DESIGN OF LAMINATES 



6-173 



Case 2. Plates with Clamped Edges Under Uniform Loads 



For a uniformly loaded panel with all edges clamped and for a small deflection, the de- 

 flection equation is: 



w = 0.031 K 2 P-^-j 



(6. 69) 



E x h^ 



where K 9 = a constant from Fig. 6-50a similar 

 to K^, i or simply supported plates. 



and 



wE]_h3 



0.031K2a L 



(6. 70) 



To apply the method of analyzing laterally loaded rectangular plates of isotropic 

 materials (19) to fiberglass reinforced laminates, it was necessary to determine additional 

 constants which are given in Tables 6-19 and 6-20. Table 6-19 gives constants for isotropic 

 materials with Poisson's ratios of 0.20, 0.30 and 0.37. These ratio values correspond to 

 the ratio values of cloth and woven roving laminates, steel and mat laminates respectively. 

 For the orthotropic characteristics of cloth and woven roving laminates the constants in 

 Table 6-19 are not directly applicable and the correction factors presented in Table 6-20 

 must also be applied. In establishing Table 6-20, the warp direction of the reinforcement 

 has been assumed parallel to the short side of the panel. Correction factors for shear force 

 constants have not been determined. 



The following equations and Tables 6-19 and 6-20 are applicable only to Case 1 and give 

 approximate values. 



Case 1. Simply Supported Plates Under Uniform Loads 



Deflection at the center of the panel: 



Isotropic 



Orthotropic 



v "T2ET 



12wEI 

 P= ^a^ 



m x = 3 x pa< 



V = PyP a ' 



(6.71a) 



(6.72a) 



(6.73a) 

 (6.74a) 



