A Limited Investigation of the Bending of 24S-T Aluminum Alloy Angle Beams in the Plastic Range

Abstract : An earlier investigation revealed the necessity for further study of the bending of unsymmetrical beams in the plastic range, inasmuch as twist occurs and has a marked effect. Angle cross-section beams of aluminum alloy 24 ST material were subjected to bending in the plastic range with the plane of loading at angles of 0 deg, 30 deg, 60 deg and 76 deg 7 min to the minor principal axis of the cross-section. The moment was applied by means of an eccentric load, with a relatively long moment arm. For a simplified approach, it was found that Cozzone's method of plastic bending analysis and an analysis based on an exponential relationship between stress and strain both gave reasonable correlation between theoretical and experimental bending moments in the plastic range beyond the yield strength. Both methods are approximate since they assume that the neutral axis does not rotate or translate and the cross-section does not rotate. The exponential method is not valid in the range below the yield strength. Other factors concerned with the general behavior of angle beams subjected to plastic bending are also considered.