Keywords: methodology, multi-function, composite.

The use of composite multifunction structures leads both to acoustic and thermal comfort enhancement inside railcars as well as the improvement of structural performance (stiffness-weight ratio). Moreover there is an improvement in quality with respect to cost. Composite materials inside railcars are able to: decrease weight; eliminate wood components; enhance thermal protection; enhance acoustic performance; speed up manufacturing and assembling; and enhance product flexibility. Composite materials allow inconceivable shapes and solutions with respect to metallic structures showing an incredible adaptability to multifunction embedded solutions typical of multi-material and multi-thickness components. The use of composite materials has been quite low up until now as a consequence of their high cost. Newer technologies such as thermoplastic and pultrusion enable a higher rate of production with lower cost. Composite materials, respect to metallic ones, have not have corrosion problems and provide for economic maintenance.

The aim of the work described in this paper is the development of a numerical simulation methodology able to predict the global performance of composite multifunction components. The new methodology is able to go beyond the typical metallic components design limits. The expected benefits arising from the use of the methodology are: component performance global enhancements; weight reduction; manufacturing improvement; maintenance simplification; and production and operating cost reduction. Multifuncion composite material structures numerical simulation needs numerical codes able to detail accurately both materials and their interfaces. The study has been carried out using the GENOA code (AlphaStar Corp.) embedded in MD Nastran. The GENOA code is able to determine the optimized, robust and multi-target solutions by means of progressive failure analysis (PFA) technique. PFA is able to predict the ultimate structure behaviour and to lead to a robust and optimized solution.

In this paper design solutions are investigated by performing static, dynamic and crash calculations. Numerical correlations with testing are presented in terms of accuracy and repeatability taking care of material uncertainties, environment influence, code reliability and time to market needs. A section is dedicated to bonding techniques useful to understand limits and strength. Bonding techniques are very important to join composite panels and to speed up manufacturing processes.

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