Fatigue crack propagation analysis using XFEM for cladded C(T) specimens and its validation

Abstract

To investigate the crack growth behavior in a cladded structure, a numerical simulation method based on the extended finite element method (XFEM) was developed. This method employs 8-node hexahedral continuum elements enriched only with the Heaviside step function, which can model planar crack independently of finite elements. For a crack across the interface of dissimilar materials in cladded structures, stress intensity factors along the crack front are evaluated by the domain integral method. Crack front shapes are updated by using Paris’ law and then smoothed by cubic Bézier curves in each region. In addition, fatigue crack propagation analyses for cladded compact tension [C(T)] specimens were performed. The relationships between crack length and load cycles as well as the transition of propagating crack front shapes were compared with experimental results and validated. Furthermore, sensitivity analyses were performed to explore the influence on the crack propagation behaviors of analysis parameters and conditions. The developed method was shown to provide an appropriate approximation of fatigue crack growth behaviors in cladded C(T) specimens.

Keywords

• extended finite element method (xfem)
• stress intensity factor
• fatigue crack propagation
• cladding structure
• compact tension specimen
• orthotropic material