I'm modeling the girts for metal panel backup on a building, and I want to have a slip connection at the head of my jambs (i.e. i don't want to prop up the girt). Is this possible to model? The "AXI" release toggle on these elements makes it such that the model fails to converge.
The jambs should transmit shear into the continuous girt at the head but not moment, and should only accumulate axial load from the girts/headers they support and take that load to the base.
Take the post or jamb member on the right. There are two horizontal beams or girts supported by this post. If axial is released, they fall to the ground under gravity load. If you want just the top third to be released, then you would have to segment the post and release only the top so that the bottom 2/3 takes axial. There is also no need to pin the base end of the post if the nodal restraint is already a pin.
Answer Verified By: TLiebhold
Got it - the K end on those posts is the top, so that's why they're pinned in KM3 and KM2, and the J end is the base which has a Pinned node. It would be nice if there was just a control for which end is axially released instead of adding addition members to models. Other general purpose finite element programs do this already (I guess you could consider this my feature request).
Axial releases are complicated. For a single finite element, an axial release applies to the full member and so there is no "end" assigned. To say there is an axial release at one end of a physical member makes some sense, because then only the last segment of the meshed model would have the release. There are also tricky bits related to loads along the length that have a component along the member (self-weight of a column or loads on a sloped beam for example).
For your problem, you could add a very short column at the top end and release that connecting member in axial if you don't want to mesh the physical column at the third point.