Identification of the elastic characteristics of a composite material based on the results of tests for the stability of panels made from it

Abstract

© 2019, Kazan Federal University. All rights reserved. The problem of identifying the mechanical characteristics of a fibrous composite material (FCM), from which cylindrical panels or pre-curved plates are made by superposition at an angle to the edge, has been considered. The problem has been solved using the analysis of the results of the tests of structures with bringing them to the loss of bearing capacity due to loss of stability. The advantage of the proposed approach is no necessity to measure the deformation or movement of these structural elements during experiments (this does not require the presence of complex measuring devices, their calibration, long-term debugging of the experimental techniques). Only the critical values of the load, which can be tested in a short period of time, must be determined. In addition, such tests are not destructive under loading, which enables the repeated use of the sample under different types of load and conditions of fixing. The identification technique is based on minimizing the quadratic discrepancy between the results of solving direct problems of stability and the results of experiments. By introducing the discrepancy of possible errors in experimental data measurement, an extended formulation of the problem has been obtained. Numerical solutions of the model problems show that the solution of the problem is stable to variations of the original data. The proposed approach allows to obtain the calculated mechanical characteristics of the composite material close to true even in the case of a considerable variation in the stiffness characteristics of the composite material from sample to sample and errors in determining the critical load.