This page is devoted to frequently asked questions (FAQ) related to solids.
Are solid objects with less than eight nodes available?
Answer: Yes, degenerate solids are available, which are solid objects with collapsed (duplicated) nodes. These solids have less than eight nodes, and are useful for modeling wedges and tetrahedra. Joints may be collapsed in a variety of ways. An error message will report any creation of an illegal solid object.
How are solid objects drawn in SAP2000?
Answer: Solid objects may be created in SAP2000 through one of the following two methods:
- Extrude area objects by using Edit > Extrude; or
- Define solid objects directly by using interactive database editing to modify the Connectivity - Solid table, available through Edit > Interactive Database Editing > Model Definition > Connectivity Data > Object Connectivity > Table: Connectivity - Solid.
Why are red springs automatically generated on my solid objects?
Answer: Red springs are typically generated for solid objects with edge constraints to restrain their joints from rotation.
Solid objects activate only three translational degrees of freedom (DOF) at each joint location. Edge-constraint implementation then activates the three rotational DOF. Since solid objects do not provide rotational stiffness, internal rotational springs are generated at affected joints to provide rotational stiffness such that local numerical instabilities do not occur.
Without these internal rotational springs, warning messages in the output log would report zero stiffness at affected DOF. These warnings may either be ignored or eliminated by providing rotational springs.
