I claim the ornamental design for dihedral beam for structural systems, as shown and described.
FIG. 1 is a perspective view of my design for the dihedral beam for structural systems. The beam is broken in the center indicating indefinite length.
FIG. 2 is a front elevation view of dihedral beam for structural systems shown in FIG. 1.
FIG. 3 is further embodiment of my design for a dihedral beam for structural systems. The beam is broken in the center indicating indefinite length; and,
FIG. 4 is a front elevation view of the dihedral beam for structural systems of FIG. 3.