PSI - Issue 20

Gusev E.L. et al. / Procedia Structural Integrity 20 (2019) 294–299

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Gusev E.L. et.al. / Structural Integrity Procedia 00 (2019) 000–000

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1. Introduction

Composite materials, as a rule, are constantly under the influence of static and dynamic loads, which are additionally influenced by extreme environmental factors. In accordance with this, the problem of developing mathematical models, mathematical methods for solving inverse problems of predicting changes in the durability of composite materials under the influence of operational loads and extreme environmental factors is of great importance, founded by Bolotin (1984), Bulmanis et al. (1987), Filatov and Bochkarev (1986), Potapova and Yartsev (2005), Reutov (2007), Reutov et al. (2002), Reutov (2009), Stepanov and Zinin (2007), Bashkarev et al. (2016), Gusev (2016, 2018), Gusev and Babenko (2015), Gusev and Bakulin (2017, 2018).

Nomenclature R

residual life

R 0

the initial value of the residual resource

p

number of different factors number of model parameters

N

t

time

T min T max γ max R(t) R * (t)

lower limit of the predicted interval top limit of the predicted interval the maximum allowable required precision the predicted dependence of residual life

the real dependence on the time determining the properties of the composite

2. Disadvantages of existing approaches to solving problems of predicting the residual life of composites

At present, the problems of predicting the life, reliability, durability of composite structures under the influence of extreme environmental factors and operational loads are solved in a much simplified formulation that does not take into account a significant number of factors that have a significant impact on the accuracy of the solution: 1) A.N. Tikhonov's property of incorrectness of forecasting problems as inverse problems of mathematical physics is not taken into account; 2) Do not take into account additional information about the laws of distribution of errors of measurement of the determining properties of polymer composites; 3) The theory of estimation of forecast accuracy is not fully developed; 4) The applied methods of predicting the residual life, strength, reliability, durability of polymer composites do not take into account modern achievements in the field of mathematical and computer modeling. At the same time, as a rule, the solution of the problems of forecasting the resource, the durability of the components, is carried out within the framework of the statements of direct forecasting problems , ie, with the conduct of calculations based on the known up to the parameters of the durability models. Within the framework of the currently solved simplified statements, it is not possible to justify the correctness of the obtained predicted solutions, which can differ significantly from the real dependencies. 3. Promising ways to improve forecasting methods In accordance with this, the actual problem is the development of effective, refined methods for predicting the resource, reliability, strength, durability of structures made of polymer, composite materials , based on modern achievements in the field of mathematical and computer modeling. As noted in the works of the corresponding member RAS Yu. S. Urzhumtsev, an effective solution to the problem of forecasting is possible if the results of short-term experiments can be identified stable qualitative patterns of behavior of polymer, composite materials, under the influence of extreme environmental factors, by Urzhumtsev (1982). Such stable qualitative regularities are determined by the characteristics of micro-and macrostructures of