Corrosion and Corrosion Fatigue of Airframe Materials
Abstract
This report summarizes research performed under Grant 92-G-0006 and complementary programs sponsored by the Air Force Office of Scientific Research under Grants F49620-96-1-0245 and F49620-9g-1-0198. The objectives of these programs are (1) the development of a basic understanding of the processes of localized corrosion and corrosion fatigue crack nucleation and growth in high strength aluminum alloys used in airframe construction, (2) the formulation of kinetic models for these elemental processes, and (3) the integration of these models into probabilistic models that can provide guidance in formulating methodologies for service-life prediction and airworthiness assessment. The research showed that localized pitting corrosion acts as crack nuclei and causes early crack nucleation and the onset of fatigue crack growth. It can significantly reduce the service lives of structural components. Fundamental understanding of these targeted mechanisms and measurements of their kinetics of evolution are summarized. A simplified, probability model, based on this understanding, was developed and used to demonstrate the feasibility of translating laboratory data into predictions of the evolution and distribution of damage of aircraft in service. Agreement between model predictions and distribution of damage in the lower wing skin of an aircraft that had been in commercial service for 24 and 30 years illustrates the efficacy of this approach. It confirms the importance of incorporating the impact of localized corrosion into the structural reliability and airworthiness assessment methodologies.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2000
- Accession Number
- ADA382761
Entities
People
- Robert P. Wei
Organizations
- Lehigh University