In research on the automatic forming of ship bidirectional curvature plates, the calculation method of in-plane strain and out-of-plane strain distribution is an important problem. In light of the limitations of existing methods of calculating strain, a new method is proposed that can improve the calculation accuracy of the strain distribution of ship bidirectional curvature plates. The new method has high calculation efficiency and meets the needs of engineering applications.

Taking a circular flat plate as the research object, the secondary development of a subroutine in finite element software is carried out, and the displacement field load is gradually applied, improving the accuracy of strain distribution calculation. Considering that the actual machining process is an elastoplastic deformation process, the influence of material nonlinearity on strain distribution is discussed. From the perspective of calculation accuracy and efficiency, the applicability of various calculation methods is discussed.

The subroutine-based calculation method solves the problems of insufficient precision, complex modeling and low calculation efficiency of existing methods. From the perspective of calculation efficiency, it is recommended to use the elastic large deformation finite element method to calculate the strain. For target shapes with different curvature radii, several reasonable suggestions are given for the selection of calculation method.

The proposed method can quickly provide accurate strain distribution calculations for the automatic forming systems of ship bidirectional curvature plates, giving it practical engineering application value.