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BELL SYSTEM TECHNICAL JOURNAL 



manner that the rectangular coordinates of the deflected specimen may 

 be read on the micrometer heads. Readings were taken to 1 micron. 

 The stress per unit deflection is then calculated from the formula 



5 = 



6Pl 



where 6" = stress in pounds per square inch, 

 P = load in pounds, 

 I = length in inches, 

 b = width in inches, 

 d = thickness in inches. 



60 



50 



40 



30 



20 



10 



0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.^ 



DEFLECTION IN CMS. 



Fig. 3.— Relation of Load to Deflection, Alloy G Brass, No. 24 B. & S. Gauge. 



The curve shown by Fig. 3 for alloy "G" brass sheet gives the load 

 for uniform deflection of the specimen upon the fatigue machine. 

 The various stresses are then obtained by varying the amount of 

 deflection of the end of the specimen by adjustment of the roller 

 bearing that operates the reciprocating bar. 



Fatigue Endurance Results 



The curves shown on Fig. 4 are for high brass sheet annealed and 

 rolled four and ten numbers hard. Figs. 5, 6, 7 and 8 give similar 

 results for alloy "G" brass, nickel silver, phosphor bronze and Everdur 

 respectively for annealed material and rolled four and ten B. & S. 

 gauges numbers hard. Fig. 9 gives the fatigue results for the alpha 



