Crack initiation and growth simulations of functionally graded dental implant subjected to cyclic axial loads

• Published in: Fatigue & fracture of engineering materials & structures Vol. 45; no. 11; pp. 3123 - 3136
• Main Authors: Mohammadi Anari, Ali, Selahi, Ehsan
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01-11-2022
• Subjects: Axial loads; Crack initiation; crack initiation and propagation; Crack propagation; cyclic loading; Cyclic loads; Dental implants; extended finite element; fatigue; Fatigue cracks; Fatigue failure; Finite element method; Fracture mechanics; Fracture toughness; functionally graded materials; Functionally gradient materials; Hydroxyapatite; Mathematical models; Numerical prediction; Power factor; Protective coatings; Visual programming languages
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1111/ffe.13802

Two essential characteristics in designing dental implants are having high fracture resistance and being compatible with jawbone. One of the best implant choices to achieve this aim is titanium‐hydroxyapatite functionally graded (FG) material. Also, fracture of implants under cyclic loads is one of the most common causes of destruction of dental implants. However, the crack initiation location and growth path as well as the optimum material distribution for the FG implants are questions that have not been answered yet. The aim of this study was introducing a new and powerful numerical approach to predict the crack initiation behavior and progressive damage in the FG dental implants, subjected to cyclic axial loadings. The approach is developed by employing extended finite element method (XFEM) in ABAQUS software, Visual Studio, and FORTRAN Compiler. Also, the Python code was modified for crack growth modeling in fatigue fracture analysis based on Paris law. The result showed that the micro‐cracks below the outer surface of FG implant are created, due to the application of cyclic load, which is invisible. This research shows that FG implants with power factor less than 1 show much more resistance to crack growth under pre‐tightening and cyclic loadings.
Highlights
A new numeric method is present to predict crack initiation and progression in FGMs.
Crack initiation and growth of FG dental implants under cyclic loads are studied.
FE model is linked to visual studio and Fortran compiler to write subroutine codes.
Formation and growth of crack due to cyclic axial is investigated, using XFEM.
Generally cracks occur below the outer surface and are not visible at first.