[drumm_ing]

hello everyone, I am writing to you because I would need to model what I have shown in the image scheme. Specifically, I need to propagate ultrasonic waves on a deformed body, due to a load F. I would leave the comsol condition of elastic predeformation alone for now.
I am trying but find some difficulty also due to the different scales of analysis in relation to the relative tolerance that the two loading conditions require.

At first a load ramp that takes F from 0 N to a constant level over time (FIG 1 and step 1 ramp) range (0 s,0.1 s,90 s). This F then must remain constant (FIG 2 and step 2 constant) (90 s,0.1 s,100 s). So far the direct solver works with a relative tolerance of 0.01. Here the first problem happens due to the concatenation of the first two steps, in FIG step 2 constant we see the oscillation of the solution of the displacements around a value of -3.28e-6 m.

Next I would like to apply the wave as one a prescribed displacement (a kind of transducer simulation) but the solver fails to solve the problem by varying the relative tolerance, even down to 1e-14. Only convergence errors appear. The time dependent in this case should last 3 μs so I had set the range range(100000000 μs, 0.003μs ,3+100000000+3 μs).


How can I do this?
Thank you very much

[Jason967]

It sounds like you're facing challenges with modeling ultrasonic wave propagation in a deformed body under varying load conditions in COMSOL; consider refining your mesh and adjusting the solver settings, such as increasing the maximum number of iterations or using a different solver approach, to improve convergence.

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