A HYBRID TUBULAR BRAID WITH IMPROVED LONGITUDINAL STIFFNESS FOR MEDICAL CATHETER

Abstract

Medical catheters are widely used in various medical procedures, such as diagnostics, biopsies and air change. A desirable catheter needs to be flexible for low discomfort, and stiff in longitudinal direction for easy manipulation. Tubular braid is often employed as reinforcement structure for catheters, which plays an important role in the overall mechanical properties. Current tubular braids adopt identical braiding angles for all the yarns, resulting in limited longitudinal stiffness. In this paper, a novel hybrid braid with different braiding angles for the two sets of yarns is proposed and analyzed. Both experimental and numerical results show that the hybrid braid has a higher longitudinal stiffness than the uniform one due to the geometrical incompatibility generated by the hybrid braiding angles. The effects of design parameters are also investigated through a parametric study, and an increase of 418.3% is achieved in the optimum case. In addition, the bending flexibility of the hybrid braid is found to be comparable with the uniform one. The new structure shows great promise for engineering applications where high longitudinal stiffness is required.