Nonlinear Vibration: Find Behaviors of 3D Structures

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    Linear Vibration
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Discussion Overview

The discussion focuses on understanding the nonlinear behavior of assembled 3D structures, particularly in the context of nonlinear vibrations. Participants explore methods for predicting this behavior, including numerical techniques and experimental approaches.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant inquires about methods to find nonlinear behavior and seeks resources related to nonlinear vibration of 3D structures.
  • Another participant suggests that finite element methods (FEM) are a good starting point for analyzing complex 3D structures with nonlinear material responses, emphasizing the need to incorporate nonlinearity in the analysis stages.
  • A different participant proposes using perturbation analysis to investigate higher-order nonlinearities and questions the extent to which this method will yield results.
  • There is a suggestion to use an Impact Testing Hammer Apparatus to observe nonlinear behavior, with a note that the effectiveness of this approach may depend on the specific configuration of the structure.
  • One participant expresses that the results are highly dependent on the type and degree of nonlinearities present in the system, indicating that without this information, it is challenging to predict outcomes.
  • A later reply requests additional resources to clarify concepts of nonlinearity in 3D structures, mentioning a focus on second-order nonlinearity due to observed resonance modes.

Areas of Agreement / Disagreement

Participants do not reach a consensus on specific methods or outcomes, and multiple competing views regarding the analysis of nonlinear behavior remain evident throughout the discussion.

Contextual Notes

Limitations include the lack of specific details about the nonlinearities in the structures being discussed and the dependence on the definitions of terms like "nonlinear behavior" and "assembled structure." There are also unresolved mathematical steps related to the proposed methods.

Who May Find This Useful

Researchers and practitioners interested in nonlinear dynamics, structural analysis, and vibration testing of complex 3D structures may find this discussion relevant.

kashoo
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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 ?
 
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No Reply? :cry:
 
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.
 
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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?
 
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 ... :smile: . Sure hammering the thing would probably be really interesting, putting on some instrumentation ever more so.
 
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.
 

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