can 3mmx20mmx1000mm stainless steel cantilever subject to constant vibration be broken?

Question

any one know how to calculate if it has infinite life cycles ? hope somone can show calculation.

Answer 1

sure can infinite=forever/survival odds=nil

what a silly question

1 what grade of steel
2 what frequency of vibration
3 what amplitude
4 what stress points in the design

what is the point !

Answer 2

The material property you are looking for is called the "endurance limit", often using the symbol Sn. You would need to find what that limiting stress value is for the specific type of Stainless Steel you are using. My textbook defines endurance limit as, "The maximum reversed stress that may be repeated an indefinite number of times on a polished, standard specimen in rotating bending without causing failure."

There are a variety of theories that are then applied to simulate your loading condition (the extent of the vibration and the stresses it creates verses time) so that you can predict/estimate the life of the beam. The endurance limit is generally the highest stress that a part can be subjected to in repeated MinusSn-to-PlusSn-to-MinusSn cycles without failure. But there is always a possibility of failure anyway, since the endurance limit is an empirical value. And, with vibration, you do not have a well-defined maximum stress, so the solution becomes even more subjective.

I could not possibly answer your question with a few equations - my college textbook spent a whole chapter on this subject. You might do some searching on "endurance limit", and "Goodman diagram" and see what turns up.

Answer 3

if my kids are involved, heck yeah it'll break and most likely in more than one spot.