Abstract
The bending strength of cast iron circular plates with annular ribs was evaluated for various dimensions and locations of the ribs. In view of the non-elastic behavior of cast iron, strength analysis was carried out using the finite element method for the calculation of stress distribution in the plate, and using the stress boundary layer δ as fracture criterion as proposed by the authors in an earlier report. Results were well verified experimentally. An annular rib is most effective when its distance from the center is 0.3 to 0.4 of the plate radius, where the strength is increased by more than 50% with an increase of only 8% of the casting weight. If a rib is nearer to the center than the above distance, it is less effective, because it can cause fracture at the top or outer fillet of the rib. Tapered plates are superior to plates with ribs in terms of the ratio of strength to weight increase. An advantage of castings is that the structural strength can be increased easily by appropriate desigh of ribs and wall thickness.
