Tham khảo tài liệu 'bruhn - analysis and design of flight vehicles structures episode 3 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | ANALYSIS AND DESIGN OF FLIGHT VEHICLE STRUCTURES CIO. 15 of 358 lb. Thus rivets could be spaced further apart as margin of safety is rather large. The rivets attaching the skin to the upper flange should be spaced to prevent inter-rivet buckĩlng of the skin since the skin was assumed effective in computing the beam moment of Inertia. The rivets attaching the lower skin to the lower angles would be checked for the shear flow load and not for Inter-rivet buckling since skin is In tension. The general subject of rivet design for structures Is treated In Chapter DI. The web stiffeners at the external load points and at the beam support points must be designed to transfer the concentrated load to the beam web. Refer to Chapter A2Ĩ which treats of loads In such stiffeners. General Comments The reader should understand that the margin of safety for the beam web in the preceding beam check was based on the design requirement of no Initial buckling under the design load. The buckling stress as calculated Is not the stress that would cause web to fall or collapse as the web could take considerably more load in the buckled state. The subject of beam design with buckling webs is treated In Chapter Cll. In general this type of beam web design is not widely used In flight vehicle structures because It is heavy construction since the web thickness must be relatively large to prevent buckling and the cost of fabrication and assembly Is relatively high because of many parts and much riveting. The aerospace structures engineer decreases these disadvantages by using a web sheet with closely spaced beads or a series of flanged lightening holes which stabilize web against buckling and provide low fabrication and assembly cost. This type of web design is treated In Part 2 of this chapter. CIO. 15a Use of Longitudinal stiffener to Increase Bending Buckling Stress of Web Sheet. The strength check of the beam In the example problem showed that the compressive stress on the web due to beam
