Florin Breaban

Laser Scanning Vibrometry and Holographic Interferometry Applied to Vibration Study

The applications of high performance materials in the aerospace and in the automotive technology in the next years need to develop new vibration study, nondestructive testing, predictive maintenance and industrial control methods.The Laser Scanning Vibrometry and Holographic Interferometry methods of vibration study and nondestructive testing by modal analysis are described. The Laser Scanning Vibrometer PSV 400 is made by Polytec GmbH and the PSV software reconstructs the 3D model of the measured micro-deformation of the object. The holographic laser system HLS-3 from Lumonics Inc. has 100 MW ruby laser peak power and 30 ns pulse width.Using mechanical excitation to induce a measurable vibration, the Laser Scanning Vibrometry and Holographic Interferometry modal analysis measurements show up the vibrational signatures and the damaged areas of the objects made by high performance materials - polymers, composites.

Active thermography based on the heat transfer process in determining the influence of micro defects in bio-ceramic materials surface

This paper presents a non-destructive technique (NDT) using active infrared thermography and the thermal excitation consisting in an electric plane, applicable for bio-ceramic surface micro-defects detection. For this work we chose to study samples made of bio-ceramic (hydroxyl-apatite), having a cylindrical form with a diameter of φ = 15.20 mm and a thickness of 2.00 mm. The aim of this paper was to study the influence of surface defects in the heat transfer process for the bio-ceramic materials. The advantages of this method are the rapidity of determining and the safety of the material structure after the thermal excitation. For the concluding results there are necessary only a few seconds and a temperature difference of few Celsius degrees to discover the defect and the heat loss on the sample surface.

Active thermography method using an CO 2 laser for thermal excitation, applied to defect detection in bioceramic materials

This paper presents a non-destructive technique (NDT) using active infrared thermography and a thermal excitation consisting in a CO2 laser, having a wavelength of 10.6 μm, applicable for bioceramic interior defect detection. For this work we used two samples of bioceramics (Al2O3), having the same size, 16 mm diameter and 3 mm thickness. A non-defect sample it was used as the basis for the temperature differences between the healthy and the defective one. In the second sample an internal defect was created. In order to make possible the thermal excitation of the samples it was necessary to deflect the laser beam from vertical to horizontal direction, towards the material. The first advantage of this method represents the detection of internal defects in bioceramic materials, the microscopic method not being reliable in this purpose. The second advantage represents the rapidity of the determinations, just few seconds necessary for internal defect detection.