Multiscale Design of Piezoelectric PLA/BaTiO₃ Composites for Electrically Active Bone Grafts

Introduction

Piezoelectric polymer–ceramic composites based on poly(lactic acid) (PLA) and barium titanate (BT) are promising candidates for bioactive structures capable of enhancing bone regeneration through electromechanical stimulation. In this work, we present a multiphysics computational homogenization framework to evaluate the effective electromechanical response of PLA/BT composites as a function of microstructural parameters.

Methods

A periodic representative volume element (RVE), consisting of a BT inclusion embedded in a PLA matrix, was implemented using a multiphysics finite element framework within structural mechanics and piezoelectric formulations to account for mechano-electrical coupling. The full set of homogenized elastic tensors, piezoelectric stress–charge coefficients, and dielectric properties was derived. The analysis systematically investigates the influence of key microstructural parameters, namely inclusion volume fraction and mechanical contrast between matrix and filler, on the effective composite response.

Results

The homogenization framework provides stable and consistent predictions of the effective electromechanical properties of PLA/BT composites. The results indicate a non-linear dependence of both electromechanical coupling and individual components of the mechanical tensor on BT content, with a marked sensitivity of shear-related terms. This aspect is particularly relevant for bending-dominated structures, where shear contributions can significantly influence strain distribution and, consequently, the generated electrical potential.

Conclusions

The proposed finite element-based framework enables the preliminary design of piezoelectric composites by identifying trade-offs between electromechanical performance and the full mechanical tensor response, supporting the fine-tuning of voltage generation in load-bearing bone grafts to modulate cellular activity. Overall, we establish a first multiscale homogenization approach for PLA/BT systems, capturing non-linear composition effects while emphasizing the importance of rigorous model validation.