Numerical Investigation of Flexural Bending in Biaxial Braided Structures for Flexor Tendon Repair

Abstract

Flexor tendon repair has conventionally been done by suturing techniques. However, in recent times, there have been attempts of using fibrous braided structures for the repair of ruptured tendons. In this regard, the numerical analysis of the flexural stiffness of a braided structure under bending moments is vital for understanding its capabilities in the repair of flexor tendons. In this paper, the bending deflection, curvature, contact stresses and flexural bending stiffness in the braided structure due to bending moments are simulated using Finite Element (FE) techniques. Three dimensional geometry and FE models of five sets of biaxial braided structures were developed using a python programming script. The FE models of the hybrid biaxial braids were imported into ABAQUS (v17) for post-processing and analysis. It was established that the braided fabric with largest braid angle, θ = 52.5˚ had the highest flexural deflection while the lowest deflection was seen in the results of the braided structure with the least braid angle, θ = 38.5˚. The results in this study also portrayed that the curvature in biaxial braids will increase with a decrease in the angle between the braided yarns. This was also consistent with the change of bending angle of the biaxial structures under a bending moment. The deformation of the structures increased with increase in the braid angles. This implies that the flexural bending stiffness decreased with increase in braid angle. The stress limits during bending of the braided structures were established to be within the range that could be handled by flexor tendons during finger bending.

Numerical analysis of crimping behaviour of triaxial braided structures

“…The nodes and elements were extracted in a text file and imported into Abaqus v17 for analysis and post-processing. The mesh size was adopted from previous studies [26–28].…”

“…The nodes and elements were extracted in a text file and imported into Abaqus v17 for analysis and post-processing. The mesh size was adopted from previous studies [26][27][28]. In order to save on computation time, the final 3 D model of the biaxial braided structure was made up of 32 helical yarns half with þh o in-plane orientation angle (16 clockwise yarns), and half with �h o in-plane orientation angle (16 anticlockwise yarns).…”