170 BELL SYSTEM TECHNICAL JOURNAL 



_2 T , . d , . d 



V = Laplacan =_ + _ + - 



% 'V 2 1 



' ^ ' ^ > unit strain components 



Xy J Xz J yz J 



> unit stresses 



7.8. Stress-Strain Equations for Isotropic Media 

 Xx = r- {Xx — (rYy — aZz) 



Jy = -j^ {Yy — (^^x — (tZz) 



Zz = — (Zg — (jXx — (tY'^ 



shear strain = - X shear stress 

 A 



X^ = 2{aBe+ A 





X = A (~ 4- —\ 

 ^ \dy dxj 



X = A (— 4- — ^ 

 \dz dx/ 



For plane stress in xy plane 



1 



X =ix 



Xy . -^y 



