Meshing of Fluid structure interaction in a blood vessel

hi all,

I am doing a FSI steady state analysis of blood vessel, the fluid domain surrounds by 4 layers (solid domains). the thickness of fluid domain is in millimeters but solid domains have diameters in micro meters. I tried different mesh like free triangular, mapped, quad and edge type but the solution gives error of negative square power error . But when i apply free triangular , there are too much elements are created that my computer hangs up.

Can anyone can help me , i have attached file of 4.2a version


regards

Ali