Short-Crack Growth Behaviour in an Aluminum Alloy - An AGARD Cooperative Test Programme

摘要

An AGARD test program on the growth of short fatigue cracks was conducted to define the significance of the short-crack effect, to compare test results from various laboratories and to evaluate and existing analytical model to predict the growth of such cracks. The first phase of this program, the Core Program, was aimed at test procedure and specimen standardization and calibration of the various laboratories. A detailed working document has been prepared and is included in this report. It describes the testing fundamentals and procedures and includes the analytical procedures used for handling the test data. The results from the test program showed good agreement among the participants on short-crack growth rates, on fatigue life to various crack sizes and breakthrough (surface- or corner-crack became a through crack), and on crack shapes. A crack-growth model, incorporating crack-closure effects was used to analyze the growth of short cracks from small (inclusion) defects in the material along the notch surface. Keywords: Aluminum alloys; Crack propagation; Mathematical models; experimental data; Fatigue life; Comparison. (Jes)