Materials Aspects of the Degradation Theory Conception of a Multi-Criterion System of Estimation of the State of Material.

Systemic investigations concerning the degradation of properties of materials submitted to a long-term operational use have been carried in Poland. That research work results directly from the needs of power stations and brown coal mines. Installations and machines of these large and important enterprises are exploited already for several scores of years. On this account exploiters are faced with important problems and a need of decision making. These problems concern the determination of the residual life and the disposability of the functioning machines, of the sequence of their repairs or their modernization, and the prolongation of their safe exploitation. Finally, rational and objectivized motives of decision making what concern finishing the operational use of these machines have to be defined.