Further Advances in a Recently Developed Cumulative-Damage Reliability Method

Recent advances in helicopter fatigue engineering have demonstrated great promise for providing efficient reliability calculations during iterations of the design process. These methods are intended to replace more computationally intensive Monte Carlo methods which have provided practical insight in the past. This paper expands on recently developed analytic cumulative-damage reliability tools (namely, the "Benton α- and Δ-functions") to study the effects of fatigue strength and usage distribution assumptions in the presence of load variation. Gaussian quadrature is introduced to expand the tools to handle non-integer exponents within the fatigue strength curve parameterization. Adaptations of the tool are also explored to allow for alternative characterizations of the fatigue strength curve. Finally, the method is expanded to cover the case of probabilistic usage.