An Interval Fracture Analysis Method for Cracked Structures with Unknown-But-Bounded Parameters

An interval fracture analysis method based on the Taylor expansion is presented to predict the stress intensity factor (SIF) bounds for cracked structures with unknown-but-bounded param -eters. Traditional probabilistic fracture analysis requires numerous sample points, because large errors will occur when the probability density distribution function of the parameters cannot be described by sufficient sample points. In the present paper, the expression of the SIF crack structure is given using the quarter-point displacement method. Then, the interval expressions of mode-I and mode-II SIF are obtained using the Taylor expansion and the interval finite element method, and the upper and lower limits of an equivalent SIF (ESIF) are deter-mined. Finally, the new method is analytically compared with the interval Monte Carlo method. Numerical examples show that the influence of load uncertainty considerably surpasses that of the dimension uncertainty. The mode-I SIF has a greater impact on the ESIF. As the uncertain level increases, the accuracy of the upper and lower limits of the ESIF calculated by the new method is maintained at a high level.