Daria Dolgikh

In this study, methods for enhancing the structural strength of conical orthopedic transtibial exoprosthetic sockets are investigated through the implementation of non-planar reinforcement using structured rods made of continuous carbon fiber. Numerical modeling based on progressive failure analysis according to an instantaneous damage law, incorporating material property degradation models, effectively demonstrated the damage accumulation process in the examined structures.

This study investigates strategies to enhance the structural integrity of 3D-printed orthopedic transtibial exoskeleton sockets by integrating non-planar reinforcement with structured prepreg rods composed of continuous carbon fibers, leveraging multi-axis additive manufacturing techniques. A prototype of a cylindrical polyamide 3D-printed exoskeleton socket is examined. Numerical modeling using progressive failure analysis, incorporating material property degradation models, successfully simulated damage accumulation in the studied 3D-printed structures. Numerical simulations revealed that crack formation initiates in the socket’s distal section, aligning with physical test observations. Targeted localized reinforcement with carbon rods effectively strengthened the high-load regions of the prosthetic devices. A method to improve product strength by optimization of the internal architecture of the embedded reinforcements in the local stress concentrator zones is proposed. The results demonstrate a reduction in stress concentrations within prostheses when using carbon fiber reinforcements. Multi-axis dual extrusion non-planar additive manufacturing techniques were used to produce the developed prototypes. Surface morphology was examined, and optimal process parameters were determined to enhance printing quality. The developed approach enables precise reinforcement of custom-shaped sockets with complex geometries.

This research is aimed at development of 3D-printed sockets for an orthopaedic prosthesis using methods of pressure redistribution on the inner surface of the socket. Topological freedom provided by modern additive manufacturing allows optimization of the parameters of the socket to create an orthopaedic prosthesis with properties adapted to the needs of a particular patient. This paper proposes an approach to redistribute the pressure in the prosthesis by controlled reinforcement with continuous carbon rods to artificially create zones of higher and lower pressure to facilitate prosthetic wear. Numerical modelling is used for the pre-design of a unique internal architecture of the prosthesis, which can redistribute the pressure on the inner surface of the socket, thus relieving excessive pressure from sensitive soft-tissue zones. The influence of socket thickness, inclination angle of the rods and the elastic behaviour of the polymeric materials on the extent of pressure redistribution is investigated.