Analysing Aircraft Barrier Nets to Improve Pilot Safety
As the UK Ministry of Defence Design Authority for Aircraft Arrestor Barrier Nets, AmSafe products are used to stop aircraft from over-running the end of runways. The British Arrestor Net (BAN) Mk2 is suspended across the runway over-run area by two electrically driven stanchions and raised or lowered by remote control from the Air Traffic Control tower. The Hawk T Mk2 was selected as the new Advanced Jet Trainer for the UK armed forces. The aircraft features an extended nose and front mounted Smart Probes making it necessary to assess the performance of the AmSafe barrier nets with the new aircraft.Solution:
AmSafe selected Altair ProductDesign to assist with this complex set of analysis challenges. The objective of this project was to apply virtual simulation techniques in order to make an assessment of the following issues:
- Does the net webbing make contact with the canopy and what level of loads may be expected?
- Is there a possibility that the steel central support cable will be dragged down onto the canopy?
- What levels of loads are generated at the smart probes when net elements are caught on them?
The geometry of the Hawk T Mk2 was supplied as a CAD files and modeled using Altair’s own HyperWorks suite of simulation tools along with the barrier net and supporting structure. A wide variety of load cases had to be defined in order to accurately assess the net’s reliability. These included initial engagement velocity, height of the canopy and barrier as well as the yaw and approach angle of the aircraft. A total of eighteen combinations of approach velocity, aircraft approach/yaw angle and engagement position were analyzed during the study.Result:
Examination of the engagement phase of all eighteen simulations performed did not indicate that the steel Centre Suspension Cable was brought into contact with the canopy of the aircraft - in each case the canopy was well clear of the cable by the time the cable was released from the rest of the suspension system. The aircraft’s Smart Probes did make contact with the net but the analysis found that this did not cause any adverse effects to the safety of the pilots.