Abstract:
Acoustic Emission testing for material failure is considered as a non-destructive testing methode used for online material monitoring. It is the transient elastic wave in a material caused by the rapid release of localized stress energy. This research aimed to develop Acoustic Emission testing process and study the characteristic of its signals during crack propagation of 4 different materials.
This Acoustic Emission system included a sensor, pre-amplifier, and Acoustic Emission analyzer to monitor the work piece under tension force (moving speed of 5 mm./min). The Acoustic Emission signal was recorded continuously from the beginning process through the complete fractured phase of the work piece. This Acoustic Emission signal was also analyzed by using Labview Program in order to identify the Acoustic Emission parameters such as Amplitude. Steel S45C, Steel SCM440, Aluminum 5083-H112, and High-density Polyethylene (HDPE) were compared for the testing.
The results showed that the Acoustic Emission signal of the work piece under tension force related with its deformation. S45C Steel had the average amplitude values at 842 mV while SCM440 steel had its average amplitude values at 460 mV. Aluminum 5083-H112 had its average amplitude at 290 mV. Before yield point, the amplitude increased clearly when there was an act on the material. However, for the High-density Polyethylene (HDPE), there was no clear change of amplitude over threshold with an act on the material.