US 11,772,823 B2
Estimating fatigue damage in a structure
Monadl Abd Al-Abbas Mansour Al-Ameri, Preston (GB); and Bhadrayu Manherlal Ranat, Preston (GB)
Assigned to BAE Systems plc, London (GB)
Appl. No. 16/759,410
Filed by BAE Systems plc, London (GB)
PCT Filed Nov. 22, 2018, PCT No. PCT/GB2018/053377
§ 371(c)(1), (2) Date Apr. 27, 2020,
PCT Pub. No. WO2019/110957, PCT Pub. Date Jun. 13, 2019.
Claims priority of application No. 1720172 (GB), filed on Dec. 4, 2017.
Prior Publication US 2020/0339286 A1, Oct. 29, 2020
Int. Cl. B64F 5/60 (2017.01); G01L 1/22 (2006.01); G01L 1/06 (2006.01); B64D 45/00 (2006.01)
CPC B64F 5/60 (2017.01) [G01L 1/06 (2013.01); G01L 1/22 (2013.01); B64D 2045/0085 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method of estimating fatigue damage in an airframe, the method comprising:
performing a test flight over at least part of an operating envelope of the airframe;
during the performance of the test operation:
obtaining fatigue damage data using at least one strain gauge fixed to the airframe; and
obtaining airframe use parameter data comprising aircraft flight data and control surface actuator data that corresponds to the fatigue damage data;
using the obtained fatigue data and the obtained airframe use parameter data to compute coefficients of a generic polynomial function that outputs a fatigue damage value based on inputs representing the airframe use parameter data;
transferring data representing the computed coefficients to a computing device on-board a second airframe, wherein the computing device on-board the second airframe comprises the generic polynomial function; and
incorporating the computed coefficients into the generic polynomial function of the computing device on-board the second airframe; and
using the generic polynomial function to output an estimated fatigue damage value based on inputs representing airframe use parameter data collected during use of the second airframe;
comparing an accuracy of the estimated fatigue damage values associated with the second airframe with a desired accuracy, and, if the accuracy does not meet the desired accuracy then:
dividing the obtained fatigue data and the obtained airframe use parameter data associated with the second airframe into two or more sets; and using the obtained fatigue data and the obtained airframe use parameter data associated with the second airframe of each said set, computing coefficients of a said generic polynomial function associated with that set,
wherein the computing device is configured to receive airframe use parameter data associated with the second airframe, and
wherein the computing device is configured to periodically calculate a fatigue damage value associated with the second airframe.