Dynamic / Impact loads 5

[329moss]

I'm conducting an experiment by which I am dropping a weight (1kg) from different heights (0.1m – 1.5m) on a model scaffold structure. How can I differentiate when the load is dynamic and when it becomes an impact load, and how can I establish a transition between the two?

This question arose as someone told me that dropping an object from a small height i.e. 1kg falling from 0.1metres will/can be considered as a dynamic load whereas 1kg falling from 1metres will be an Impact load.

Response with information in regards to the question will be appreciated.

 

[mech2926]

I've never thought of it that way before; I always considered "impact" to be a type of "dynamic load." I'm a mechanical engineer; perhaps this differentiation is specific to structural/civil engineering?

Perhaps the distinction has to do with whether kinetic energy is significant. If you drop the weight from a "negligible" height, then there's not much velocity reached during the fall. How high is "negligible" is a matter of judgment.

 

[csd72]

I agree,

Impact and dynamic are just different shades of the same thing. I would think that all cases have an impact followed by a dynamic phase(when all objects are moving as one).

 

[MiketheEngineer]

Since you might use the same equations to define the loads - then what is the difference?? I agree, they are the same - just semantics.

 

[FeX32]

I also agree. No difference at all.


Fe

 

[IRstuff]

One way of segregating something like this might be to compare the load transition time to period of the lowest natural frequency of the structure. This makes all drops impacts.

TTFN

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