An Evaluation of 3D Crack Growth Using ZENCRACK

DSTO has been continuously enhancing its capability to provide through-life support to the ADF in aircraft engine life extension and engine component life management. One of the major requirements is an enhancement in computational 3D crack growth modelling and analysis. This report presents the critical issues involved in 3D crack growth and evaluates the results of a 3D crack growth capability in the ZENCRACK software with an emphasis on its validity and applicability to our major requirements. The primary issues to be dealt with in practice for 3D crack modelling are outlined together with the limitations of existing software. The methodology and techniques implemented in ZENCRACK are described and discussed. Four practical applications of ZENCRACK and individual evaluations for particular problems are presented and discussed in detail. The various limitations and uncertainties encountered in the practical applications are identified. In particular, it is found that ZENCRACK is a useful tool for the calculation of stress intensity factors but is limited in terms of its accuracy for predicting crack growth rate. Conclusions and recommendations are made for more accurate 3D crack growth modelling. --Original contains color plates: All DTIC reproductions will be in black and white.