Evaluation of the Effect Composite Samples Cyclic Loading on Their Residual Strength

When studying the fatigue resistance characteristics of polymer composites in the process of constructing the fatigue curve, so–called censoring often takes place - namely, samples that have not collapsed before the completion of the tests. To extract additional information on these samples, the use of destructive and non-destructive methods is proposed. The specificity of composite materials and materials reinforced with polymers consists of a significant variation in their strength properties, especially fatigue strength. The purpose of this study was to create a methodology combining destructive and non-destructive methods to solve the problem of clarifying the equation of the fatigue curve. Non-destructive in this study is an industrial tomography of samples, which later allowed assigning ratings to censored samples, which can later be used in constructing a fuzzy regression model. This will make it possible in the future to competently plan a research plan concerning polymer composite. Small-sized samples of polymer composites previously subjected to cyclic compression loading and not destroyed upon reaching the test base (censored samples) were studied. As part of this study, a tomographic examination was carried out. The final stage was the compression test (destructive method) with the associated dynamic determination of stiffness. At the stage of the destructive test, a promising optical-correlation method of speckle interferometry was used to determine the deformation fields. Correlation indicates the correctness of the chosen methods of testing. The developed technique can be successfully applied in the task of planning the study of the quality of polymer composite materials.