Stacking sequences in composite laminates through design optimization

Abstract

Composites are experiencing a new era. The spatial resolution at which is to date possible to build up complex architectured microstructures through additive manufacturing-based and sintering of powder metals 3D printing techniques, as well as the recent improvements in both filament winding and automated fiber deposition processes, are opening new unforeseeable scenarios for applying optimization strategies to the design of high-performance structures and metamaterials that could previously be only theoretically conceived. Motivated by these new possibilities, the present work, by combining computational methods, analytical approaches and experimental analysis, shows how finite element Design Optimization algorithms can be ad hoc rewritten by identifying as design variables the orientation of the reinforcing fibers in each ply of a layered structure for redesigning fiber-reinforced composites exhibiting at the same time high stiffness and toughening, two features generally in competition each other. To highlight the flexibility and the effectiveness of the proposed strategy, after a brief recalling of the essential theoretical remarks and the implemented procedure, selected example applications are finally illustrated on laminated plates under different boundary conditions, cylindrical layered shells with varying curvature subjected to point loads and composite tubes made of carbon fiber-reinforced polymers, recently employed as structural components in advanced aerospace engineering applications.

Unveiling a new shear stress transfer mechanism in composites with helically wound hierarchical fibres

“…Results of FE analysis highlight how shear stresses due to monoclinic cord behaviour propagate to the surrounding matrix and increase with unexpected peaks close to the material interface. Since the distance between cords as well as their mutual orientation represent important design characteristics that largely influence the magnitude of such effects, as demonstrated for example in experimental tests in the literature [52], a sensitivity analysis is additionally provided in the simulations, to highlight multiplicative effects related to nonlinear superposition of shear stresses that could contribute to explain failure phenomena and help optimal design procedures for fiber-reinforced laminates [53].…”

Functionally Graded Plate Fracture by Field Boundary Element

“…The interface, the joints, or the surfaces, have great importance in graded material because the stress is usually limited to these locations. In these cases, the specific zone is the so-called "graded zone" and, if the volume fractions of the constituent materials change, by a certain smooth function, the material is defined as a Functionally Graded Material, FGM [19,20,21]. Furthermore, several benchmarks and reports calving models using Linear Elastic Fracture Mechanics (LEFM) are presented in [22].…”

Stress Analysis of Hole Orientation and Laminate Geometry Impacting on Boron/Epoxy Composites Laminates

“…Such superior mechanical properties of composite materials such as high stiffness and strength to weight ratios and its attractive replacement for metallic materials made it possible for it to be used increasingly in many areas of technology including marine, aerospace, automotive and others. This has generated an increasing interest in the study of new possible design solutions aimed to enhance the performances of E3S Web of Conferences 309, 01160 (2021) ICMED 2021 https://doi.org/10.1051/e3sconf/202130901160 composite laminate structures under prescribed rules through the appropriate choice of materials, orientation, number of stacking sequence of layers that make up composite material and the determination of the optimal fiber orientation for each FRC layer [3][4][5][6][7][8].…”