Mode II delamination toughness of z-pin reinforced composite laminates is investigated using finite element (FE) method. The z-pin pullout process is simulated by the deformation and breakage of non-linear springs. A critical shear stress criterion based on linear elastic fracture mechanics is used to simulate crack growth in an end-notched-flexure (ENF) beam made of z-pinned laminates. The mod...

fiber metal laminates (fmls) are new composite materials consisting of thin metal layers and high strength composite layers. arall (aramid aluminum laminate) is a family of the fml that consists of thin aluminum sheets along with kevlar/epoxy composite layers. this material has many advantages such as light weight, excellent corrosion, fatigue and impact resistance. since, arall is a new materi...

In this paper, the problem of tensile strength prediction of composite laminates containing artificially implanted holes is confronted. An approach based on the integration of acoustic emission and load data through neural network is presented. The obtained results show that neural networks can be a useful tool in the monitoring of fracture behavior of composite laminates through acoustic emiss...

The first form of damage in composite laminates is often matrix microcracks that are defined as intralaminar or ply cracks across the thickness of the ply and parallel to the fibers in that ply (see reviews in [1,2]). Tensile loading, fatigue loading, environment, and thermal cycling can all lead to microcrack formation. Microcracks can form in any ply that has a significant component of the ap...

-Dynamic delamination of thick fiber reinforced polymeric matrix composite laminates is investigated using optical techniques and high-speed photography. The laminates used in this work are graphite/epoxy fiber reinforced, 65 percent fiber volume fraction, composite plates consisting of 48 plies (6 mm plate thickness). Two different laminate layups are tested: a quasi-isotropic arrangement and ...

A laminated composite plate element with an interface description is developed using the finite element approach to investigate the bending performance of two-layer cross-ply laminated composite plates in presence of a diagonally perturbed localized interfacial degeneration between laminae. The stiffness of the laminate is expressed through the assembly of the stiffnesses of lamina sub-elements...

Optimal design of laminated composite stiffened panels of symmetric and balanced layup with different number of T-shape stiffeners is investigated and presented. The stiffened panels are simply supported and subjected to uniform biaxial compressive load. In the optimization for the maximum buckling load without weight penalty, the panel skin and the stiffened laminate stacking sequence, thickne...

Impact tests were carried out on composite laminates and composite scarf repairs, while both were subjected to in-plane loading with tensile pre-strain levels up to 5000 microstrain. The results show that pre-straining of the composite laminates has no noticeable influence on the size of the delamination area for the given impact energy of 8 J, which represents a typical barely-visible impact o...

The mechanical problem discussed in this paper focuses on the stress state estimation in a composite laminate in the vicinity of a free edge or microcracks. To calculate these stresses, we use two models called Multiparticle Models of Multilayered Materials (M4). The first one can be considered as a stacking sequence of Reissner-Mindlin plates (5 kinematic fields per layer), while the second is...

Fiber-metal laminates (FMLs) such as Kevlar reinforced aluminum laminate (ARALL), 18 Carbon reinforced aluminum laminate (CARALL), and Glass reinforced aluminum laminate 19 (GLARE) offer great potential for weight reduction applications in automobile and aerospace 20 construction. In order to investigate the feasibility for utilizing such materials in the form of 21 laminates, sheet hydro-bulgi...