Development of Fastener Performance Testing Machine for Bolted Joint Tightened in Elastic or Plastic Region

Abstract

In this study, a micro-computer-aided testing machine is designed and produced by way of experiment, which can realize various fastener tightening methods in elastic or plastic region and continuously apply an external force on the fastener. It consists of a DC-servo motor, a hydraulic cylinder, a new-type load cell, a new-type extensometer and a micro-computer, and can detect following nine factors : tightening torque, thread torque, bearing surface torque, axial tension, external force, elongation of bolt, torsional angle of bolt, rotational angle of nut, time. They are processed in a micro-computer and recorded on an X-Y plotter. Fundamental test was made with the bolts and the nuts of M 10 in elastic or plastic region of bolt material, and it is confirmed that the testing machine satisfies the specifications needed.