The paper presents the results of the study of registered acoustic emission (AE) parameters during static deformation and damaging of polymer composite materials (PCM). Mechanical tests were done by a static tension and a static three-point bend, accompanied by an acoustic emission method. The assessment of the loading rate effect on defects formation processes was done by additional static tension test at rate equal half of recommended by the standard and static three-point bend test at rate ten times lower than that calculated by the standard. Clustering by frequency components of the recorded AE signals with a self-organizing Kohonen map was performed. The characteristics of the types of PCM structure damage by the centroids of the obtained clusters are given. Based on the clusters accumulation during mechanical tests, the stages of damage formation for static tension and static three-point bend, the loading rate effect on the process of damage formation are described.

The article presents the data of an experimental study on how heat treatment influences the physical and mechanical properties of cured samples of sandwich structures. The sandwich structures were made using VaRTM method. Heat treatment at 80 °С and 60 °С leads to increase in the bending strength. Three-point bend tests of sandwich structures and FGRP were conducted. Also, hardness and tensile strength were determined. Heat treatment results in increase of bending stress of FGRP by 71%, via the the tensile strength of heat-treated FGRP increased by 78%. The results characterize the relationship between the durability and the temperature and exposure time of the sandwich structures. The results correlate with the data of swelling of the cured binder. As a result of heat treatment at 80 °С for 4 hours, the extent of swelling decreased by 14%. The heat treatment of sandwich structures at a temperature of 80 °С for 4 hours is optimal and leads to increase in the tensile strength by 30.7%.

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Аннотация. В статье представлены данные экспериментального исследования влияния термической обработки на физико-механические свойства сэндвич-конструкций. Сэндвич-конструкции были получены с использованием метода VaRTM. Термическая обработка проводилась при значениях температуры, равных 80 °С и 60 °С при различном времени выдержки. Были проведены испытания разрушающего контроля сэндвич-конструкций и стеклопластиков. Полученные данные коррелируют с результатами исследований степени набухания отверждённых связующих. Исследования структуры стеклопластиков показывают, что при термообработке происходит трансформация надмолекулярной структуры полимерной матрицы.Summary. The article presents the data of an experimental study heat treatment influence on the physical and mechanical properties of cured samples of sandwich structures. The sandwich structures were made using VaRTM method. Heat treatment at 80 °С and 60 °С leads to increase in the bending strength. The tests of destructive control of sandwich structures and fiberglass plastics have been carried out. The SEM micrographs of the microstrustructures of fiberglass reinforced plastic samples show that during heat treatment there is a structural refinement of the polymer matrix. The results correlate with the data of swelling of the cured binder.Ключевые слова: сэндвич-конструкции, полимерный композиционный материал, прочность, набухание, сканирующая электронная микроскопия, эпоксивинилэфирное связующее, термическая обработка.

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