Statistical strength criterion for materials with hexagonal close-packed crystal lattice

Dependences of concentration of the normal microstresses arising from interaction of elastic anisotropic grains, on a type of a combined stress-strain state are investigated. With use of the received dependences, for polycrystals which grains have no cleavage planes, the statistical strength criterion of the oriented fracture is suggested. The experimental data analysis for titan has shown that the criterion suggested provides more reliable strength prognosis for rigid stress states in comparison with known phenomenological criteria. Two parameters of a suggested criterion for hexagonal close-packed crystal lattice materials are determined for polycrystal model using the finite element analysis. Three others are suggested to be defined experimentally by means of a tension test performed on cylindrical specimens with notches of a various tip sharpness.