ANALYSIS OF MESOSTRUCTURE AND FRACTURE KINETICS OF ELEMENTS OF LATTICE COMPOSITE STRUCTURES UNDER TRANSVERSAL COMPRESSION USING STOCHASTIC FEA MICROMECHANICS

The paper analyses the mesostructure of structural elements lattice aircraft shells – ribs consisting alternating layers equal thickness and made from unidi-rectional CFRP pure matrix material. In experimental studies, elastic characteristics unidirectional were obtained under three-point bending transversal compression. As a result, longitudinal modulus elasticity layered composite turned out to be 101 GPa, shear was 2.95 GPa. Numerical modeling meso- micromechanics interaction noticed compression has been performed up failure. ANSYS FEA software (explicit implicit formulations) used. regular stochastic stacking fibres in cross section is considered. fiber diameters element measured on thin sections using Zeiss Axio Observer D1m digital microscope 5.1 ± 0.8 µm. Layers with volume fraction about 60 % alternate epoxy. It proposed use only first principal stress as micromechanical criterion for failure com-pression tension. At stage calculations, problem cell laying solved (the error value less than 2 %). second stage, an assessment strength accumulation microdamages model structure fibre stacking. analysis stress-strain state it possible explain reason that rib trans-verse twice lower homogeneous CFRP. calculated values ultimate are good agreement ones.