Eccentriciyt in mass matrix

[Son_new]

Dear All,

How can be implemented the eccentricity in mass matrix due to some regulational stipulations or resitrictions?

In some codes, EC-8 to be specific, it requires to include accidental torsional effects in calculations, if the structure has
rigid diaphragm that case simplifies the implementation because you can directly apply the forces with +%5, -%5 to
the mass center of diaphragm.

But how is the scenario if the structure doesn't have any diaphragm and masses are assumed to be
1.) lumped only at the nodes in translational direction,
2.) in consistent mass formulation

How am I supposed to apply the eccentricity in that case?

Your help will be appreciated,

Regards,

[Prof. R.L. Taylor]

If you have a non-rigid system you need to apply a set of forces (for the resultant translation and couple effects) at the nodes. Of course this will have a variable effect depending which nodes you pick -- due to structural deformation.

[Son_new]

Dear Professor,

Can you elaborate that procedure a bit further, because it is not clear for me what set of forces(and how to formulate them) to apply at the nodes to get the eccentricity included. How that technique is called in engineering literature? I sought through the net with "nodal masses for eccentricity" sentence but that didn't retrieved anything useful.

Regards,

[Prof. R.L. Taylor]

This is a question for you supervisor.  We can provide answers that relate to specific feap instructions or bugs, but not advice on how to do a particular analysis that may have professional implications.