Nondestructive Evaluation Laboratory
This laboratory is used for detection and analysis of internal damage and flaws in advanced polymer composites and other engineering materials. The methods utilized include acoustic emission, acousto-ultrasonics, and ultrasonic scanning. A state-of-the-art acoustic emission system is used for studying damage evolution under loading. This system combines a fully digital architecture with high processing dynamics that allows for studying material response under fast dynamic loads.
The system is capable of simultaneous acquisition of acoustic emission parameters and transient data, and is equipped with location software and FFT software. Extensive filtering, cluster analysis, and pattern recognition capabilities, including unique AE signal classification methods developed by the group, enable damage type identification and extraction of histories for different micromechanisms.
This acoustic emission system with a pulser is also used in acousto-ultrasonic experiments. Shape and spectrum analyses of acoustic waves propagated through partially damaged materials are used to evaluate average damage parameters. A leading edge ultrasonic immersion system is used for spatial mapping of internal flaws. In addition to regular A-scan, B-scan, and C-scan, the system provides specialized capabilities such as full digital waveform storage and analysis at each location, digital filtering, FFT analysis, and 3-dimensional imaging. A high signal conversion rate permits use of high resolution transducers with resonant frequencies within a frequency range of scanning acoustic microscopes.
Multiscale NDE capability in the scale range from structural to nanometers are provided by a unique Multiscale NDE Facility comprising ultrasonic immersion scanner, scanning acoustic tomograph, scanning acoustic microscope (SAM) with 1.3 GHz imaging capability, and a scanning probe microscope with specimen modulation capability.
Quantitative NDE outcomes are assisted by wave-propagation modeling and simulations. Predictive capabilities are established by linking quantitative NDE with damage and fracture models developed based on damage and fracture mechanics evaluations of materials under quasi-static, dynamic, and fatigue loadings (see Advanced Composites Laboratory).