Modeling

A finite element model consists of Nodes, Elements, Constraints, and Loads. In OpenSees the Constraints are divided into two types: single-point constraints (SP_Constraints) for specifying the boundary condition for a specific degree-of-freedom at a node and multiple-point constraints (MP_Constraints) for specifying the relationship between the responses between the degrees-of-freedom at two separate nodes. The loads in OpenSees are assigned to LoadPatterns. Also associated with load patterns are TimeSeries objects ans sometime SP_Constraints when the user wants to specify time-varying SP_Constraints.

In OpenSees there are commands to add each of these types of objects to a domain:

• Model Class
• Nodes
• Materials
• Section
• Elements
• Transformations
• Constraints
• Pattern Command
• Damping