Intro

Triangle element is only area or surface element in BFE. It is consist of a CST (Constant Stress (and Strain) Triangle) element for in plane loads, and a DKT (Discrete Kirchhoff Triangle) element for carying out off plane loads and moments and also an additional stiffness for drilling DoF.

# Deprecated This element is Deprecated, use TriangleElement instead

# DoFs Triangle element in BFE does have three nodes, each one for a corner of triangle in 3D space. Each node have 6 DoFs in global coordination system.

# Properties The properties of Triangle element:

## Mechanical Properties:

ElasticModulus: Elastic Modulus measures in [Pascal] or [Pas] PoissonRatio: poisson ratio, in [0,0.5] range, dimension less

## Geometrical Properties:

Thickness: Thickness of element, measures in [m] unit

## Modelling properties:
Behavior: Determines the behaviour of element, three possible values: (by default is ThinShell)

FlatShellBehaviour.ThinPlate: based on discrete Kirchhoff theory, only plate bending behaviour FlatShellBehaviour.Membrane: The membrane, only in-plane forces, no moments. Only membrane behavior. FlatShellBehaviour.ThinShell: The thin shell, based on discrete Kirchhoff theory, combination of Plate and Membrane

MembraneFormulationType: Determines the formulation type of membrane. only if Behaviour is either Membrane or ThinShell, then this property does taken into account. Two possible values:

MembraneFormulation.PlaneStress: plane stress situation MembraneFormulation.PlaneStrain: plane strain situation

AddDrillingDof: neither DKT and CST elements does have stiffness in rotation DOF about element’s local Z axis. If this is set to true, based on solution provided in ref[1], an additional stiffness in rotation DoF about local Z axis is added to element.

## Notes:

# References ref[1] “Development of Membrane, Plate and Flat Shell Elements in Java” by Kaushalkumar Kansara available from https://theses.lib.vt.edu/theses/available/etd-05142004-234133/unrestricted/Thesis.pdf ref[2] “AN EXPLICIT FORMULATION FOR AN EFFICIENT TRIANGULAR PLATE-BENDING ELEMENT” by JEAN-LOUIS BATOZ