Search results for "Lamina"
showing 10 items of 439 documents
Drilling characteristics and properties analysis of fiber reinforced polymer composites: A comprehensive review
2023
Fiber-reinforced polymer (FRP) composites play a vital role in the production of structural and semi-structural components for engineering applications. The drilling process is a commonly employed machining process for FRP composites to join the FRP structural elements. Usually, the FRP composites possess a heterogeneous nature because of their multi-layered structure, hybridization, and the presence of multi-phase materials. Hence, common problems like delaminations, fuzzing, buckling, cracking, matrix and fiber burning occur during the drilling operations. These problems cause dimensional inaccuracy, poor surface finish, and tool wear and reduce the mechanical strength of the composites. …
Evaluation of interlaminar delaminations in titanium-graphite fibre metal laminates by infrared NDT techniques
2018
Abstract Fibre Metal Laminates (FMLs) describe a number of aerospace-grade layered structural materials where thin metal alloy foils are interleaved with Fibre Reinforced Polymer (FRP) plies. Such material hybridisation at the layer meso-scale poses a challenge for non-destructive testing (NDT). On the other hand, the need for NDT inspection of FMLs arises due to the potential development of interlayers disbonds, both during fabrication or in-service. This work describes the successful implementation of two Infrared-NDT approaches to evaluate a defected FML panel made of Titanium/Graphite (Ti-Gr). One technique is based on the modulation of the deployed heat from a low-cost halogen lamp, to…
An analysis of interface delamination mechanisms in orthotropic and hybrid fiber-metal composite laminates
2007
Abstract The onset and propagation of interlaminar defects is one of the main damage mechanisms in composite materials. This is even more the case when considering layered materials comprising metallic laminae (typically Aluminium) and FRP laminae. Propagation of delamination mainly depends on the initial crack extension and its loading mode. This work presents some results of a combined analytical–numerical–experimental study on the onset and propagation mechanisms regarding interlaminar defects. Two cases have been analysed in particular, the first consisting of a glass-fibre reinforced epoxy resin laminate, and the second consisting of a hybrid laminate where a lamina of aluminium is lay…
Dependence of fracture toughness of composite laminates on interface ply orientations and delamination growth direction
2004
A critical review has been performed of the published experimental research concerning delamination onset and growth in composite laminate interfaces of different lay-ups under single-mode loadings. It was found that, depending on the loading mode and interface lay-up, the traditional fracture toughness characterization by unidirectionally reinforced composite tests can lead to marked under- or overestimation of material resistance to crack growth. Empirical models of fracture toughness as a function of delamination front orientation with respect to reinforcement directions of the adjacent laminae have been validated and their applicability range established.
Delamination study of through-thickness reinforced composite laminates via two-phase interface model
2007
A technique to enhance the strength of the composite laminates in the thickness direction consists in inserting through-thickness reinforcement, by which the potential delamination crack faces are bridged in order to increase the interlaminar fracture strength. In this paper, the composite delamination is analyzed in the context of non-linear fracture mechanics making use of the interface concept. The presence of the reinforcement fibres provides an anisotropic elastic and post-elastic mechanical response, which herein is described by an original two-phase interface model. The two phases, namely the adhesive joint (or matrix of the composite) and the reinforcement, are characterized by thei…
Modal and Structural FEM Analysis of a 50 ft Pleasure Yacht
2012
In this paper a structural Finite Element analysis of a 50 ft pleasure vessel is presented. The study is performed under different loads conditions: modal analyses have been done in order to find the natural frequencies of the vessel, structural analyses to verify the strength of the vessel to design loads. The design loads for the vessel considered are computed according to RINA rules for the construction and classification of pleasure vessels [1]. Two different composites are used for the lamination: one is a monolithic sequence of short fibre and balanced glass lamina, used for the bottom of the vessel and for structural reinforcements, the other is a sandwich made of glass fibre composi…
Finite elements for nonlinear free vibrations analysis of smart laminates subjected to in-plane loadings
2015
Advanced composites, able to provide multi-functional capabilities besides the traditional structural functions, has been gaining attention in many technological fields. This inherent coupling of different physical fields can be exploited in transducer applications, structural health monitoring, vibration control, energy harvesting and other applications. Magneto-electro-elastic (MEE) composite materials are attracting increasing consideration as they couple mechanical, electrical and magnetic fields and this makes them particularly suitable for smart applications. Generally, single-phase materials exhibit either piezoelectric or piezomagnetic behavior and no direct magneto-electric couplin…
PANORMUS-SPH. A new Smoothed Particle Hydrodynamics solver for incompressible flows
2015
Abstract A new Smoothed Particle Hydrodynamics (SPH) solver is presented, fully integrated within the PANORMUS package [7] , originally developed as a Finite Volume Method (FVM) solver. The proposed model employs the fully Incompressible SPH approach, where a Fractional Step Method is used to make the numerical solution march in time. The main novelty of the proposed model is the use of a general and highly flexible procedure to account for different boundary conditions, based on the discretization of the boundary surfaces with a set of triangles and the introduction of mirror particles with suitable hydrodynamic properties. Both laminar and turbulent flows can be solved (the latter using t…
Anti-acids lead to immunological and morphological changes in the intestine of BALB/c mice similar to human food allergy
2008
Abstract We have shown that anti-acid medication for treating dyspeptic disorders can block protein digestion and induce a higher risk for food sensitization. This mechanism was confirmed in human and animal studies on the humoral as well as the cellular level. Here we aimed to investigate the outcome of the treatment with the anti-acid drug sucralfate on the intestine in our murine model, assuming that morphological and immunological changes will occur. BALB/c mice were fed codfish extract plus sucralfate. Antibodies were examined in ELISA, RBL assay and Western blot. Quantitative morphological analysis of the intestine was performed by design-based stereology, focussing on epithelium, lam…
Algunas microestructuras presentes en las costras calcareas del piedemonte de betera (provincia de valencia)
1988
Las formaciones aluviales que constituyen el piedemonte de betera, situado al norte de la provincia de valencia, presentan a techo de sus secuencias sedimentarias importantes acumulaciones carbonatadas. Las diferentes muestras que se han analizado desde un punto de vista micromorfologico, pertenecientes a las cinco macrofacies descritas en los perfiles seleccionados, permiten reconocer gran variedad de microestructuras. De todas ellas aqui se detallan las que aparecen con mayor frecuencia, tales como laminaciones, oolitica-pisolitica, grietas de retraccion y estructura de raices. Estas microestructuras sugieren condiciones subaereas en la genesis de las costras. (a)