The display problem of deformation results of folding structure simulation

Hi,

I am new to COMSOL. This model is a folded structure, and its simulation process is: PNIPAM folds the surrounding elastomer board through thermal contraction (the coefficient of thermal expansion is negative), the ideal effect is that it can be folded into a square box, and the surrounding four boards's thermal expansivity is 0, but l see that results → stress → surface → deformation, the surrounding plates are stretched, and it is not clear why or where the problem is.

Thanks!