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I am trying to model a cylindrical joint. Like an actuator that can only translate in 1 DOF. My cylinder joint length is ~10 inches and I am modelling it ONE CBUSH Element (BAR 2-topology)

1) Is it correct to use 1 element and BAR2 topology?
2) I am giving it PBUSH Element type property and defining my 6 spring constant to determine ​the stiffness of the cylindrical joint. Is it a correct approach?
3) Since, it will be cylinder joint, I am defining a local LBC to restrict the motion in other 2 axes (so it only translates in one axis). What should I do with the Rotational DOF? little confused on this
 
Let me know if my approach is good, or is there a better way to tackle this. Thanks