A methodical approach to the estimation of the localization zone and geometric parameters of a delamination defect in layered composite materials is presented on the basis of mathematical processing of the experimental results of deformation measurements obtained with a grid of fiber-optic sensors. The results of methodological developments related to the determination of the optimal topology of the grid of sensors to ensure the detection of defects of a given size with the necessary accuracy and determination of their parameters are presented. We present methods for computational analysis and simulation of the strain-stress state in the defect zone, based on the algorithm used for modeling the problems of strain-stress analysis in the defect zone using 2D finite elements, instead of 3D ones, thus allowing the use a model of lower dimensionality and retain all the features of the stress-strain state. The results of methodological developments related to the determination of the defect parameters from the results of strain measurements using the methodology of solving the inverse problem, based on solving the problem of minimizing the discrepancy between the vector of deformation response and the vector of initial parameters are presented. The technique is implemented as a software consisting of a series of macros for ANSYS and programs for MATLAB. The results of cyclic testing of a sample from a multilayer CM with a delamination type of defect are presented. Estimation of the increment in the defect size upon loading is performed by mathematical processing of data recorded by fiber-optic strain sensors glued on one of the sample surfaces, based on the solution of the inverse problem. Comparison of the results of calculations of geometric parameters of the defects with the measurement data obtained by the method of ultrasonic flaw detection showed good agreement between them.

Существуют два основных подхода решения задачи тепломассопереноса при численном моделировании промерзания грунтов: 1) решение методом конечных разностей с учетом граничных условий (границей, например, является фронт промерзания); 2) решение методом конечных элементов без учета границ модели. Оба подхода имеют существенные недостатки, что оставляет проблему решения задачи для численной модели промерзания грунтов острой и актуальной. В данной работе представлена физическая постановка промерзания, которая позволяет создать численную модель, базирующуюся на решении методом конечных элементов, но при этом отражающую ход фронта промерзания - то есть модель, в которой объединены оба подхода к решению задачи промерзания грунтов. Для подтверждения корректности модели был проделан ряд экспериментов по физическому моделированию промерзания модельного грунта и выполнен сравнительный анализ полученных экспериментальных данных и результатов расчетов на базе представленной численной модели с такими же граничными условиями, как в экспериментах. There are two basic approaches to solving the problem of heat and mass transfer in the numerical modeling of soil freezing: 1) using the finite difference method taking into account boundary conditions (the boundary, for example, is the freezing front); 2) using the finite element method without consideration of model boundaries. Both approaches have significant drawbacks, which leaves the issue of solving the problem for the numerical model of soil freezing acute and up-to-date. This article provides the physical setting of freezing that allows us to create a numerical model based on the solution by the finite element method, but at the same time reflecting the route of the freezing front, i.e. the model that combines both approaches to solving the problem of soil freezing. In order to confirm the correctness of the model, a number of experiments on physical modeling of model soil freezing have been performed, and a comparative analysis of the experimental data obtained and the calculation results based on the provided numerical model with the same boundary conditions as in the experiments was performed.

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