Abstract :
The project involved a theoretical study of different radius for rectangular notches on steel (C35) models which analyized by using the theory of elasticity .Maximum stresses were calculated theoretically using the finite element approach.In the theoretical analysis , the effects of increasing the elements numbers in the meshes of the models was studied. It was found that in all models, three or four grid sizes were sufficient to achieve an acceptable convergence.17Three modifications for the rectangular models were analyized theoretically. These modifications were employed in order to reduce the stress concentration factors. These modifications of the rectangular models yielded a reduction in stresses of (39.87% , 18.17% and 17.75 %) for modifications (RI, RII, and RIII) respectively and reduction in kt of (39.8%), 18.2% and 17.35% for modifications (RI, RII, and RIII) respectively
