Torsional Spring Defination

Dear Friends,

I am going to define a torsional spring with specified damping and elasticity at the corner of two cubes (Please See.

A concentrated load is applied to the opposite side of the  upper cube and the lower cube is fully fixed and cause the upper cube rotate along the connector.

I want to know how is it possible to define a torsional spring and joined both cubes with them.

 

Thanks