Learning Forum

[TTT]

Hello, I work on my master thesis and am a novice in CAD and FEM. I try to simulate ultrasonic metal welding process but currently stuck with boundary conditions.

The main problem at the moment is that I cannot apply the vibration motion to my system.

In ultrasonic welding an upper metal sheet slides along the x-axis on top of another one with a frequency of 20 kHz.

In some paper I found a formula: Ux = Xsinwt,

where X is the amplitude of vibration (27.5 micrometers). E.g., upper sheet first goes to the left direction, then returns to the initial position, then goes to the right direction and so on.

w = 2πf , f is 20 kHz.

Welding time in the real process is about 1-2 s, but for saving computational time it could be 0,1 s in Ansys for the beginning.

So I need to apply this equation in Ansys as a displacement. Perhaps it usually applies with APDL but do not understand how.

[1shan]

If you are performing a harmonic analysis note that all loads and displacements are sinusoidally time varying. And the solution is the steady state response to these loads. Given that it wont be possible to input a left-right time varying displacement in a harmonic analysis. However, you could perform multiple analysis where the force location is changing and get the steady state results for each. If you want to insert a displacement at a fixed location right click on harmonic response>insert displacement and then specify the maximum amplitude (27.5) in the required direction, along with the desired frequency range under analysis settings. You could specify space time varying loads in a transient analysis but for your case I don't think it would be feasible since the time step required is too small.
Regards Ishan.