Prediction of Ductile Fracture of Thin-Walled Cylinders Subjected to Localized Intense Heat

摘要

The objective of this research was to further develop two models that are capable of predicting crack growth in ductile materials. In this study, we measured CTOA (crack tip opening angle) at elevated temperatures for a stainless steel and aluminum alloy 2014-T6. The CTOA curves were then used as the fracture criterion to simulate crack extension and instability in thin- walled cylinders subjected to localized intense heat. The commercial finite element code ABAQUS was used in conjunction with a user subroutine to implement the CTOA fracture criterion to perform the simulation. The result of the numerical simulations indicated that the effect of temperature on the level of burst pressure of the cylinder is not very significant. One explanation for this interesting behavior is that the heated zone that contains the crack would be subject to compressive stresses because of a greater thermal expansion. In this study, an analytical damage length (DL) model has been further developed to account for the thermal effect in addition to the large deflection effect. The DL model was also used to predict the burst pressure of steel and aluminum cylinders and the results are compared favorably with those predicted by the CTOA approach.