End conditions
End conditions describe the properties of connections between member and reference joints. The number of considered degrees of freedom can be specified by the user.
Free, fixed and spring connection
All six degrees of freedom at the beginning and end of the joint are fixed as a default. Any of these connection components may be switched off or replaced by a spring. In these cases, the occurrence of mechanism may appear when switching off certain components. It isn't possible to get results for structures with mechanism.
Spring end conditions are included in "Special" properties of member. The spring constant K has to be specified for this type of connection.
The end conditions are defined in the local coordinate system of member. During the analysis, the stiffness of springs is combined with stiffness of member, that is defined relatively to the cross-sectional axes. The analysis provides exact results only for structures, where the local member axes 2,3 and cross-sectional axes y,z are identical. Otherwise (structures with rotated cross-sections), the results are only approximate.