Instability type 2 and 3 when modelin tensegrity

Anonymous — Mon, 23 Mar 2015 16:39:43 GMT

Hi,

I have a problem with instability, i read many posts and don't find solution. If anyone can help me, thanks.

Re: Instability type 2 and 3 when modelin tensegrity

Pawel.Pulak — Tue, 24 Mar 2015 17:51:40 GMT

Hi,

cables in Robot have no bending stiffness so single bars connected in the net of cables will behave as truss elements (tension or compression). That is why I declared all TRON 101x3.6 bars as "truss" elements. This way I avoided instabilities related to rotational degrees of freedom.

Moreover I have activated big displacements (Non-linear + P-delta)

And all cables were defined with -0.01 relative elongation.

Such model is convergent even with 5 load increments - attached to this post.

But significant lateral displacements are observed in it - close to 500mm.

Probably they can be reduced fine-tuning definitions (elongations) of individual cables - but it requires a lot of work, iterations and time.

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Regards,

Re: Instability type 2 and 3 when modelin tensegrity

Anonymous — Tue, 24 Mar 2015 19:03:08 GMT

Thank you for your help, it's working.

topic Instability type 2 and 3 when modelin tensegrity in Robot Structural Analysis Forum

Instability type 2 and 3 when modelin tensegrity

Re: Instability type 2 and 3 when modelin tensegrity

Re: Instability type 2 and 3 when modelin tensegrity