Frame#
Frame elements are used to model slender structural members like beams and columns. All frame elements are constructed with the form
- Model.element(name, tag, nodes, section, transform)
Add a frame element to the model.
Available frame elements include
Name |
Description |
---|---|
Prismatic linear-elastic frame |
|
Force formulation |
|
cubic displacment formulation |
|
geometrically exact displacement formulation |
To use frame elements in OpenSees models, you’ll need to:
Define nodes with appropriate coordinates
Create a coordinate transformation with the element orientation
Define section behavior for the element
Create the frame element, connecting it to nodes, sections, and transformation
Apply loads and boundary conditions
Loads include
Theory#
A frame element represents a directed medium with a scalar characteristic coordinate \(\xi\). The embedding in space is described by:
A vector field \(\boldsymbol{x}(\xi)\) identifying positions in space,
A rotation field \(\boldsymbol{\Lambda}(\xi)\), and
A vector field \(\boldsymbol{\alpha}(\xi)\) identifying cross-sectional warping.
Some phenomena that can be modeled with frame elements include:
Distrubuted loads
Follower loads
Plastic hinges
Arbitrarily large rotations
Lateral-torsional buckling of beams,
Restrained torsional warping