G-forces (Accelerations) from Collision of 2 Ships 1

[researchguru]

I am currently researching the kind of g-forces (accelerations) to be expected during the collision of two ships. Any help would be greatly appreciated.
Thanks.

 

[rob768]

Over here in the Netherlands, TNO did some full scale collision testing on ships, to check the effetivenes of double hulls. Maybe they obtained usefull information regarding accellerations.

 

[researchguru]

Great, thanks, I'll look into it.

 

[gunnarhole]

researchguru,
per ISO 19902 Fixed Steel Offshore Structures / Appendix A.10.3 Vessel Collisions / A.10.3.2 Collision events

The kinetic energy of a vessel may be calculated using the equation:

E = 0.5 (a x m) v^2

Where:
E = the kinetic energy of the vessel, MJ
a = added mass factor.
1,4 for broadside collision.
1,1 for bow/stern collision.
m = vessel mass, tons
v = velocity of vessel at impact, m/s

The added mass coefficients given are typical values for large (5000t displacement) supply vessels. For smaller vessels a slightly higher value than 1,4 should be applied, e.g. 1,6 for a typical 2500t supply vessel.

There is a similar discussion with additional references given at

http://www.hse.gov.uk/offshore/shipimpact.pdf

Regards, Gunnar

 

[researchguru]

Thanks!

Can you tell me ...
Is there any suggested added mass factor increase (over 1.1) for a 2400 tonne displacement vessel in a head on collision.

You have been very helpful.

 

[flamby]

The answer to your original question is very difficult, as velocities and stiffness of the ships involved are the variables in the equation. Why do you need to know this?
thread404-36240 may be helpful.


Ciao.

 

[researchguru]

I am doing a FE analysis, and have run a 1 g loading scenario and now wish to scale the stresses according to a more realisting load ...
I realize that there are many variables, I have managed to get some information ... and with a few assumptions... I think I will be able to proceed... thanks!