Using Ritz vector to capture 90% Mass participation

[ahmedhegazi]

i am doing modal analysis for one structure where i started by using eigen vector to define modes of vibration
after running 150 modes , i captured only 70% of mass in X,Y and Rz direction with last mode = 0.08 second

Thinking to shift from Eigen to Ritz vector as many articles recommend it to achieve mass participation for my such a case

the question is , which parameters i should define , should i include acceleration UX,Uy,Rz in one case only or shall i include other load pattern in the same case

 

[JasonMcKee71]

Please include acceleration in all 3 global dofs. The method will then converge properly.

Jason McKee
proud R&D Manager of
Cross Section Analysis & Design
Software for the structural design of cross sections
Moment Curvature Analysis
Interaction Diagrams
Reifnorcement Design etc.