Maksymovych Y. Calculation of trajectories and velocities of fatigue cracks propagation in lamellate elements of designs.

A procedure for calculation of trajectories and velocities of fatigue cracks propagation in plates of different shape is developed. It is based on the tracing method. For its realization at each stage we have developed: a) a procedure for description of the crack shape by cubic splines with given tangentional inclinations at the tops; b) a modified algorithm for the SIF definition in the bounded and infinite plates with curvilinear cracks of arbitrary configuration, which is based on the method of integral equations and Green's - type solutions; c) a procedure for definition of the crack shape often its growth at the end of the stage. The process of fatigue failure is studied in the semi - infinite, circular, rectilinear plates, a strip and plate with elliptic hole concerning 75XГCT steel, with utilization criterion for definition of directions and the Yarema-Mykytyshyn formula for description of velocily of fatigue cracks-growth. The regularities are determined for growth of rectilinear and curred cracks in plates of different shape under the unilateral, manifold tension and under concentrated forces. The efficiency of the way of damping of the fatigue cracks motion is defined by short-term change of the loading form.