Determination of elastic moduli and Poisson’s ratios of bi-modulus materials based on the results of four-point bending test

The paper considers the variant of determining elastic moduli and Poisson’s ratios of bi-modulus materials based on the results of strain measurements by fiber Bragg grating sensors in rectangular specimens under four-point bending. Formulas for calculating elastic constants using the results of strain measurement are presented. Variants of fixation of Bragg grating sensors on the surface of specimens are discussed and the employment of numerical methods for the analysis of possible errors of strain determination is considered. The conducted studies allow to estimate errors in the determination of elastic constants associated with the correspondence of the specimen dimensions to the relations for calculating the elastic constants based on the strain measurements and the accuracy of strain measurements with considered sensors. The results of determining the elastic constants of duraluminum, cast iron, granite, foamed concrete are presented along with the analysis of different errors occurring during their determination.