6-182 



DESIGN OF LAMINATES 



$ 



4- 



h 



Fig. 6-52. Cantilever Sandwich Beam 



DESIGN EXAMPLE 6-27. DEFLECTION OF CANTILEVER SANDWICH BEAM 



Consider a 1 in. wide strip of the cantilever sandwich beam as indicated in Fig. 6-52 to 

 have a length of 10 in. and to support a load of 10 lbs. at its free end. The beam is con- 

 structed of the materials indicated below. Determine the deflection at the free end. 



FACINGS: 



10 ounce cloth laminate 



Thickness t = — in. 

 8 



ELj. = 1.60 y. 10 6 psi 

 G f = 0.52 x 10 6 psi 



CORE: 



(Table 5-10) 

 (Table 5-14) 



Balsa wood - h lb. density. Grain 

 direction placed parallel to span 

 of beam. 



Thickness, c = 1 in. 



J xc 



0.1^2 x 10 6 psi (Reference 23) 

 0.006 x 10 6 psi (Reference 23) 



1. Deflection with equations 6.86 through 6.88 previously discussed. 



= ^£ = h§° * 10 6 = 10 . 53 



2x0 0.152 x 10 6 



(6.88) 



c = 1 in., h = 1.25 in., £ = 0.80 



2e = 



1.60 x 10' 

 0.52 x 10 



6 



80 + 0.80 V 

 3 x 10.53 \ o.8o ) - 3 x 10.53 (o.8o) + 



0.152 x 10 



6 



0.008 x 10 6 



(6.87) 



(o.8o) 



e = 96.36 



EI .^E^ = E xc |2 

 = 0.1397 x 10 6 



+ E. 



xf 



bt 3 

 2 x — *• 2 x bt x 



12 



d = 



10 x 10 



3 



3 x 0.1397 x 10° 



1 + 



1.25 x 96.36 

 k x 10 2 



(6.16) 



(6.86) 



