Electromechanical impedance method for monitoring incipient looseness in jointed structure for railway safety

摘要

Detection of incipient looseness in structural is a very important issue among the practicing engineers, especially in civil, mechanical and aerospace structure. In Railway track system various mechanically fastened joint are available which subject to complex in service stress and ensuring structural safety of such joint is a vital task. Safety is one of the major challenges for railway engineers in the 2st century. Although various non-destructive techniques available for maintenance and monitoring, but most of this human intervention with subjective decision. It clearly indicates the urgent need for improving and to provide an efficient monitoring approach. This paper presents a structural health monitoring (SHM) approach with AD5933 impedance converter using electromechanical impedance (EMI) technique for monitoring mechanically fastened joint. In this investigation, experiments are conducted on tin material strip, a piezoelectric circular diaphragm surface bonded with the structure for damage detection based on EMI method. The experimental results report that the technique successfully measures the impedance signal from bolted joint and good repeatability using AD5933. These experiments basis for electromechanical impedance technique applied in railway safety application.