Fatigue Crack Growth Prediction on Su-30MKM Horizontal Stabilizer Lug Using Static Analysis

Abstract

The critical aircraft structure is the load-bearing members are a vital component for any aircraft. The effect of fatigue loading, operating conditions, and environmental degradation has caused the structural integrity of the airframe to be assessed for its airworthiness requirement.   Using the fatigue design concept of Safe Life, the RMAF adopts the fatigue life assessment and crack growth prediction to monitoring its critical components' structural integrity. Various methods were used, and for this analysis, the Crack Growth Prediction method was used to determine the crack growth behavior and its ultimate failure point in case of any crack occurrences. The horizontal stabilizer lug was chosen since it has the highest possibility of fatigue failure. The analytical methods discussed are Crack Growth Analysis and Low Cycle Fatigue. For the numerical method, Nastran was used to simulate crack growth. The result from the crack growth analysis was validated with the numerical result. The conclusion is that, based on the fatigue life cycle, the structure condition is not affected by severe damage, and its failure is approximately around 1 million cycles, and the crack growth location on the bottom of the lug is the critical location. The research outcome will be on the extension of the structure life of the lug.