Fracture Mechanics Design Methodology
ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRANCE)
Pagination or Media Count:
Ths lecture series presents a review of the state of the art of damage tolerance analysis of airplanes. It shows that damage tolerance and fail safety assessment are out of the stage that tests were the only means to get answers to the pertinent questions regarding crack growth and residual strength. It also shows that tests are still indispensable, so that the question can be raised what has been gained by the development of analysis procedures. Tests only give information for a few specific areas e.g., in a full scale test only one representative spectrum and load history are applied and only a limited number of critical locations can be evaluated. Analysis provides the means to evaluate spectrum variations, different airplane usage, other critical locations, and most important, design alternatives. Analysis still has shortcomings, but many of these apply equally much to experiments insomuch as the reliability of test data and analysis results depend largely upon spectrum evaluation, flight load analysis, stress history, etc. Other shortcomings of the analysis can be largely overcome by using the tests to adjust predictions of crack growth and residual strength.