Research and applicative activities on non-destructive testing and structural health monitoring of structural materials and components are performed both experimentally and numerically. Traditional and advanced techniques are employed, while innovative ones are developed. Additionally, in-service monitoring and prognostics are studied and implemented.

INSTRUMENTS & FACILITIES

• Harfang X32 phased array ultrasonic flaw detector with 2.25, 5 and 10 MHz probes. Encoders for C-Scan mapping
• Eddify M2M Mantis phased array ultrasonic flaw detector with 2.25 and 5 MHz probes. TOFD, conventional ultrasonic channels and TFM functionalities are available, as well
• RDG500 and RDG2500 conventional ultrasonic flaw detectors with straight, twin, angled and creeping probes
• Innerspec Temate Powerbox H EMAT ultrasonic flaw detector with permanent magnets and coils for different beam forming opportunities
• Specific equipment for implementing and managing Lamb and guided ultrasonic waves
• Vallen AMSY-6 acoustic emission unit (8-channels). Managed by the PoliNDT interdepartmental lab
• Nortec 1000S+ eddy current flaw detector with probes working at a 500-2000 Hz frequency range
• NSI X25 x-ray micro-computed tomography scanner. Managed by the AMALA interdepartmental lab
• Electromagnetic yokes and permanent magnets for colour contrast and fluorescent magnetic particles (calibration blocks, luxmeter, radiometer, UV lights, ASME probe, gaussmeter)
• Colour contrast and fluorescent liquid penetrants (calibration blocks, luxmeter, radiometer, UV lights, thermocouples, chronometer)
• Lenses, mirrors and dedicated white and black lights for visual testing
• CIVAnde specific software package for NDT simulations (ultrasonic testing, eddy current testing, radiographic testing and x-ray computed tomography)
• AST X-Stress 3000 portable X-ray diffractometer
• Equipment for holographic interferometry and for transmission and reflection photo-elasticity.

ACTIVITIES

Experimental and numerical characterization of NDT capabilities

• Characterization of experimental “Probability of Detection” curves for different NDT methods
• Characterization of numerical “Model Assisted Probability of Detection” and “Multi-Parameter Probability of Detection” curves for different NDT methods
• Interaction between NDT capabilities and the damage tolerant design approach

Traditional and advanced ultrasonic testing of materials and components

• Phased array monitoring of fatigue crack propagation in adhesive bonded composite lap-joints
• TOFD inspection of welded and seamless metallic pipes
• Guided waves monitoring of pipes and rails
• Residual stress measurements in railway wheels by EMAT
• Application of creeping waves to coarse grain metals

Structural health monitoring by ultrasonic lamb waves

• Determination and characterization of dispersion curves in metallic, composite and polymeric components
• Definition of an innovative way to induce a single anti-symmetric propagation mode of Lamb waves
• Analysis of the reflection and transmission of Lamb waves through artificial delaminations in composite laminates
• Analysis of the reflection and transmission of Lamb waves through natural defects, obtained by low energy impacts, in composite laminates

Structural health monitoring by acoustic emission

• In-service monitoring of railway axles by means of acoustic emission
• In-service monitoring of adhesive bonded joints by means of acoustic emission
• Comparison of acoustic emission response with optical, micro-computed tomography scans and ultrasonic NDT approaches during crack propagation tests
• Comparison of acoustic emission response with low frequency vibrations during crack propagation tests
• Post-processing and interpretation of acoustic emission data by machine learning and artificial intelligence

Eddy current testing of corrosion-fatigue phenomena

• Experimental eddy current measurements of developing corrosion-fatigue damage in small-scale specimens and full-scale components
• Correlation between damage and eddy current response at different stages of corrosion-fatigue life
• Numerical simulations of eddy current response at different stages of corrosion-fatigue life