Numeric Simulation of Fatigue Crack Growth in a Material Graded Structure

Abstract

This article deals with the development of functional graded materials which is pursued by the collaborative research centre Transregio 30. The functional gradation is produced by a thermo-mechanical production process and is characterized by different fracture mechanical specific values. Because cracks are by all means responsible for failure of structural elements crack growth has to be considered during the development of these materials. In this contribution simulations of crack growth which were carried out with the system ADAPCRACK3D are presented to illustrate the influence of a material gradation on crack growth.

Crack propagation in fracture mechanical graded structures

“…The use of a pronounced smoother transition with better fracture mechanical properties than the martensitic microstructure results in a higher critical crack depth ac  12 mm and increases the tolerated load cycles by the factor 1.6 compared to the sharp transition. This simulation with ADAPCRACK3D clarifies among other things that a good choice of material gradation might influence the lifetime of structure in a positive way [4,9].…”

“…In the following, simulations with the two-dimensional program FRANC/FAM*, which is modified by the TSSR-concept to be able to consider the influence of the fracture mechanical gradation, and the three-dimensional program ADAPCRAKC3D are used. More information and further examples considering the crack simulation in fracture mechanical graded structures can be found in [4,8,9].…”