MODELING THE ELASTIC AND DAMPING PROPERTIES OF THE MULTILAYERED TORSION BAR-BLADE STRUCTURE OF ROTORS OF LIGHT HELICOPTERS OF THE NEW GENERATION 2. FINITE-ELEMENT APPROXIMATION OF BLADES AND A MODEL OF COUPLING OF THE TORSION BAR WITH THE BLADES

摘要

A rod-shape finite element with twelve degrees of freedom is proposed for modeling the elastic and damping properties of rotor blades with regard to their geometric stiffness caused by rotation of the rotor. A model of coupling of the torsion bar with blades is developed based on the hypothesis of linear deplanation of the connecting section of the torsion bar and a special transition element to ensure the compatibility of displacements of the torsion bar and blades upon their vibrations in the flapping and rotation planes. Numerical experiments were carried out to test and assess the validity of the model developed. Suggestions are made for ensuring unconditional stability of the iteration method in a subspace in determining the specified number of modes and frequencies of free vibrations of the torsion bar-blade structure.