Collision analyses enables us to predict vessels' local structural behaviour and ultimate strength

Mon, 05/16/2016 - 09:09

In the collision simulation we have demonstrated a collision between an icebreaker and an offshore platform.

The simulated icebreaker is a ca. 100 m long, 10 000 BRWT and the platform leg is a concrete pillar with a 16 m diameter. In the simulation the impact is to the midship of the icebreaker. The side collides directly to the platfrom leg, at the speed of 2 m/s. The actual physical collission is simulated in advanced dynamic non-linear FE-simulation. To create this highly informative representation of the collission, we use the HyperView.

The simulation is built from three separate screens. The vertical screen shows the general view of the midship's double shell. The screen on the right top, present the shell's inner structure without the longitudinal bulkhead. The bottom one of the screens on the right present the displacement and the Von Mises stress in a timeline.

 

After watching the simulation you are able to recognise how great the impact force is, and how it affects to the stress load of the structure. Impact velocity is a bit exaggerated to show interesting structural behaviour.

When the icebreaker collides, its hull suffers permanent yielding damage that remains after the impact force retires. The representation shows distinct buckling.
An interesting effect can also been seen, when the icebreaker bounces backwards after the impact. This is because a part of the energy that was stored as potential energy in the structure flows back into it, just like a spring.

This simulation is only one demonstration of how we are able to simulate the most challenging physical events and analyse them. Our experience and advanced solvers, enables the aforesaid.
By using these simulations, we are able to develop our hull design and technical analysis, which helps us to obtain the optimal structural design.

Janette Aaltonen

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