The paper deals with the mechanical behaviour of natural fibre composites subjected to tensile test and dynamic mechanical analysis (DMA). Three types of natural fibre composites were prepared and tested: wood particle reinforced composites with six different sizes of grains (WPC); hemp mat reinforced composites (HMP) and flax reinforced composite with mixed wood particles (FWPC). The tensile test performed on universal testing machine LS100 Lloyd’s Instrument highlights the elastic properties of the samples, as longitudinal elasticity modulus; tensile rupture; strain at break; and stiffness. The large dispersion of stress–strain curves was noticed in the case of HMP and FWPC by comparison to WPC samples which present high homogeneity of elastic–plastic behaviour. The DMA test emphasized the rheological behaviour of natural fibre composites in terms of energy dissipation of a material under cyclic load. Cole–Cole plots revealed the connection between stored and loss heat energy for studied samples. The mixture of wood particles with a polyester matrix leads to relative homogeneity of composite in comparison with FWPC and HMP samples which is visible from the shape of Cole–Cole curves. The random fibres from the hemp mat structure lead to a heterogeneous nature of composite structure. The elastic and viscous responses of samples depend on the interface between fibres and matrix.

The implementation of the image processing techniques for the analysis of the thermal field images captured with infrared scanners from the shield of the rotary kilns increase the quality of the information required for the optimization, monitoring and failure prevention of the kiln. In this work, authors presented a method that implement advanced algorithms such as the Radon transform, the segmentation and labeling of images for estimating the space-distributed, parametric model of the kiln’s thermal field. The aim of the investigation is analyzing the similarities/differences between the thermal profile of the kiln and the kiln’s maintenance events. The implementation of the proposed method proved that the correlations between the changes of the thermal profile and the renewal of the thermal coating of the kiln may be well emphasized. In this perspective, this method is suitable for building a thermal profile of the kiln during an entire maintenance time span.