Development of Transfer Functions to Relate F-111 Aircraft Fatigue Data AnalysisSystem (AFDAS) Strain Outputs to Loads and Control Point Stresses

摘要

The Aircraft Fatigue Data Analysis System (AFDAS) is a strain based fatigue datacollection and analysis system, fitted to several aircraft types including eleven of the RAAF's F-111 fleet. AFDAS gauge strain data from various static strain surveys were used to develop transfer functions which relate strain from the AFDAS gauges to stresses at nearby control points as well as aircraft loading information. Relating the strain to load was a straightforward exercise, and in some cases it was also a simple matter to relate AFDAS strain to control point stress. In many cases however, the process of establishing a link between AFDAS strain and control point stress involved utilising existing load to stress relationships from the manufacturer. This process identified deficiencies/inaccuracies in several of the manufacturer's stress equations. This report documents the development of the transfer functions, and details the deficiencies in the manufacturer's stress equations. Additional work to develop the transfer functions by direct analysis is recommended.