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Subject: Re: Modal Participation Factor Calculation
Author: Prapoj Phataraphruk
Date: 2001-01-29 15:16:00

The participation factor is similar to the eigenvector. It is for the mode
shape. I used it to determine which mode/modes are important to my
analysis. Then, I can calculate the amplification factor or damping ratio
(using the corresponding frequency) for the force response analysis.

Prapoj Phataraphruk

Honeywell Engine&System

-----Original Message-----
Sent: Monday, January 29, 2001 11:36 AM
To: 'xansys '

Hello All,
I've been running a modal analysis (Block Lanczos). After Ansys computes the
natural frequencies, it does a participation factor calculation. It computes
these in the X, Y, Z and ROTX, ROTY, ROTZ directions. For each of these it
prints six columns:

Mode Cumulative_Freq_Mass Fraction Period Participation_Factor
Ratio Effective Mass

Can someone please help me interpret this information? Is it something I
should be interested in?
Also, some of the participation factors are negative while some are postive.
What is the significance of this?
Should rigid body modes have a special interpretation?

I've always thought participation factors were something you computed after
a dynamic simulation, i.e., here is the participation of each mode in the
final response of the structure. How does this Ansys information fit in with
such an interpretation?

Any help would be greatly appreciated.

Thanks,
Carlos

Carlos Cosme
Western Star Trucks, Inc.
Kelowna, British Columbia
Canada V1Y 6H8
tel. (250)-868-6250 ext 5234
fax. (250)-868-6210
email: ccosme@w...

Posts possibly associated with message #20596AuthorDateScore
20585Modal Participation Factor CalculationCosme, Carlos ccosme@2001/01/2910
20596Re: Modal Participation Factor CalculationPrapoj Phataraphruk2001/01/29 
20600Re: Modal Participation Factor CalculationChris Andersen2001/01/29 
20603Re: Modal Participation Factor CalculationChristopher Wright1991/01/29