212 



MR ANGUS E. FULTON ON 



rectangular beams in which an ultimate rectangular distribution of stress is reached, 



• (1) 



gives : 



b<P C ' bd? T 



where t = the ultimate extreme tensile fibre stress in beam, 



c= „ ,, ,, compressive fibre stress in beam, 



M= ,, external bending moment, 

 T= ,, ultimate direct tensile stress of the material, 

 C = ,, ,, ,, compressive stress of the material, 



b = ,, breadth, and d = depth of the beam. 



Substituting for M = — — , since the beams were loaded in the centre and supported 



at the two ends, and for T and C the average values obtained, we have 



WL WL 



£ = •70 — - and c=3'33 — - for cast iron. 

 bd 2 bd? 



Table I. gives the results of the beam experiments, and it will be seen that the 

 calculated values of the extreme fibre stresses t and c agree very well with the 



Table I. 



Cast-Iron Beams. 













Tons per sq. in. 



Elastic Formula. 



xlO 7 . 



No. 



Span. 



b. 



d. 



Breaking 

 Weight 





























in Tons. 



*=-70^. 



c = 6 66 — - . 



t = c= 1-5 — w - 



E s . 



E„. 













bd 2 



bd 2 



bd 2 







1 



36 



2-00 



1-02 



•8 



9-7 



46-17 



20-77 



1-48 





2 



12 



1-02 



200 



4-43 



9-14 



43-50 



19 



57 







3 



36 



100 



1-95 



1-45 



9-65 



45-93 



20 



67 





1-85 



4 



12 



1-00 



1-95 



4-29 



9-45 



45-00 



20 



25 







5 



12 



1-95 



1-00 



217 



9-31 



44-33 



19 



95 







6 



36 



1-05 



2 05 



1-6 



9-17 



43-67 



19 



65 





1-53 



7 



12 



105 



205 



434 



8-30 



39-50 



17 



77 







8 



12 



2-05 



1-05 



2-2 



8-61 



41-10 



18 



45 







9 



36 



203 



1-07 



•65 



7-07 



33-67 



15 



15 



1-35 





10 



12 



2-03 



1-07 



193 



7-00 



3333 



15 



00 







11 



12 



107 



2-03 



4-43 



8-47 



40-33 



18 



15 







12 



36 



2-00 



1-05 



•72 



8-26 



39-33 



17 



7 



1-48 





13 



12 



2-00 



1-05 



21 



8-01 



3817 



17 



17 







14 



12 



1-05 



2-00 



4-4 



8-75 



4167 



18 



75 







15 



36 



1-03 



2-05 



1-34 



7-77 



3700 



16 



65 



1-51 



1-51 



16 



12 



103 



2-05 



4-74 



9-18 



43-87 



19 



74 







17 



12 



2-05 



1 03 



243 



941 



44 83 



20 



17 







18 



36 



105 



204 



1-55 



8-94 



42-57 



19 



15 



1-48 



1-67 



19 



12 



2-04 



105 



233 



8-71 



41-47 



18 



66 







20 



12 



1-05 



2-04 



4-75 



9-14 



43-50 



19 



57 







21 



36 



2 06 



1-03 



•76 



8-50 



4050 



18 



22 



1-45 



1-61 



22 



12 



2-06 



103 



2-38 



8-88 



42-30 



19 



03 





• • • 



23 



12 



1-03 



2-06 



4-32 



830 



39-53 



17-79 







