Superposition of flight loads for a probabilistic damage tolerance design for an acrobatic aircraft

摘要

Purpose - To present a method of interaction between flight loads that is applied to a probabilistic damage tolerance analysis in an acrobatic aircraft. Design/methodology/approach - The uncertainties concerning material strength, initial crack size and loads in the aircraft are considered. We place special emphasis on stress distribution, using superposition criteria that distinguish between gust, maneuver and ground-air-ground loads. Gust load is generated form its power spectral density and modified using service load data (exceedance curves). Crack initiation time and propagation time are considered in calculating the service time. Findings - A new and realistic method of interaction between loads during acrobatic flight is proposed. This method was compared with other methods in an example. The effects of the interaction criteria are related to the influence between loads (stress levels and frequency). Originality/value - In commercial aircraft, maneuver loads have a lower influence than gust loads, and the mission concept is the correct approach. Training aircraft have the opposite king of behavior and the proposed superposition method is shown to be better approach. This method would have more pronounced effects in aircraft types with behaviors between commercial and training (for example, amphibious aircraft).