DESIGN OF LAMINATES 



6-145 



Design Example 6-21 illustrates the advantage of Tables 6-4 through 6-15. 



DESIGN EXAMPLE 6-21. CRITICAL COMPRESSIVE BUCKLING OF A PANEL 

 For the panel indicated in Fig. 6-44 assume a mat laminate with the following properties: 



Width of panel 



Length of panel 



Thickness 



Moduli of elasticity 



Poisson's ratio 



Shear modulus 



b 

 h 



J TL 



} TL 



20 in. 

 h0 in. 

 0.50 in. 



(Table 5-10) 



7 LT = 0.37 (Average of Tables 5-8 and 5-13) 

 0.)j0 x 10 6 psi (Table 5-14) 



E = 0.86 x 10° psi 



Find the critical buckling load, P cr , for all edge conditions: 



Case 1. All edges are simply supported. 



Case 2. Loaded edges simply supported, remaining edges clamped. 



Case 3. Loaded edges clamped, remaining edges simply supported. 



Case 4. All edges clamped. 



Constants: 



A = Ef Ojrn + 2\ Gmr 



,6 



= 0.86xl0 6 x0.37 + 2(1-0. 37 2 )0.U0xl0 6 (6.45) 



K = 



D l = D 2 



1.0087 x 10" 



Ah 3 1.0087 x 10 6 x 0.50 3 

 12 12(0.8631) 



Eh 3 0.86 x 10 6 x 0.5O 3 



12A 



12(0.8631) 



12170 



= 10376 



(6.46) 



(6.44) 



(DlD 2 )2 



12170 

 10376 



1.1729 



(6.47) 



ho 



20 



10376 

 10376 



= 2 



(6.48) 



