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This paper proposes a numerical solution to deep beams using the layerwise displacement theory. Most of the methods for performing structural analyses of deep beams have geometric and boundary conditions limitations, as well as modeling inconveniences. This paper provides a finite element solution for deep beams based on a layerwise displacement field considering the full stress/strain tensors. In this formulation, the cross section is discretized in a pre-defined number of independent virtual layers, with linear interpolation within the thickness direction. To validate the model developed, two numerical examples are analyzed. The first is a reinforced concrete deep beam with two supports, loaded over the top face, validated by finite element analysis based on solid-element ABAQUS TM software. Next, an isotropic deep beam with both ends cantilevered is analyzed and the outcome is compared to the literature. The results of both numerical examples are accurate and can estimate the complete state of stress over all domains of the element. Moreover, the layerwise formulation does not suffer from shear and membrane locking, and it may use fewer computational resources than equivalent 3D finite element analyses.

Abstract. The study of smart materials for uses in the aerospace

Composite materials are very attractive for structural applications due to its inherent mechanical properties and low density. However, during their service life, composite structures can be damaged by impact such as tool drop during assembly or maintenance. Several studies have been developed for impact on composite plates, but there are only few scientific investigations about impact on composite cylinders. This study presents experimental analyses of low energy impact on filament-wound cylinders. Three different lay-ups were evaluated for 9J and 31J impact levels. Bidirectional strain gauges, one accelerometer sensor, force and displacement sensors were used for data acquisition from the results The influence of the lay up on the behaviour of the filament-wound cylinder was discussed.

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Composite laminates are being more employed as fundamental structures due to its low weight and high stiffness. To predict the material response in presence of damage can be demanding due to composite’s complex nature. Hence, superior computational models should be further investigated to speculate a more accurate composite behavior. This paper proposes an extended finite element procedure, based on the layerwise displacement theory, to simulate delamination to composite laminate. It is assumed a cohesive behavior to the damaged domain, described by a traction separation law. An extra degree of freedom associated to the strong discontinuity (delamination) is added at each layer top and bottom surface for out-of-plane displacement. This extra degree of freedom is only active on the failed nodes. To validate the model, a pre-delaminated composite analysis is performed and compared to results already reported in the literature. In addition, all stress components can be precisely calculated due to layer wise displacement field assumption, without any concern about the membrane and shear locking, not to mention its greater computational efficiency when compared to equivalent three-dimensional elements. Therefore, in the present work, it is shown the limitations and potentialities when a cohezive formulation is combined to extended finite element method using a new kind of approach. Additionally, this formulation makes easier to model delaminations using finite element method keeping a good accuracy without the need of cumbersome finite element models.