Discussion Groups

## Robot Structural Analysis

*Expert Elite* | International Moderator
Posts: 559
Registered: ‎09-29-2009

178 Views, 3 Replies
10-21-2013 08:25 AM

Hi, I wonder why load is distributed an unexpected way?

Product Support
Posts: 4,932
Registered: ‎04-26-2010

# Re: Planar load on bars

10-21-2013 08:33 AM in reply to: Romanich

Rafal Gaweda
*Expert Elite* | International Moderator
Posts: 559
Registered: ‎09-29-2009

# Re: Planar load on bars

10-21-2013 08:37 AM in reply to: Rafal.Gaweda

But it is dangerous for new users in Robot.

Product Support
Posts: 4,544
Registered: ‎12-17-2010

# Re: Planar load on bars

10-22-2013 01:27 AM in reply to: Romanich

Robot generates the anisotropic planar load on bars in the following way:

• Based on the list of elements, given in the definition of the load, the convex polygon is built with the vertexes in the nodes of the elements from the list.  In the general case this polygon may be assembled with the group of smaller polygons, which sides are the bars from the loaded bars list.
• For the defined angle of anisotropy, the row of the virtual bars, which intersect with the edges of polygons, is generated in the defined direction.  It is assumed that the sheathing has the rigidity only in this one direction.  The rigidity in the perpendicular direction is not taking into account.  The length of the segments of the bars between the intersections with the polygons, influences directly the value of the load applied to the corresponding segment of the polygon edge.

• For the general case, on the given edge, separate trapezoidal loads may be generated on the separate segments.  In order to not generate too many load data, one statically equivalent trapezoidal load is defined on the whole edge of the polygon.

• In case, that the polygon edge is identical with the bar element, the load is applied directly to this bar.  In case, that the polygon edge does not correspond to any bar, the load on this edge is replaced with the statically equivalent set of concentrated forces at the end of this edge.

In case of the isotropic load, the series of anisotropic load generation is performed, with the angle of anisotropy changing every 15 degrees.  After that the average results for every anisotropic case are treated as the isotropic case

Artur Kosakowski