I'm running a static analysis of a steel saddle bolted to a pipe (a left half + a right half) and I'm getting half of the bolts with negative values for axial force:
as it makes no sense for a preloaded bolt to experience compression in real word do I have to ignore these values???
This behaviour is seen in lower bolts (I expect the load to try to separate the bolts from the saddle surface, so decreasing the preload), while upper bolts are under traction as expected with values compatible with my hand calculation.
Sorry for the brutal simplification.