Effects of Tensile Speed on Fracture Strength of Notched Plates for GFPP and Recycled GFPP
Toshihiro YAMAMOTO, Shohei MORIYAMA and Hidetoshi TAKEDA
Abstract: The effects of tensile speed on the fracture strength of notched plates made from virgin and recycled materials were investigated. The virgin material was short-glass-fiber-reinforced polypropylene (GFPP). GFPP plates, each containing 30% E-glass fiber by weight, were fabricated by injection molding. In addition, pellets of recycled GFPP were kneaded and an injection-molded plate, referred to as the recycled GFPP (R-GFPP) plate, was fabricated from these pellets. The mean fiber lengths of GFPP and R-GFPP were 3.5 and 0.4 mm, respectively. The notch-root radii of both the GFPP and the R-GFPP plates were 0.5, 1, and 2 mm, while their notch depths ranged from 2 to 5 mm. Tensile tests were performed at tensile speeds of 103, 102, 10, 1, and 8.33 ~ 10-5 mm/s at a temperature of 23oC. It was found that all the notched specimens (GFPP and R-GFPP) failed in a brittle manner at the maximum load. The maximum elastic stress at fracture was determined from the notch-root radius and the time to fracture but was independent of the notch depth. The obtained results could be explained of the basis of the severity of the stress fields near the notch roots of the specimens. Key Words:Fiber reinforced plastics, Tensile speed, Notch, Fracture criterion, Recycle