DESIGN OF LAMINATES 6-77 



Neutral axis from equation 6.39 



x = ^Z* ■ 0.771 in. 

 3.293 



Section moduli to outermost fibers and various laminae in plate, from equation 6.41 



Stiff ^ner; woven roving outermost top fiber: 



_ 2.5663 2.06 x 10 6 . -, 



*m ~ —7— x — — tzk " 1 - 6 °3 m 3 



1.601 ?.06 x 10 6 



Plate 



Cloth outermost bottom fiber: 



z . = 2,5663 2.06 x 10* . 3 ^ in 3 



01 0-771 i. 9 5 x i 6 



Mat bottom fiber: 



„ 2^662 2.06 x 106 m 7 in3 



^ 0.755 0.91 x 10° 



Woven roving bottom fiber: 



2.5663 2.06 x 10 6 . ,_, . 3 



Zrjr, ■ — — — x t- ■ 3.693 in- 3 



^ 0.695 2.06 x 10 6 



Values for the moment of inertia and section moduli to cloth, and woven roving can be 

 easily obtained from Fig. 6-37 part c. The corresponding values from the curves are: 



I. M - 2.53 in^ 



Stiffener » Z^ = 1.62 in 3 



Plate « Z cl = 3.33 in3 



The ultimate moments for the ultimate compressive stresses are obtained from: 



M = F c x Z (6.31b) 



Stiffener 



Woven roving: M^ = 15800 x 1.603 = 25,330 in-lbs. 

 Plate 



Cloth: Md = 18900 x 3.5l5 ■ 66,U30 in-lbs. 



Mat: M = 15900 x 7.695 ■ 122,350 in-lbs. 



Woven roving: M^ = 15800 x 3.693 = 58,350 in-lbs. 



