User Guide

Tutorial 2 - Modifying
Version 5.0 67
Submeshing Plates
How many plate elements do you need to use to get accurate results? Entire texts
can be devoted to the topic of “mesh size”. The finite element method is an
“approaching method”. This means that finite elements give more accurate
answers as you use a finer mesh of plates to model a given surface. See the
RISA-3D General Reference for parametric studies that demonstrate this along
with some design examples for shear walls, horizontal diaphragms and spread
footings. Our studies have shown you should try to have a 4x4 mesh of plates
between points of support and load concentrations to get accurate results.
RISA-3D provides a submesh feature to refine the plate mesh, allowing us to
draw one plate where we need many. To get a 4x4 mesh in each bay we need to
submesh into a 8x4 grid of plates.
Press Ctrl-D to recall the last dialog, then click on the Submesh Quads tab. The
default entries will divide our plates into a 4x4 submesh so change the first field
to an “8”. Also select Apply Split to All Selected Plates.
Click Apply. We now have a 4x4 mesh of plates in each bay.