Structural Design and Mechanical Performance Analysis of Carbon Fiber Closed Fixtures for UHV Transmission Lines

The closed clamp is a standard tool for the insulator replacement in ultrahigh voltage (UHV) transmission lines, which is mainly made of titanium alloy material and weighs more than 27 kg that greatly reduces the working efficiency for operators. Due to the lightweight demand, carbon fiber composite materials are applied to design a new type of clamp, in which mechanical properties of new fixtures need to be fulfilled while considering poor impact resistance and low interlaminar shear strength of carbon fiber composite materials. To excavate a high-strength ply structure, finite element progressive damage strength analysis is employed to evaluate the mechanical properties of three different ply angles of the carbon fiber closed fixture, in which Tsai–Wu strength theory is thought as the strength judgment basis for carbon fiber composite materials. After comparison with the displacement-load curves, the three different ply angles fail to meet the strength requirements. So, a carbon fiber laminate structure with an outer cladding for carbon fiber closed fixtures is raised and verified. The analysis results show that the laminate structure meets the strength requirements. Destructive test of the new closed clamp is conducted to verify the correctness of the proposed method, and the weight is reduced by 36.46%.