Abstract: A new method for solving the large deflection curve by using the section-coordinate rotation approach is presented in this paper. The present method in suitable for derivation, interpolation and integration of enclosed curves and unenclosed curves with both y'>>1 and y'<<-1.
The method has been applied to the design of three-dimensional impellers and the smooth treatment of the indicator diagram of the internal combustion engine. Results show that the present method is satisfactory.