have a look at the comment I quoted above, that you have made here. Can you kindly explain why would applying displacement constraints or force at a node (or point) on beams and at a line on shell will not give any singularity? Because you said in the same comment that, 'because the force is being divided by geometry (point or edge) with zero area'. Well, for the case of displacement constraint or a force on a single node on beam or a line on shell wouldn't eventually mean that the force is being divided by zero area?