The general similitude described here might conceivably serve as 

 the basis for a model test, although the limited variability of S is 

 likely to be inconvenient. 



In practical cases the influence of shear warping tends to be small. 

 It may be sufficiently accurate to omit this effect by letting K -»- » 

 (hence 5 = 0). For this case write the relation \i = (p-^A/p' A' ) y' in 



the form: 



,2 . 1 %^ 



Vi=nAy' ; n = — — - 



Thus re is replaced by n or t by n/e in all formulas , and 



k 



Since e « EI/X , t can easily be varied without affecting A or n ; for 

 example, by changing all linear dimensions of the cross sections parallel 

 to the principal plane of the beam in a ratio r and the perpendicular 

 dimensions in the ratio l/r, thus A is left unchanged. Variation of S 

 in any desired ratio can be effected in the same manner. 



Pb ^'^e 

 * With ql invariant, t= "T ^^^ • Since p^ , K, and G^ cannot vary much, 



b e 



then the variation of S is limited. 



TO 



