For continuous fiber reinforced composites turbo-shaft structural failure mode analysis

based on the macro-mechanics and meso-mechanics analysis method of cross-scale

a micro-mechanics representative volume element (RVE) model was established

through programming and simulation

the periodic boundary conditions of model were realized

the stress response of fiber reinforced composites was calculated and the mean stress was converted into real stress

then the failure envelope was determined. It established mechanical model of fiber reinforced composite shaft structures

and the principal stress response was calculated. Through the transformation of the principal-partial axial stress for the composite laminated plates

the macroscopic stress response calculation results of the dangerous elements in all directions were transformed into the microscopic mechanics RVE model

reflecting the microscopic mechanics load condition of the RVE model. The failure mode of composite shaft structure at dangerous position was determined by the failure boundary of micro-mechanics; when the torsional load was between 5 000-5 500 N·m

the outermost layer of the composite

also the layer 6 (+45°)

reached the tensile failure load of the matrix firstly. The failure mode test of composite shaft structure was carried out; when the torsional load had reached 6 000 N·m

acoustic emission signals stacked with each other

most of which were intermediate frequency signals

of which most were matrix and interface cracking signals. Then compared with the simulation results

it verified the effectiveness of the failure mode analysis method. The failure load and failure mode of a certain engine low pressure turboshaft have been predicted by using the proposed model.