The previous version of 3DFrame allowed for spring releases at beam ends, but if the release stiffness was entered as zero it was treated as a rigid connection for that freedom. Effectively zero stiffness releases could be modelled by entering a very low stiffness value, but this sometimes caused arithmetic problems, resulting in enormous deflections being reported for the released freedoms. To avoid this problem the code has been modified so that any freedom entered as zero stiffness is treated as fully released. The new version (Rev. 2.08) may be downloaded from:
The solver links to two dll files that need to be installed as described here:
The download zip file also includes a VBA only version, that should work without any further installation, other than extracting from the zip file.
Typical input showing both spring and zero stiffness releases is shown in the screen shot below:
Further details of the program 3Daxis system and the related stiffness matrices can be found at: