# Non Linear Vibration

1. Apr 14, 2005

### kashoo

how can we find the nonlinear behaviour of an assembled Structure....what are useful links regarding Nonlinear Vibration of 3D Structures...what are basic steps to predict the Nonlinear Behavior ?

2. Apr 18, 2005

### kashoo

3. Apr 18, 2005

### PerennialII

If the "assembled" refers to a structure with some complexity (you're not referring to a straightforward structural element like a rod/beam etc. with minute nonlinearities, but rather a general 3D structure with nonlinear time-dependent material response etc.), any finite element method source dealing with vibrations would be a good start (other numerical means will do, but FEM is the best with this intel). The sequence of solving the eqs of motion is in principle the very same, the nonlinearity of the terms just needs to be incorporated within the different stages of analysis. Most general FEM books do a decent job at the basics.

Last edited: Apr 18, 2005
4. Apr 19, 2005

### kashoo

If i use Perturbation analysis to see second order ,third order etc. non linearity and model the structure according to that analysis ....till what extent it will give me results?.....what about using Impact Testing Hammer Apparatus to see the Non Linear Behavior?

5. Apr 20, 2005

### PerennialII

I'd say everything depends very much about your configuration, without knowing the degree, type etc. of your nonlinearities let alone how they manifest in the system it's tough to give you the results ....... . Sure hammering the thing would probably be really interesting, putting on some instrumentation ever more so.

6. Apr 20, 2005

### kashoo

May i have some useful links regarding the non linear vibration....so as i clear my concepts regarding non linearity in 3d STRUCTURE...i think i would rather go up to only second order non linearity.....actually the modes i m getting in the result of modal analysis are in the resonance of about 1:2...which is basic reason behind to go for non linearity.