Date post: | 05-Oct-2015 |
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MODAL ANALYSIS RESPONSE OF MDOFS MODELS(uncoupled models ) to arbitrary loadsWe consider that the external forces act after the degree of freedom (translation)
Known: M, K, C;
(normalized modal matrix);
One uses the modal transformation :
(1)
Equation of motion:
(2)
Using (1) determine : (3)
Where :
=[]
The system equation is:
Or for i mode of vibration:
Where
Sollution is:
The value of displacement is :
Particular case: harmonical external forces
The sollution of displacements is:
Where:
The displacement will be:
Taken into account the unnormalized forms of vibration we have: