FEASIBILITY STUDY ON WELD NUTS WITH FLANGE FOR ONE-SIDED FASTENING FOCUSING ON PRETENSION CONTROL

A new type of one-sided fastening system using weld nuts with flange is proposed and experimentally investigated to examine its practical feasibility especially in terms of pretension control. The weld nut is designed to show a special performance such that the incorporated flange undergoes elastic deformation, then plastic flow and finally contact on the seating plate during the tightening process. These sequential behaviors are confirmed experimentally, which indicates that the pretension greater than the plastic flow load can be introduced into the bolt. In addition, an analytical method to calculate the flow load is presented and ascertained.