Stress and Failure Onset Analysis of Thin Composite Deployables by Global/Local Approach

The purpose of this work is to propose an innovative global/local approach for the failure onset analysis of deployable composite thin and ultrathin structures. The adoption of this technique allows for overcoming the weaknesses related to the commercial calculation codes, which make use of three-dimensional finite elements to capture the local stress field arising within the booms. In this framework, the proposed approach leads to a reduction of computational cost while keeping a high level of accuracy. This is possible thanks to the Carrera unified formulation, which allows for the modeling of higher-order plate elements for the analysis of local critical regions of complex composite assemblies. To show the potentialities of the global/local approach, particular attention is given to the problems that mostly characterize composites, among which are those related to the free edge, the failure concept, and the interlaminar continuity of the displacements and shear stresses. The analyzed booms are the triangular, rollable, and collapsible; a tape-spring hinge; and a telescopic tubular mast. The results show a perfect accuracy of the in-plane stress components and an accurate description of the out-of-plane components, which is essential for a reliable design of these components in terms of free-edge debonding and failure phenomena.