LIFTING LUG

[methoni]

Having drawn and created a lifting lug ,i now wish to prove its strength,adding a force of 49258 N to the inner pin hole with constraints around the lower edge i find that the safety factor is very low.This suprises me for when doing a hand calc i have a safety factor of over 2.

The load is at 60 deg to the horizontal (in the top left hand quadrant).

If i find that the lug needs to increase in thickness so be it but the question still remains about the factor of safety.

Any comments please would be appreciated.

[admaiora · Accepted solution]

Hi,

the model is not robust/correct:  sketches not constrained,no tangencies where they would be supposed to be, unconsumed sketches, useless geometry, no-parametric modeling use.

I suggest you to pass before throught a basic Inventor modeling path before approching adavnced modules as Stress Analysis.

Your calculations are (probably) correct. Your 3d modeling and the approch to stress analysis need to be redifined.

You have created a stress singularity (stress concentration), with the plane cut to the internal hole.

A great force over a little surface >>>  great stress concentration (not real), that will false your results and your safety factor (that will be largely above 2)

[methoni]

Thanks Admaiora
Interesting about the stress concentration, I did this to create a flat plane to enable the force vector to align at the correct angle of 60 deg, is there another way of input to make sure that the load direction is correct.
Regards

[admaiora]

You can use an edge, a sketch line, an axis  workfeature, decompose your force in vectors, etc

[methoni]

Thanks
I will try that approach
Regards

[JDMather]

I haven't looked at your file yet, but from the image I suspect you should have a Bearing Load with direction selected from a sketch.

You can Split a face to apply loads rather than creating extraneous geometry.