Simulation-Based Development of Gradient Woven Fabrics for Biomimetic Implants to Restore Tendons and Ligaments

Tendons and ligaments are complex tissues that are necessary for human movement. Injuries occur very commonly and treatment quite often requires implants. Such implants must be adapted to the biological and structural composition of human tendons and ligaments. Thus, the objective is to realize graded, biomimetic tendon and ligament implants that are long-term resorbable. First, basic woven fabrics are fabricated from biocompatible silk fibroin yarns. Starting from the basic fabrics, gradient fabrics, with three different weave zones, are then developed and produced. In addition, fabrics with variable width and lateral warp yarn offset are fabricated on the basis of open reed weaving (ORW) technology on a modified shuttle narrow weaving loom. Meso-scale finite element models are developed in order to support the design of the gradient weaves. First, TexGen software is used to create a close to reality fabric geometry. Models are then converted into beam element models using a Python script. Results of real and virtual tensile tests show a clear relationship between the crimp of the warp yarns in the fabric structures and the resulting elongations. The additional ORW yarn system influences the stiffness. The tensile behavior of experiments and simulation agree very well, so the models are suitable for further development of woven implants.