notch effect

noun
  1. metallurgy building trades the increase in stress in an area of a component near a crack, depression, etc, or a change in section, such as a sharp angle: can be enough to cause failure of the component although the calculated average stress may be quite safe
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012