DESIGN OF LAMINATES 



6-55 



The maximum shear stress at the neutral axis is obtained from: 



where 



(6.33) 



in- 



Rearranging the terms and substituting the known values, the required depth or thickness is: 



3 V 



2 bf c 



(6.33a) 



3 x 2bP 

 2 x 2 x 9900 



0.018 in. 



The thickness required is governed by flexure and is 0.265 in. 



The maximum deflection of the fixed ended uniformly loaded beam, including the effect 

 of shear is obtained from: 



d = 



33hEI $ 



+ T X 



8AG 



(6.34) 



Shear modulus, G, for mat laminate = 0.U0 x 10° psi (Table 5-14) 



bt 3 2 x 0.265 3 „ M1 „ . h 



I = 



Deflection d = 



12 12 



10 x 12^ 



.00310 in L 



(6.23) 



6 

 + - x 



331o0.86xl0° x .00310 5 



10 x 12 2 



0x2x0. 265:<0.liOxlO° 



= 0.2026 + 0.0011 = 0.2037 in. 



DESIGN EXAMPLE 6-19. BENDING OF A COMPOSITE LAMINATE 



Compute the ultimate carrying capacity per in. of width of the simply supported com- 

 posite laminate when uniformly loaded, Fig. 6-35. Assume the cloth and woven roving plies 

 to be parallel laminated in the direction of the span. 



