Identifying crack tip position and stress intensity factors from displacement data

• Published in: International journal of fracture Vol. 243; no. 1; pp. 47 - 63
• Main Authors: Gupta, Swati, West, Grant, Wilson, Mark A., Grutzik, Scott J., Warner, Derek H.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2023; Springer Nature B.V; Springer
• Subjects: Asymptotic properties; atomistic fracture; Automotive Engineering; Characterization and Evaluation of Materials; Civil Engineering; Classical Mechanics; Crack tips; digital image correlation; Digital imaging; displacement data; Engineering; finding crack tip positions; fracture; Fracture mechanics; Inelastic materials; Linear elastic fracture mechanics; MATERIALS SCIENCE; Mathematical analysis; Mechanical Engineering; Molecular dynamics; separability approach; Stress intensity factors; Unstructured data; Digital Image Correlation; Fracture; Displacement data; Separability approach; Finding crack tip positions; Stress Intensity Factors; Atomistic fracture
• ISSN: 0376-9429; 1573-2673
• DOI: 10.1007/s10704-023-00729-4

Fracture prognosis and characterization efforts require knowledge of crack tip position and the Stress Intensity Factors (SIFs) acting in the vicinity of the crack. Here, we present an efficient numerical approach to infer both of these characteristics under a consistent theoretical framework from noisy, unstructured displacement data. The novel approach utilizes the separability of the asymptotic linear elastic fracture mechanics fields to expedite the search for crack tip position and is particularly useful for noisy displacement data. The manuscript begins with an assessment of the importance of accurately locating crack tip position when quantifying the SIFs from displacement data. Next, the proposed separability approach for quickly inferring crack tip position is introduced. Comparing to the widely used displacement correlation approach, the performance of the separability approach is assessed. Cases involving both noisy data and systematic deviation from the asymptotic linear elastic fracture mechanics model are considered, e.g. inelastic material behavior and finite geometries. An open source python implementation of the proposed approach is available for use by those doing field and laboratory work involving digital image correlation and simulations, e.g. finite element, discrete element, molecular dynamics and peridynamics, where the crack tip position is not explicitly defined.