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The work presents the results of a study and identification of damages formed in a polymer composite material (PCM) under conditions of flexural deformation using the acoustic emission (AE) method. The object of the study was fiberglass reinforced plastic made by vacuum infusion technique using a binder DION 9300 FR and 46 layers of fiberglass T-11-GVS-9. Mechanical test was made by three-point static bending. Damages in the PCM structure was assessed using the scanning electron microscopy method and compared with the results of acoustic emission (AE) data clustering. Based on the damage clusters accumulation data, a description of the PCM failure process under bending deformation is presented. [ABSTRACT FROM AUTHOR]

The paper studies the kinetics of fatigue damage accumulation in VT1-0 titanium by the acoustic emission (AE) method. Technical grade titanium VT1-0 in various structural states was tested under cyclic bending. Submicrocrystalline Ti-specimens (SMC, with subgrain size of 200-300 nm) were fabricated by equal channel angular pressing (ECAP) from polycrystalline titanium. Ingots with ultrafine grain structure (UFG, with structure element size of 1-2 µm) and coarse grain structure (CG, with structure element size of 20-30 µm) were prepared by annealing at different temperatures. Fatigue stages were identified by analyzing the AE signal parameters with their classification by the source type (dislocations, micro- and macrocracks). It was revealed that the specimens with a smaller grain size are of higher fatigue durability, while AE signals at the stages of yielding and microcracking are detected later because of their low energy. [ABSTRACT FROM AUTHOR]

Strength properties of the glass fiber reinforced polymers (GFRP) fabricated by vacuum and vacuum autoclave molding techniques were analyzed. Measurements of porosity of the GFRP parts manufactured by various molding techniques were conducted with the help of optical microscopy. On the basis of experimental data obtained by means of acoustic emission hardware/software setup, the technique for running diagnostics and forecasting the bearing capacity of polymeric composite materials based on the result of three-point bending tests has been developed. The operation principle of the technique is underlined by the evaluation of the power function index change which takes place on the dependence of the total acoustic emission counts versus the loading stress. [ABSTRACT FROM AUTHOR]