An investigation on the thermal endurance of EPR model cables

Research results are presented concerning the thermal endurance of EPR (ethylene/propylene rubber) model cable. Thermal life graphs and indices which characterize the endurance of this kind of cable to thermal stress are reported and discussed. Particular care is taken in the problem of the selection of the properties related to aging and their end points. A method of obtaining an objective failure criterion for different properties and then a unique thermal endurance graph is described. A life mode which takes into account the tendency of the life lines to threshold temperatures, detected from life tests at low temperatures, is proposed, and its fit to the experimental results has been verified. The agreement of life data with the aging compensation effect and a new life model which relates the slopes of life lines with end point selection are considered