to determine the drawing force and study the stress concentration around the hole at zero and 90 degrees locations. The finite element analysis took into consideration various parameters such as expansion ratio and mandrel angle. The simulation results, which were calibrated through generated experimental data, confirmed the experimental observations when studying the stress concentration around the hole for various mandrel angles and expansion ratios at 90 degrees angle. The finite element results also showed that the stress concentration is much higher at 90 degrees position where failure occurred in all tested samples as compared to the zero degree angle.BACKGROUND