Reliability based design with a degradation model of laminated composite structures

• Type: Article in International Scientific Journal
• Date: 1996

Authors

Antonio, GAC (Author) FEUP; Marques, AT (Author) FEUP; Goncalves, JF (Author) FEUP

Journal

Title: Structural Optimization

Vol. 12 No. 1

Pages: 16-28

ISSN: 0934-4373

Publisher: Springer

Indexing

ISI Web of Knowledge - 19 Citations

Scopus - 25 Citations

Scientific classification

FOS: Engineering and technology > Other engineering and technologies

Other information

Authenticus ID: P-001-DZM

Abstract (EN): Uncertainties in deviations of physical properties lead to a probabilistic failure analysis of the composite materials. The proposed optimization model for laminate composites is based on reliability analysis considering the ultimate failure state. To avoid difficulties associated with the complete analysis of the failure modes, bounds are established for the failure probability of the structural system. These bounds are related with the intact and degraded configurations of the structure. Using the first ply failure and the last ply failure theories and a degradation model for the mechanical properties with load sharing rules we obtain the failure probabilities corresponding to the two above configurations. The failure probability of each configuration is obtained using level 2 reliability analysis and the Lind-Hasofer method. The optimization algorithm is developed based on the problem decomposition into three subproblems having as objectives the maximization of the structural efficiency at intact and degraded configurations of the structure and weight minimization subjected to allowable values for the structural reliability. Additionally, the search for the initial design is performed introducing a weight minimization level. It is expected to explore the remaining load capacity of the structures after first ply failure as a function of the anisotropic properties of the composites. The design variables are the ply angles and the thicknesses of the laminates. The structural analysis for the model developed is performed through the finite element method mainly using the isoparametric degenerated shell finite element. The sensitivities are obtained using the discrete approach through the adjoint variable method. In order to show the performance of the analysis two examples are presented.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13