In this paper, the weldability of AA 5083-H111 (non-heat treatable) and AA 6082-T6 (heat treatable) aluminium alloys, which are widely used in welding fabrication, is compared by analysing the welds obtained from both materials under a large range of welding conditions (varying tool dimensions, rotation and traverse speeds, axial loads and tilt angles) chosen to ensure high welding speeds. The differences in friction stir weldability, assessed by weld defect analysis and weld strength characterisation, will be related to the markedly different plastic behaviours of both base materials. Based on the experimental results, a methodology for determining suitable friction stir welding parameters is proposed.

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A6sfracf-This paper describes a fuzzy classifier for fault diagnosis of valve actuators. The belongingness of a feature vector to the normal class and/or a faulty class of system behavior is described using fuzzy sets. The actual diagnostic task is performed using the fuzzy membership functions for the feature vector to be classified. The theoretical aspects of the classifier are presented. Then the case study -the DAMADICS benchmark flow control valve, is shortly introduced and also the method used to generate the data for designing and testing the classifier. Finally, the simulation results are discussed.