Heuristic approach to solving two-criterion problem of optimization of composite materials

Introduction. Presented the approach to optimal choice of materials, in particular, composite materials. An important task of modern materials science is the development of effective composite materials, which is associated with numerous scientific studies in this area and the search for materials with certain additives in order to obtain the necessary properties. First of all, it is an indicator of the hardness of the composite material. Materials and methods. Traditionally, different compositions are studied and property values are analyzed, and experimental results are processed in different ways. Multi-criteria optimization occupies a special place in the theory of optimization of objects, which include composite materials, in particular concrete with various additives. For this it is necessary to formulate a multicriteria optimality problem, in particular a two-criterion minimization problem. Results. Two heuristic optimization criteria are considered, according to which a vector criterion is formed, which allows to carry out the selection of composite materials from experimental data at its minimization. Vector criterion connects the change of the studied properties of the composite material with the simultaneous preference for the choice of the composition that optimizes the given criterion of optimality. The basis of the construction of the optimization scheme of choice of materials is a piecewise linear approximation of the test results, which allows to determine the scalar criteria on the basis of which the vector optimization criterion is constructed. To demonstrate two-criterion optimization, the results of experiments for cement composites exposed under the cyclic influence of negative and positive temperatures are considered. The search for the optimal composition in terms of hardness from the time of exposure. Conclusions. The proposed approach of optimal choice of materials, in particular, composite materials, can be tested on large numbers of test samples, or to automate calculations. This approach has a certain heuristic character. But its practical significance is confirmed by the expert evaluation of the quality of composite materials due to the existing methods of evaluation of materials, for example, in terms of changes in its hardness

RESEARCH OF BEHAVIOR OF CEMENT COMPOSITES IN CONDITIONS OF HIGH HUMIDITY AND VARIABLE POSITIVE TEMPERATURES

In this paper, the results of testing cement composites under the conditions of the effect of high humidity and variable positive temperatures are given.By the coefficient of variation of hardness (stability), the compositions are compared with various fillers, plasticizing and other fungicidal additives.To decide on the stability (stability) of the structure and properties of composites, it is proposed to rely on the area of the polygon obtained as a result of piecewise linear approximation of the exposure points. Explanations of the influence of environmental factors on hardness change of the composites