Effects of Ultraviolet Radiation with and Without Heat on the Fatigue Behavior of Below-Knee Prosthetic Sockets

This work focused on below-knee (BK) prosthetic sockets, which have gained wide application due to the increasing number of patients with BK amputation as a result of terrorist attacks and life-threatening situations in warstricken areas, such as Iraq. Given the hot weather in Iraq, a number of studies have explored the effects of temperature on specific socket materials. The current study attempts to explain the effects of ultraviolet (UV) radiation, in combination with temperature, on the properties of socket materials. In the experimental work, two sets of specimens, namely, Material A (acrylic resin and hardener reinforced with 10 layers of perlon, and Material B (acrylic resin and hardener reinforced with 8perlon layers and2carbon fibers), were manufactured using a vacuum technique. The socket materials were subjected to tensile testing to obtain their mechanical properties. The failure characteristics of sockets were determined by fatigue testing using a machine (alternating bending fatigue) manufactured specially for this purpose. Fatigue testing was carried out in four different exposure environments (at room temperature with and without UV radiation and at 50 °C with and without UV radiation). Interface pressure between the stump and the socket was measured using an F-socket device. In the numerical study, a prosthetic socket was drawn by using AUTOCAD software. Finite element technique (ANSYSWorkbench 15) was used to analyze and evaluate the fatigue characteristics by observing the maximum stress, total deformation, and safety factor. Results show that the modulus of elasticity (19.7), ultimate tensile strength, and yield stress of socket material sunder group B were superior to those of group A. The material with carbon fiber reinforcement showed the highest fatigue limit and safety factor values (5.0638, 4.6565, 5.0424, and 4.4613). However, the combined effect of temperature and UV radiation decreased the safety factors and rendered the materials of group A as unsafe. The equivalent von Mises stress reached a maximum of16.9MPaand was centered at the anterior side of the tibia bone