Fatigue Fracture Analysis and Development of Fundamentals of Predictive NDE of Adhesive Composite Joints
Abstract
The objective of this research was a systematic fatigue fracture analysis and development of fundamentals of predictive nondestructive evaluation of adhesive composite joints for aerospace structural applications. Fatigue fracture of joints was studied using fracture mechanics methods. A mixed mode fracture model was developed and validated. Feasibility of prediction of fatigue life of joints was demonstrated. Several methods of nondestructive evaluation of cracks in joints were significantly enhanced based on wave propagation modeling. Ultrasonic through thickness and longitudinal (acousto-ultrasonic) methods were explored and sensor configurations were optimized based on modeling. The accuracy of crack location evaluation was enhanced by modal analysis. A pioneering method of nondestructive evaluation of loading mode mixity at the crack tip was developed based on the pattern recognition acoustic emission (AE) analysis. The method was validated experimentally and confirmed by modeling. The feasibility of real-time monitoring of adhesive joints using built-in sensors was demonstrated. A new method and specimen for experimental evaluation of transverse fracture resistance of an isotropic composites was developed. The results provide better understanding of fatigue behavior of adhesive composite joints. The demonstrated combined modeling-based QNDE and advanced fracture mechanics approach for life prediction constitutes a fundamental basis for the next generation Smart NDE (SNDE) systems with mechanics- based predictive capabilities. The research was performed in close collaboration with AFRL/MLBC.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2005
- Accession Number
- ADA431776
Entities
People
- Y. A. Dzenis
Organizations
- University of Nebraska–Lincoln