Numerical investigation of fan-blade out using meso-scale composite modeling

The effects of ingesting foreign bodies or other fragments into an engine is a major hazard that could potentially result in a blade-out event. Due to the high rotational speeds, an ejected fan blade can pose an even greater risk than the original foreign body, necessitating the current certification requirements. As such a test is prohibitively expensive, effective computational analysis to simulate a fan-blade out scenario is necessary. The current work investigates a fan-blade out scenario that is consistent with certification requirements for a modern high-bypass engine. Emphasis is placed on two casing designs that incorporate a Kevlar 29 overwrap while a fully Ti-6Al-4V casing serves as a baseline. A meso-scale approach is used for the composite modeling, which is validated against a ballistic experiment for three different composite damage theories. In addition to comparing the response of a conventional and composite fan casing, the effect of bonding between Kevlar layers is explored.