Effect of Welded Stiffeners on Crack Growth Rate

摘要

The growth of large fatigue cracks was studied in welded, stiffened panelsthrough the use of analytical, numerical, and experimental means. Large-scale testing was conducted by integrating welded, stiffened panels into a box girder configuration subjected to cyclic fatigue loading. The experiments shows a decrease in the crack growth rate between stiffeners, which is attributed to compressive residual stress between stiffeners, case residual stress between stiffeners, case residual stress field representation. Numerical modeling is performed using finite element models, with temperature gradients simulating residual stresses, to calculate the J-Integral around the crack tip at different stages of crack development, and transforming the results of the experiments conservatively with reasonable accuracy. Simply crack growth calculations that ignore the residual stress fields and the stiffeners give results that are too conservative by a factor of about three on the life. On the other hand, simple correction factors for the stiffeners give very unconservative results, also by a factor of about three.