A local approach to creep fracture by slow crack growth in an MDPE: Damage modelling

Slow crack growth (SCG) behaviour has been investigated under creep conditions in a medium density ethylene–butene copolymer (MDPE) on both axisymmetrical Full Notched Creep Tensile (FNCT) and Double Edge Notched Tensile (DENT) samples tested at 60 °C. An attempt is made to predict the long-term failure of a component under creep loading conditions, using an incremental damage law. The experimental creep damage observations were compared to the creep stress–strain distributions calculated by finite element method. Such comparison can provide a damage evolution law as a function of the maximum principal stress and the creep strain. The failure criterion is expressed in terms of a critical creep damage over a critical distance. This model is applied to creep crack growth on the FNCT and DENT samples.