Equivalent Loads

[HungryDinosaur_imported]

Hi All,

Please see attached file. There is a element AB, with a point load at F. The point load has three components (in metric tonnes) in X, Y and Z directions. Can someone advise/calculate the equivalent forces in X, Y and Z directions on points A & B due to the point load F? Thanks in advance.

Regards,

Subseaocean

 

[hokie66]

Assuming the member is pinned one end and has a roller on the other, the axial force goes to the pinned end. The y and z direction forces go to point A in the ration 35/55, and to point B 20/55.

 

[ferrarialberto]

If the element is locked at both ends, even for the axial load is valid the rule 20-35/55, as long as the axial stiffness EA/L is constant along the rod.

ing. FERRARI Alberto -

http://www.ferrarialberto.it

 

[ztengguy]

Unless I am going nutty, I dont see F...do you mean P?

 

[BAretired]

ztenguy, I was wondering the same thing.

BA

 

[woodman88]

I think that the forces are the x, y and z components of the force F at point P.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[HungryDinosaur_imported]

Apologies gentlemen. The statement above should read as "equivalent forces in X, Y and Z directions on points A & B due to the point load P."
While the load in the Y direction can be found on points A and B, what will be the loads in the X and Z directions on points A and B?

Regards,

SubseaOcean.

 

[hokie66]

See my answer above.

 

[BAretired]

It depends on the boundary conditions. You have not properly defined the supports at A and B. Are they pinned, fixed, pin and roller or something else? It makes a huge difference.

BA

 

[HungryDinosaur_imported]

Yes, the supports are pinned.

 

[BAretired]

If both supports are pinned, then the reactions at A and B are 35/55 and 20/55 respectively times the force P. This is true for each of the X, Y and Z components.

BA

 

[HungryDinosaur_imported]

All/BAretired,

1. Thanks for your comments and please see attached.

2. Please see beam CD, with a load L of 10mT as shown. Is it not that the load in the same directions will be 10 mT each at C and D (or 5 mT each at C and D), irrespective of the distance of the load from each end ? Just have some confusion here.

THanks.

 

[hokie66]

No, see ferrarialberto's post above (the one after mine and the second one down from your first post). The nearer the load is to the support, the more that support takes, as the shortening of the compression section and the elongation of the tension section must equate. BAretired's post agrees.

 

[HungryDinosaur_imported]

All/Hokie,

Appreciate all your suggestions. Thanks a lot.

Regards,

SubseaOcean