Stress Concentration at the corner of a "change in angle"

Does anyone know how to calculate the stress concentration at the corners (a change in angle of a straight line)??? if you do, could you explain it to me and present equations.

 


Ying Li's picture

here it is

see http://www.imechanica.org/node/2689 for the detail

Ying Li Department of Engineering Mechanics Tsinghua University Beijing, 100084, P. R. CHINA