FATIGUE STUDIES OF NON-FERROUS SHEET METALS 577 



designing a cantilever beam that will have a uniform bending moment 

 for part of its length. The dashed lines indicate the shape of a beam 

 of uniform bending moment; the heavy lines show the final shape 

 of the specimen and how the portion of uniform bending moment has 

 been connected by means of fillets. This is essential in order to 

 eliminate the possibility of the clamping stresses affecting the applied 

 stress as would be the case if a uniform rectangular cantilever beam 

 specimen had been employed. The specimen is deflected at a point 

 14 inch from the operated end or, in other words, where the hypo- 

 thetical beam of uniform bending moment terminates. 



"thickness of stock, submitted 



Fig. 1 — Sheet Metal Fatigue Specimen. 



The specimens are prepared by blanking rectangular samples which 

 are clamped together and then cross milled with a form milling cutter 

 in a manner similar to that described elsewhere for the preparation of 

 tensile specimens.'* The specimens were cut with the direction of 

 rolling parallel with their length. 



Sheet Metal Fatigue Machine 



Referring now to Fig. 2, it is seen that the specimens {S) are clamped 

 between phenol fiber blocks {B). This is done in order that reasonably 

 rigid material will be provided and at the same time a material 



*" Methods for Determining the Tensile Properties of Thin Sheet Metals," by 

 R. L. Templin. Proc. A. S. T. M., Part II, Vol. 27 1927. 



