Functional composite materials allowing stiffness reduction upon external stimulation are being developed within the European projects ENLIGHT and SafeEV. The aim is to develop material concepts to reduce the severity of injuries involving vulnerable road users. The current work addresses the development of textile composite material models aimed to be employed in a car front structure during static loading to low velocity impact situations. The modelled material is a non-crimp fabric reinforced thermoplastic (LPET) composite, in which the stiffness reduction relies on resistive heating of the carbon reinforcement upon application of electric current through the fibres. The stiffness reduction is achieved by a phase transformation of the thermoplastic matrix material. In this paper it is shown how a micro- and mesomodelling methodology in concert with only a few simple DMTA measurements can be utilized to model the macroscopic stiffness response of an impacted beam at various temperatures and loading rates. The material models used for simulation of the material show a good correlation with the experimental data despite the exclusion of a damage model and failing to account for the temperature variation within the specimens used in the experimental testing. The peak loads are well predicted.
Funding details: European Commission, 314567, 314265; Funding text 1: The authors like to express their gratitude to Runar Långström for manufacturing of composite materials. Moreover, the authors like to express their gratitude to COMFIL for providing material. The presented work was funded by the European Commission within the project ENLIGHT and SafeEV (Grant agreement No: 314567 and 314265).