The Structural Engineer's Corner

Eng. Onorio Francesco Salvatore

Impact and sudden loading: how to evaluate stresses and deformations?

Written By: Francesco Salvatore Onorio - May• 13•12

Another interesting problem for a structural engineer regards the impact. How to evaluate an impact on a structure? How to evaluate a sudden loading?
It is assumed that an impact will cause stresses distribuited throughout any elastic body exactly as in the case of a static loading.
So, it can be shown that the vertical deformation di and stress σi produced in a structure (for example, a beam or a truss) by the vertical impact of a body falling from height of h are greater than the deformation d and stress σ produced by the weight of the same body applied in a static way.
We could define a ratio di / d (impact deformations / static deformations) that equal to the stress ratio σi / σ (impact stresses / static stresses).

If h = 0 we have the definition of sudden loading. In this case the ratio di / d = σi / σ = 2, as is usually assumed.

If the impact is horizontal instead of vertical, the impact deformation and stress are given by:

where, as in the previous case, d is the deformation the weight of the moving body would produce if applied as a static load in the direction of the velocity and v is the velocity of impact.

That’s all, for now.



For guidance, reports and more you can contact the author at:

Eng. Onorio Francesco Salvatore

You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

Leave a Reply

Your email address will not be published. Required fields are marked *