Statistical energy analysis parameters prediction under thermal environment

With the combination of the power injection method (PIM) and the finite element method (FEM), a statistical energy analysis parameters prediction method is presented which is applicable of vibration analysis of complex structures under thermal environment. A simply supported L-shaped folded plate under ROF excitation is studied and the accuracy of proposed method is verified with numerical examples. The influence of thermal effect on the parameters in statistical energy analysis is investigated under three cases: (1) only the material properties are affected by the thermal environment; (2) only the additional stiffness due to thermal stress is considered; (3) considering both (1) and (2). Results show that the increasing temperature changes the material properties of the L-shaped plate and decrease the value of coupling loss factor, but has little influence on internal loss factor. The thermal stress have great influence on the parameters in statistical energy analysis, the increasing temperature decrease both internal loss factor and coupling loss factor. When both (1) and (2) are considered, the influence of thermal stress is dominant, the internal loss factor and the coupling loss factor are gradually decreased with the increase of temperature. Similar trend is found between the change of temperature and modal density.