MI;, .i. \n ii; i IN TIM: i;i-:m\i.i;\ 



ICON n;o\i <>\ i I;STI; \i\ 



'I'll.- manner in which vic'ldin^ umli i a constant load proceeds after tin- yield-jxiint 

 has just IMMMI passed is often \ erv iiregulw. Tin- curves gi\ en on I Jia^ram II. ilhis- 

 tmto this yielding with time for two entirely different sjwciiiit-iis. Tin- tirst shows 

 tin- creeping referred to a hove as having started 1 minutes aftei- the application of the 

 load whii-li \va.s its cause. Tlie second curve sliowH n larger yit-ldinix of mucli longer 

 duration. It occurred under a load of _'(', tons JH.M- 8<|iiare inch, luit U-fore this loml 



NCI. II. (Manner in which yielding occurs at the yield-point.) 



mini. 

 tOt 



mm : 



40 



30 





O 



LOA J-7i OHA/if * 



Cu, 



00 



'ensiOfis 



voo^ 

 in, 



Load 



Curvet* 



If 00 



t6toia/in* 



inch. 



1,6 X) 



{400 



SflOO 



Extensions in iojooo -of&n inch. 

 (Zero extension *hen no load on). 



.ittained \\lien _'.") and 'Joi tons per square inch were acting considerable 

 creeping |, a d already taken place. The readings from which these curves have heen 

 obtained were taken at intervals of one minute. 



To return to the tahle of figures given above, the maximum load (of 30 tons to the 

 sipiare inch of original section) was found, after its removal, to have produced a 

 permanent set of (>"J'J of an inch on the 8-inch length ; this corresj>onds to an 

 extensonietei reading of 1 1,000 ; such a reading is, of course, far beyond the range of 

 the e.xtenscimeter. Immediately after the maximum load had been removed, the 



