Negative results occur frequently in AI/ML research (and perhaps in other domains too). Most of the time, these results are not published. This is mostly because your typical AI/ML conference doesn't accept such papers.
However, are there any venues to publish these results? I believe these results can be still useful to look at before you delve into a certain project so that you'd at least know what approaches don't work.
As an example venue, there seems to be PerFail workshop from pervasive computing domain. So, is there something similar for AI/ML ?