Crack path predictions in anisotropic structures considering residual stresses

Abstract

AbstractDifferent mechanical processes induce a directional microstructure (texture) during the production of a material, e.g. during the hot rolling of aluminum plates or the injection molding process of natural fiber reinforced bio‐polymers. In such materials the anisotropic mechanical features are related to the texture and have a decisive impact on the fracture process. Rolling or shot peening processes, on the other hand, induce an irreversible plastic deformation and residual compressive stresses for the purpose of a surface toughening. Similarly, residual stresses are induced if a circular core with interference fit is inserted into a drilled hole. The measurement of crack paths in specimens with residual stresses due to a core reveals an influence of the core's interference with respect to the crack deflection and the resulting paths [1,2]. Numerical investigations of fatigue crack growth show that conventional crack deflection criteria are not valid in such specimens, as the deflection angle depends on the magnitude of the external loading, going along with a rotation of the principal stress axes and thus the Jk‐vector [2]. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)