New Method for the Statistical Evaluation of Constant Stress Amplitude Fatigue-Test Results

REGRESSION MODELS, BASED ON LINEAR ELASTIC FRACTURE MECHANICS, ARE USED TO INTERPRET THE EFFECT OF STRESS RATIO ON FATIGUE CRACK GROWTH RATE IN 7075-T6 ALUMINUM ALLOY. IT IS SHOWN THAT FATIGUE CRACK GROWTH RATE CAN BE RELATED TO RANGE AND MAXIMUM VALUES OF STRESS-INTENSITY FACTOR. STATISTICAL TECHNIQUES ARE USED TO EXAMINE THE ERROR WHICH MAY ACCUMULATE WHEN REGRESSION EQUATIONS ARE USED TO PREDICT CRACK GROWTH VERSUS CYCLES CURVES. /ASTM/