**torque#

Description#

This boundary condition applies a torque on a boundary set resulting from shear forces.

(38)#\[T = \int \vect r \cdot \vect \tau dA\]

where \(T\) is the torque to be applied, \(\vect r\) is the position vector and \(\vect \tau\) is the shear forces.

../../_images/torque.svg

Syntax#

**torque \(~\,~\,\) bset_name (origin) (axis) value table

bset_name

is the name of the bset on which this shear forces are applied.

origin

is the rotation origin vector.

axis

is the rotation axis vector.

value

is the value of shear forces to be applied (to be multiplied by the table).

Example#

An example can be found in $Z7PATH/TESTS/Static_test/INP/torque.inp.

../../_images/torque_ex.svg 
***bc
 **impose_nodal_dof
   bottom  U1 0.0
   bottom  U2 0.0
   bottom  U3 0.0
 **torque top_face (0.,0.,2.) (0.,0.,1.) 100. time

The previous load is applied to a cylinder with radius \(R=1\) mm. To verify the applied torque, the following post-processing can be used:

****post_processing
 ***global_post_processing
  **nset top
  **file node
  **process static_torsor
   *point (0. 0. 2.)
   *file torque.dat
****return

The output of this post-processing is torque.dat which will contain the values of resultants and moments. The torque value can be found in the last column of the file, which shows a value of \(209.435\). The analytical value is given by

(39)#\[T = \int_{\theta=0}^{\theta=2\pi}\int_{r=0}^{r=1} 100 r^2 dr d\theta = \dfrac{200\pi}{3}=209.439\]