Post composite insulators are essential components for supporting insulation in ultra-high voltage power equipment. However

as voltage levels and core diameters increase

large-diameter cylindrical posts face issues such as uneven curing and cracking

resulting in low production yields. To address these issues

an I-shaped cross-section design was proposed to reduce the cross-sectional area and optimize structural performance. A comprehensive evaluation algorithm

integrating network analysis and coefficient of variation methods

was developed to simulate stress and displacement under compression

bending

and torsion conditions. Four I-shaped cross-sections were evaluated

and the optimal 320 mm×250 mm design was selected. Prototype tests demonstrate that the I-shaped post not only meets the rated bending load requirements but also achieves a bending failure load of approximately 60 kN

which is 2.75 times the value in China’s relative standard;meanwhile

the deformation is half that of a Φ=220 mm cylindrical post. Under torsion

the I-shaped post exhibits 3~4 times greater resistance and excellent elastic recovery

with residual angles ranging from 0.1° to 0.5°. Finite element simulations confirm that the I-shaped post can replace Φ=240 mm cylindrical posts in bending performance. This research provides theoretical guidance and practical insights for improving the molding quality and mechanical performance of post composite insulators.