The Static Behavior of a Ship Deck Panel Made of Composite Materials

A study on the static analysis of a naval panel made of composite sandwich materials is presented. By using FEM, the modeling of a naval floor with a length of 5 m and a width of 2.5 m is performed. Two distinct cases, have been performed: the first model consists of the plate and stiffeners made of steel and the second model concerns a panel made of composite material sandwich type steel / SANFoam103 / steel, and the stiffeners made of steel. A parametric study has been performed. The thickness of the steel faces have 6 mm, and for the core of SANFoam have been selected the thicknesses 5 mm, 10 mm, 20 mm, 40 mm.

Novel Methodology for Experimental Characterization of Micro-Sandwich Materials

Lightweight components are in demand from the automotive industry, due to legislation regulating greenhouse gas emissions, e.g., CO2. Traditionally, lightweighting has been done by replacing mild steels with ultra-high strength steel. The development of micro-sandwich materials has received increasing attention due to their formability and potential for replacing steel sheets in automotive bodies. A fundamental requirement for micro-sandwich materials to gain significant market share within the automotive industry is the possibility to simulate manufacturing of components, e.g., cold forming. Thus, reliable methods for characterizing the mechanical properties of the micro-sandwich materials, and in particular their cores, are necessary. In the present work, a novel method for obtaining the out-of-plane properties of micro-sandwich cores is presented. In particular, the out-of-plane properties, i.e., transverse tension/compression and out-of-plane shear are characterized. Test tools are designed and developed for subjecting micro-sandwich specimens to the desired loading conditions and digital image correlation is used to qualitatively analyze displacement fields and fracture of the core. A variation of the response from the material tests is observed, analyzed using statistical methods, i.e., the Weibull distribution. It is found that the suggested method produces reliable and repeatable results, providing a better understanding of micro-sandwich materials. The results produced in the present work may be used as input data for constitutive models, but also for validation of numerical models.

Natural cork and its agglomerates as substitutes for high-density expanded polystyrene foams in sandwich cores

Natural cork (NC) and its agglomerates are renewable materials that could be effective substitutes for non-renewable foams, such as expanded polystyrene (EPS), in the cores of sandwich materials. Although many existing studies have analysed the behaviour of different cork agglomerates under tensile, compression, or shear loads, no studies to date have simultaneously analysed the behaviour of multiple cork materials under all these loads. Therefore, in this study, the behaviour of NC and five cork agglomerates were analysed under tensile, compression and shear loads, and the mechanical and specific properties and the shape of the stress–strain curves were compared with those obtained for five EPS counterparts to analyse the relationship between the mechanical behaviour of the core and the main failure modes of the sandwich. Although EPS exhibited higher specific properties, NC exhibited higher mechanical properties under all the loads. The agglomerates all exhibited lower mechanical properties except for shear strain. Additionally, because no specific standards were available for testing cork products, slightly modified standards for testing other materials were adopted.

Sandwich materials with a crumpled aluminium core

Sandwich materials made of two aluminum sheets and a crumpled aluminum core have been manufactured for the first time using a reproducible process. This very specific core aims to drastically improve the elasticity performance indexes of the sandwich. The structure has been studied mainly in bending.

Mechanical characterisation of kenaf/PALF reinforced composite-metal laminates: Effects of hybridisation and weaving architectures

Fibre metal laminates are advanced sandwich materials that offer various outstanding properties over conventional metallic alloys and composites. This research study intends to investigate the effects of weaving architectures and stacking configurations on the mechanical properties of fibre metal laminates based on kenaf/pineapple leaf fibre. Fibre metal laminates were fabricated through the hot moulding compression technique. Mechanical tests were performed on the kenaf/pineapple leaf fibre-based fibre metal laminates. In accordance with the findings obtained, hybridisation had led to the improvement in the mechanical properties of fibre metal laminates in comparison with [K/K/K] fibre metal laminates. Overall, twill woven-ply [P/P/P] fibre metal laminates showed the highest tensile and flexural strength, which was 14.53% and 33.50% higher than twill woven-ply [K/K/K] fibre metal laminates, respectively. Besides, the twill woven-ply [P/P/P] fibre metal laminates also displayed the highest impact strength and indentation properties compared to other non-hybrid and hybrid fibre metal laminates. When comparing the fibre metal laminates with different weaving architectures, twill woven-ply fibre metal laminates were shown to have higher mechanical properties over those of plain woven-ply fibre metal laminates.

Fire - mechanical behaviour of sandwich composite beam

We have analyzed the fire-mechanical behaviour of sandwich composite materials used in marine applications, as a function of the combustion time. In this light, sandwich beam samples are analyzed in terms of fire resistance kinetic and of post-combustion mechanical strength. We have shown that the materials undergo a strong degradation during 100 s of fire exposure at 750 ° C and this degradation is linked to the top skin. Finally, a finite element modelling work is being developed to predict the thermal behavior of composite sandwich materials; this modelling must include all thermal, physical and chemical degradation processes in order to realistically report resistance of materials in extreme temperature environment.