Development of a regression model for the life assessment of open-hole specimens with double through cracks utilizing stress intensity factor calculations via XFEM

Shabestari S. S. H., KAYRAN A.

1st International Workshop on Plasticity, Damage and Fracture of Engineering Materials, IWPDF 2019, Ankara, Turkey, 22 - 23 August 2019, vol.21, pp.154-165 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 21
  • Doi Number: 10.1016/j.prostr.2019.12.097
  • City: Ankara
  • Country: Turkey
  • Page Numbers: pp.154-165
  • Middle East Technical University Affiliated: Yes


In this study, a regression analysis model has been developed to calculate the fatigue life of open-hole specimens with a double through cracks without significantly compromising on the accuracy. In the first phase of the study, experimental fatigue life data for open-hole 2024-T3 aluminum specimens with double through the thickness cracks is extracted from experimental test data. Life assessment model corresponding to the experimental data is generated using the Forman equation to fit the da/dN vs delta K crack growth data, and material constants and plane stress intensity factor of 2024-T3 alloy in the Forman equation are obtained. Extended finite element method (XFEM) has then been employed to model the same open-hole specimen geometry with a double through the thickness cracks to check the accuracy of the XFEM results with the experimental fatigue life data. XFEM simulation for the crack growth and determination of the stress intensity factor during the crack propagation has been performed for different combinations of the initial crack length, rivet hole diameter and applied far field stress utilizing design of experiments based on Response Surface (RS) method. Utilizing the transformed fatigue life results obtained by the XFEM method, a regression analysis of the RS experiments has been performed and a regression model capable of acceptable life prediction of open hole specimens with DTC has been developed. (c) 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( Peer-review under responsibility of the 1st International Workshop on Plasticity, Damage and Fracture of Engineering Materials organizers