Get Started in OpenSees with STKO: W7 Definitions and Conditions

In the 7th class in the Get Started course, Francesca tackles the topic of Definitions and Conditions in STKO and OpenSees
1:03 Definitions:
-6:43 Concept of timeSeries
-9:08 Concept of time in OpenSees
-10:14 Types of timeSeries
11:35 Conditions:
-13:34 Constraints: single point and multi point constraints in STKO and OpenSees (fix, equalDOF, rigidDiaphragm and rigidLink)
-21:51 Loads: NodalLoads and ElementalLoads
-27:19 Masses
-28:12 Q&A with Francesca
Download the files for the class here: hasdea.eu/softw...

[@kamrantousi6896]

Rigid diaphragm makes axial forces equal to zero corresponding to zero strain. The second paragraph should be corrected.

[@asdeasoftwaretechnology7930]

What Francesca said is absolutely correct. Since the RidigDiaphram imposes a zero relative axial displacement on every beam in the X-Y plane (Floor is not deformable in its own plane), the Axial Deformation of the beam to be constrained is Zero. Then, if and only if the section is elastic and there is no section offset, the Axial force will also be zero. But this is not a rule. For example, in RC beams, upon cracking, the neutral axis shifts from the center, so that a zero axial strain can lead to non-zero axial stress if there is also a non-zero curvature.