Implicit and explicit finite element models predict the mechanical response of calcium phosphate-titanium cranial...

Area of Science:

• Biomaterials Engineering
• Computational Mechanics
• Neurosurgical Devices

Background:

• Cranial implants are crucial for protecting the brain after trauma or surgery.
• Patient-specific implants require efficient methods to predict mechanical behavior.
• Experimental characterization of each patient-specific implant is often impractical.

Purpose of the Study:

• To develop and validate finite element models (FEMs) for titanium-reinforced calcium phosphate (CaP-Ti) cranial implants.
• To assess the predictive accuracy of FEMs under quasi-static and impact loading conditions.
• To compare the mechanical response of CaP-Ti implants with cranial bone.

Main Methods:

• Development of FEMs for two CaP-Ti implant designs (D1 and D2).
• Validation of FEMs against experimental data for force-displacement response.
• Loading simulations at quasi-static (1 mm/min) and impact (5 kg, 1.52 m/s) rates.
• Comparison of FEM predictions with experimental peak loads and displacements.

Main Results:

• FEMs demonstrated good agreement with experimental force-displacement data for both designs.
• Implicit FEMs showed minor under/overestimation of peak loads (9% for D1, 11% for D2).
• Explicit FEMs predicted peak loads with low differences (5% for D1, 2% for D2) and maximum displacements accurately (1-4% difference).
• Cranial bone FEM exhibited a stiffer response, higher energy absorption, and less deformation than CaP-Ti implants under impact.

Conclusions:

• Validated FEMs provide a reliable method for predicting the mechanical performance of CaP-Ti cranial implants.
• The developed modeling framework can be extended to other CaP-based composite implants.
• FEMs are valuable tools for evaluating patient-specific CaP-Ti implant designs under various loading scenarios.