Abstract: Turbine blade is subjected to combined action of high temperature, high pressure and centrifugal force under working state, and its geometric shape is different from the cold-state shape. As a key component of turbine design, back calculation for cold-state geometric shape of turbine blade, is to obtain undeformed geometric shape of turbine blade according to its deformed shape and load conditions. An iterative algorithm is presented based on finite element thermal and structural analysis to solve this problem effectively. The algorithm is to iteratively approach the undeformed geometric shape by modifying nodal coordinates, and guarantee the quality of modified mesh by smoothing technique. The algorithm is easily to implement with high efficiency and accuracy, applicable to structures with complex deformation behavior, and independent to finite element software to be applied. Back calculation for cold-state geometric shape of a turbine blade is successfully performed to verify the practicability and reliability of the presented algorithm and its implementation.

Key words: turbine blade;cold-state;back calculation;modification of nodal coordinates;mesh smoothing