Cross section records

These records specify a cross section model descriptions. The general format is following:

*CrossSectType

(num#)(in)

The order of particular cross section records is optional, cross section model number is determined by (num#)(in) parameter. The numbering should start from one and should end at n, where n is the number of records.

The crossSectType keyword can be one from following possibilities

• Integral cross section with constant properties
  

  SimpleCS	[thick #(rn)] [width #(rn)] [area #(rn)]
  	[iy #(rn)] [iz #(rn)] [ik #(rn)]
  	[shearareay #(rn)] [shearareaz #(rn)] beamshearcoeff #(rn)

  
  
  Represents integral type of cross section model. In current implementation, such cross section is described using cross section thick (thickVal) and width (widthVal). For some problems (for example 3d), the corresponding volume and cross section dimensions are determined using element geometry, and then you can omit some (or all) parameters (refer to documentation of individual elements for required cross section properties). Parameter area allows to set cross section area, parameters iz, iz, and ik represent inertia moment along y and z axis and torsion inertia moment. Parameter beamshearcoeff allows to set shear correction factor, or equivalent shear areas (shearareay and shearareaz parameters) can be provided. These cross section properties are assumed to be defined in local coordinate system of element.
  

• Integral cross section with variable properties
  

  VariableCS	[thick #(expr)] [width #(expr)] [area #(expr)]
  	[iy #(expr)] [iz #(expr)] [ik #(expr)]
  	[shearareay #(expr)] [shearareaz #(expr)]

  
  
  Represents integral type of cross section model, where individual cross section parameters can be expressed as an arbitrary function of global coordinates x,y,z. Similar to SimpleCS, for some problems (for example 3d), the corresponding volume and cross section dimensions are determined using element geometry, then you can omit many (or some) parameters (refer to documentation of individual elements for required cross section properties). Parameter area allows to set cross section area, parameters iz, iz, and ik represent inertia moment along y and z axis and torsion inertia moment. Parameters (shearareay and shearareaz determine shear area, which is required by beam and plate elements. All cross section properties are assumed to be defined in local coordinate system of element.
  

• Layered cross section
  

  LayeredCS	nLayers #(in)
  	LayerMaterials #(ia)
  	Thicks #(ra) Widths #(ra)
  	midSurf #(rn)

  
  
  Represents the layered cross section model, based on geometrical hypothesis, that cross sections remain planar after deformation. Number of layers is determined by nLayers parameter. Materials for each layer are specified by LayerMaterials array. For each layer is necessary to input geometrical characteristic, thick - using Thicks array, and width - using Widths array. Position of mid surface is determined by its distance from bottom of cross section using midSurf parameter (normal and momentum forces are then computed with regard to it's position). Elements using this cross section model must implement layered cross section extension. For information see element library manual.
• Fibered cross section
  

  FiberedCS	nfibers #(in) fibermaterials #(ia)
  	thicks #(ra) widths #(ra) thick #(rn) width #(rn)
  	fiberycentrecoords #(ra) fiberzcentrecoords #(ra)

  
  
  Cross section represented as a set of rectangular fibers. It is based on geometrical hypothesis, that cross sections remain planar after deformation (3d generalization of layered approach for beams). Paramater nfibers determines the number of fibers that together form the overall cross section. The model requires to specify a material model corresponding to particular fiber using fibermaterials array. This array should contain for each fibre corresponding material model number (the material model specified on element level has no meaning in this particular case). The geometry of cross section is determined from fiber dimensions and fiber positions, all input in local coordinate system of the beam (yz plane). The thick and width of each fiber are determined using thicks and widths arrays. The overall thick and width are specified using parameters thick and width. Positions of particular fibers are specified by providing coordinates of center of each fiber using fiberycentrecoords array for y-coordinates and fiberzcentrecoords array for z-coordinates.

• Warping cross section
  

  WarpingCS

  WarpingNode #(in)

  
  
  Represents the cross section for Free warping analysis, see section 3.1.12. The WarpingNode parametr defines the number of external node with prescribed boundary condition which corresponds to the relative twist of warping cross section.