I'm still not sure that the program is taking into account the BF command. If I try to run your original code and then the same but without BF command, final results are the same (i.e. only Dy effect is applied on the structure and veasible with the command plnsol,u,sum).
Could you please confirm that you find the same solution too?
There must be something wrong in the definition of LINK180 when an element is oriented with an inclined position (because DT works if nodes are oriented along x,y or z axes).
Probably I need to find another way to simulate the elongation of the bar if I want also its rotation. I was thinking about using a spring element, but I'm not sure it could work only in tension. Do you maybe know if there are other possibilities?
Thank you as usual for your help.