Abstract

Abstract

In this paper a multi-stage numerical analysis is presented with the aim to investigate effects of forming on the high-cycle fatigue performance of a deep-drawn aluminum sheet structure for use in a floating photovoltaic system. Forming simulations of a subsection of the full geometry are performed in a realistic two-step drawing-springback cycle. A simplified global analysis of service load response is performed to obtain displacements at the submodel boundary, that are used to generate boundary conditions for a local service load analysis. The local analysis is then performed on three different models of the subsection: (I) excluding forming effects, (II) including effects of thinning, and (III) including effects of thinning and residual stresses. The critical location with respect to the fatigue limit criterion in the Ottosen-Stenström-Ristinmaa high-cycle fatigue model was identified for case (I), and this location was used to compare the different models to assess effects of forming on high-cycle fatigue performance. Furthermore, the dynamic friction coefficient , and the isotropickinematic mixing coefficient were varied in order to investigate their respective effects.

Abstract

Currently, the railway sector demands novel lighter designs for the structural components of rolling stock that compensate for the increase in weight due both to the incorporation of new technologies for passenger comfort and experience, as well as to face new environmental challenges (reduction of emissions, consumption power, etc).

With this objective in mind, Aernnova-Talgo-FIDAMC-Tecnalia have proceeded to develop a car body structure design for a high-speed passenger car that introduces up to 70% of high-performance composite material (CFRP). This makes it possible to achieve weight reductions of more than 20% when it is compared to the original 100% aluminum structure.

The solution combines frame, sidewalls and roof in an integral solution in CFRP with the usual solution in welded aluminum for the closing endwalls.

The use of composite material for these structures also implies the introduction of non-conventional manufacturing methods for the railway sector (Semipreg-Sandwich-Pultrusion) with curing outside of autoclave and compliance with the demanding fire and smoke requirements of the EN 45545.

The final objective of the project is the bench validation of the prototype according to the usual standards of the railway sector, EN 12663.

Abstract

Abstract

Abstract