Sudden Impact Loads

[rick8466]

I have a component that is a 20mm diameter pin with a necked section of diameter 11mm. This component is design to fail when there is an excessive force within the machine.

I have carried out testing and have got a failure load for when the pin fractures.

But this load is applied gradually using an hydraulic pump. In service this load will be applied instantaneously. I think that with a instantly applied load the pin will fracture at a lower load than a gradually applied load.

Does anyone know of a factor to calculate this?

 

[rob768]

A sudden impact-like load causes the section to fail at a slightly HIGHER load than with a gradually applied load. This may sound controverse, i admit, but it is true.
Brittle fracture is the exception. The occurrence of this depends on the presence and sensitive of notches.