Mathematical Analysis and Structural Optimization of an Insulated Support for the 25 kv–50 hz Railway Contact Line

Abstract

This paper presents a structural analysis of an insulated support assembly used in 25 kV–50 Hz railway overhead contact
lines. The study is based on the supplied engineering drawings of the stay rod, brace, direct steady arm, reverse fixing device,
bar, couplings, fixing plate and contact-wire clamp. The dimensions and materials explicitly readable in the drawings are incorporated
into a simplified analytical model for bending, shear and elastic displacement. The reference configuration mainly uses
S235/S235JR/FMN35 steels with corrosion protection by hot-dip galvanizing, while CuZn15 and other steels/stainless components
are present in the contact clamp and fasteners. AlCu4Mg is investigated as a lightweight alternative for selected structural members.
The analysis confirms the substantial mass-saving potential of aluminium alloys, but also the associated loss of stiness;
therefore, a material substitution must be accompanied by geometric redesign. For the ?34 4 mm tubular direct steady arm, with
L = 400–1600 mm, the section properties are calculated and a conservative Fd = 90 N case is used to quantify the sensitivity of
bending moment and elastic displacement to length. The proposed methodology combines mass, strength and stiness criteria and
can be extended by finite-element analysis.