Section Forces
Add a Section Forces node to compute the integrated section forces for a cross section in a solid. The cross section can consist of more than one boundary, but all the selected boundaries must be planar and located in the same plane. The section forces are computed in a local coordinate system. The details are described under Coordinate System Selection below.
The local section forces are denoted as follows:
N — Axial force
T1 — Shear force along first local axis
T2 — Shear force along second local axis
Mt — Twisting moment
M1 — Bending moment around first local axis
M2 — Bending moment around second local axis
The section forces will be shown in an evaluation group, named Section Forces. Optionally, you can also generate two plot groups showing the section forces as arrows.
When a Section Forces node has been added or modified, you do not need to compute a new solution. It is sufficient to perform an Update Solution () to make the variables for the new section forces available.
Note that when you add a Section Forces node after solving a study, then neither the evaluation group nor the plots will be generated.
Cut Plane Selection
Select the boundaries that define the cross section over which the section forces are to be computed. As a default, it is assumed that the cross section is contiguous. This assumption can be relaxed by selecting the Allow disconnected boundaries check box.
Coordinate System Selection
Select a coordinate system that defines the orientations of the section forces. Only boundary systems with constant axis directions can be selected. The orientation of the local axes are defined as follows:
If the Symmetry plane check box is cleared, the first local axis defining the section forces is the same the first in-plane direction of the selected coordinate system.
If the Symmetry plane check box is selected, only the normal orientation of the boundary system is used. The first local axis is taken as the inward normal from the symmetry plane into the structure.
Symmetry Plane Selection
This section is only visible if the Symmetry plane check box is selected. In that case, select one boundary in the symmetry plane, in order to identify its location and orientation. The symmetry plane should be orthogonal to the cut plane.
Cut Plane
Select the Allow disconnected boundaries check box for the case that the cross section is defined by boundaries that are not all adjacent to each other. As a default, this situation will generate a warning message, and no results are computed.
Select the Symmetry plane check box if the section forces are to be computed for a cross section for which only one half is modeled due to symmetry. When selected, choose a Symmetry typeSymmetry or Antisymmetry, matching the type of symmetry conditions being used. Also, you need to select a boundary in the symmetry plane in the Symmetry Plane Selection section.
Using a symmetry plane has the following effects:
Updating a Solution in the COMSOL Multiphysics Reference Manual.
Location in User Interface
Context Menus
Ribbon
Physics tab with Solid Mechanics selected in the Model Builder tree: