Effect of hydroxyapatite fiber’s shape on mechanical properties of calcium phosphate cement

Calcium phosphate cements are one the best grafting materials in bone fracture repair. They are easily shapeable, bioactive, and biocompatible. These group of materials have lower fracture toughness and compressive strength, due to their porosity. For enhancement of some mechanical properties and reducing porosity, they are combined with materials such as hydroxyapatite fibers. This combination makes it possible to control and increase elastic modulus and compressive strength. The shape and the orientation of fibers can affect these parameters. In this study, mechanical properties of calcium phosphate cement which is enhanced by three different shaped fibers of hydroxyapatite is investigated via FEM simulation. Ratio of the fibers added in this composite cement is 10 vol.% and they are in spherical, ellipsoidal, and polyhedral shapes. Three specimens have about same elastic modulus but compressive strengths of each specimen and the stress distribution among the fibers are different.