Smoothing the propagation of smeared cracks

• A new local crack propagation algorithm is developed to reduce mesh-induced directional bias.
• The algorithm determines smooth curved crack paths within and across conventional continuum elements.
• Furthermore, the algorithm includes the possibility to postpone the moment of crack path fixation.
• Combined with a classical fixed smeared crack model a significant increase of mesh objectivity is obtained.
• Specifically, quadratic elements show mesh independence and good agreement with experimental results.

This work presents a new local crack tracking technique to improve numerical simulations of localized fracture processes in quasi-brittle structures. The algorithm primarily focuses on reduction of mesh-induced directional bias by the determination of smoothly curved C1C1 – continuous crack paths within and across conventional continuum elements with quadratic displacement fields. The algorithm further enables to postpone the moment of crack path fixation.Combined with a classical smeared crack model, the proposed crack propagation algorithm is validated by sequentially linear analyses on tensile and mixed-mode plain concrete fracture tests. Specifically for quadratic elements the results show an increase of the mesh objectivity, and more realistic load–displacement and cracking behaviors are obtained.