Modelling and Characterization of Ultrasonic Consolidation Process of Aluminium Alloys
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1079-N09-05
Modelling and Characterization of Ultrasonic Consolidation Process of Aluminium Alloys Amir Mohammed Siddiq, and Elaheh Ghassemieh Mechanical Engineering, University of Sheffield, Mappin street, Sheffield, S1 3JD, United Kingdom ABSTRACT Ultrasonic consolidation process is a rapid manufacturing process used to join thin layers of metal at low temperatures and low energy consumption. In this work, finite element method has been used to simulate the ultrasonic consolidation of Aluminium alloys 6061 (AA-6061) and 3003 (AA-3003). A thermomechanical material model has been developed in the framework of continuum cyclic plasticity theory which takes into account both volume (acoustic softening) and surface (thermal softening due to friction) effects. A friction model based on experimental studies has been developed, which takes into account the dependence of coefficient of friction upon contact pressure, amount of slip, temperature and number of cycles. Using the developed material and friction model ultrasonic consolidation (UC) process has been simulated for various combinations of process parameters involved. Experimental observations are explained on the basis of the results obtained in the present study. The current research provides the opportunity to explain the differences of the behaviour of AA-6061 and AA-3003 during the ultrasonic consolidation process. Finally, trends of the experimentally measured fracture energies of the bonded specimen are compared to the predicted friction work at the weld interface resulted from the simulation at similar process condition. Similarity of the trends indicates the validity of the developed model in its predictive capability of the process. INTRODUCTION Ultrasonic consolidation is a rapid manufacturing process in which ultrasonic energy is used to create a solid state bond among different layers of composites, metals and alloys. It is a solid state joining process with low temperature and requires low process energy. Main advantages of ultrasonic consolidation include, absence of liquid-solid transformations, no atmosphere control required, low energy consumption, and low temperature allows embedding of electronics, such as sensors and actuators. Ultrasonic power required to join two components increase as the size (thickness) of the specimens being joined increase. Therefore, this limitation of thickness has restricted its use to microelectronics industry. Typical applications include, metal encased sensors, metal composite shields, fibre reinforced metal/matrix composites, satellite panels, electrical and electronic joints. A number of researchers [1-6] have performed experimental studies on ultrasonic consolidation process. However, very little effort has been made to develop theoretical models to simulate ultrasonic consolidation process [7]. In all the theoretical and simulated works, the effect of ultrasonic vibration is attributed in the friction coefficient rather than taking into account both surface and volume effects. In the presented work, a material
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