Figure 2<1-18. Compression Frame Analysis Technique N is the load distributed along the six catenary rope elements. The basic catenary equation is then used to calculate the restraining force (F) at the catenary rope/compression frame intersection. Hence: For purposes of analysis Ymax (allowable catenary deflection) was set at 15 meters. For small angles between the compression frame and catenary rope, F is also equal to the compression frame axial load. Applying an arbitrary 1.5 factor of safety to F established the critical load (PCr) that each of the six (6) compression frame columns must be designed to carry, (i.e., Pcr = 1.5 F) . The frame column was broken down into the subelements indicated in Figure 2.1-19. Subelement "t" was assumed to have properties equivalent to an inscribed tube and was designed such that the Euler column and local crippling stresses were equal. Hence: This allows the selection of a T/R ratio for subelement "t" that will result in minimum weight.

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