Biomechanical Analysis and Material Properties of "Ngoo Kin Kied" Water Hyacinth Weave: Application as a Finger Traction Device for Treating Lom Plai Pattakat and Trigger Finger

Abstract

This study aimed to investigate the biomechanical principles of "Ngoo Kin Kied," a traditional Thai woven toy, and to compare the material properties of bamboo strips and water hyacinth fibers to evaluate its potential development as a finger traction device for pain relief and the resolution of joint stiffness in Thai traditional medicine and rehabilitation. The structural mechanics of the helical braid were analyzed through the relationship between the braid angle and radial compressive force, based on the principle of converting axial tension into radial compression. Furthermore, comparative analyses of Young's Modulus and surface characteristics between bamboo and water hyacinth were conducted using secondary data and friction theory. The findings revealed that the woven structure of Ngoo Kin Kied aligns with the physical principles of mesh expansion and friction-induced locking phenomena. In terms of material science, water hyacinth fibers exhibited a Young's Modulus of approximately 6-8 GPa, which is three to four times lower than that of bamboo (10-30 GPa), indicating significantly higher compliance. Coupled with a spongy micro-texture that facilitates uniform pressure distribution, these properties suggest that water hyacinth has a greater tendency to minimize the risks of soft tissue injury and localized ischemia compared to highly rigid materials. In conclusion, the traditional water hyacinth weave possesses mechanical properties capable of adjusting compressive force in response to applied tension. This mechanism corresponds with the therapeutic approach for treating "Lom Plai Pattakat" (digital wind element obstruction) in the fingers according to Thai traditional medicine, highlighting its potential for further development as a safe, physiologically compatible, and alternative physiotherapeutic device.