End Effects for Residual Stresses in Bars

Long members, such as bars, beams, rods and rails, often contain longitudinal residual stresses that are constant along the central portion of their length. Such stresses can be measured by sectioning or X-ray methods. End effects are important in both methods. A finite-element study of these end effects gave: (1) The minimum length of specimen necessary to retain the full residual stresses that were present in the original bar, (2) the length over which end effects extend, and (3) the magnitude of the error caused by neglecting end effects in measuring residual stresses. This information was obtained for various distributions of residual stresses that typically occur in bars and other similar members. The aspect ratio is the specimen length divided by the specimen depth.