Probabilistic load and damage modeling for fatigue life management

A method for determining a remaining fatigue life of a component of an aircraft, the method comprising:

• subjecting the component to structural usage caused by operational loads during usage of the aircraft;
• generating, by a flight data recorder, flight data recordings of the aircraft during the usage of the aircraft;
• monitoring, by a sensor of the flight data recorder, the component while the component is being subjected to structural usage caused by operational loads during the usage of the aircraft and generating, by the sensor, at least a subset of the flight data recordings;
• receiving, by a first processing circuit, the flight data of the aircraft from the flight data recorder and selecting, by the first processing circuit, portions of the received flight data, the selected flight data of the aircraft including at least portions of the subset of flight data of the aircraft;
• receiving, by a first storage circuit, the selected flight data of the aircraft from the first processing circuit and storing, by the first storage circuit, the selected flight data of the aircraft;
• storing, by a second storage circuit, regression models for probabilistic prediction of minimum load, maximum load, and timeframe damage of the component;
• receiving, by a second processing circuit, the selected flight data from the first storage circuit and the regression models from the second storage circuit;
• generating, by the second processing circuit, probability density functions of minimum load, maximum load, and timeframe damage for predetermined time intervals based on the selected flight data and the regression models;
• computing, by the second processing circuit, an accumulated fatigue damage estimation based on the probability density functions and a probabilistic fatigue strength model to generate a distribution of the accumulated fatigue damage estimation of the component;
• comparing, by the second processing circuit, the distribution of the accumulated fatigue damage estimation with a reliability requirement to determine the remaining fatigue life of the component;
• outputting, by the second processing circuit, an increased flight-hour-based interval between replacement of the component when the remaining fatigue life of the component is greater than a fatigue life of the component based on a fixed fatigue damage accumulation rate assumed by an original equipment manufacturer (OEM) of the aircraft;
• and
• outputting, by the second processing circuit, a decreased flight-hour-based interval between replacement of the component when the remaining fatigue life of the component is less than the fatigue life of the component based on the fixed fatigue damage accumulation rate assumed by the OEM of the aircraft.

An aircraft comprising:

• a component that is subjected to structural usage by operational loads during usage of the aircraft;
• a fatigue life management system for determining a remaining fatigue life of the component, the fatigue life management system including
• a flight data recorder that generates flight data recordings of the aircraft during the usage of the aircraft, the flight data recorder having a sensor coupled to the component, the sensor monitors the component while the component is being subjected to structural usage caused by operational loads during the usage of the aircraft to generate at least a subset of the flight data recordings;
• a first processing circuit that receives the flight data of the aircraft from the flight data recorder and selects portions of the received flight data, the selected flight data of the aircraft including at least portions of the subset of flight data of the aircraft;
• a first storage circuit that receives the selected flight data of the aircraft from the first processing circuit and stores the selected flight data of the aircraft;
• a second storage circuit that stores regression models for probabilistic prediction of minimum load, maximum load, and timeframe damage of the component;
• and
• a second processing circuit that receives the selected flight data from the first storage circuit and the regression models from the second storage circuit, generates probability density functions of minimum load, maximum load, and timeframe damage for predetermined time intervals based on the selected flight data and the regression models, computes an accumulated fatigue damage estimation based on the probability density functions and a probabilistic fatigue strength model to generate a distribution of the accumulated fatigue damage estimation of the component, compares the distribution of the accumulated fatigue damage estimation with a reliability requirement to determine the remaining fatigue life of the component, and outputs an increased flight-hour-based interval between replacement of the component when the remaining fatigue life of the component is greater than a fatigue life of the component based on a fixed fatigue damage accumulation rate assumed by an original equipment manufacturer (OEM) of the aircraft and outputs a decreased flight-hour-based interval between replacement of the component when the remaining fatigue life of the component is less than the fatigue life of the component based on the fixed fatigue damage accumulation rate assumed by the OEM of the aircraft.