November 16, 2021 at 3:06 pm

tumulpurwar

Subscriber

Hello Peter

For global bending moment, we take cantilever beam case, where one end is rigidly fixed, and other end is set to be free in all dof, meanwhile on this free side (or node) we apply global bending moment numerical value.

I think as even my sliced hull case, I have global bending moment value, which is occuring in middle of vessel almost, in region where also my crane load in near region acting.

And I don't have local bending moment at sliced frames (extreme nodes)

Now if you understand, I have two loads:

1) crane load acting near to region where bending moment of whole hull is maximum

2) offcourse & this bending moment value( global bending) or a bending maximum value , because we are interested in knowing when our ship can face maximum bending load.

And as ship is symmetric, most of time maximum bending we see in the middle region of ship.

In my case it's not 100% middle bit offset from middle.

But my cute little sliced geometry of hull, is a, part where maximum bending of complete hull will show maximum stresses.

As well as, luckily the crane load also acting in that area.

So my little sliced structure contain both important region, as this region will face maximum bending and as well as will face crane load on top deck.

Now because I can't make full hull structure it's time consuming, I am left with option of sliced hull, my idea is I will play with density of sliced structure, I will replace with whole hull structure density and apply those remote displacement conditions which you told?

What you think it's correct idea, to get correct stress without making full model??

Need your suggestions

If we consider a heavy solid rod 1 meter long for example, and due to some reason, I can only make 30% of solid rod.

If we apply bending to rod on one end, and just put density of full length rod, it will still give correct bending stresses I guess at any section of rod?

And as rod shape is uniform it will be more easy.. Normally ship are symmetric too and uniform on both sides.

One more question when we are applying here maximum bending moment of full length ship, which is coming maximum probably near centre... I guess do we still need apply hydrostatic load? (Pgh)?

I guess this global maximum bending value probably would have been calculated taking the upward reaction effect of hydrostatic load? I guess?

So no need again take hydrostatic load? I think?

Thanks

For global bending moment, we take cantilever beam case, where one end is rigidly fixed, and other end is set to be free in all dof, meanwhile on this free side (or node) we apply global bending moment numerical value.

I think as even my sliced hull case, I have global bending moment value, which is occuring in middle of vessel almost, in region where also my crane load in near region acting.

And I don't have local bending moment at sliced frames (extreme nodes)

Now if you understand, I have two loads:

1) crane load acting near to region where bending moment of whole hull is maximum

2) offcourse & this bending moment value( global bending) or a bending maximum value , because we are interested in knowing when our ship can face maximum bending load.

And as ship is symmetric, most of time maximum bending we see in the middle region of ship.

In my case it's not 100% middle bit offset from middle.

But my cute little sliced geometry of hull, is a, part where maximum bending of complete hull will show maximum stresses.

As well as, luckily the crane load also acting in that area.

So my little sliced structure contain both important region, as this region will face maximum bending and as well as will face crane load on top deck.

Now because I can't make full hull structure it's time consuming, I am left with option of sliced hull, my idea is I will play with density of sliced structure, I will replace with whole hull structure density and apply those remote displacement conditions which you told?

What you think it's correct idea, to get correct stress without making full model??

Need your suggestions

If we consider a heavy solid rod 1 meter long for example, and due to some reason, I can only make 30% of solid rod.

If we apply bending to rod on one end, and just put density of full length rod, it will still give correct bending stresses I guess at any section of rod?

And as rod shape is uniform it will be more easy.. Normally ship are symmetric too and uniform on both sides.

One more question when we are applying here maximum bending moment of full length ship, which is coming maximum probably near centre... I guess do we still need apply hydrostatic load? (Pgh)?

I guess this global maximum bending value probably would have been calculated taking the upward reaction effect of hydrostatic load? I guess?

So no need again take hydrostatic load? I think?

Thanks