The figure shows the free body diagram around the flange at B. The free body diagram cuts across the rod above and the post below. The axial forces on the rod and the post are F subscript 1 directed vertically upwards and F subscript 2 directed vertically downwards respectively. The parameters corresponding to the rod are A subscript 1, L subscript 1, alpha subscript 1 and E subscript 1.

Write the force-deformation relationship for each member.

For member (1), the force-deformation relationship is:

δ1=F1L1A1E1+α1TL1