What are the generalized coordinates of each node?

[Jiang-Cui]

Dear professor,

I am studying ANCF now. I know that each node of this ANCF beam has 6 generalized coordinates. What are the generalized coordinates except the position vector? Is this a 2D or 3D beam? Is there an original paper for this beam?

Thank you!

[rserban]

The reference for this formulation (ANCF gradient deficient cable element) is: "Analysis of Thin Beams and Cables Using the Absolute Nodal Co-ordinate Formulation", J. Gerstmayr, A. Shabana, Nonlinear Dynamics (2006) 45: 109-130, DOI: 10.1007/s11071-006-1856-1

This is a 3D element, with the 6 generalized coordinates at each of its 2 nodes representing the position vector and a gradient vector. Note that this gradient deficient ANCF beam element cannot describe a rotation of the beam about its own axis, so torsional effects cannot be modeled.

If you are interested in more complex ANCF elements, I suggest you look at those implemented in Chrono (https://github.com/projectchrono/chrono). But that's C++ code.

[Jiang-Cui]

Professor, thank you very much! I have got it!