T2D2
2D Linear Truss
Number of Nodes: 2
Number of DoFs: 2 (Translation, Translation)
Syntax
element T2D2 (1) (2) (3) (4) (5) [6] [7] [8] [9]
# (1) int, unique element tag
# (2) int, node i
# (3) int, node j
# (4) int, material tag
# (5) double, cross sectional area
# [6] bool string, nonlinear geometry switch, default: false
# [7] bool string, if to update sectional area, default: false
# [8] bool string, if to use log strain, default: false
# [9] double, flexural rigidity, positive to activate Euler buckling limit, default: -1.0
Remarks
The corotational formulation is implemented, turn on the nonlinear geometry switch to use it.
According to different implementations of details, either a constant area or a constant volume assumption is adopted. If the volume is constant, the cross-sectional area would be updated based on .
The computation of strain can be altered from engineering strain (by default) to log strain.
By turning on all three switches, full nonlinearity can be achieved.
Euler Buckling Limit
[added in version 2.8]
The parameter [9]
allows one to define a positive flexural rigidity that will be used to compute the Euler buckling load. When [9]
is negative, the check is disabled.
The truss element matches a pinned-pinned condition, for which the Euler buckling load is given by
where is the length of the truss element.
For a given positive , can be computed using only the , regardless of the used material model. The computed axial resistance will be compared to and an error will be issued if the axial resistance (in compression) exceeds .
This is a theoretical upper bound, the design value requires an additional reduction.
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