Today's KNOWLEDGE Share:Skin is in Tension

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Today's KNOWLEDGE Share

I recently talked about residual stresses on the skin of a molded part, since that could be critical for part performance .



But how can you verify if a skin is in tension ? ESCR is one way, but you can also use this neat "layer removal" method.

If you machine out say 50 microns, and observe the remainder of the part, a curvature will appear due to the broken force moment equilibrium. If the part bends downward, the skin is indeed in tension (keeping the part straight to begin with)!

If it bends upwards, the skin is in compression.


Quantitative methods, initially limited to homogeneous and isotropic materials, have been developed to reconstruct the entire residual stress profile from successive layer removal.


Source:Vito leo

Blog: http://polymerguru.blogspot.com


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