A low-res version of a presentation animation for a combined teetering rotor dynamics and fuselage/tailboom damage study
(for a range of fictitious rotor and rotor root properties).
Main rotor angular velocity is driven at 40rad/s until the tailboom contact. Animation framerate is 60fps, simulation framerate is 1000fps.
A fast take-off was initiated in the simulation followed by 'beyond limits' cyclic to aft,
the result being the rotor disc tilting back and contacting the tailrotor driveshaft and boom.
In practice this usually results in much more damage to the boom, and has been known to sever
the boom completely rather than break its attachments to the fuselage. The simulation does not show this
in this model as the main rotor blades in this simulation have a uniform mass distribution when in fact
in reality the blades are heavier nearer the tips to aid their strength, damage tolerance and dynamics.
Transportation Damage Assessment - Satellite Liquid Apogee Engine
This presentation animation shows the internal relative motions of the foam suspended Liquid Apogee Engine (LAE)
envelope inside its 'oil drum' packaging in this simulation of an actual impact event. The cost of such a LAE
is in the region of $400k and program delays to replace it would have also been in similar figures, thus potentially
a very expensive incident.
The impact was due to a lateral strike on the rim of the drum almost in line with the drum's cylindrical axis.
The drum is strapped to the pallet by two standard steel band strappings.
The impactor (most probably a forklift) is not shown, just prior to the impact a rectangular panel can be seen entering
the drum, this panel represents the documents that were shipped with the article and has a thickness representative contact
zone surrounding it. The 'documents' are included in the shipment quasi-statically (under heavy damping) therefore once inside
there are no residual dynamics from their insertion and the foam surrounding the documents is correctly compressed. The damping
terms are terminated just prior to impact event. Animation framerate is 24fps, simulation framerate is 1000fps.
The time domain analysis correlated on the first 'attempt' and underpinned an existing nonlinear analysis
with respect to the observed permanent set damage to the drum. More importantly the analysis records the nature of
rotational and translational accelerations of the various interconnected bodies, in particular the LAE.
These accelerations were compared to test data limits for the LAE and due to the very comfortable margins
the LAE was declared unaffected by the incident and therefore fitted to the satellite.
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