Separate from the computational and problem solving classes, are classes for building models (termed ModelBuilder classes). The Version 0 release of OpenSees includes a general model-builder for creating three-dimensional frame and continuum models using TCL. Users can generate models using TCL procedures, and are encouraged to share these generation procs with others! Additional ModelBuilder classes suited to a particular type of model may also be developed.
Beam-column -- 3D elements with the following integration rules
- Linear elastic material (closed form),
- Concentrated plasticity integrated over specified hinge lengths, or
- Distributed plasticity integrated along the element length.
- Linear -- first order geometry,
- P-Delta -- second order "leaning truss" transformation, or
- Corotational -- large displacement transformation.
- Zero length -- 3D element which uses multiple uniaxial materials to model the element force-deformation relation.
Truss -- 3D element with material non-linearity modeled by
- Uniaxial material stress-strain integrated over cross-sectional area, or
- Section force-deformation relationship.
- Quad -- 2D bilinear isoparametric element which uses ND materials at each of its integration points.
- Elastic -- linear elastic material tangent with optional linear damping tangent
- ElasticPP -- elastic-perfectly plastic
- ElasticPPGap -- one-sided EPP with an initial gap
- Hardening -- bilinear model with combined linear isotropic and kinematic hardening
- Steel01 -- bilinear steel model with linear kinematic and exponential isotropic hardening
- Concrete01 -- concrete model with Kent-Park envelope, degraded linear unloading/reloading, and no tensile strength
- Hysteretic -- trilinear backbone with pinching, damage, and degraded unloading stiffness
- Parallel -- multiple uniaxial materials in parallel
- Series -- multiple uniaxial materials in series
- BiLinear -- bilinear hysteretic model with degradation
- Clough -- Clough type hysteretic model with degradation
- Pinch -- pinching hysteretic model with degradation
- ElasticIsotropic -- plane stress and plane strain formulations for use with the quad element.
- Elastic -- uncoupled axial and bending response.
Fiber -- discretized by fibers which collectively define section response.
The fiber models available are
- Uniaxial2d/3d -- associates with a uniaxial material and enforces the Bernoulli beam assumption for axial and uni/bi-directional bending
- Generic1d/Nd -- map stresses from uniaxial and ND materials to section stress resultants. For example, a uniaxial material can be used to model section moment-curvature behavior, or an ND plasticity model can be used to model section moment-axial-shear interaction.
- Aggregator -- combination of a section and multiple uncoupled uniaxial materials used to define additional section force-deformation relations. For example, a fiber section can be combined with an uncoupled shear force-deformation relation.