Harmonic analysis with a crack?

Hello everybody,

                          I am trying to perform a harmonic analysis of a material sample (say a simple 2D plate) with an edge crack in it using 'Ansys R16'. I see that under sinusoidal loading condition, the two crack faces open or close and interpenetrate (after closing which is not possible practically).

          1.  I believe, stiffnesses of the crack faces change during interpenetration and so the results are not credible anymore.

          2.  I also cannot define non-linear contact behaviour (between the two crack faces) in a linear (harmonic) analysis.

How do I overcome this problem?

Bigger idea is to fit the frequency response result from the simulation with that of the experimentally determined response.

I am more than ready to provide further information if required.

Thanks in advance for your time. !!

Regards,

Shreeraman S