Seminar Announcement, November 26, 2019, Thermal Methods for the Damage Evaluation of Metallic and Composite Materials, by Davide Palumbo, Department of Mechanics, Mathematics and Management, Politecnico di Bari, Via Orabona, 4, 70125, Bari, Italy

Thermal methods represent the set of techniques and procedures based on the investigation of the thermal phenomena related to damage during static or fatigue stresses or more in general to the behaviour of damaged and defected areas. In the last years, these methods were used in many applications regarding both the metallic and composite materials such as fatigue damage, crack detection and crack growth monitoring, defects detection with non-destructive testing. In particular, the use of focal plane array detectors (FPA) allowed the development of new Infrared Thermography techniques and new methods for data analysis.

The increasing use of Thermography in industrial applications was principally due to its peculiarities that combining the full-field information of data with a relatively simple experimental set-up and consequent reduction of time and costs.

In literature are present two different approaches to the Infrared thermography: active and passive thermography. The first one does not require external heat sources and is based on the measurement of heat sources variations generated by thermoelastic coupling and damage phenomena when the material is subjected to dynamic stresses. The second approach requires external heat sources such as, halogen lamps, flash lamps, laser source, etc. This latter is used for detecting surface or sub-surface defects in metals and composites. In this regard, in literature there are two main techniques, Pulsed (PT) and Lock-in Thermography (LT) and several algorithms for data processing capable to provide quantitative information about defects.

In this seminar both the approaches will be presented. The passive one for investigating the fatigue and fracture mechanics behaviour of stainless steels and for crack monitoring in aerospace materials with TSA. The active approach has been used for the quantitative defect detection on aluminium and GFRP and CFRP materials. The final aim is to show the capability of thermal methods assessing the damage in several applications quickly and with relative low cost with respect to traditional methods.