torsion

Hi,

I have a bar with an analytical rigid surface attached at the free end with a RP at the centre of it. I am applying a rotational BC of UR3 = 0.017 (1 deg) with respect to the Z axis, but the resulting rotation at the end of the bar is more than 1 degree. Any idea why? Or how to have a full control of the twist of the bar? Also the bar deforms in shape where the end at which the twist is applied expands, making this cross-section bigger (clearly no the deformation expect for torsion). Input file attached in a word doc. 

This treatise provides a broad overview of the definitions of
fundamental quantities and methods of analysis for the use of solid materials
in structural components. The presentation is limited to the linear elastic
range of material behavior where there is a one to one relationship between
load and displacement.  Fundamental
methods of analysis and typical results for structures made of elastic solid materials
subjected to axial, bending, torsion, thermal, and internal pressure loading;

Hello,

I am trying to derive/find an analytical expression
for the torsion of a round bar made of an heterogeneous material. But I just do
not seem to find any solution available in the literature other than for a
homogeneous material, which can be find in any theory of plasticity book (e.g.
Theory of Plasticity, 3rd Ed., J. Chakarabarty, pp. 132-136).

 Liu, D., He, Y., Zhang, B., 2013. Towards a further understanding of dislocation pileups in the presence of stress gradients.  Doi: 10.1080/14786435.2013.774096

http://www.tandfonline.com/doi/abs/10.1080/14786435.2013.774096#preview

I would like to know how to write a stiffness matrix for a bar under torsional load. I would like to write a code in C++ to do this. I would like to know of any material regarding this.

Thanks in advance

With Br

Ashwin