การลดแรงกระแทกด้วยโครงสร้างลักษณะแซนด์วิชสำหรับอุปกรณ์ป้องกันข้อสะโพก

Abstract

Hip fracture is a common incident that occurs in elderly and it causes the suffer and increases the mortal rate. Hip protector is a solution to solve this problem by protecting the hip from falling impact force. Generally, there are 2 types of hip protector. They are a hard-shell which has good energy shunting and a soft-pad that has high energy absorption. However, there are not many studies that combine and focus the advantages of these materials for force attenuation. Therefore, this study investigated the effects of sandwiched structure on force attenuation using a computational simulation and experimental study. The materials used in the study were polypropylene (PP), polyethylene foam (PE) and ethylene-vinyl acetate (EVA). The combination of the models consisted of hard and soft materials and the bottom layer was soft material. In the computational simulation, the models were assessed in 3 thickness ratios (3:6:3, 4:4:4, 5:2:5) which were in total 30 models. The computer simulation result showed that model D with thickness ratio 3:6:3 (EVA:PP:EVA) had the lowest von Mises stress. On the other hand, the experimental result showed that model E with thickness ratio 3:6:3 (PP:PE:PE) had the highest force attenuation performance. The different results between computer simulation and experimental study could be the assigned conditions in computational study that might be not exactly similar to the experimental conditions such as testing conditions, the shape of the model, and material properties etc. Furthermore, the experimental study from model E indicated that the arrangement of material which provided the high force attenuation performance. Therefore, this study could be extensively applied in medical application such as hip protectors.