Reengineer 3D Durable Hand Knob

I have a small circular 3D printed hand-knob that is currently. The ring-shaped section feels stringy and flexes more than I’d like, so the goal is to toughen that area without changing the overall outside dimensions or the mating interface... (Budget: $10 - $30 AUD, Jobs: 3D CAD, 3D Design, 3D Modelling, 3D Print Design, 3D Printing, 3D Rendering, CAD/CAM, Solidworks)