Effect of notch on static and fatigue properties of T800 fabric reinforced composites

Abstract

To investigate the effect of notches on static and fatigue properties of T800 fabric carbon fibre reinforced epoxy, comparative tests were conducted between specimens of three depths of notches and un-notched specimens. Results demonstrate that the residual tensile strength of specimens is linearly decreased with the increasing depth of notches from 2mm to 4mm. The tensile strength on notched specimens dropped 31.5% comparing with no-damaged laminate. Due to the effect of notches, the fatigue limit was reduced to 55% of UTS and the slope of the S-N curve tends to be horizontal. In-situ damage expansion process was observed and the shape of proposed normalized S-N curves could be explained and concluded as two stages: the first stage accounts for 20% of the fatigue life, showing a dramatic decrease of fatigue strength; the remaining stage takes up the rest of the total life span, representing a steady decline in strength. It shows that no-damaged and notched laminates exhibit different behaviours in terms of damage evolution.

Keywords

• t800 fabric cfrp
• double-edge notch
• tensile strength
• fatigue properties
• s-n curve
• in-situ damage expansion