The general author‘s mesomechanical model with tensorial internal variables is applied to creep of steel 0,5Cr0,5Mo0,3V under different loading levels. It is shown that the creep process can be described by the mesomechanical model in its whole course up to rupture. However, the model parameters can be influenced at the very beginning by the application of the applied load if it is high enough to cause changes in the internal structure. This problem is specific for creep at high temperatures and significant differences in the loading levels (contrary to the small-strain plasticity studied usually at low temperatures, where the model parameters can be considered the same for different loadings). and Obsahuje seznam literatury
For assessment of safety and durability of any large-scale concrete structure, prediction of the behaviour of the structure under various service and extreme conditions is crucial. To perform reliable analysis of the complete structure, a sufficiently realistic but still feasible numerical model must be used, in which the relevant physical phenomena are reflected. Therefore, a constitutive model for concrete including effects on moisture and heat transfer, cement hydration, creep, shrinkage and optionally microcracking of concrete should be chosen.
The present paper focuses on the simulation of the service life of a NPP containment, aiming to determine the material and model parameters to enable reliable prediction of durability and structural behaviour under various conditions. The purpose of the work is to provide a numerical model calibrated using existing measurements to predict the long-term behaviour reliably. Extensive in situ measurements are used to calibrate the model and to check the validity of model hypotheses. Moreover, the material model parameters are systematically re-calibrated based on continuous monitoring of the structure. The structural integrity test is reanalysed numerically to show the model capability of predicting behaviour of the structure under given loading and climate conditions. and Obsahuje seznam literatury