Fracture toughness and notch sensitivity of jute fiber mats reinforced unsaturated polyester matrix composites based on the characteristic distance

Abstract

Recycled needle punched natural jute fiber mats were used to reinforce unsaturated polyester matrix composites via modifying the hand lay-up technique with resin pre-impregnation into the jute fiber mats in vacuum. The notch sensitivity of these composites was investigated by using the characteristic distance do calculated by Finite Element Method (FEM) according to Whitney and Nuismer model definition. In this work, the concept of the characteristic distance was discussed from the point view of fracture mechanics, therefore the aim of this study is to investigate and reconfirm the physical meaning of do by investigation the fracture toughness (KIc) of jute mat composites (JMC) based on do calculated by Finite Element Method (FEM) with width, W, to the hole diameter (D = 10 mm) ratio (W/D = 3) with 25 wt% fiber weight content. The results showed that JMC composites in terms of residual tensile strength (σn/σo) (the ratio of notched to unnotched strength) that there is only 16 % loss in the tensile strength due to the presence of the hole. Moreover, the experimental maximum load during tension test with hole is almost near to the maximum load calculated using KIc and do which validates the physical meaning of do which represents the distance from the hole boundary at which the brittle fracture starts to occur.