This example shows how to implement a new element and material in .NET environment for OpenSees via delegates. also, MATLAB and C# code of 2D Truss element provided for static and dynamic analysis
The model consists of three stories and one bay in each direction. Rigid diaphragm multi-point constraints are used to enforce the rigid in-plane stiffness assumption for the floors. Gravity loads are applied to the structure and the 1978 Tabas acceleration records are the uniform earthquake excitations.
For loading OpenSees.NET in MATLAB, we use addAssembely command. When .NET assembly successfully loaded in MATLAB, we can create the model. theDomain is the container of all components of the structure. NodeWrapper, TrussWrapper, ElasticMaterialWrapper and SP_ConstaintWrapper commands generate an instance of Node, Truss, ElasticMaterial and SP_Constaint OpenSees objects respectively
Nonlinear geometric analysis of A cantilever beam subjected to end bending moment
In this example, the Uniaxial Section of Example 2b is replaced by a fiber section. Inelastic uniaxial materials are introduced in this example, which are assigned to each fiber, or patch of fibers, in the section.
The nonlinear beam-column element that replaces the elastic element of Example 2a requires the definition of the element cross section, or its behavior. In this example, the Uniaxial Section used to define the nonlinear moment-curvature behavior of the element section is "aggregated" to an elastic response for the axial behavior to define the required characteristics of the column element in the 2D model. In a 3D model, torsional behavior would also have to be aggregated to this section.
Example 1-a & 1-b is a simple model of an elastic cantilever column. The objective of this example is to give an overview of input format.