Discussion Forum

Here we will show two different results in simulation but in the same boundary condition(BC). So it must be something wrong. To the geomertry, two Al cicles r=0.43m in a EP rectangular 1*2m, we apply the prediscribed displacement at the left boundary of the rectangular, and apply the periodic boundary condition(PBC) at the up and down boundaries. In the end, we caculate the frequency domain problem, and discuss the deformed mode in 1440Hz. There are two PBC we can consided, the continuity and the Floquet periodicity BC. And we know that when kx=ky=0 in the Floquet periodity, the two BC are equivalent and we can get a same result, a same deformed mode. Now, we will apply each BC, the continuity or the Floquet periodicity(kx=ky=0) in each calculation. It means, we make the simulation with the continuity BC firstly, and then we only exchang the Floquet periodicity BC from the continuity BC. we can predict the two results are similar. But when we exchange the continuity BC from the Floquet periodicity BC again. It shows a very different result. So we suspect the fault occures in the echanging process, maybe it's a bug of the software. I'm not sure. So we ask for help here, to discuss this problem. We get the same results in different comsol version 4.4, 5.2 or 5.2a. Thanks a lot, if you can give ant help.