Abstract: | The lifetimes of two types of amorphous polymers (polyvinyl chloride and plasticized epoxy resin) under intermittent loading have been investigated. It is established that the lifetime, determined without allowance for recovery time, is less than that under constant load. Under periodic loading at constant stress the lifetime varies with the loading regime. For each of the investigated polymers a lifetime minimum is observed at a certain duration of the loading and recovery periods.Higher Chemical Technology Institute, Sofia. Translated from Mikhanika Polimerov, No. 5, pp. 912–916, September–October, 1971. |