6-152 



DESIGN OF LAMINATES 



Boat hulls and other marine structures are usually subject to hydrostatic or uniform 

 pressures. Since the preparation of plate load tables covering all conditions would be a 

 voluminous task, only tables for uniformly loaded plates with simply supported edges have 

 been completed at this time. However methods of analyses are also presented for plates 

 under uniform loads and clamped edges. Fig. 6-47 indicates the direction of the plate axes. 

 The coordinate planes are parallel to the planes of elastic symmetry. 



WARP D I RECT I ON - 



Fig". 6-47. Flat Plate Under 

 Uniform Lateral Load 



The following terminology previously not given will apply: 



p = load per unit area 



e = unit strain 



m x = bending moment per unit length of a 

 vertical section of the plate per- 

 pendicular to the X-axis 



m v = bending moment per unit length of a 

 vertical section of the plate per- 

 pendicular to the Y-axis 



"xy 



= twisting moment per unit length of a 

 vertical section of the plate per- 

 pendicular to either the X- or the 

 Y-axis 



Plates With Small Deflections: For this condition, the deflection of the plate is limited 

 to a maximum of one-half the thickness of the plate, (w = " ). 



Case 1. Simply Supported Plates Under Uniform Loads 



The deflection of a uniformly loaded simply supported plate is obtained from the follow- 

 ing equation (18): 



(6.57) 



