抄録
Importance of bone fracture treatments has been increasing with the number of bone fracture patients with arrival of the aging society. Bioabsorbable bone fixation devices are required to improve quality of life of patients. Poly(lactic acid) which has high biocompatibility is expected as a material for the device. However, applications of PLA bone fixation device are limited to low loaded region, because of their lower mechanical characteristics. As a method to improve mechanical properties of PLA, drawing has much attention. In this study, molding conditions are investigated to improve mechanical properties of PLA. Deformation behavior of PLA rods in drawing was numerically investigated by finite element method. Orientation for the rods was estimated from principal strain caused calculated. Effects of extrusion ratio on orientation for the rods were investigated by comparison of computed principal strain in extrusion ratio 4 and 8. As a result, the magnitude of principal strain along drawing direction in the drawing ratio 4 and 8 was comparable, which suggested that degree of orientation in extrusion ratio 4 and 8 was comparable.
