Deflection of unbonded multiple steel plates

[Aldsap]

How do you calculate the deflection of three unbonded layers of steel plates with a middle point load ?

 

[Compositepro]

It will be one third the deflection of one plate.

 

[HTURKAK]

How do you calculate the deflection of three unbonded layers of steel plates with a middle point load ?

If you neglect the friction , you may assume one third the deflection of one plate as Compositepro stated.

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[IDS]

Assuming weightless plates of zero depth and a true point load, the top two plates will curve upwards at the point of contact and lift off the plate below. All the load will therefore transfer to the lower plate at the load position, which will deflect exactly the same as if the top two plates were not there.

For real plates with real loads it gets a little more complicated of course, but the full deflection of the bottom plate alone is a reasonable conservative assumption.

For a discussion of what happens with a UDL see:

Beams may kiss, but do not hug …

… not full length anyway. This post was inspired by a now very long discussion at Eng-Tips on the apparently simple question of what happens when you place one short beam on top of a longer o…

newtonexcelbach.com

 

[GregLocock]

If you could sketch you setup perhaps a leaf spring designer would help you out. An experiment with 3 steel rules might be instructive.

 

[IDS]

On reflection my previous post was a little over-conservative.

The bottom plate will deflect downwards until the upper plates have the same curvature and are in contact over the full length, so the load will be distributed between all the plates in the stack.