TRANSFER COEFFICIENT DUAL CASING UNDER NON-EVEN LOAD

The transfer coefficient is one of the main indexes used to evaluate the efficiency of dual casing,while it is difficult to obtained Under the non-even load by the theoretical method, due to the complicity of the stress changes The finite element method is proposed in this condition, to calculate the transfer coefficient and and analyze the changing tendency. Based on large amount of calculating results, the regression of the transfer coefficient calculating formula is carried out, and the regression equation, together with the fitting curve under the elliptic distributed load is presented. This is a supplement to the theoretical and provides a calculating foundation for the designing of dual casing. Some of the testing results of the dual casing is verified by calculating using this method, and the characteristics of this type of casing is further identified. When calculating the transfer coefficient under even load, the deviation between this method and the theoretical method is lower than 0.6%, and it is lower than 2% when in curve fitting.