TY - JOUR

T1 - A phase-field fracture model for fatigue using locking-free solid shell finite elements

T2 - Analysis for homogeneous materials and layered composites

AU - Asur Vijaya Kumar, Pavan Kumar

AU - Dean, Aamir

AU - Reinoso, José

AU - Pettermann, Heinz E.

AU - Paggi, Marco

N1 - Funding Information: MP would like to acknowledge funding from the Italian Ministry of University and Research to the Research Project of National Interest PRIN 2017 “XFAST-SIMS: Extra fast and accurate simulation of complex structural systems” (MUR code 20173C478N). JR is grateful to the financial support of Ministerio de Ciencia e Innovación (Projects TED2021-131649B-I00 and PID2019-109723GB-I00) and the funding received from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 101086342 – Project DIAGONAL (Ductility and fracture toughness analysis of functionally graded materials; HORIZON-MSCA-2021-SE-01 action)

PY - 2023/10

Y1 - 2023/10

N2 - A computational framework to model fatigue fracture in structures based on the phase-field method and the solid-shell concept is herein presented. With the aim of achieving a locking free solid-shell finite element formulation with fracture-prediction capabilities, both the combination of the Enhanced Assumed Strain (EAS) and Assumed Natural Strain (ANS) methods with phase field of fracture is exploited. In order to achieve realistic prediction, the crack driving force is computed using positive/negative split of the stress field. Moreover, the difference between the driving forces are pinpointed. Furthermore, based on thermodynamic considerations, the free energy function is modified to introduce the fatigue effect via a degradation of the material fracture toughness. This approach retrieves the SN curves and the crack growth curve as expected. The predictive capability of the model is evaluated through benchmark examples that include a plate with a notch, a curved shell, mode II shear, and three-point bending for homogeneous materials, as well as a dogbone specimen for homogenized fiber-reinforced composites. Additionally, comparative analysis is performed with previous results for the plate with notch and mode II shear tests, while the dogbone specimen is compared with experimental data to further validate the accuracy of the present model.

AB - A computational framework to model fatigue fracture in structures based on the phase-field method and the solid-shell concept is herein presented. With the aim of achieving a locking free solid-shell finite element formulation with fracture-prediction capabilities, both the combination of the Enhanced Assumed Strain (EAS) and Assumed Natural Strain (ANS) methods with phase field of fracture is exploited. In order to achieve realistic prediction, the crack driving force is computed using positive/negative split of the stress field. Moreover, the difference between the driving forces are pinpointed. Furthermore, based on thermodynamic considerations, the free energy function is modified to introduce the fatigue effect via a degradation of the material fracture toughness. This approach retrieves the SN curves and the crack growth curve as expected. The predictive capability of the model is evaluated through benchmark examples that include a plate with a notch, a curved shell, mode II shear, and three-point bending for homogeneous materials, as well as a dogbone specimen for homogenized fiber-reinforced composites. Additionally, comparative analysis is performed with previous results for the plate with notch and mode II shear tests, while the dogbone specimen is compared with experimental data to further validate the accuracy of the present model.

KW - A. Phase-field method

KW - B. Solid-shell

KW - C. Finite element method

KW - D: Fatigue

KW - E. Fracture

UR - http://www.scopus.com/inward/record.url?scp=85167983621&partnerID=8YFLogxK

U2 - 10.1016/j.tafmec.2023.104029

DO - 10.1016/j.tafmec.2023.104029

M3 - Article

AN - SCOPUS:85167983621

VL - 127

JO - Theoretical and Applied Fracture Mechanics

JF - Theoretical and Applied Fracture Mechanics

SN - 0167-8442

M1 - 104029

ER -