Investigation of Mixed-Mode Fatigue Crack Growth Phenomenon with a New Computational Procedure

Abstract

Analysis of 3-D fatigue crack growth problems with mixed-mode loading has always been an interesting area in the field offracture mechanics. Fracture failure under the influence of fatigue loading has been a common experience for variousindustries’ products, such as aerospace and automotive components. Any possible failure in these structures can result in highdamage to these components or a serious risk for people’s health. The analysis of such failures may involve great challengesand complexities for obtaining the accurate solution. The complexities of the problem may not only be related to the loadingtype, but also to the specific geometry itself. Such problems are hard and costly to analyze with experimental methods.Therefore, it is important to establish the theoretical aspects of the process initially, and then having a computationalprocedure to solve the problem at hand. The crack growth law used in this procedure is NASGRO-type, and determination ofthe propagation angle is based on the maximum hoop stress criterion. Hypermesh and ANSYS APDL software are benefitedduring preprocessing of the propagation steps and application of submodeling procedure. Solution of the problem isperformed with FRAC3D program, its enriched element methodology and newly implemented tools for crack growth. Aspecific example that includes cracking within an aircraft engine compressor blade is shown for demonstration purpose.