(3) if desired, at other points in the section; 

 if there is a plane of symmetry, only one- 

 half of the section need be used but a node 

 is assigned where any number crosses this 

 plane. Assuming linear plating between 

 two nodes, extra nodes should be assigned 

 along curved members. Moreover, sub- 

 division of long straight sections by 

 assignment of additional nodes along the 

 length improves the accuracy of the results 

 obtained. Each node, and plate which must 

 lie between two nodes, is numbered with an 

 integer which runs sequentially from 1 to 

 150; the positive direction of each plate is 

 indicated by an arrow drawn beside the plate. 



Areas* and Thicknesses 



To calculate the elastic parameters, 

 data are required on the areas (A) (see 

 FORTRAN symbols defined in Table lb). 

 If a node represents a longitudinal beam, its 

 area should be found; otherwise zero area is 

 assigned to the node. The area of nearby 

 plates is not assigned to the node because 



this is done by the computer program. The program also computes the length of each plate as 

 the distance between the nodes it joins. The thickness (PT) of each plate is found and must 

 not be zero. To maintain constant plate thickness, a node is assigned at each point where 

 the thickness changes, thus subdividing the plate. If symmetry is used, nodes on the center- 

 line and plates lying along the centerline are assigned only one-half the total area and thick- 

 ness, respectively. 



Figure 1 — Typical Symmetric Section 

 Showing Node and Plate Numbering 



Etfectiveness (AK for Nodes, PK for Plates) 



Longitudinal members which end a relatively short distance from the section to be 

 analyzed will not be completely effective in carrying tension loads. An effectiveness value 

 is assigned to each node area; 1.0 for completely effective members, 0.0 for members which 



*It is convenient to replace the actual area distribution by a set of "concentrated areas" at a set of nodes. 

 These nodes will be closely spaced and the area of any structure between nodes can be divided between the 

 nodes at the ends of the segment. This idealization separates the problem so that the nodes (longitudinals) 

 carry all the tension, and the panels between the nodes carry only shear. 



