Fatigue Life Estimation of Typical Fighter Aircraft Main Landing Gear Using Finite Element Analysis

Fatigue analysis of main landing gear of typical fighter aircraft was carried out using MSC Fatigue software considering the strain spectra measured at critical location during the flight starting from taxiing, take-off to landing. In the absence of load information on the landing gear, a methodology was proposed to calculate the equivalent load system from measured strains and verified. Fatigue life of landing gear was obtained using various stress spectra based on stress-life approach and was compared with the fatigue life calculated using constant life diagram (CLD) approach. Fatigue life estimation using Gerber mean stress correction was found to be in good agreement with the fatigue life estimation using CLD approach. Fatigue analysis using maximum absolute principal stress criterion and linear damage rule give the conservative fatigue life, and hence, these criteria may be used as fatigue life estimation criteria for design.