A novel testing apparatus for evaluating the resistance of structural materials to thermo-mechanical cyclic loading

摘要

Every machine transforming heat in mechanical work or electric energy experiences thermally induced stresses that superimpose mechanical loading. Such stresses arise in steady-state condition (isothermal or quasi-isothermal working phases) from intrinsic physical properties mismatch (linear thermal expansion, heat conductivity, specific heat) or from cyclic, fast evolving temperature of coupled components. This latter is the worst condition to manage from the designer's point of view. ENEA developed and realised in conjunction with an important Mechanical Testing load frames manufacturer, a sophisticated closed loop fatigue machine. The peculiarities of this experimental facility are the possibility to use the temperature as a driving parameter and an operator-defined load frame compliance. Using these features, a systematic, metallurgicalapproach on thermal fatigue behaviour of materials becomes possible.