Prediction of stiffness field of thin-walled curved surface part based on the method of equivalent curved bar

Thin-walled curved parts exhibit the characteristics of low stiffness and uneven stiffness distribution, and these characteristics exert a significant impact on machining deformation. Therefore, to achieve effective control of machining deformation, it is necessary to analyze the stiffness of thin-walled parts at any position. Taking thin-walled spherical shells as the research object, this paper establishes a predictive model for calculating the stiffness of thin-walled spherical shell with bottom edge fixed support based on the equivalent curved bar method, which consider the radius-thickness ratio of the spherical shell and the polar angle. The forced deformation of the spherical shell is equivalented to the forced deformation of two orthogonal curved bars, the stiffness of the spherical shell was calculated with the method of elastic center and principle of virtual work. The trend of stiffness with polar angle was firstly decreasing and then increasing, and within the polar angle range of 40° to 50°, the stiffness of the spherical shell was the lowest. The average error between the stiffness obtained by the equivalent curved bar method and the experimental stiffness was less than 10%. This model can provide theoretical support for deformation control during the machining process of thin-walled curved surface part.