A curvilinear integral method for multiaxial fatigue life computing under non-proportional, arbitrary or random stressing |
| |
Authors: | S. Stephanov |
| |
Affiliation: | S.H. Stephanov is with the Higher Institute of Forestry and Wood Technology, Sofia, Bulgaria |
| |
Abstract: | Some popular concepts for reducing three variable stress components σx(t), σy(t), τxy(t) to one equivalent amplitude spectrum, and the use of the linear damage accumulation hypothesis, have been evaluated as not fully correct when these components vary non-proportionally and arbitrarily. A different approach is suggested: computing damage accumulation by means of an integral directly on the non-radial arbitrary path, called the ‘trajectory’, described in the σx−σy plane when τxy(t) = 0, in the σx−τxy plane when σy(t) = 0, or in a special coordinate space where this trajectory is invariant of stress directions x, y. If the trajectory is random, it may be replaced by a statistical two-dimensional density of distribution. The integrand, called the R-function, is derived from various S−N fatigue curves under different determined loadings. Thus the traditional S−N function is replaced by the R-function for direct damage summation with differential analysis, which allows the loading to be arbitrary (non-cyclic, multiaxial and non-proportional). The method works by means of computer programs and is applicable to real structures. |
| |
Keywords: | fatigue life prediction multiaxial fatigue non-proportional arbitrary stressing non-proportional random loading damage accumulation |
本文献已被 ScienceDirect 等数据库收录! |
|