Load

[vikrameng]

Under what circumstances should the gravitational load be neglected for stress analysis.

 

[EricZhao]

Depends on your parts’ stiffness and weight and your application. There is no general rule. What is the problem you encountered?

 

[JStephen]

In some cases, a design code (or common sense) tell you specifically that gravitational loads should be included. Typical in structural applications, for example.

Otherwise, you should be able to come up with an order-of-magnitude type value of stresses due to the weight of the object being analyzed.

Consider then, what the uncertainty is on your applied loadings. For example, if your applied loads are assumed, or based on some probabilistic analysis, they aren't going to be accurate to 8 decimal places. If you get, say, 10,000 PSI stress based on a load that could actually vary +/-25% or more, and estimate that gravity loading gives you 100 PSI, there really isn't much point in calculating gravity loading.

 

[ahad29]

I agree with JStephen. See how much stress your gravity load alone gives and compare it with the stress obtained by applied full-scale load. Also see how much your part/assembly weights and how it is supported.

ahad

 

[rb1957]

vikrameng

as ericZhao said, more details otherwise we'll all answer the question from our own perspective (like maybe in the zero g environment of space).

generally, if the structure's weight is small compared to other applied loads, and if the inertial accelerations are small.