thank you once again. So what you have said implies that the stress concentrations which starts to form a few elements before the left end boundary condition is real because of the existence of force in the Y direction at the left end. This force in the Y direction actually makes the stresses in those few elements to rise, and the load paths (or the vector principal stresses) will be a result of the stress in the X direction (due to external force) and the stress in the Y direction (arising due to fixed left end boundary condition).nHow do we determine critical distance, in this case, of the singularity happening at the top and bottom corner nodes of the left end? [beyond which the St. Venant's principal is going to be valid].n