I am looking into the four-point bend test, such as one in this YouTube video.
I am a little confused as to how the loads are prescribed numerically as boundary conditions. My intuition tells me that the object has to have a Dirichlet BC somewhere. But it appears that the 4 supports (2 on top and 2 on bottom) exert the vertical loads, hence they should be all Neumann BCs.
Am I thinking about this incorrectly?