Autodesk Inventor

[#1]

When adding pressure loads to a perpindicular face  inventor states that the pressure is applied uniformly to the selected face.

As an example a disc of 300 mm dia(area= 70685 sq mm) with a uniform pressure load of 10MPa.

The Question is this !

Is the 10MPa load input  construed by inventor as 10MPa per square mm or 10MPa over the entire disc area.

which is the correct interpretation?

[#2]

10MPa total over the area.

[#3]

Thanks for the reply,if that is the case then i will have to rethink the plate thickness,the deflection seems awfully

high.

just for the record the input is as follows.

Plate dia = 488mm

thickness say 12 mm

pressure on plate area 29 psi(0.199 Mpa)

plate constraint on perimeter.

material .mild steel

analysis shows max displacement =0.48

If you wish have a look.

Regards

methoni

[#4]

oops, let me wake up a bit and look at this again.

...back in a while.

In any case - it should be really easy to do a couple of virtual experiments to verify.

[#5]

The answer is in your question.  What's a MPa?

A MPa is 1,000,000 N/m² or 1 N/mm²

which is an expression of pressure.

[#6]

Thanks for your input.

What started out as a simple problem now seems to be confusing.

So are you saying that if you enter a figure in inventor of say 10MPa,inventor knowing the surface area of plate(from original sketch input calculates the total load over the plate area.

The deflection/stress is then derived from this extrapolation.

Does this make sense ?

[#7]

That makes sense.

As JD suggested, experiment.  Try some simple exercises for which you can determine the results using classical methods until you're comfortable with the FEA interface.

[#8 · Accepted solution]

There is a difference between "Pressure" and a "Force" load in Inventor. A pressure load of 10 psi on a 12" x 12" plate will produce a total "load" of 1440 lb. A "Force" load of 10 lb on a 12" x 12" plate will produce a total "load" of 10 lb.

The pressure load will always be acting perpendicular to the surface whereas a force load can be in any direction (vector) to the surface.

The area that Inventor will use is dependent of the units used. If you are using Imperial and apply a 10psi, then the load force will be the 10 lb on every square inch.

So a Pa is force of one Newton per square Meter and a MPa is 1,000,000 Pa