A study on the failure detection of composite materials using an acoustic emission

Fiber reinforced composite materials have been increasingly used as structural material in airplanes, in space applications, and in robot arms because of their high specific stiffness and strength. Structural design and nondestructive test techniques have evolved as increased emphasis has been placed on the durability and damage tolerance of these materials. There are several methods used to detect damaged regions of composite materials. Acoustic emission is one of these. It is a suitable technique for detection of a wide range of micro-structural failures in composite materials. In this paper, an AE signal analyzer was designed and fabricated with a resonance circuit to extract the specified frequency of an acoustic emission signal. From the tests that were completed, the disturbance noise levels, such as impact or mechanical vibration, of the fabricated AE signal analyzer had a very small value in comparison to those of the conventional AE signal analyzer. Also, the fabricated AE signal analyzer was proven to have generally the same crack detection capabilities as a conventional AE signal analyzer, under static and dynamic tensile tests of the composite materials.