Biaxial mechanics of 3D fiber deposited ply-laminate scaffolds for soft tissue engineering part II: Finite element analyses

Tissue engineering (TE) is an emerging intervertebral disc (IVD) repair strategy to alleviate pain and mitigate the functional impairment associated with IVD disease. A prevalent strategy to fabricate annulus fibrosus (AF) repair scaffolds is 3D fiber deposition (3DF) which generates scaffolds with highly tailorable mechanics due to a diverse range of print parameters. An essential element of TE is providing the requisite micromechanical environment for the generation and maintenance of healthy mature tissue. However, experimental mechanical testing of printed scaffolds is time and resource intensive. Accordingly, there is an interest in computational methods for high-throughput assessment of 3DF scaffold mechanics. In this study, a parametric FE model was developed and evaluated to elucidate the influence of various print parameters on the uniaxial, transverse constrained uniaxial, and biaxial tensile mechanics of 3DF angle-ply laminate scaffolds. Of the print parameters considered in this study, fiber angle, fiber diameter, and fiber spacing had the most dramatic influence on Effective Elastic modulus (EE) in all loading regimes and equibiaxial Effective Elastic modulus ratio (EEr). Layer thickness and contact area were found to have moderate influence on EE and EEr, and the number of layers was found to have only a minor influence on EE and EEr. The material elastic modulus scaled EE to numerical precision, and therefore, EEr was not affected. The data presented in this study both aid the selection of design parameters and highlight the importance of controlling process parameters in the fabrication of micromechanically-tailored tissue engineered scaffolds.