Measurements of material local characteristics (density, porosity)

The high quality of the ultrasonic signal emitted by the laser source makes it possible to measure not only the surface profile and ultrasound velocities, but also the local density of the investigated material. According to these measurements a set of elastic moduli of the test sample and its porosity are calculated. The figures show the measured density distribution of the carbon-carbon composites. Blue zones are areas of increased porosity.There are no analogues of this local density of the material determining technique.
 


This technique allows measurements of local characteristics of carbon-carbon composite materials (C-C composites) after special tests. The area of special impact is poorly visible on the profilogram (left), however it is clearly defined on the measured density map (right). The irradiation zone has a sharply reduced density and, obviously, increased damage.
 


The proposed technique allows to measure the local density of thermal-protective coatings. Blue bars on the right picture are areas of reduced density (increased porosity).
 


Areas of increased porosity (blue zones on the right) are preserved, despite the alignment of the average relief (left).