Some studies on mechanical properties of friction stir butt welded Al-6082-T6 plates
The conventional fusion welding of cast aluminium alloys is generally difficult due to some common defects such as porosity, oxide inclusion, and hot cracking, which in turn reduce the weld strength. In recent years, friction stir welding (FSW) was found to be very effective for the welding of various wrought aluminum alloys. This paper investigates a metal joining process called Friction Stir Welding (FSW), an innovative welding technique invented by TWI Ltd. in Great Britain in 1991. The purpose of the paper is to study the effects of process parameters in the butt welding of Al-6082-T6 plates with a thickness of 3 mm. Joints were made using different combinations of tool rotation speed, welding speed, and axial force, each at different levels. The quality of weld zone was analyzed using macrostructure. The study aims in identifying the process parameters of welding the Al6082 alloy and the effect of welding speed on the weld performance of the joint was investigated by conducting tensile and hardness tests.
Ultrasonic waves time series analysis for damage detection and assessment in composite and metallic structures
Thesis. M.E. American University of Beirut. Department of Mechanical Engineering, 2016. ET:6493
Dimensional Errors of Fixtures, Locating and Measurement Datum Features in the Stream of Variation Modeling in Machining
Machining processes are usually multi-station processes involving a large number of operations and several locating datum changes. Machining errors are thus introduced, transformed and accumulated as the workpiece is being machined. This paper introduces procedures for expressing the influence of errors in fixtures, locating datum features and measurement datum features on dimensional errors in machining. These procedures are essential in the derivation of the Stream of Variation model of dimensional machining errors using the CAD/CAPP parameters of the machining process. The linear state space form of the Stream of Variation model allows for advanced control theory achievements to be employed in formal solutions to problems in multi-station machining. Modeling procedures presented in this paper were experimentally verified in machining of an automotive cylinder head.