Damage Tolerance Analysis of Grinding Burn Cracks in High Strength Steels

High strength steel landing gear parts may develop material burns from grinding during manufacture and overhaul or from in-service friction loads. Material burns can develop micro-structurally small cracks that lead to part failure. The feasibility of applying damage tolerance analysis (DTA) using linear elastic fracture mechanics (LEFM) to selected areas of landing gear parts will be evaluated. For this, the initial crack state of material burns will be characterized, the conditions that develop material burns will be characterized, the feasibility of applying DTA to selected areas of landing gear parts will be demonstrated, non-destructive inspection capabilities to quantify cracks in material burns will be surveyed, and a test plan that develops data to apply DTA methods using LEFM to predict critical crack sizes and crack growth rates for high strength steel with material burns will be developed.