The issues of control and identification of multidimensional and closed systems of metal structures diagnostics have been considered. The main varieties of identification and modeling of processes for managing the functional diagnostics of metal structures dealing with the improvement of the input information quality due to limited restrictions satisfaction, searching for additional a posteriori information in the process of dynamic changes of the controlled object, forecasting changes in the internal structure of the material have been specified and discussed in detail. The scheme of a priori information in the form of parameterized mappings of inputs and outputs interactions of the diagnostic system has been presented. The results of simulation are associated with the selection of variables measured diagnostic parameters. A methodology for quantitative estimations of posterior inflow information due to entropy values has been developed. Using the marked apertures of modelling and forecasting at each stage of identification, it is possible to obtain a mathematical model adequate to the real situation.