Some areas of experience

​Spacecraft, Aircraft and Vehicle
Primary and Secondary Structure
Aircraft Passenger Safety
Vehicle Occupant & Pedestrian Safety
Crash Simulation and Analysis
Birdstrike Simulation
Pressure Vessels
Fluid/Structure Interaction
Structural Support of Precision Optics
Fracture Mechanics
Passenger
Occupant & Pedestrian Safety

 

 

Passenger safety in aircraft, and occupant and pedestrian safety in the automotive environment are governed by strict regulations in Europe and USA.

The basic principle for aircraft occupant safety is that, after a severe crash landing deemed survivable, the passengers should be able to evacuate safely and quickly.  To this end the regulations specify occupant injury criteria for the head, lumbar and femurs, and that safe and rapid egress post-incident is not impeded.  Other requirements regarding such aspects as retention of items of mass must also be met.

 

The regulations governing the automotive industry are tighter and much more comprehensive regarding the extent and types of injury, this being due to the much greater variety and number of survivable incidents.

Crash Simulation

 

Crash simulation normally uses nonlinear transient finite element analysis employing the explicit time integration scheme.  The technology has been driven predominantly by the car industry, which cannot afford to test its way through R&D.  This is because without a production line, new model prototypes are in the order of 100x more expensive than their production equivalents.  Even with simulation technology the NRE costs for a new vehicle model are simply huge.  Crash simulation has assisted greatly in the development, refinement and tuning of crash safety technologies such as vehicle crumple zones, airbags and seatbelt pre-tensioners.

The train and aircraft industries have also helped drive crash simulation.  The aircraft industry has a wealth of test data to correlate against as a prototype aircraft seat is much cheaper than a prototype vehicle.

Pressure Vessels

 

 

Pressure vessel experience is predominantly with spacecraft propellant tanks, for conventional propellant and ion propulsion, and pressurant tanks.  All the aforementioned have very demanding operating environments.  For example, partially filled conventional propellant tanks can experience significant sloshing on launch, and with direct structural links to the final stage of the launch rocket are subject to significant clampband release shock loads, which may damage the tank, or components such as the propellant management device (PMD).

 

The helium pressurant tank has its own challenges; it ideally needs to be pressurised to several hundred bar and so is typically constructed as an aluminium or titanium-lined composite overwrapped pressure vessel (COPV).

Fluid/Structure Interaction

 

 

Fluid/structure interaction in its simplest form uses the technique of smearing the mass of the fluid onto the walls of its container.  More advanced techniques are employed if issues such as sloshing or cavitation need to be evaluated.

 

Structural Support of Precision Optics

 

 

Optical systems using chained optics such as lenses, mirrors, prisms, filters and diffraction gratings require very careful attention with respect to thermal loading of the supporting structure deforming or misaligning the optical system.  Furthermore, if the operating environment involves dynamic loading then coupled loads together with optical assessment including phase effects are required.