A Study on Transverse Deflexion of Cast Iron Beams

• Published in: THE JOURNAL OF THE JAPAN FOUNDRYMEN'S SOCIETY Vol. 49; no. 2; pp. 63 - 69
• Main Authors: NOGUCHI, Tōru, NAGAOKA, Kingo
• Format: Journal Article
• Language: Japanese
• Published: Japan Foundry Engineering Society 25.02.1977
• ISSN: 0021-4396; 2186-0335
• DOI: 10.11279/imono.49.2_63

In order to elucidate the meaning of rupture deflexion, an inelastic analysis of the transverse test for cast iron beams was carried out. Calculated load-deflexion curve was derived from the stress-strain curve of the iron, and the theoretical and experimental rupture load and deflexion were compared. Rupture deflexion was related to rupture elongation in the tensile test. 1) Load-deflexion curve of an arbitrary cross section of a cast iron beam was calculated by a numerical method using an electronic computer. The calculated curves agreed well with the experimental curves of round bars under three-point bending. 2) Cast iron beams did not rupture at the theoretical load and deflexion values under maximum stress conditions. The actual rupture deflexions were 1.5-2.0 times the theoretical values and double the elastically calculated values. 3) The rupture deflexion could be related to the tensile rupture strain using the “factor of bending strain” φ (bending rupture strain ε1m/tensile ruptre strain εt). For the average value of φ, the deflexion of 6-10mm in the transverse test, with the 30mm diameter and 450 mm span beam was equivalent to the tensile rupture strain 0.4-1.2%. 4) Factor φ depends not only on the mechanical properties of iron but also on the non-material factors such as surface properties and dimensions of the beam. Mechanical and metallurgical studies to find out the roles of the factors must be carried out. 5) In evaluating the results of transverse test with as cast specimens, it must be noted that the rupture deflexion is affected by the properties of cast surface apart from the ductility of the material.