LAWS OF BONE ARCHITECTURE 



205 



stiffness of the beam has been reduced and each thin strip sUdes 

 over the adjacent strip when the beam is loaded, as shown in 

 figure 10, c. In the sohd beam the stiffness is greater than in 

 the beam of the same dimensions composed of a number of 

 separate thin strips. This increased stiffness is due to the 

 cohesion of the fibers which prevents the shding of adjacent 

 sections past each other. But the tendency of adjacent sections 

 to slide is present and causes horizontal shearingj^s tresses in 

 every horizontal plane of the loaded beam. 



Fig. 10 Manner in which a vertical load produces horizontal shearing stresses 

 in a loaded cantilever beam, explained in paragraph 50. 



From the application of the laws of equilibrium, the theory of 

 beams and by the aid of the differential calculus the amount of 

 the horizontal shear in any beam is given by the following 

 formula : 



V 



V 



Sh = — 2. (-^^) • ^ 



1 ' t e 



