Hello, I am running  a harmonic study on a pipe in which one end is fixed in all directions and the opposite end is forced in one direction. When I examine the sum of the reaction forces in the direction that the pipe is forced at the fixed end, I get an interesting answer. At zero frequency (which should pertain to the static case if my theory is correct), the reaction forces add up to around 4 N in the X-direction when only 1 N in the X-direction is applied at the opposite end. When I run a static study for the pipe under the same conditions, the reaction forces add up -1 N which seems correct. Anyone have any insight? *Model picture attached