hogging and sagging

I try to calcultae the strength of keel beam

But first I have to find the loads and that depends of loads of hogging and sagging.

Also it is confsing where the strains come. Is there somebody how can give me a push in the good direction.

Ron de Vos

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Permalink Reply by Michael Freytag on April 27, 2015 at 3:03pm

Hello Ron,

First, let me say I am not a marine engineer or designer. However maybe this is helpful:

First I split the wetted faces of the hull amidship so I could specify separate loads to the front and rear sections.

I then applied 2 separate hydrostatic loads (one forward and one rearward) to the corresponding wetted faces of the hull. When specifying the water surface for each hydrostatic load, I oriented the surface normal so the water surface was aligned with the planar water surfaces depicted here for the "hogging" configuration.

For the "sagging" configuration, I made a copy of the model and redefined the water surface to align with the planar water surfaces depicted here.

Does this make sense? Is it helpful?

~Michael