Geo nonlinear (Implicit dynamic)

Karthic_22061
Karthic_22061 Altair Community Member
edited October 2020 in Community Q&A

Hi,

1. Whether Geo nonlinear (Implicit dynamic) analysis is inclusion of Inertia and Momentum terms ??

 

2. I think Geo nonlinear (Implicit static) does not include Inertia and Momentum.............  Geo nonlinear (Explicit dynamic) include Inertia and Momentum.

 

Please share your comment related to my query 

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2017

    Hi Karthik,

    The primary difference between NLSTAT and NLTRAN analysis is:

    in the case of the NLSTAT (Non linear quasi static), it is assumed that the simulated physical phenomenon is not influenced by temporal aspects, in other words that the expected results do not depend on the speed of application of efforts. This makes it possible to satisfy the equation of equilibrium with each step, the effects of inertia being ignored. Therefore, the weakly dynamic problem can be solved as a static (quasi-static) problem. 
    Quasi-static analysis can be performed in both small and large deformations, and nonlinearities can come from these large deformations, contact or materials.

  • Karthic_22061
    Karthic_22061 Altair Community Member
    edited December 2017

    Hi Prakash,

    If Nonlinear Quasi-static analysis considers the Geometric Nonlinearity(LGDISP).

    whats the difference between the Geometric nonlinear implicit static and Nonlinear Quasi-static analysis ??

     

    Thank you Prakash.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2017

    Hi karthik,

     

    Please read my previous reply where it states that NLSTAT ignores inertia and mass effects. 

    Altair Forum User said:

    in the case of the NLSTAT (Non linear quasi static), it is assumed that the simulated physical phenomenon is not influenced by temporal aspects, in other words that the expected results do not depend on the speed of application of efforts. This makes it possible to satisfy the equation of equilibrium with each step, the effects of inertia being ignored. Therefore, the weakly dynamic problem can be solved as a static (quasi-static) problem. 

     

  • Karthic_22061
    Karthic_22061 Altair Community Member
    edited December 2017

    Hi Prakash,

    Please go through my question once again. I am clear that NLSTAT ignores inertia and mass effects. 

     

     whats the difference between  Geometric nonlinear implicit static and Nonlinear Quasi-static analysis.

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2017

    karthik,

     

    For Implicit static general Newark method is used where Mass and damping are omtted (K*DeltaU= P) but for implicit dynamic an extension of Newark method Alpha-HHT (Huges, Hibler and Taylor) is used. It allows for effective algorithmic damping of high-frequency spurious vibrations.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2018

    Hello

    Do you know a tutorial for an implicit dynamic analysis, please?

    Thank you.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited July 2018

    Hi,

     

    For large displacement analysis you can use NLSTAT with LGDISP.

     

    Here is a tutorial for the same: OS-T: 1520 Finite Sliding of Rack and Pinion Gear Model 

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