Attaching Loads

[ecope]

Hello, I need this cleared up in a hurry. At one time I was told when applying a load in Algor I would select all of the surfaces that the load was being applied to, then if the load was 500 lbs. for example I would just type in 500 with the correct xyz movement. So the 500 lbs. would be divided by the software for each surface resulting with a total load of 500 lbs.

Then I was told I had to divide the load by how many surfaces that the load was being applied to. Example...if I had 5 surfaces then I would put as my load in Algor as 100 lbs. not 500 lbs. since I have 5 surfaces at 100 lbs.

Thanks for your help!

 

[GBor]

I'm not at my office to verify this, but I think the software will divide the 500 pounds over the area regardless of how many surfaces are selected. My understanding of the application of a surface load is that it will calculate the pounds/in^2 based on the surface area selected.

The question may be in how the physical load is being applied in the real world. For instance, if you have 5 different surfaces each being pressed upon with a 100 pound load and the surfaces are different sizes, then you need to apply the 5-100 pounds loads. If, however, you have 5 surfaces reacting a 500 pound load, then you should be able to select all 5.

It comes down to the total load you need applied to a particular surface. If you need larger surfaces to take more of the load, a surface pressure will do this when all 5 surfaces are selected. 5 surfaces totaling 100 in^2 would result in 5psi, but that means that a surface having 20 in^2 would carry twice the load (100 pounds) of a surface with only 10 in^2 (50 pounds). On the other hand, applying 100 pounds to each of these two surfaces would result in the smaller surface carrying a higher psi loading, but an equivalent force (the 20 in^2 surface would carry 100 pounds as 5psi while the 10 in^2 surface would carry the load as 10psi).

A small, simple model should verify this.

Garland E. Borowski, PE
Borowski Engineering & Analytical Services, Inc.
Lower Alabama SolidWorks Users Group
Magnitude The Finite Element Analysis Magazine for the Engineering Community