Composites Evaluation

The laser ultrasonic (LU) method is successfully used for the polymeric composite materials evaluation. The laboratory solves the full range of problems for composites monitoring: carrying out laser-ultrasonic diagnostics of samples from PCM in the process of testing to detect defects in the structure of the pore type, bundles, cracks. a study of the growth of defects in the process of loading tests based on the results of laser-ultrasonic diagnostics of PCM samples. The development of a laser-ultrasound transducer on an automatic translator for the automated study of large-sized PCM samples. development of technological recommendations for the introduction of automated laser-ultrasound diagnostics.
  • laser ultrasonic evaluation of CRFC composite samples while testing process to detect defects in the structure of the pore type, delaminations, cracks
  • a study of the defects growth in the stress testing based on the results of laser ultrasonic diagnostics of CFRC samples
  • the development of a laser ultrasound transducer on an automatic translator for the automated study of large-sized CFRC samples
  • the development of technological recommendations for the implementation of automated laser ultrasound diagnostics
 


Contact laser-ultrasonic evaluation allows to obtain information about the internal structure of composite integrated structures during their operation. The results of laser ultrasonic testing of experimental torsion boxes during static stress tests are presented below.
 




Laser ultrasonic impact failures evaluation of CFRC part is performed with one-sided access to the sample in a automated mode. During the inspection the volume pattern of failures is determined. The short duration of the laser ultrasonic pulse makes it possible to perform a layer-to-layer inspection. The results of laser ultrasonic testing for the CFRC part with 6 mm thickness are presented below, the impact energy was 30 J. Its clear that destruction in each layer propagates along the direction of the fibers. The ratio of the depth and diameter of the failure zone correlates with the ultrasound velocities ratio along and across the fibers.
 


Laser ultrasonic inspection of CFRC stringers part failures is permormed both along and across the T-connection with one-sided access to the sample.
 




Laser-ultrasonic CFRC inspection allows layer-to-layer inspection of the material state with a resolution of about 50 μm. Prepreg placement and structural failures are visualized. Areas of increased porosity are clearly visible.
 


Zones of heterogeneity of the composite structure in the T-connection area (excess resin, lack of bonding, cracking and void formation) are revealed.