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In this paper thermal analysis of sheetmetal during ultrasonic welding

are studied. Patented in 1960, ultrasonic welding for metals, has received

significant research and there have been advances in the technology.

Because of these advances, the process has been developed into apractical production tool .Ultrasonic welding process is a rapid

manufacturing process used to weld thin layers of metal at low

temperatures and low energy consumption. In ultrasonic welding, high

frequency vibrations are combined with pressure to join two materials

together quickly and securely, without producing significant amount of

heat. During ultrasonic welding of sheet metal, normal and shear forces

act on the parts to be welded and the weld interface. These forces are the

result of ultrasonic vibrations of the tool, pressed onto the parts to be

welded.Experimental results have shown that ultrasonic welding is a

combination of both surface (friction) and volume (plasticity) effects.

. The thermo-mechanical analysis of an ultrasonic spot welding process was performed using

developed finite element models. specimens during welding were successfully obtained from the

analysis and validated by physical tests. It was shown that the effect of frictional heating on theplastic deformation of sheetmetal during ultrasonic spot welding was significant and should be

included in the analysis of the welding process in order to achieve good correlation with the

physical phenomenon.

In the presented work, a very first attempt has been made to simulate

the ultrasonic welding of metals by taking into account both of these

effects (surface and volume). A phenomenological material model has

been proposed which incorporates these two effects .In this study a

model for the temperature distribution during welding are presented.

With the knowledge of the forces that act at the interface it is possible to

control weld strength and avoid sonotrode welding (sticking of the

sonotrode to the parts). The presented finite element model is capable of

predicting the interface temperature during welding and their influences

in the work piece, sonotrode and anvil. The study also included the

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effect of clamping forces, material thickness and coefficient of friction

during heat generation at the weld interface.

. The thermo-mechanical analysis of an ultrasonic spot welding process was performed using

developed finite element models. Temperature

time histories of aluminium specimens duringwelding were successfully obtained from the analysis and validated by physical tests. It was

shown that the effect of frictional heating on the plastic deformation of aluminium during

ultrasonic spot welding was significant and should be included in the analysis of the weldingprocess in order to achieve good correlation with the physical phenomenon.