Ahmed Awadallah Ahmed Elsayed Mowafy <br/><br/>
Determination of parameters to manipulate the evenness of perforated sheets with non-circular contours of holes /  
Ahmed Awadallah Ahmed Elsayed Mowafy ; Supervised Nahed Elmahallawy , Rainer Hank , Alexander Tatarczyk 
 - Cairo :   Ahmed Awadallah Ahmed Elsayed Mowafy ,   2013 
 - 123 Leaves :   phorographs ;   30cm 
<br/><br/>Thesis (M.Sc.) - German University - Faculty of Postgraduate Studies and Scientific Research - Department of Design and Production Engineering 
<br/><br/> During the punching operation the work piece is subjected to residual stresses. A compressive layer of residual stresses is formed on the top side while a tensile residual stress layer is formed on the lower surface of the sheet, which create a bending moment on the sheet which lead to its unevenness. The unevenness can be stated as the non-flatness of the sheet metal on a flat surface