Eccentricity correction for the evaluation of fracture toughness from cylindrical notched test small specimens. Establishing K 1c from eccentrically fatigue cracked small circumferentially grooved cylindrical specimens. Estimating fracture toughness from small specimens. ASTM International: West Conshohocken, PA, USA, 2012.

ASTM E399 Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness K Ic of Metallic Materials.

The funders had no role in the design of this study in the collection, analysis, or interpretation of data in the writing of the manuscript and in the decision to publish the results. The authors declare no conflict of interest. In addition to the fatigue crack path study, closed-form stress intensity factor (SIF) solutions for the considered geometry (a cylinder with an outer annular crack) are provided in the form of third-degree polynomial expressions as a function of the ligament diameter and the crack eccentricity (both in dimensionless terms). The paper also analyzes in depth the different situations regarding contact between crack faces during subcritical cyclic fatigue propagation, covering a wide range of cases including no contact, partial contact, and full contact depending on the ligament diameter (during the process of fatigue crack advance) and the relative eccentricity of the annular crack that loses its axial symmetry in relation to the round bar (cylinder) axis. This phenomenon is more pronounced when the solicitation consists of a remote tensile loading than when it is an axial displacement, when the initial eccentricity of the ligament increases (for a given initial diameter), and when the Paris exponent characteristic of the material rises.

Results show how the eccentricity (in relation to the wire axis) of the circular resistant ligament increases with the growth of outer circumferential cracks by subcritical fatigue mechanisms. In this paper, a numerical modeling was developed to study (on the basis of the Paris law) the fatigue propagation paths of eccentric external (outer) cracks in circumferentially cracked round bars (CCRB) subjected to a cyclic type of loading in the form of either remote tensile loading or imposed axial displacement.

Film impact transitions crack