DESIGN OF LAMINATES 



6-153 



where 



L =h£-l *n = 



aD 



a 



Y n = C n JK _sinh Yn n sin6 n (p-n) + sinh y n ( 3~n) si n 6 n nJ 



t VI - i< 2 cosh y^ cos ^ n {$'"■) + cosh Y n { ^~ J] ) COSl5 n r lJj 



Cn = 



\/l - k 2 cosh Y n P + cos ° n (3 



'1 + K 



K V — 5 — » ' n n H 



a = 



1 - K 



6 n ■ x n° 



n = e,y ; P = eb 



8 = 



K = 



K = 



r- -, 1 



Dl 

 l D 2j 



-, 1 



El 



\/0lD2 



E L°TL + 2G 



LT 



h3 



12 



The basic plate moment equations are given as follows (18): 



bending moment m x = -D]_ 

 bending moment m„ = -Do 



2 



ax 



+0-16^ — k 



Z71 i s^ 



2 8 2 W 3 2 W 



e — o + o. 



dn 



2 3x2 



twisting moment m^y = - lji w 



6 3x6^, 



(6.58) 



(6.59) 



(6.60) 



The solution of these equations becomes a formidable task when more than one plate 

 configuration has to be investigated. To reduce the amount of work required by the designer, 

 Tables 6-16 through 6-18 have been established with the use of electronic digital computers. 

 These tables give the ultimate uniform lateral loads in psi that mat, woven roving and cloth 

 laminates can sustain when considered as rectangular plates with a deflection limitation of 

 one-half the laminate thickness or for the ultimate flexural stresses of the laminates. For 

 the development of these tables, the low average physical properties values previously given 

 were also used but the direction of the axes has been modified. 



X = 90 degrees and warp direction 



Y = degrees and fill direction 



The advantage of these tables is illustrated in Design Examples 6-24 and 6-25, 



