FUNDAMENTAL STUDY ON DEVELOPMENT OF A NOVEL SHAPE OF HIGH-STRENGTH NUT FOR ITS ANTICORROSIVE PERFORMANCE ENHANCEMENT

Abstract

Corrosion of hexagonal high-strength nuts used in infrastructures like steel bridges quickly occurs owing to the corner's thin coating, therefore becoming a burden on the maintenance system. This study conducts FEA to make the nut’s corner round and smooth, considering its stress distributions, then manufactures the novel shape nut. The mechanical performance of the set consisting of a hexagonal bolt and the novel nut was also investigated by tensile, tightening, and relaxation tests. Mechanical performances like tensile resistance, tightening property and the relaxation extent of bolt tensions between the novel and conventional shape nuts are almost identical.