Determination of load condition of standard screws during tensiletests using acoustic emission analysis

摘要

We examined the acoustic behaviour of screws under applied load todevelop an in-process monitoring system for endangered screwconnections. To apply load to a screw, a hydraulic tensile testingmachine was designed. Signals occurring during tensile tests weredigitally recorded and analysed using acoustic emission (AE) technique.We established an increase of the AE-rate at the yield limit and weakerAE-activity during the plastic deformation. The AE-signals containeddominant frequencies in two narrow frequency ranges, namely at 590 kHzand 1010 kHz and therefore we were capable of distinguishing betweenfriction processes in the screw thread and abrupt dislocation processesunder load. The significance of the results for in-process monitoring ofscrews is illustrated