A methodology to assess damage tolerance of composite structures by fea simulation technique

Abstract

CFRP structures have been widely used since decades in aerospace industry resulting in improvements in payload, fuel consumption and range. The Airbus A350, Boeing B787 in civil airplane industry as well as military products like the NH90 transport helicopter are examples of this development towards "all compo-site"-aircrafts with nearly all structural parts made of composite materials. In spite of such extensive use, the extent of knowledge of composites remains still low compared to metallic materials. A significant effort in terms of prediction of material response, especially during impact events, is needed to optimize the use of composites. A new time-efficient modelling approach using conventional shell elements is addressed in this paper which allows for an effective evaluation of the damage tolerance of coupons. A methodology based on intermediate tests (DCB and ENF) is proposed to work out relevant material parameters for both damage initiation and evolution of interlaminar and intralaminar modes of failure. The implementation of smart simulations of low velocity impacts and compression after impact (CAI) using Python and Perl scripts, performed to deal with the residual strength of fabric composite materials, is also addressed.