An electric machine assembly for a vehicle is provided. The electric machine is in operational communication with a traction battery and includes a stator core defining a cavity and a rotor disposed within the cavity having an inner region defined by sets of triangle-shaped holes tessellated about respective central regions to form a truss structure such that the holes of the truss structure, during operational rotation, do not influence magnetic flux paths generated by magnets of the rotor. The rotor may have a strain energy value less than or equal to 16,100 Joules. The truss structure may include pairs of symmetrical portions each including segments arranged with adjacent rotor portions to define the triangle-shaped holes.