The Beam Cross Section Interface
The Beam Cross Section (bcs) interface (), found under the Structural Mechanics branch () when adding a physics interface, is used for computing cross-section properties for beams and also for a detailed evaluation of stresses in a beam when the section forces to which it is subjected are known. It is mainly used in conjunction with The Beam Interface.
As input you give a 2D sketch of the cross section, and computed results are area, moments of inertia, center of gravity, principal axis directions, torsional rigidity, shear center location, shear correction factors, warping constant, and stress distributions for different load types.
Studies and Solvers in the COMSOL Multiphysics Reference Manual
Settings
The Label is the default physics interface name.
The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.
The default Name (for the first physics interface in the model) is bcs.
Domain Selection
The default setting is to include All domains in the model to define the cross section. To select specific domains, select Manual from the Selection list.
Material Properties
Enter a value for Poisson’s ratio v (dimensionless). The default is 0.3. This value only influences the detailed distribution of shear stresses caused by a transversal load.
Section Forces
If you want to perform a detailed computation of the stress state in a beam cross section, enter the section forces.
Enter values or expressions for the following:
Axial force N (SI unit: N).
Twist
Enter a value or expression for the Axial twist, φxl. The twist is used to compute the axial warping displacement.
Discretization
Select an Element orderLinear, Quadratic (the default), Cubic, Quartic, or Quintic.