prksh's blog

Dear all,

I am doing 3d modal analysis using Ansys. When I checked the "Effective Mass-EM" for rotational dof, it is very large compared with total mass of the model. can you share your ideas for this question.Run simulation upto 90% of EM in all dof or only in translation dof or only for 2 translation dof (any rule of thumb)?

Thanks in advance.

Dear All,

I am doing modal analysis using ANSYS.

1) why every one is particularly taking first six modes of vibration for their results?. Is the probability of occurance of the first six exitation is very higher?

2) But how the frequencies for first 6modes are in ascending order ?

3) Just for verification, Assume ,

a) the earthquake frequency is around 22 to 25Hz.

b)Obtained natural modes for a system 5,7,8.8,9,10.2.

c) so here I need to extend my analysis to furter modes near to 22 to 25hz.