Prediction of fatigue crack growth in steel bridge components using acoustic emission

Acoustic emission analysis is used to investigate microscopic damage mechanisms and damage progress in unidirectional glass and carbon fibre reinforced composites. Under static loading the influence of fibre orientation on damage initiation and propagation is determined. A novel polyurethane matrix system significantly enhances material performance in terms of crack initiation load levels, crack growth, damage tolerance and off-axis tensile strength. Hysteresis measurements during stepwise increasing dynamic load tests highlight the effect of fibre–matrix-adhesion and resin fracture toughness in unidirectional 0° fibre reinforced composites. Acoustic detection of beginning fibre breakage correlates with a significant increase of loss work per cycle.

Acoustic emission analysis for characterisation of damage mechanisms in fibre reinforced thermosetting polyurethane and epoxy

Acoustic emission signal processing framework to identify fracture in aluminum alloys

The acoustic emission (AE) generated during tensile tests performed on Q345 steel specimens was investigated in this study. Two typical types of AE signals were obtained during the test: Type A signals with burst type waveforms in the micro-yielding and work-hardening stages and Type B signals with continuous-type waveforms during the discontinuous yielding (Luders band propagation) stage. The effects of the strain rate and notch on these two types of signals were studied. The AE energy of Type B signals increased with increasing strain rate and was much higher in notched specimens compared to unnotched ones at high strain rates. However, for Type A signals, less AE energy was generated in notched specimens than in unnotched specimens, and it showed little sensitivity to changes in the strain rate. These results were fully analyzed by relating the AE behavior to the deformation properties and transmission electron microscope (TEM) observations of the materials. Thus, the AE source mechanisms and the effects of the strain rate and notch during plastic deformation were determined for discontinuous yielding materials.

M. Rosen

Papers

Fatigue life prediction by distribution analysis of acoustic emission signals

Acoustic emission generated during the tensile testing of aluminium alloys