Evaluation of Fracture Strength of Corroded Steel Bolted Joints Using Acoustic Emission Method

Abstract

Acoustic emission （AE） method was used to evaluate the fracture strength of corroded steel bolt joints. AE monitoring was carried out on steel bolted joints subjected to corrosion accelerated test using NaCl solution with different duration. After the corrosion test, the tensile strength of bolted joints was evaluated. A correlation was found between the fracture strength of corroded bolted joints and cumulative AE events. Next, the relationship between the parameters of the AE waveforms and the corrosion conditions was evaluated. As a result, waveforms with a strong amplitude of the guided wave L（0, 1） mode were detected in the bolted joints with severe corrosion, and the peak frequency of AE signals tended to decrease. In addition, many AE signals with high maximum amplitude were detected in the bolted joints where corrosion had progressed. These results indicated the possibility of estimating the fracture strength of bolts from parameters such as amplitude and frequency.