Coupled Thermal-Structural Interactions
Thermal loadings on structures encompass a variety of disciplines including duty cycles, material properties are a function temperature and time, thermal shock treatments, thermal creep effects, etc. Coupling the thermal analysis with the structural dynamics gives a full picture of the development of stresses. Thermal loading can take place during the construction processes, over the lifetime of the structure, or as a shock treatment to a component. Understanding the thermal-structural relationship can be critical in meeting design requirements and verification.
Nuclear containment structures are susceptible to long term thermal effects as their structural integrity has a lifetime design of 60-year. Analyses of the long term effects of thermal cycling analysis on structural performance, enables engineers to invoke material degradation due to temperature, time at temperature and thermal creep. An understanding of this process and ways to prevent material degradation ensures the design of primary containment systems.
Nuclear structures are designed to resist deformations due to internal pressure, temperature extremes, and other loads such as impact and seismic loading. Because such structures with thick concrete sections and heavy reinforcement are inherently stiff, large internal stresses due to temperature differentials can develop. ANATECH, a Structural Integrity Associates company performs detailed modeling and analysis to capture the dissipation of these thermal loads, which may result in cracking and associated global stress redistribution as the structural stiffness is reduced.