Ohlinger,

ZPA what we are entering in control parameters is for predefined spectrums.


For user defined spectrum, ZPA required for calculating force (F=MA) (FOR INCLUDED MISSING MASS) after cut off frequency (mostly we will give 33 Hz in the control parameters)

Now, we have choice to select ZPA either from spectrum or from extracted mode.

A.SPECTRUM instructs CAESAR II to use the largest entered frequency of the input spectrum.

Example: take this spectrum :

RANGE
* FREQ (Hz)
10.0000 ------------ Corresponding to 10 hz we have one acceleration
value, that value is taken as ZPA for calculation of force
5.0000
3.3333
2.5000
2.0000
1.6667
1.2500
1.0000
0.8333
0.7143
0.6250
0.5556
0.5000
0.4167
0.3571
0.3333


B.Extracted instructs CAESAR II to use the acceleration (that acceleration =ZPA) associated with the frequency of the last extracted mode

For example, if the user specifies cut‐off frequency 33 Hz then CAESAR takes related to 33 Hz what is the acceleration value that acceleration considers as ZPA

This is the concept for calculation of included missing mass

But my doubt is

1.If i select extracted and i keep the cut off freq 33 HZ how Caesar know what is the acceleration value at 33 HZ???? & in what way Caesar is calcating force then…..

2.RESULTS: Neither it is changing for spectrum nor it is changing for extracted mode???

i didnt understand what ZPA value CEASAR is taking for calculating the included missing mass....