A Latch-Based Weibull Model for Polymerie Creep and Recovery

A model to represent creep and recovery in polymeric materials is described. This is based on the Weibull distribution function, which is commonly used for representing the failure of elements in mechanical systems. A mechanical representation of viscoelasticity is discussed, in which viscoelastic response is described by the action of time-dependent latch elements. By analysing experimental data on nylon 6,6, polypropylene and polyether-ether-ketone (PEEK) from a range of sources, it is shown that creep and non-elastic recovery can be represented by two equations, each containing four parameters. The model correlates well with the experimental data analysed, from which it can be used to predict both time-dependent and time-independent strain.