Erik Kostson
Ansys Employee

So this is wrong: "the cumulative mass fraction in 3rd row should equal to the ratio of the effective mass to the total mass since the upper two rows equal zero!!". What you mention here is closer to the ratio of effective mass to total mass for a mode (so last column in the solve.out table)

Please read through my example above it is not the total mass we divided with it is the total effective mass (sum) which is 0.130237 in your example in the Y-dir, and it was 67.9 kg in my example (the total mass in that example is somewhere around 75 kg).

So the cumulative mass fraction in you case up to mode 3 is for the 3 modes: 0/0.130237 + 0/0.130237 + 0.992688E-1/0.130237 = 0.762216 which is what we get.
So the value in the solve.out from the solver is of course correct.