DESIGN OF LAMINATES 



6-171 



Referring to Fig. 6-li9, for 



X = 



P 



^x 



m y 



-°n A 



A^ 2bcd . 3 / , , \ 



- fe— + — s — sincr- ^cos ca + cosh da) 



-D 2 > o 2 A 



B^ 2bcd P / v 



2~ + ~ — sino g (cos ca + cosh da) 



Deflection at center of plate: 



w = 2A< 



a£p_ 2 

 32 



a 

 H 



£ 1 

 2 



2 



_a b 

 2 ~ K 



ca 



da 



aP 



sin — - sin — - - 7 sin 2~ sinh p - sin — p~ 



Referring to Fig. 6-hS , then for: 



X = ^ and n = 



"X = " D l| X E 



m y -, -D 2 



"V = °l m x 



2 y 6 a sin \ a/t? 



r.i!. 



L 2 



2 Y 6a sin^a^ 

 H 



(cos 6P + coshySj 



(cos 5p + coshY3 ) 



(6.62) 

 (6.63) 



(6.64) 



(6.62a) 



(6.63a) 

 (6.63b) 



From the above equations the ultimate uniform loads for laminates with clamped edges may 

 be determined. As previously stated, load tables for this condition have not been developed. 



Since there are so many possible combinations of reinforcements that may be used in 

 laminates, equations with accompanying graphs and tables of necessary constants developed 

 for orthotropic materials and applied to plywood (5) and isotropic materials (19) are presented 

 to obtain the unit loads and bending moments for both simply supported and clamped edges. 

 Tables 6-19 and 6-20 have been developed for simply supported plates only. 



Fiberglass reinforced laminates are assumed to behave similar to plywood panels and 

 the following equations apply (5): 



Case 1. Simply Supported Plates Under Uniform Loads 



For a uniformly loaded panel with all edges simply supported and for a small deflection, 

 the deflection at the center of the panel is: 



w = 0.153 K ?°t- (6.64) 



1 E]_h 3 



where 



K-, 



a constant from Fig. 6-50a 



a = the short side of the panel 

 Other symbols as previously defined. 



