Experimental measurement of fracture energy of API X65 steel using drop weight tear test equipped with accelerometer

The drop weight tear test has been used for nore than seven decades in oil and gas industries to measure fracture energy and to study the features of ductile and brittle fracture of energy trsnportaton pipelines. In this study, the fracture energy of API X65 steel was measured using the acceleration signal of the drop weight tear test equipped with accelerometer. The test sample was cut from the natural gas transmission pipe with outside diameter of 1219 mm and wall thickness of 14.3 mm. The test was carried out in accordance with API 5L standard on drop weight tear test apparatus with a 700 kg hammer equipped with accelerometer having 3 m drop. Using the obtained natural frequency and the low-pass Batterworth filter, the unwanted oscillations were removed from the high-velocity test data. The fracture energy (area under load-displacement record) obtained as 6791 J, which was around 4 percent less than the energy value of the drop weight tear test equipped with strain gauge in previous studies. Due to this small difference, the accuracy of the drop weight tear test equipped with accelerometer was confirmed.