A Historical Example of Fatigue Damage

Abstract

X-ray diffraction methods are a well-established tool today for the assessment of fatigue damage. It is both instructive and fascintating to look back at the work of an early pioneer in this field. F. Regler, Vienna, Austria, reported in the 1930’s his “live” investigations on railroad bridges which had been in heavy use for 80–100 years. X-ray diffraction on positions subjected to unidirectional pulsating loads from passing trains showed very fine grain (continuous, broadened Debye-rings) and orientation, while diffractograms from unloaded members of the same bridges showed the fairly coarse grain of the original construction steel, without orientation. Regler’s interpretation of grain rotation and fragmentation when a load was renewed before complete relaxation from the previous one drew strong criticism from proponents of classical elasticity theory.

Regler, in his 76th year, died on the very day (August 25, 1976) that this presentation was delivered at the 23rd Sagamore Conference.