RETRACTED: Composite structures with local zones of variable stiffness

Abstract

In this paper, a new class of composite structures of variable stiffness is considered. In composite parts with stress concentrators, localized regions are created in which the angle of unidirectional reinforcement changes, causing a decrease in the stress concentration coefficient at the discontinuity and an increase in ultimate stresses. Unlike recently popular composites with curvilinear reinforcement paths, such structures are much easier to design, calculate and fabricate. The paper presents the results of numerical calculations showing the effectiveness of such reinforcement method in composite plates with a hole. On the basis of the obtained data the parameters (shape, size and reinforcement angle) of the local zone of variable stiffness, providing the highest reduction of stress concentration at the hole and increase of composite strength according to Hashin’s failure criterion, have been chosen.