Tham khảo tài liệu 'bruhn - analysis and design of flight vehicles structures episode 1 part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | EQUILIBRIUM OF FORCE SYSTEMS. TRUSS STRUCTURES. The wing beams hue to the distributed Hit air loads acting upon them are also subjected to bending loads In addition to the axial loads. The wing beams thus act as beam-columns. The subject or beam-column action Is treated In another chapter of this book . If the wing Is covered with metal skin Instead of fabric the drag truss can be omitted since the top and bottom skin act as webs of a beam which has the front and rear beams as Its flange members. The wing Is then considered as a box beam subjected to combined bending and axial loading. Lengths k Directional Components of Cabane Struts Member Sy Bl. V D s i L V L D L S L Front Cabane CF 30 10 27 1 41 59 . 721 .240 . 648 Diagonal Cabane Strut CD 30 30 27 j .597 .597 . 538 Rear Cabane Strut CR 23. 5 6 27 Ị . 731 . 1495 .668 L n v2 D2 s2 Example Problem 11. 3-Sectton Externally Braced Wing . Fig. shews a high wing externally braced wing structure. The wing outer panel has been made Identical to the wing panel of example problem 1. This outer panel attached to the center panel by single pin fittings at points 2 and 4 . Placing pins at these points make the structure statically determinate whereas If the beams were made continuous through all 3 panels the reactions of the lift and cabane struts on the wing beams would be statically indeterminate since we would have a 3-span continuous beam resting on settling supports due to strut deformation. The fitting pin at points 2 and 4 can be made eccentric with the neutral axis of the beams hence very little Is gained by making beams continuous for the purpose of decreasing the lateral beam bending moments. For assembly stowage and shipping It Is convenient to build such a wing in 3 portions. If a multiple bolt fitting Is used as points 2 and 4 to obtain a continuous beam not much is gained because the design requirements of the various governmental agencies specify that the wing beams must also be .
