SOLUTION-ADAPTIVE CODE FOR ANALYSIS OF FATIGUE CRACK PROPAGATION IN AEROSPACE STRUCTURES

THIS PROJECT WILL DEVELOP SOLUTION-ADAPTIVE TECHNIQUES AND ACOMPUTER CODE FOR USE IN ANALYZING FATIGUE-CRACK PROPAGATIONIN AEROSPACE STRUCTURAL COMPONENTS. A FRACTURE ANALYSIS COMPUTATIONAL TOOL WILL BE CREATED USING MODERN ADAPTIVE FINITE ELEMENT TECHNIQUES, EXTRACTION FORMULAS, AND CRACK-PROPAGATION THEORIES. THE CODE WILL BE VIRTUALLY A STAND-ALONE MODULE IN THAT IT WILL REQUIRE NO ADDITIONAL STRUCTURAL MODELING OTHER THAN A DESCRIPTION OF THE MATERIALFLAW. IT WILL BE DEVELOPED AS A POST PROCESSOR TO EXISTING FINITE-ELEMENT PROGRAM PACKAGES. THE FINITE-ELEMENT MODEL OF THE UNFLAWED STRUCTURE WILL BE PREPARED IN THE SAME MANNER AS IS CURRENTLY DONE. FLAWS CAN BE INTRODUCED INTO THESE EXISTING FINITE-ELEMENT MODELS AND THE FRACTURE ANALYSIS PERFORMED IN A MANNER VIRTUALLY TRANSPARENT TO THE USER. WITH VERY LITTLE ADDITIONAL EFFORT THE STRESS ANALYSTCAN THEN PERFORM A FRACTURE-MECHANICS ANALYSIS. PHASE I WILL FOCUS ON SOLUTION-ADAPTIVE ALGORITHM DEVELOPMENT AND WILL UTILIZE STRESS-INTENSITY FACTOR CALCULATIONS FOR FATIGUE-LIFE PREDICTION. PHASE II WILL INCLUDE RESEARCH ANDDEVELOPMENT INTO CONSTITUTIVE THEORIES OF FRACTURE, ACCURATESTRESS RECOVERY PROCEDURES, ADAPTIVE REFINEMENT STRATEGIES, AND DEVELOPMENT AND DELIVERY OF A GENERAL THREE-DIMENSIONAL CODE. THIS PROJECT WILL DEVELOP SOLUTION-ADAPTIVE TECHNIQUES AND ACOMPUTER CODE FOR USE IN ANALYZING FATIGUE-CRACK PROPAGATIONIN AEROSPACE STRUCTURAL COMPONENTS. A FRACTURE ANALYSIS COMPUTATIONAL TOOL WILL BE CREATED USING MODERN ADAPTIVE FINITE ELEMENT TECHNIQUES, EXTRACTION FORMULAS, AND CRACK-PROPAGATION THEORIES. THE CODE WILL BE VIRTUALLY A STAND-ALONE MODULE IN THAT IT WILL REQUIRE NO ADDITIONAL STRUCTURAL MODELING OTHER THAN A DESCRIPTION OF THE MATERIALFLAW. IT WILL BE DEVELOPED AS A POST PROCESSOR TO EXISTING FINITE-ELEMENT PROGRAM PACKAGES. THE FINITE-ELEMENT MODEL OF THE UNFLAWED STRUCTURE WILL BE PREPARED IN THE SAME MANNER AS IS CURRENTLY DONE. FLAWS CAN BE INTRODUCED INTO THESE EXISTING FINITE-ELEMENT MODELS AND THE FRACTURE ANALYSIS PERFORMED IN A MANNER VIRTUALLY TRANSPARENT TO THE USER. WITH VERY LITTLE ADDITIONAL EFFORT THE STRESS ANALYSTCAN THEN PERFORM A FRACTURE-MECHANICS ANALYSIS. PHASE I WILL FOCUS ON SOLUTION-ADAPTIVE ALGORITHM DEVELOPMENT AND WILL UTILIZE STRESS-INTENSITY FACTOR CALCULATIONS FOR FATIGUE-LIFE PREDICTION. PHASE II WILL INCLUDE RESEARCH ANDDEVELOPMENT INTO CONSTITUTIVE THEORIES OF FRACTURE, ACCURATESTRESS RECOVERY PROCEDURES, ADAPTIVE REFINEMENT STRATEGIES, AND DEVELOPMENT AND DELIVERY OF A GENERAL THREE-DIMENSIONAL CODE.