With the combination of the finite element method (FEM) and the power injection method (PIM) under modal coordinate considering thermal effect

a statistical energy analysis method applicable of vibration analysis of complex structures under thermal environment was presented. A simply supported L-shaped folded plate under rain on the roof excitation was studied and the accuracy of proposed method was verified with numerical examples. The influence of thermal effect on the parameters in statistical energy analysis was investigated under three cases: (1) only the material properties were affected by the thermal effect; (2) only the additional stiffness due to thermal stresses was considered; (3) both (1) and (2) were considered. Results showed that the increasing temperature changed the material properties and decreasd the value of coupling loss factor

but had little influence on internal loss factor. The thermal stresses had great influence on the parameters in statistical energy analysis

the increasing temperature decreasd both internal loss factor and coupling loss factor. When both (1) and (2) were considered

the influence of thermal stresses was dominant

the internal loss factor and the coupling loss factor gradually decreased with the increase of temperature. Similar trend was found between the change of modal density and temperature.