Today's KNOWLEDGE Share
Many people I meet or help with consulting, believe that a higher Yield Strength is always preferable, when choosing a plastic material for an application.
After all, why would "more strength" possibly be a bad thing ?
However, while a high yield means a high resistance before...yielding, i.e. going into plastic deformation and failing as a part, it is NOT always a good thing.
When Yield Strength is high, the overall principal stresses can grow higher before any sign of yielding.
When the average state of tension in the part has a chance to grow high, the probability of a brittle failure is quickly increasing !
Because most of us in this industry tend to ignore (or just don't know) this, we end up with frequent "unexpected" brittle failure, usually associated with huge liabilities.
source: Vito leo
#polymers #yieldstrength #brittlefailure
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