ES3’s MARS code enables simulations of complex, highly dynamic systems. Provided are some examples of cabling systems modeled using MARS.
This example shows an F-14 being caught by a sample barricade. The barricade is modeled using elastic truss type finite elements. These are similar to beams, but do not include bending effects and respond only when stretched. Estimated values were used for barricade properties. The external surface of the F-14 interacts with the barricade through edge-edge contact conditions with friction. The carrier deck was modeled for visualization purposes. However, in future more realistic simulations, both aircraft and barricade will interact with the deck through contact conditions. For this simulation, the ends of the horizontal elements of the barricade were fixed to the ship frame. For complete models, the barricade will be connected to the purchase cable and engine. The first 0.4 seconds of the landing were modeled.
Time series frames of an
F14-Tomcat being caught by a barricade
Comparison of our simulation with an actual photo of a barricade
test (downloaded from www.lakehurst.navy.mil/nlweb)
The objective of this simulation is to show “what happens above the deck”. As such, it is not intended to be a complete simulation of the system. Sheave damper and engine components are not modeled. Their effect was replaced by constant forces at both ends of the cable which always keep the cable in tension.
The tailhook of the landing F-14 catches the crossdeck pendant and two kink waves propagate away from the tailhook toward the sheaves. The kink waves get reflected back and forth.
Kink waves propagating from tailhook
Secondary kink wave reflected from the sheave.
More information is available regarding how we model the components (click here) of these highly dynamic cable systems.
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