13 November 2009
13 November 2009
Lightning strike tests of a helicopter at Eurocopter's Donauwörth facility have verified the accuracy of finite element analysis techniques for characterising the electromagnetic behaviour of complete and custom-cabled modern aircraft structures constructed using advanced composite materials.
The exercise was performed using the Opera electromagnetic design software from Cobham Technical Services, as a final element of the company's work for the ILDAS (In-flight Lightning Strike Damage Assessment System) project.
Commercial passenger aircraft are struck by lightning once a year on average. Powerful strikes can result in costly delays for inspection and repair. The industry's current certification against lightning is based on threat levels derived from measurements of cloud-to-ground strikes.
While this approach has served well for traditional airframes with good metallic conduction, modern aircraft are incorporating increasing amounts of lightweight composite materials. This makes them more susceptible to direct damage at lightning entry and exit points, and potentially to indirect energy coupling effects into the electrical systems as current flows through the aircraft.
As a result, it becomes increasingly important to understand the exact nature of the threat by accruing data on actual in-flight strikes. Modelling the current flow patterns within complete assembled airframes with validated software can also reduce costly testing procedures.
""Airframe structures making extensive use of composite materials have less natural protection against lightning,"" adds John Hardwick of Cobham Technical Services (Lightning Testing & Consultancy). ""As lightning protection measures such as conductive coatings or strips add weight it's important to optimise the design, and simulation provides an effective means of achieving this.""
TRB Lightweight Structures has recently gained the highest DIN 6701 (Parts 1-4) A1 type certification.
Composite products, based on polyurethane technologies from global chemical company Huntsman, are taking centre stage at a design exhibition at the Design Museum Gent, Belgium.
In late November, the 14 project partners in the MoPaHyb consortium developing a modular production plant for hybrid high-performance components wrapped up their successful efforts with a two-day symposium in Pfinztal, Germany.